Title of Invention	MULTIFUNCTION NUMERICAL LINE PROTECTION RELAY WITH INTEROPERABILITY AND METHOD OF INTEGRATING IEC 61850 COMMUNICATION PROTOCOL WITH THE RELAY FEATURES
Abstract	A multifunction numerical line protection relay with interoperability comprising of: - power supply module (6.1); - processing module (6.2) which comprises of real time module (201), non-real time module (203), IEC 61850communication module (204) and interprocess communication (202, 205); - transformer module (6.3); - filter module (6.4), - relay module (6.5), - local interface (6.6) and - front panel (6.7); characterized in that the communication module (204) makes the relay IEC 61850 compliant, thereby implementing IEC 61850 communication protocol so as to achieve significant increase in the communication capability for state-of-art substation communication.

Title of Invention

MULTIFUNCTION NUMERICAL LINE PROTECTION RELAY WITH INTEROPERABILITY AND METHOD OF INTEGRATING IEC 61850 COMMUNICATION PROTOCOL WITH THE RELAY FEATURES

Abstract

A multifunction numerical line protection relay with interoperability comprising of: - power supply module (6.1); - processing module (6.2) which comprises of real time module (201), non-real time module (203), IEC 61850communication module (204) and interprocess communication (202, 205); - transformer module (6.3); - filter module (6.4), - relay module (6.5), - local interface (6.6) and - front panel (6.7); characterized in that the communication module (204) makes the relay IEC 61850 compliant, thereby implementing IEC 61850 communication protocol so as to achieve significant increase in the communication capability for state-of-art substation communication.

Full Text	Field of the invention: The invention relates to protective relays for electric power systems in general and to a multifunction numerical line protection relay with interoperability between IEC 61850 compliant devices in particular, and also to a method for realization of IEC 61850 communication protocol in such a relay. Background and prior art: A new generation of microprocessor based Intelligent Electronic Devices (IEDs) with high speed peer to peer communication for protection and control is now becoming common in electric power industry. This has led to the necessity to standardize the communication protocol between the IEDs in substations and power stations, which resulted in the evolution of a universal platform based on an International Electro technical Commission (IEC) 61850 that will not only allow plug-and-play technology, but also ascertain interoperability between the IEDs of different vendors. The full implementation of the standard ensures open, future-proof and flexible system architectures with state-of-art performances. IEC 61850 is becoming the widely accepted solution for communication within substations all over the world. One of great advantages provided by this standard is the real time communication for the high priority messages. Traditionally interconnection between the IEDs was made with wire by means of electrical circuit using communication interfaces and proprietary communication protocols. Technology today provides us with solution using an optical Ethernet network to perform far superior tasks in shorter time. The IEDs can now exchange status and control signals with other IEDs by exchanging data packets containing status and control signals over a communication link using Ethernet on the local area network. They can also send reports and logs, file transfer of disturbance records to clients. The benefits can be assessed in terms of new features for a better operation (automation), maintenance (access to more accurate data) and engineering (e.g. avoid data duplication) within the substation and also within the overall grid information scheme. Logical integration of the protection, control and communication features is to design the proper architectural mechanisms both at device and system levels to ensure a sustainable industrial model. A simple architecture, scalability and testability are important for market acceptance of IEC 61850 compliant IED. A multifunction numerical line protection relay is known from Indian patent application no. 00575/KOL/2007, filed on 04.06.2007. The invention relates to protective relay for electric power systems, and more particularly relates to a method for realization of multifunction numerical line protection relay adopting a real-time operating system and a single processor. The multifunctional numerical line protection relay of the prior ait was a stand alone relay which did not have the interoperability feature. Increasing demand on protection relays for delivering higher level services, like high speed and accurate protection along with networking - for communication between peers, client and server; user interfaces and file system management - call for efficient integration of custom hardware and software resources. The present invention proposes a methodology of integrating the IEC 61850 communication protocol with the protection and control features of the multifunction line protection relay with the up-gradation of the device's firmware. Objects Of The Invention:- It is therefore an object of the invention to incorporate IEC 61850 communication protocol in the Multifunction Numerical Line Protection Relay that has been designed with single processor architecture and a realtime operating system, so as to achieve a significant increase in the communication capability for the state-of-art substation automation. Another object of invention is to provide a method of configuring the logical device, various logical nodes, data sets, control blocks (reports, logs and GOOSE). A further object of invention is to provide a client - server communication and peer-to-peer communication with Generic Object Oriented Substation Events (GOOSE) messages over the Ethernet. A still further object of the invention is to provide a method of inter process communication between the various realtime, non realtime applications and communication interface within the same intelligent electronic device. Yet another object of invention is to provide an easy and quick method for converting a non-IEC 61850 device (which is described in the prior art) to an IEC 61850 compliant IED without an additional protocol converter or hardware. Moreover, the method depends on a simple change / upgrade of the firmware to make the relay IEC 61850 compliant. Summary Of The Invention: The present invention is concerned with substation automation (SA) systems, in particular with a methodology for implementing an IEC 61850 standard in a Multifunction Numerical Line Protection Relay in order to make it IEC61850 compliant Intelligent Electronic Device (IED). The IED is made IEC 61850 compliant with the augmentation of the communication protocol with the features which are coded in the IED capability description (ICD) file. The invention proposes a unique method to incorporate IEC 61850 communication protocol in a multifunction numerical protection relay. This has been achieved without any additional hardware and by integrating additional software with the existing software. More particularly, the invention relates to a method of implementation of IEC 61850 communication protocol in the multifunction numerical line protection relay. The present invention relates to a method used for configuring the various protection, non-protection functions as data models in the relay based on the IEC 61850 standards. The models that are configured in the relay are: Association model, Server / Logical device/Logical node/Data, Data set model, Substitution model, Setting Group model, Reporting model, Log model, Goose- Subscribe and Publish model, File transfer model, Time and time synchronization model. The relay is configured to record the performance statistics during the occurrence of a major disturbance or fault in substation in the form of Disturbance Records (DR) stored in the Common Format for Transient Data Exchange (COMTRADE). The relay is configured to perform as Simple Network Time Protocol (SNTP) Client so that the polled time from a SNTP Server is accessed and the relay (Real Time Clock) RTC time is updated with the new time. The relay is a physical device with a communication interface. It has an IP address and is accessible over a network by an external client. It can access connection from one or more (maximum of 8) clients. It contains one logical device and several logical nodes that represent the basic building blocks (objects) of the functionality of the relay. Each logical node contains data that can be written to or read individually and in groups (data sets). It: also responds to control inputs or triggers control outputs;. It provides solicited and unsolicited reports, and contains logs that can be queried. Services are provided to read and write the data in the logical node. Measured data and status information are normally read only. Control and configuration information are generally read and write. The dataset which is a collection of data values that are commonly needed, is given a name, and clients can retrieve them with a single read operation. Brief Description Of The Accompanying Drawings:- Fig. 1 is a block diagram of the software modules in the prior art arrangement in the multifunction numerical line protection relay. Fig. 2 is a block diagram of the modules arrangement in the present invention for the augmentation of IEC 61850 communication protocol. Fig. 3 shows the inter-process communication of data between the various software modules in the device. Fig. 4 shows the organization of the Logical Nodes in the Logical Device along with the IEC 61850 services. Fig. 5 shows the relay in accordance with the invention connected in a protective arrangement with an electrical system. Fig. 6 shows the block diagram of the relay according to the invention. An exemplary embodiment of the invention as depicted in the accompanying drawings will now be described. However, there may be other embodiments of the same invention all of which are deemed covered by this description. The invention provides the method of implementation of the IEC 61850 communication protocol in the multifunction numerical line protection relay incorporating the present invention. The numerical relay described in the prior- art shown in Fig.l can be configured as an IEC 61850 compliant IED (Fig.2) in the substation environment capable of interacting with the other substation devices which are also IEDs themselves. The data modeling in the relay has been done taking into account the functionality and data exchange requirements with the other substation devices. The various protection and non protection functions of the relay are divided into the smallest entities called the logical nodes in the standard, which are used to exchange information. The logical nodes are modeled and defined from the conceptual application point of view in IEC 61850- 5. In this implementation, the relay, which is a real device is modeled as a virtual model. A set of basic services have been defined which are used by the communication interface to accomplish the information exchange. These services referred to as Abstract Communication Service Interface (ASCI ) have been standardized as per the parts IEC 61850-7-1 & IEC 61850-7-2. The communication is established through Transmission Control Protocol / Internet Protocol (TCP/IP) port available in the relay hardware. The relay which is configured as a server for the purpose of IEC 61850 communication, has the following models programmed in it. a) Association model - Association services is a basic requirement in order for a client to connect to the IEC 61850 compliant IED. There are three association services - Associate, Abort, and Release. The Basic Information Model with two party access control is available for bi-directional connection oriented information exchange between IEDs which is reliable and provides end-to-end flow control. The multicast and broadcast access control is available for unidirectional information exchange between one publisher and one or many subscribers. The subscriber shall be able to detect loss and duplication of information received. The relay is capable of both publishing and subscribing to GOOSE messages.(304) b) Server / Logical device / Logical node / Data model (303,305)- The server represents the external visible behaviour of the relay. It can communicate with clients, send information to peer devices. The logical device contains the information produced and consumed by a groyp of domain specific application functions. This is made up of several logical nodes - each for one domain specific application function. Data is the status and information of object it represents in the substation. c) Data set model - This constitutes the group of data and data attributes collected from the various logical nodes that need to be sent with any of the services or as GOOSE messages. The server is configured for fixed data sets. d) Substitution model - This provides a replacement of process value in the server with reference to the measurands of analogue values or status values of various digital signals. e) Setting Group model - The relay has four setting groups with one set of setting values as active and another as edit setting groups. Active and edit setting groups can be dynamically changed as per the need. f) Reporting model - This describes the conditions for generating reports based on parameters set by the client. Reports may be sent immediately or deferred. Any data update, data change, quality change in the associated dataset or the integrity period triggers the formation of report and its onward transmission to the respective client. g) Log model - Describes the conditions for generating logs based on the parameters set by the client. Logs can be queried for later retrieval. h) GOOSE -Subscribe and Publish model(304)- This supports a fast and reliable system-wide distribution of input and output data values. Simultaneous delivery of the same generic substation event information to more than one physical device through the use of broadcast services. This model is used for fast transmission of substation events such as commands, alarms and indications as messages. A single GOOSE message sent by an IED can be received by several receivers. This model makes use of the Ethernet and supports real-time behaviour. j) File transfer model - The server defies the exchange of large data blocks such as programs and disturbance record files (DR) stored in the relay's memory. The DR files in the Common Format for Transient Data Exchange (COMTRADE) format are stored in the flash memory, under the folder YCOMTRADE' of the relay. The file directory service will give client, the list of files and /or directories mentioned in the request. k) Time and time synchronization model for SNTP - This enables the relay to accepts the UTC synchronized time over the local area network and reset its clock. Description Of The Relay Referring to Fig.l, the multifunction numerical line protection relay incorporating the present invention, is a powerful and compact multifunction numerical relay, configured for the protection of transmission lines. The relay is capable of handling the protection requirements of the transmission lines, and works based on the three phase currents and voltages. The relay is also IEC61850 communication protocol compliant. The entire application software is divided into real and non-real tasks wherein the real time tasks are repeated exactly with the same cyclicity as has been originally defined by the application. The non-real tasks on the other hand, are not time critical and run in the background. The real time tasks are handled by the RT (Real-time) module while the non-real time tasks are handled by NRT (Non-realtime) module. The relay software is designed and implemented such that it supports many features. It uses RT FIFOs (real time first in first out) as Inter Process Communication (IPC) mechanism for communication between RT module and NRT module. They act as pipes between the RT and NRT tasks. The multifunction line protection relay of the invention is configured to perform the following protection and non protection functions : PROTECTION FEATURES 1. Phase and earthfault distance protection: Each with five independent zones of protection, four in the forward and one reverse direction: This is based on impedance, which is high during the normal operation, and, during fault condition, the impedance becomes less, and when it is below the set value, trip command to the breaker is issued to isolate the fault. 2. Overcurrent protection: Two elements with direction control, with first element as either Inverse Definite Minimum Time (IDMT) or Definite Time (DT) and the second element as Hiset instantaneous. This is provided to limit damage from phase faults. 3. Earthfault protection: Two elements with directional control, with first element as either Inverse Definite Minimum Time (IDMT) or Definite Time (DT) and the second element as Hiset instantaneous. This is a protection scheme with the zero sequence component of the three phase currents. 4. Overvoltage protection: One element with selectable characteristics as either Inverse Definite Minimum Time (IDMT) or definite time (DT) for each of the three phase voltages. 5. Undervoltage protection: One element with selectable characteristics as either Inverse Definite Minimum Time (IDMT) or definite time (DT) for each of three phase voltages. 6. Negative sequence overcurrent protection. This element can provide backup protection for many unbalanced fault conditions. 7. Switch on to fault (SOTF) protection: This is provided for high speed clearance of any detected fault immediately after a manual circuit breaker closure. 8. Trip on reclose protection (TOR): This is provided for high speed clearance of any detected fault immediately following autoreclose of the circuit breaker. 9. Power swing blocking: Selective blocking of distance protection zones ensures stability during power swings experienced on transmission systems. 10.Voltage transformer supervision: This is to prevent wrong operation of voltage dependent protection on AC voltage input. It mainly detects voltage transformer fuse failures. 11.Current transformer supervision: If one or any of the current transformers were to become open circuited, this protection raises an alarm. 12. Broken conductor: This is to detect: network faults such as open circuits, where a conductor may be disconnected and not in contact with another conductor or the earth. 13. Circuit breaker failure protection: Whenever the circuit breaker at protected terminal fails to trip, this protection would then send a command to upstream circuit breaker to backtrip. Non-Protection Features 1. Autorecloser with checksynchronism: This provides upto 4 reclose shots, with checksynchronism for voltage, frequency and phase, and can be set for any combination of line and bus conditions. 2. Distance to fault locator. 3. Measurements of field data and computation of derived parameters are available for display at the relay as well as accessed from the serial communication facility. 4. Event / Fault / Disturbance / Oscillography Records. 5. IEC61850 communication protocol. The program continuously monitors the field data in order to determine the status of the associated transmission line, in real time. This provides information related to the line conditions and whether any alarms or trips are to be issued by the relay. Fig. 5 shows the relay connected to the transmission line for monitoring the current and voltages in real-time, along with the photograph of the relay. The field inputs viz. three phase currents, the three phase voltages and the busbar voltage are connected to the relay terminal blocks. The relay contacts are used to operate the circuit breaker (52). Fig.6 shows a block diagram of the hardware of the system. The relay hardware comprises of seven modules. The auxiliary D.C. voltage given to the relay is first stepped down to 24Vdc in module 6. 1. This voltage energizes module 6. 2, module 6.5 and module 6.7. The +15Vdc and -15Vdc is used to energize module 6.3 and module 6.4. The field inputs viz. three phase currents and the three phase voltages (described in Fig.l), connected to the relay terminal blocks, is first processed by module 6.3. The stepped down signals are then filtered by module 6.4 for any high frequency disturbances and to avoid aliasing errors. These signals are then sent to section B of module 6.2. The processing module 6.2 has the relay algorithm residing in section C. When the relay is powered ON, the program control, after necessary hardware, software and memory initializations, first digitizes the analog data in section B, and processes the data, checking for any fault. When a fault occurs, the relay senses it and issues a command in the form an annunciation or a trip, depending upon the severity of the fault. The final relay outputs are sent through section D to the module 6.5. This module has sixteen numbers of contacts with higher driving capability and these potential free contacts are brought out to relay terminal blocks (described in Fig. 1). Relay status is indicated by means of lamps provided on the front side of the panel. In addition, alarms and trip contacts are brought out in the form of potential-free contacts, which can, in turn, be used for either operating the circuit breaker or to drive audio / visual alarms. The contacts and lamps are of self resetting type.The relay functions are stored in the compact flash disk memory shown in section C. This section comprises of the realtime module (201), non-realtime module (203) and the IEC61850 communication module (204) along with the inter process communication channels (202 and 205) described in Fig. 2. Module 6.2 also has two serial ports RS232- section F, through which the metered data is communicated to the operator interface on the front of the relay (module 6.7) and also to the PC-based HMI (Human machine interface) program (module 6.6). It can also read the set parameters from the operator interface. The section E is the 100 Mbps Ethernet port that is available on the relay for communication over Ethernet using the IEC61850 communication protocol. The section G comprises of two RS485 ports which facilitate the multi drop communication features of the relay. Method of integrating IEC 61850 communication protocol: Fig.l describes the method of implementation of the software modules in the prior art system. The model consists of a realtime module 102, which accesses the wired field data - from the current and voltage transformers in the form of analog inputs, status signals from various field devices in the form of digital data through the module 101, and processes the same to ascertain the abnormal state of the transmission line using the various protection algorithms built in the module. The digital data to control the field devices viz. the circuit breaker is provided by the module 102 in the form of digital outputs from the module 103, which is wired to the respective devices. The processed data from the module 102 is transferred to non realtime module 105 through inter-process communication channel 104. This information is then passed by the module 105 to the serial ports 106 for communication to the front end terminal 107, and the storage of the oscillography data file 108, consisting of realtime data during fault. Such a system described in Fig.l meets the requirements of a multifunction numerical line protection relay. However, this relay cannot ensure interoperability between devices in the substation to exchange information. Fig. 2 shows the augmentation of an additional module with IEC 61850 communication interface 204. The realtime module 201, non-realtime module 203 along with the interprocess communication 202 is the same as those described in Fig.l with the same functions. The module 205 is the IEC 61850 communication interface with the Server, GOOSE and SNTP client processes. The bidirectional information exchange between the module 201 and 204 is by means of the interprocess communication 205 realised using First-In-First-Outs (FIFOs). The addition of module 204 makes the relay IEC 61850 compliant and associates the relay (now configured as server) to any of the clients and also processes the information to be transmitted over the Ethernet in the local area network 206 viz. the station bus. This module can also receive information from clients. GOOSE subscription and publish mechanisms are also handled. SNTP client process continuously polls for the time over the LAN and resets the hardware clock accordingly. Fig.3 describes in detail the various interprocess communication mechanisms between the various modules for data exchange. They are realised using FIFOs. The realtime module 201 interacts with the module 203, both of which comprise the relay application function. The SendFIFO 307 transmits the metering and monitoring data processed by the module 201. The SendEventFIFO 308 transmits the realtime events processed by the module 201. The SamplesFIFO 309 transmits measurands measured by the module 201. The ReceiveFIFO 306 transmits the settings information from the module 203 which has been accessed over the serial network. The Server module 303, GOOSE module 304 and SNTP Client module 305 facilitates the IEC 61850 communication protocol in the relay. The ApplicationtoServerFIFO 310, ApplicationtoGOOSEFIFO 312 cater to the information transmission from the relay application function to the IEC 61850 module. The ServertoApplicationFIFO 311 and GOOSEtoApplicationFIFO 313 are designed for information reception by the relay function application. The ServertoGOOSEFIFO 314 and GOOSEtoServeFIFO 315 serve to facilitate data exchange between the modules 303 and 304. The SNTP Client module directly accesses the SNTP clock over the LAN and resets the hardware clock in the relay. Figure 4 describes in detail the model! implementation in the relay. The organization of the various Logical Nodes (LN) and the IEC61850 Services is enumerated below. The relay is configured in a Single Logical Device (LD) model viz. PROTEC1, with the various LNs catering to the System, Measurements, Protection, Control and Records functions. The LD is the virtual device that exists to enable aggregation of related logical nodes and data sets. As the relay is a multifunctional protection IED with a complex functional hierarchy, it is modeled according to the definitions of the IEC 61850 model. LLNO is the common logical node; LPHDlis the physical device node; GGIOl, GGI02, GGI03 are the generic inputs and outputs; grouped under the System function. Measurement function is performed by the MMXU1 logical node. The server has to two groups of functions - protection and non-protection. The protection functions can be further divided into main protection - distance protection, overcurrent protection with instantaneous / definite / inverse time delayed overcurrent, instantaneous / definite / inverse time delayed earthfault, definite / inverse time delayed overvoltage protection, definite / inverse time delayed undervoltage protection; backup protection function; control and protection related functions. The local backup protection is breaker-failure. The control functions are 4-shot autorelcoser with check synchronism, power swing blocking and circuit breaker control. Non-protection features are measurements, records etc. PDIS1, PDS2, PDSI3, PDIS4, PDIS5, PDIS6, PDIS7, PDIS8, PDIS9, PDIS10 are the various instances of the Distance protection function modeled in the relay. These represent the different zones for the phase-to-ground and phase-to-phase protection. PTOC1 is the inverse time three-phase overcurrent protection function, PTOC2 is the earth-fault protection, PTOC3 is the broken conductor function and PTOC4 is the negative sequence overcurrent protection. Instantaneous overcurrent functions are modeled using the PIOC1 for the three phase currents and PIOC2 for the earth-fault current. Voltage functions for the protection of three phase voltages are catered to by the PTOV1 for the overvoltage and PTUV1 for the undervoltage protections. The trip conditioning module - PTRC1 is modeled for the logical conditioning of the pickup, operate and trip states of the various protection functions LNs. RBRF1 is the circuit breaker fail protection function. The Records section comprises of the RDRE1 - Disturbance Recorder and the RFLOl - Fault Locater. Control section comprises of a four shot Autorecloser represented by RREC1, check synchronism by RSYN1, power swing blocking by RPSB1 and circuit breaker switch by XCBR1. The field signals from the current transformers 401 and voltage transformers 402 are wired to the data acquisition section in the relay 404 and the processed parameters are mapped to the MMXU1 LN data objects. The digital inputs from the field are mapped GGIOl, GGI02 and GGI03 LN data objects. The circuit breaker switch 403 can be controlled by the GOOSE data set. IEC 61850 is built-in as a communication feature of the device. The other services programmed in the relay are the Data sets (DS), Substitution, Setting Group Control Block (SGCB), Buffered Reporting (BR), Unbuffered Reporting (UBR), Logs, File transfer and Time Synchronization. These features allow the information exchange between the relay and other IEC 61850 compliant IEDs over the Ethernet port 405. A DS is an ordered group of object references of data or data attributes. The data and data attributes are organized into DS for the convenience of the client. The DS class contains attributes for name, path name and list of dataset members which contains functionally constrained data or data attributes of the data and data attributes which are organized in the DS. As both the client and server keep track of the order of membership of a DS, only the name of the DS and the current values are transmitted. The substitution model allows for value of a data attribute to be substituted with a manually entered value if the attribute has a particular functional constraint, namely MX for analogue values or ST for status values. This allows a client operator to enter a substitution value for a particular data attribute, so that if it is retrieved, for instance by a report, the substitution value will be transmitted instead of the value determined by the process. This SGCB class model allows for a data instance to have several values, which are used at a time, and can also be applied on a set of data instances. The relay has 4 setting groups (SG) and at a time one of them is the active and the data instances have values corresponding to that SG. Any of the other three SG is set to editable SG. Reporting is handled by the REPORT-CONTROL-BLOCK class which controls the procedures that are required for reporting values of data from one or more logical nodes to one client. Three trigger options are defined - data change, quality change, and data update - which can cause a report to be sent to a client. Buffered Report Control Block (BRCB) allows for sending of reports to be issued immediately, or for the event to be buffered for transmission after an amount to time specified. BRCB provides the sequence of events functionality and if the connector is broken when reporting is to take place, the report is buffered and sent when the connection is re-established. In Unbuffered Report Control Block (URCB), there is no buffering, and if the connection is broken, the reports are discarded. The relay restricts the access to an instance of a report control block to one client at a time till the association is aborted or released. Multiple instances (5) of the report control block classes are made available so that more than one client can receive reports of the same values of the data. The maximum number of clients that may be associated with the relay at a time is configured to be 8. Logging is provided by maintaining an internal storage of historical data values for subsequent reviewing or producing statistics. It is independent of communication and should take place even rf communication breaks down. Periodic recordings and event-triggered sequence of events data are logged. LOG-CONTROL-BLOCK (LCB) class controls the logging and the log class handles logging. One log can be controlled by multiple LCBs. The LCB class controls the procedures that are required for storing values of data attribute into a log. Each enabled LOG can associate a DS with a log. Changes in a value of a member in the particular DS will be stored as a log entry filed as FIFO. When the stored data reaches the maximal size of the log, the oldest entries are overwritten. LCB contains attributes for name, path-name, whether the instance is enabled, DS being monitored, optional fields, trigger options and integrity period. Two LCBs are defined the relay IED. GOOSE class model is provided for fast and reliable system-wide distribution of input and output data values. It can also provide an efficient method for delivering the same GOOSE information to physical devices through multicast / broadcast services. Time and Time synchronization model is modeled as SNTP client which can frequently poll for the Coordinated Universal Time (UTC) broadcast from a SNTP Server, and set the real time clock of the hardware module and synchronise the time in the relay with that of the other IEDs. File Transfer Services is modeled to send files requested by clients. We Claim: 1. A multifunction numerical line protection relay with interoperability comprising of: - power supply module (6.1); - processing module (6.2) which comprises of real time module (201), non-real time module (203), IEC 61850communication module (204) and interprocess communication (202, 205); - transformer module (6.3); - filter module (6.4), - relay module (6.5), - local interface (6.6) and - front panel (6.7); characterized in that the communication module (204) makes the relay IEC 61850 compliant, thereby implementing IEC 61850 communication protocol so as to achieve significant increase in the communication capability for state-of-art substation communication. 2. The relay as claimed in claim 1, wherein power supply module (6.1) supplies 24V D.C. voltage to processing module (6.2), relay module (6.5) and front panel (6.7) and ± 15v D.C voltage to transformer module (6.3) and filter module(6.4). 3. The relay as claimed in claim 1, wherein the processor module (6.2) has the relay algorithm residing in section C, which contains IEC 61850 communication module (204), which makes the relay interoperable with other IEC 61850 compliant devices in the substations. 4. The relay as claimed in claim 1, which communicates with similar intelligent electronic devices (IEDs) via 100 MBPS optical Ethernet network to perform far superior tasks in shorter time. 5. The relay as claimed in claim 1, wherein GOOSE subscribe and publish model (304) provides fast and reliable system-wide distribution input and output data. 6. A method of integrating IEC 61850 communication protocol with the features of the relay as claimed in claims 1-5, comprising the steps of: - accessing wired field data from current and voltage transformers as analogue inputs in realtime module (201); - processing the realtime data to ascertain abnormal state of transmission line; - communicating processed data to non-realtimetime module (203) for transmission through serial ports to local interface (6.6) and front panel (6.7); - achieving IEC 61850 compliant communication protocol through communication module (204) by means of inter process communication (205) realized through First-In-First-Outs (FIFO); and - associating the relay to other clients and processing the information to be transmitted over the Ethernet in the local area network (206). 7. A method as claimed in claim 6, wherein data is continuously exchanged between the various modules through FIFOs. 8. A method as claimed in claim 6, wherein the field signals from current and voltage transformers (401, 402) are wired to data acquisition section (404) where they are processed. 9. A method as claimed in claim 6, wherein communication module (204) allows information exchange between the relay and other IEC 61850 compliant IEDs over Ethernet port (405). A multifunction numerical line protection relay with interoperability comprising of: - power supply module (6.1); - processing module (6.2) which comprises of real time module (201), non-real time module (203), IEC 61850communication module (204) and interprocess communication (202, 205); - transformer module (6.3); - filter module (6.4), - relay module (6.5), - local interface (6.6) and - front panel (6.7); characterized in that the communication module (204) makes the relay IEC 61850 compliant, thereby implementing IEC 61850 communication protocol so as to achieve significant increase in the communication capability for state-of-art substation communication.

Full Text

Field of the invention:
The invention relates to protective relays for electric power systems in general
and to a multifunction numerical line protection relay with interoperability
between IEC 61850 compliant devices in particular, and also to a method for
realization of IEC 61850 communication protocol in such a relay.
Background and prior art:
A new generation of microprocessor based Intelligent Electronic Devices (IEDs)
with high speed peer to peer communication for protection and control is now
becoming common in electric power industry. This has led to the necessity to
standardize the communication protocol between the IEDs in substations and
power stations, which resulted in the evolution of a universal platform based on
an International Electro technical Commission (IEC) 61850 that will not only
allow plug-and-play technology, but also ascertain interoperability between the
IEDs of different vendors. The full implementation of the standard ensures open,

future-proof and flexible system architectures with state-of-art performances.
IEC 61850 is becoming the widely accepted solution for communication within
substations all over the world.
One of great advantages provided by this standard is the real time
communication for the high priority messages. Traditionally interconnection
between the IEDs was made with wire by means of electrical circuit using
communication interfaces and proprietary communication protocols. Technology
today provides us with solution using an optical Ethernet network to perform far
superior tasks in shorter time. The IEDs can now exchange status and control
signals with other IEDs by exchanging data packets containing status and control
signals over a communication link using Ethernet on the local area network. They
can also send reports and logs, file transfer of disturbance records to clients.
The benefits can be assessed in terms of new features for a better operation
(automation), maintenance (access to more accurate data) and engineering (e.g.
avoid data duplication) within the substation and also within the overall grid
information scheme. Logical integration of the protection, control and
communication features is to design the proper architectural mechanisms both at
device and system levels to ensure a sustainable industrial model. A simple
architecture, scalability and testability are important for market acceptance of
IEC 61850 compliant IED.

A multifunction numerical line protection relay is known from Indian patent
application no. 00575/KOL/2007, filed on 04.06.2007.
The invention relates to protective relay for electric power systems, and more
particularly relates to a method for realization of multifunction numerical line
protection relay adopting a real-time operating system and a single processor.
The multifunctional numerical line protection relay of the prior ait was a stand
alone relay which did not have the interoperability feature. Increasing demand
on protection relays for delivering higher level services, like high speed and
accurate protection along with networking - for communication between peers,
client and server; user interfaces and file system management - call for efficient
integration of custom hardware and software resources. The present invention
proposes a methodology of integrating the IEC 61850 communication protocol
with the protection and control features of the multifunction line protection relay
with the up-gradation of the device's firmware.
Objects Of The Invention:-
It is therefore an object of the invention to incorporate IEC 61850
communication protocol in the Multifunction Numerical Line Protection Relay that
has been designed with single processor architecture and a realtime operating

system, so as to achieve a significant increase in the communication capability
for the state-of-art substation automation.
Another object of invention is to provide a method of configuring the logical
device, various logical nodes, data sets, control blocks (reports, logs and
GOOSE).
A further object of invention is to provide a client - server communication and
peer-to-peer communication with Generic Object Oriented Substation Events
(GOOSE) messages over the Ethernet.
A still further object of the invention is to provide a method of inter process
communication between the various realtime, non realtime applications and
communication interface within the same intelligent electronic device.
Yet another object of invention is to provide an easy and quick method for
converting a non-IEC 61850 device (which is described in the prior art) to an IEC
61850 compliant IED without an additional protocol converter or hardware.
Moreover, the method depends on a simple change / upgrade of the firmware to
make the relay IEC 61850 compliant.
Summary Of The Invention:
The present invention is concerned with substation automation (SA) systems, in
particular with a methodology for implementing an IEC 61850 standard in a

Multifunction Numerical Line Protection Relay in order to make it IEC61850
compliant Intelligent Electronic Device (IED). The IED is made IEC 61850
compliant with the augmentation of the communication protocol with the
features which are coded in the IED capability description (ICD) file.
The invention proposes a unique method to incorporate IEC 61850
communication protocol in a multifunction numerical protection relay. This has
been achieved without any additional hardware and by integrating additional
software with the existing software. More particularly, the invention relates to a
method of implementation of IEC 61850 communication protocol in the
multifunction numerical line protection relay.
The present invention relates to a method used for configuring the various
protection, non-protection functions as data models in the relay based on the
IEC 61850 standards. The models that are configured in the relay are:
Association model, Server / Logical device/Logical node/Data, Data set model,
Substitution model, Setting Group model, Reporting model, Log model, Goose-
Subscribe and Publish model, File transfer model, Time and time synchronization
model.
The relay is configured to record the performance statistics during the
occurrence of a major disturbance or fault in substation in the form of
Disturbance Records (DR) stored in the Common Format for Transient Data
Exchange (COMTRADE). The relay is configured to perform as Simple Network

Time Protocol (SNTP) Client so that the polled time from a SNTP Server is
accessed and the relay (Real Time Clock) RTC time is updated with the new
time.
The relay is a physical device with a communication interface. It has an IP
address and is accessible over a network by an external client. It can access
connection from one or more (maximum of 8) clients. It contains one logical
device and several logical nodes that represent the basic building blocks
(objects) of the functionality of the relay. Each logical node contains data that
can be written to or read individually and in groups (data sets). It: also responds
to control inputs or triggers control outputs;. It provides solicited and unsolicited
reports, and contains logs that can be queried. Services are provided to read
and write the data in the logical node. Measured data and status information are
normally read only. Control and configuration information are generally read and
write. The dataset which is a collection of data values that are commonly
needed, is given a name, and clients can retrieve them with a single read
operation.
Brief Description Of The Accompanying Drawings:-
Fig. 1 is a block diagram of the software modules in the prior art arrangement in
the multifunction numerical line protection relay.

Fig. 2 is a block diagram of the modules arrangement in the present invention for
the augmentation of IEC 61850 communication protocol.
Fig. 3 shows the inter-process communication of data between the various
software modules in the device.
Fig. 4 shows the organization of the Logical Nodes in the Logical Device along
with the IEC 61850 services.
Fig. 5 shows the relay in accordance with the invention connected in a protective
arrangement with an electrical system.
Fig. 6 shows the block diagram of the relay according to the invention.
An exemplary embodiment of the invention as depicted in the accompanying
drawings will now be described. However, there may be other embodiments of
the same invention all of which are deemed covered by this description.
The invention provides the method of implementation of the IEC 61850
communication protocol in the multifunction numerical line protection relay
incorporating the present invention. The numerical relay described in the prior-
art shown in Fig.l can be configured as an IEC 61850 compliant IED (Fig.2) in
the substation environment capable of interacting with the other substation
devices which are also IEDs themselves. The data modeling in the relay has been
done taking into account the functionality and data exchange requirements with
the other substation devices. The various protection and non protection functions

of the relay are divided into the smallest entities called the logical nodes in the
standard, which are used to exchange information. The logical nodes are
modeled and defined from the conceptual application point of view in IEC 61850-
5. In this implementation, the relay, which is a real device is modeled as a virtual
model. A set of basic services have been defined which are used by the
communication interface to accomplish the information exchange. These services
referred to as Abstract Communication Service Interface (ASCI ) have been
standardized as per the parts IEC 61850-7-1 & IEC 61850-7-2. The
communication is established through Transmission Control Protocol / Internet
Protocol (TCP/IP) port available in the relay hardware. The relay which is
configured as a server for the purpose of IEC 61850 communication, has the
following models programmed in it.
a) Association model - Association services is a basic requirement in order for a
client to connect to the IEC 61850 compliant IED. There are three association
services - Associate, Abort, and Release. The Basic Information Model with two
party access control is available for bi-directional connection oriented information
exchange between IEDs which is reliable and provides end-to-end flow control.
The multicast and broadcast access control is available for unidirectional
information exchange between one publisher and one or many subscribers. The

subscriber shall be able to detect loss and duplication of information received.
The relay is capable of both publishing and subscribing to GOOSE
messages.(304)
b) Server / Logical device / Logical node / Data model (303,305)- The server
represents the external visible behaviour of the relay. It can communicate with
clients, send information to peer devices. The logical device contains the
information produced and consumed by a groyp of domain specific application
functions. This is made up of several logical nodes - each for one domain
specific application function. Data is the status and information of object it
represents in the substation.
c) Data set model - This constitutes the group of data and data attributes
collected from the various logical nodes that need to be sent with any of the
services or as GOOSE messages. The server is configured for fixed data sets.
d) Substitution model - This provides a replacement of process value in the
server with reference to the measurands of analogue values or status values of
various digital signals.
e) Setting Group model - The relay has four setting groups with one set of

setting values as active and another as edit setting groups. Active and edit
setting groups can be dynamically changed as per the need.
f) Reporting model - This describes the conditions for generating reports based
on parameters set by the client. Reports may be sent immediately or deferred.
Any data update, data change, quality change in the associated dataset or the
integrity period triggers the formation of report and its onward transmission to
the respective client.
g) Log model - Describes the conditions for generating logs based on the
parameters set by the client. Logs can be queried for later retrieval.
h) GOOSE -Subscribe and Publish model(304)- This supports a fast and reliable
system-wide distribution of input and output data values. Simultaneous delivery
of the same generic substation event information to more than one physical
device through the use of broadcast services. This model is used for fast
transmission of substation events such as commands, alarms and indications as
messages. A single GOOSE message sent by an IED can be received by several
receivers. This model makes use of the Ethernet and supports real-time
behaviour.

j) File transfer model - The server defies the exchange of large data blocks such
as programs and disturbance record files (DR) stored in the relay's memory. The
DR files in the Common Format for Transient Data Exchange (COMTRADE)
format are stored in the flash memory, under the folder YCOMTRADE' of the
relay. The file directory service will give client, the list of files and /or directories
mentioned in the request.
k) Time and time synchronization model for SNTP - This enables the relay to
accepts the UTC synchronized time over the local area network and reset its
clock.
Description Of The Relay
Referring to Fig.l, the multifunction numerical line protection relay incorporating
the present invention, is a powerful and compact multifunction numerical relay,
configured for the protection of transmission lines. The relay is capable of
handling the protection requirements of the transmission lines, and works based
on the three phase currents and voltages. The relay is also IEC61850
communication protocol compliant.

The entire application software is divided into real and non-real tasks wherein
the real time tasks are repeated exactly with the same cyclicity as has been
originally defined by the application. The non-real tasks on the other hand, are
not time critical and run in the background. The real time tasks are handled by
the RT (Real-time) module while the non-real time tasks are handled by NRT
(Non-realtime) module. The relay software is designed and implemented such
that it supports many features.
It uses RT FIFOs (real time first in first out) as Inter Process Communication
(IPC) mechanism for communication between RT module and NRT module. They
act as pipes between the RT and NRT tasks.
The multifunction line protection relay of the invention is configured to perform
the following protection and non protection functions :
PROTECTION FEATURES
1. Phase and earthfault distance protection: Each with five independent
zones of protection, four in the forward and one reverse direction: This is
based on impedance, which is high during the normal operation, and,
during fault condition, the impedance becomes less, and when it is

below the set value, trip command to the breaker is issued to isolate the
fault.
2. Overcurrent protection: Two elements with direction control, with first
element as either Inverse Definite Minimum Time (IDMT) or Definite Time
(DT) and the second element as Hiset instantaneous. This is provided to
limit damage from phase faults.
3. Earthfault protection: Two elements with directional control, with first
element as either Inverse Definite Minimum Time (IDMT) or Definite Time
(DT) and the second element as Hiset instantaneous. This is a protection
scheme with the zero sequence component of the three phase currents.
4. Overvoltage protection: One element with selectable characteristics as
either Inverse Definite Minimum Time (IDMT) or definite time (DT) for
each of the three phase voltages.
5. Undervoltage protection: One element with selectable characteristics as
either Inverse Definite Minimum Time (IDMT) or definite time (DT) for
each of three phase voltages.
6. Negative sequence overcurrent protection. This element can provide
backup protection for many unbalanced fault conditions.
7. Switch on to fault (SOTF) protection: This is provided for high speed
clearance of any detected fault immediately after a manual circuit breaker
closure.

8. Trip on reclose protection (TOR): This is provided for high speed
clearance of any detected fault immediately following autoreclose of the
circuit breaker.
9. Power swing blocking: Selective blocking of distance protection zones
ensures stability during power swings experienced on transmission
systems.
10.Voltage transformer supervision: This is to prevent wrong operation of
voltage dependent protection on AC voltage input. It mainly detects
voltage transformer fuse failures.
11.Current transformer supervision: If one or any of the current transformers
were to become open circuited, this protection raises an alarm.
12. Broken conductor: This is to detect: network faults such as open circuits,
where a conductor may be disconnected and not in contact with another
conductor or the earth.
13. Circuit breaker failure protection: Whenever the circuit breaker at
protected terminal fails to trip, this protection would then send a
command to upstream circuit breaker to backtrip.
Non-Protection Features
1. Autorecloser with checksynchronism: This provides upto 4 reclose shots,
with checksynchronism for voltage, frequency and phase, and can be set
for any combination of line and bus conditions.

2. Distance to fault locator.
3. Measurements of field data and computation of derived parameters are
available for display at the relay as well as accessed from the serial
communication facility.
4. Event / Fault / Disturbance / Oscillography Records.
5. IEC61850 communication protocol.
The program continuously monitors the field data in order to determine the
status of the associated transmission line, in real time. This provides information
related to the line conditions and whether any alarms or trips are to be issued
by the relay.
Fig. 5 shows the relay connected to the transmission line for monitoring the
current and voltages in real-time, along with the photograph of the relay. The
field inputs viz. three phase currents, the three phase voltages and the busbar
voltage are connected to the relay terminal blocks. The relay contacts are used
to operate the circuit breaker (52).
Fig.6 shows a block diagram of the hardware of the system. The relay hardware
comprises of seven modules. The auxiliary D.C. voltage given to the relay is first
stepped down to 24Vdc in module 6. 1. This voltage energizes module 6. 2,

module 6.5 and module 6.7. The +15Vdc and -15Vdc is used to energize module
6.3 and module 6.4.
The field inputs viz. three phase currents and the three phase voltages
(described in Fig.l), connected to the relay terminal blocks, is first processed by
module 6.3. The stepped down signals are then filtered by module 6.4 for any
high frequency disturbances and to avoid aliasing errors. These signals are then
sent to section B of module 6.2.
The processing module 6.2 has the relay algorithm residing in section C. When
the relay is powered ON, the program control, after necessary hardware,
software and memory initializations, first digitizes the analog data in section B,
and processes the data, checking for any fault. When a fault occurs, the relay
senses it and issues a command in the form an annunciation or a trip, depending
upon the severity of the fault. The final relay outputs are sent through section D
to the module 6.5. This module has sixteen numbers of contacts with higher
driving capability and these potential free contacts are brought out to relay
terminal blocks (described in Fig. 1). Relay status is indicated by means of lamps
provided on the front side of the panel. In addition, alarms and trip contacts are
brought out in the form of potential-free contacts, which can, in turn, be used for
either operating the circuit breaker or to drive audio / visual alarms. The

contacts and lamps are of self resetting type.The relay functions are stored in
the compact flash disk memory shown in section C. This section comprises of the
realtime module (201), non-realtime module (203) and the IEC61850
communication module (204) along with the inter process communication
channels (202 and 205) described in Fig. 2.
Module 6.2 also has two serial ports RS232- section F, through which the
metered data is communicated to the operator interface on the front of the relay
(module 6.7) and also to the PC-based HMI (Human machine interface) program
(module 6.6). It can also read the set parameters from the operator interface.
The section E is the 100 Mbps Ethernet port that is available on the relay for
communication over Ethernet using the IEC61850 communication protocol. The
section G comprises of two RS485 ports which facilitate the multi drop
communication features of the relay.
Method of integrating IEC 61850 communication protocol:
Fig.l describes the method of implementation of the software modules in the
prior art system. The model consists of a realtime module 102, which accesses
the wired field data - from the current and voltage transformers in the form of
analog inputs, status signals from various field devices in the form of digital data

through the module 101, and processes the same to ascertain the abnormal
state of the transmission line using the various protection algorithms built in the
module. The digital data to control the field devices viz. the circuit breaker is
provided by the module 102 in the form of digital outputs from the module 103,
which is wired to the respective devices. The processed data from the module
102 is transferred to non realtime module 105 through inter-process
communication channel 104. This information is then passed by the module 105
to the serial ports 106 for communication to the front end terminal 107, and the
storage of the oscillography data file 108, consisting of realtime data during
fault. Such a system described in Fig.l meets the requirements of a
multifunction numerical line protection relay. However, this relay cannot ensure
interoperability between devices in the substation to exchange information.
Fig. 2 shows the augmentation of an additional module with IEC 61850
communication interface 204. The realtime module 201, non-realtime module
203 along with the interprocess communication 202 is the same as those
described in Fig.l with the same functions. The module 205 is the IEC 61850
communication interface with the Server, GOOSE and SNTP client processes. The
bidirectional information exchange between the module 201 and 204 is by means
of the interprocess communication 205 realised using First-In-First-Outs (FIFOs).
The addition of module 204 makes the relay IEC 61850 compliant and associates

the relay (now configured as server) to any of the clients and also processes the
information to be transmitted over the Ethernet in the local area network 206
viz. the station bus. This module can also receive information from clients.
GOOSE subscription and publish mechanisms are also handled. SNTP client
process continuously polls for the time over the LAN and resets the hardware
clock accordingly.
Fig.3 describes in detail the various interprocess communication mechanisms
between the various modules for data exchange. They are realised using FIFOs.
The realtime module 201 interacts with the module 203, both of which comprise
the relay application function. The SendFIFO 307 transmits the metering and
monitoring data processed by the module 201. The SendEventFIFO 308
transmits the realtime events processed by the module 201. The SamplesFIFO
309 transmits measurands measured by the module 201. The ReceiveFIFO 306
transmits the settings information from the module 203 which has been accessed
over the serial network. The Server module 303, GOOSE module 304 and SNTP
Client module 305 facilitates the IEC 61850 communication protocol in the relay.
The ApplicationtoServerFIFO 310, ApplicationtoGOOSEFIFO 312 cater to the
information transmission from the relay application function to the IEC 61850
module. The ServertoApplicationFIFO 311 and GOOSEtoApplicationFIFO 313 are
designed for information reception by the relay function application. The

ServertoGOOSEFIFO 314 and GOOSEtoServeFIFO 315 serve to facilitate data
exchange between the modules 303 and 304. The SNTP Client module directly
accesses the SNTP clock over the LAN and resets the hardware clock in the relay.
Figure 4 describes in detail the model! implementation in the relay. The
organization of the various Logical Nodes (LN) and the IEC61850 Services is
enumerated below. The relay is configured in a Single Logical Device (LD) model
viz. PROTEC1, with the various LNs catering to the System, Measurements,
Protection, Control and Records functions. The LD is the virtual device that exists
to enable aggregation of related logical nodes and data sets. As the relay is a
multifunctional protection IED with a complex functional hierarchy, it is modeled
according to the definitions of the IEC 61850 model. LLNO is the common logical
node; LPHDlis the physical device node; GGIOl, GGI02, GGI03 are the generic
inputs and outputs; grouped under the System function. Measurement function
is performed by the MMXU1 logical node.
The server has to two groups of functions - protection and non-protection. The
protection functions can be further divided into main protection - distance
protection, overcurrent protection with instantaneous / definite / inverse time
delayed overcurrent, instantaneous / definite / inverse time delayed earthfault,
definite / inverse time delayed overvoltage protection, definite / inverse time

delayed undervoltage protection; backup protection function; control and
protection related functions. The local backup protection is breaker-failure. The
control functions are 4-shot autorelcoser with check synchronism, power swing
blocking and circuit breaker control. Non-protection features are measurements,
records etc. PDIS1, PDS2, PDSI3, PDIS4, PDIS5, PDIS6, PDIS7, PDIS8, PDIS9,
PDIS10 are the various instances of the Distance protection function modeled in
the relay. These represent the different zones for the phase-to-ground and
phase-to-phase protection. PTOC1 is the inverse time three-phase overcurrent
protection function, PTOC2 is the earth-fault protection, PTOC3 is the broken
conductor function and PTOC4 is the negative sequence overcurrent protection.
Instantaneous overcurrent functions are modeled using the PIOC1 for the three
phase currents and PIOC2 for the earth-fault current. Voltage functions for the
protection of three phase voltages are catered to by the PTOV1 for the
overvoltage and PTUV1 for the undervoltage protections. The trip conditioning
module - PTRC1 is modeled for the logical conditioning of the pickup, operate
and trip states of the various protection functions LNs. RBRF1 is the circuit
breaker fail protection function. The Records section comprises of the RDRE1 -
Disturbance Recorder and the RFLOl - Fault Locater. Control section comprises
of a four shot Autorecloser represented by RREC1, check synchronism by RSYN1,
power swing blocking by RPSB1 and circuit breaker switch by XCBR1.

The field signals from the current transformers 401 and voltage transformers 402
are wired to the data acquisition section in the relay 404 and the processed
parameters are mapped to the MMXU1 LN data objects. The digital inputs from
the field are mapped GGIOl, GGI02 and GGI03 LN data objects. The circuit
breaker switch 403 can be controlled by the GOOSE data set.
IEC 61850 is built-in as a communication feature of the device. The other
services programmed in the relay are the Data sets (DS), Substitution, Setting
Group Control Block (SGCB), Buffered Reporting (BR), Unbuffered Reporting
(UBR), Logs, File transfer and Time Synchronization. These features allow the
information exchange between the relay and other IEC 61850 compliant IEDs
over the Ethernet port 405.
A DS is an ordered group of object references of data or data attributes. The
data and data attributes are organized into DS for the convenience of the client.
The DS class contains attributes for name, path name and list of dataset
members which contains functionally constrained data or data attributes of the
data and data attributes which are organized in the DS. As both the client and
server keep track of the order of membership of a DS, only the name of the DS
and the current values are transmitted.

The substitution model allows for value of a data attribute to be substituted with
a manually entered value if the attribute has a particular functional constraint,
namely MX for analogue values or ST for status values. This allows a client
operator to enter a substitution value for a particular data attribute, so that if it is
retrieved, for instance by a report, the substitution value will be transmitted
instead of the value determined by the process.
This SGCB class model allows for a data instance to have several values, which
are used at a time, and can also be applied on a set of data instances. The relay
has 4 setting groups (SG) and at a time one of them is the active and the data
instances have values corresponding to that SG. Any of the other three SG is set
to editable SG.
Reporting is handled by the REPORT-CONTROL-BLOCK class which controls the
procedures that are required for reporting values of data from one or more
logical nodes to one client. Three trigger options are defined - data change,
quality change, and data update - which can cause a report to be sent to a
client. Buffered Report Control Block (BRCB) allows for sending of reports to be
issued immediately, or for the event to be buffered for transmission after an
amount to time specified. BRCB provides the sequence of events functionality
and if the connector is broken when reporting is to take place, the report is

buffered and sent when the connection is re-established. In Unbuffered Report
Control Block (URCB), there is no buffering, and if the connection is broken, the
reports are discarded.
The relay restricts the access to an instance of a report control block to one
client at a time till the association is aborted or released. Multiple instances (5) of
the report control block classes are made available so that more than one client
can receive reports of the same values of the data. The maximum number of
clients that may be associated with the relay at a time is configured to be 8.
Logging is provided by maintaining an internal storage of historical data values
for subsequent reviewing or producing statistics. It is independent of
communication and should take place even rf communication breaks down.
Periodic recordings and event-triggered sequence of events data are logged.
LOG-CONTROL-BLOCK (LCB) class controls the logging and the log class handles
logging. One log can be controlled by multiple LCBs. The LCB class controls the
procedures that are required for storing values of data attribute into a log. Each
enabled LOG can associate a DS with a log. Changes in a value of a member in
the particular DS will be stored as a log entry filed as FIFO. When the stored
data reaches the maximal size of the log, the oldest entries are overwritten. LCB
contains attributes for name, path-name, whether the instance is enabled, DS
being

monitored, optional fields, trigger options and integrity period. Two LCBs are
defined the relay IED.
GOOSE class model is provided for fast and reliable system-wide distribution of
input and output data values. It can also provide an efficient method for
delivering the same GOOSE information to physical devices through multicast /
broadcast services. Time and Time synchronization model is modeled as SNTP
client which can frequently poll for the Coordinated Universal Time (UTC)
broadcast from a SNTP Server, and set the real time clock of the hardware
module and synchronise the time in the relay with that of the other IEDs. File
Transfer Services is modeled to send files requested by clients.

We Claim:
1. A multifunction numerical line protection relay with interoperability comprising
of:
- power supply module (6.1);
- processing module (6.2) which comprises of real time module (201), non-real
time module (203), IEC 61850communication module (204) and interprocess
communication (202, 205);
- transformer module (6.3);
- filter module (6.4),
- relay module (6.5),
- local interface (6.6) and
- front panel (6.7);
characterized in that the communication module (204) makes the relay IEC
61850 compliant, thereby implementing IEC 61850 communication protocol so as
to achieve significant increase in the communication capability for state-of-art
substation communication.
2. The relay as claimed in claim 1, wherein power supply module (6.1) supplies
24V D.C. voltage to processing module (6.2), relay module (6.5) and front panel
(6.7) and ± 15v D.C voltage to transformer module (6.3) and filter module(6.4).

3. The relay as claimed in claim 1, wherein the processor module (6.2) has
the relay algorithm residing in section C, which contains IEC 61850
communication module (204), which makes the relay interoperable with other
IEC 61850 compliant devices in the substations.
4. The relay as claimed in claim 1, which communicates with similar
intelligent electronic devices (IEDs) via 100 MBPS optical Ethernet network to
perform far superior tasks in shorter time.
5. The relay as claimed in claim 1, wherein GOOSE subscribe and publish
model (304) provides fast and reliable system-wide distribution input and
output data.
6. A method of integrating IEC 61850 communication protocol with the
features of the relay as claimed in claims 1-5, comprising the steps of:

- accessing wired field data from current and voltage transformers as
analogue inputs in realtime module (201);
- processing the realtime data to ascertain abnormal state of transmission
line;
- communicating processed data to non-realtimetime module (203) for
transmission through serial ports to local interface (6.6) and front panel (6.7);

- achieving IEC 61850 compliant communication protocol through
communication module (204) by means of inter process communication (205)
realized through First-In-First-Outs (FIFO); and
- associating the relay to other clients and processing the information to be
transmitted over the Ethernet in the local area network (206).
7. A method as claimed in claim 6, wherein data is continuously exchanged
between the various modules through FIFOs.
8. A method as claimed in claim 6, wherein the field signals from current and
voltage transformers (401, 402) are wired to data acquisition section (404)
where they are processed.
9. A method as claimed in claim 6, wherein communication module (204)
allows information exchange between the relay and other IEC 61850
compliant IEDs over Ethernet port (405).

A multifunction numerical line protection relay with interoperability comprising of:
- power supply module (6.1);
- processing module (6.2) which comprises of real time module (201), non-real
time module (203), IEC 61850communication module (204) and interprocess
communication (202, 205);
- transformer module (6.3);
- filter module (6.4),
- relay module (6.5),
- local interface (6.6) and
- front panel (6.7);
characterized in that the communication module (204) makes the relay IEC
61850 compliant, thereby implementing IEC 61850 communication protocol so as
to achieve significant increase in the communication capability for state-of-art
substation communication.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=pJ6U23/+xpHTMd9AbwE3Dg==&loc=wDBSZCsAt7zoiVrqcFJsRw==

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Patent Number

271981

Indian Patent Application Number

517/KOL/2009

PG Journal Number

12/2016

Publication Date

18-Mar-2016

Grant Date

11-Mar-2016

Date of Filing

23-Mar-2009

Name of Patentee

BHARAT HEAVY ELECTRICALS LIMITED

Applicant Address

REGIONAL OFFICES AT REGIONAL OPERATIONS DIVISION (ROD), PLOT NO: 9/1, DJBLOCK 3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, KOLKATA-700091, HAVING ITS REGISTERED OFFICE AT BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	SHYAMALA VENKATARAMAN, KOTAMARTHY VENKATA HANUMANTHA RAO	BHEL-CORP. RESEARCH & DEVELOPMENT VIKASNAGAR, HYDERABAD-500093

PCT International Classification Number

H02H3/26

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA