| Title of Invention | "AN IMPROVED GAS FILLED SURGE ARRESTE0R WITH FAST RESPONSE TIME" |
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| Abstract | A gas filled surge arrester with fast response time used in power systems in general and particularly with gas insulated substations and lines characterized in that plurality of nonlinear elements (1) are stacked in series and connected by metallic elements (2), said assembly is paced in an insulating tube (3). |
| Full Text | The invention relates to a gas filled surge arrester with fast response time used in power systems in general and particularly with gas insulated substations and lines in all voltage ranges including HV, EHV and UHV. There are several disadvantages associated with the present conventional surge arresters. The main disadvantages associated with the present system of surge arrester is that the response of the surge arrester is slowed down as the voltage rating of the surge arrester increases. This is undesirable as the performance of surge arrester and insulation co-ordination is affected in the power system. Another disadvantage associated with the present system of surge arrester is that the thermal runaway problem increases with the voltage rating of the arrester and the non-linear elements are used inefficiently to comp.ensate the effect in conventional gas ( Pure SF6 or Mixtures) filled surge arrester. SUMMARY OF THE INVENTION Therefore, the main object of the present invention of a gas filled surge arrester with fast respoirse time is to reduce the inductance and increase capacitance coupling between blocks of the device to improve the response of the surge arrester. Another object of the present invention of a gas-filled surge arrester with fast response time is to keep the interstage members and the non-linear elements at a uniform temperature to overcome thermal runaway problems in the surge arrester and improve surge current carrying capabilities of the arrester. Yet another object of the present invention of a gas-filled surge arrester with fast response time is that it has improved and uniform voltage distribution on the non-liner elements to help optimise "overall performance of the surge arrester element. Further object of the present invention of a gas-filled surge arrester with fast response time is to further refine the voltage distribution across the elements. According to the present invention there is provided a gas filled surge arrester with fast response time used in power systems in general and particularly with gas insulated substations and lines wherein the plurality of non-linear elements are stacked in series and connected by metallic elements, said assembly is placed in an insplating tube. The nature of the invention, its objective and further advantage residing in the same will be apparent from the following description made with reference to the non-limiting exemplary embodiments of the invention represented in the accompanying drawings. Figure 1 shows the non-linear elements stacked in series and connected by means of metallic element as proposed in the invention. Figure 2 shows the insulating tube with metallic flanges at both ends; Figure 3 shows hair pin arrangement of non-linear elements; Figure 4 shows the multi hair pin arrangement non-linear elements; Figure 5 shows a high voltage shield with window; Figure 6 shows the top view of the enclosure housing the hair pin arrangement. DETAILED DESCRIPTION OF THE INVENTION: In the proposed invention, the non-linear elements (1) are stacked in series and connected by means of a metallic element (2) functioning as inter-stage cooling member as shown in Fig. 1. The arrester elements (1) are made of silicon carbide,metallic or zinc oxide. The assembly of non—linear elements (1) stacked in series and connected by metallic element (2) is placed in an insulating tube (3) of high mechanical and dielectric strength.The insulating tube (3) is terminated in metallic flanges (4) with openings (5,6) for gas circulation as indicated by arrow 'A1 and shown in Fig. 2. The gas circulation- (A) driven by the buoyant forces keeps the metallic inter-stage members (2) and the element (1) at a uniform temperature and overcome the thermal runaway problems. The stacks are arranged in a hair pin like fashion and connected by means of a connector (6) to reduce the inductance of the device as shown in Fig. 3. This reduces the inductance and improves the response of the surge arrester.The hair pin arrangement also increases the capacitance coupling between the stacks and helps improving the response characteristics of the device. This arrangement also results in uniform voltage distribution on elements. To improve the surge current carrying capabilities of the arrester, multi hair pin arrangement as shown in Fig. 4 is provided. The surge current path is indicated by (I).The voltage distribution across the element is further refined with the help of a high voltage shield (7) and shown in Fig. 5, which features a special window (8) towards the enclosure to compensate the leakage currents due to stray capacitances and provides capacitive coupling to all blocks of surge arrester and refines the voltage distribution further. The hair pin assembly is housed in an oval shaped enclosure (9) as shown in Fig. 6 with clearances as per the voltage class. The present invention with the above features incorporated to a gas insulated surge arrester characterises a fast response surge arrester and helps truncating the surges (switching, lightning and temporary) at an early event and safe-guarding the connected equipment effectively. The invention described hereinabve is in relation to a non-limiting embodiment and as defined by the accompanying claims. WE CLAIM 1 An improved gas filled surge arrester with fast response time used in power systems in general and particularly with gas insulated substations and lines characterized in that plurality of arrester elements (1) are stacked in series and connected by metallic elements preferably made of Aluminum (2), said assembly placed in an insulating tube (3). 1. A gas filled surge arrester as claimed in claim 1 wherein the said insulating tube has high mechanical and dielectric strength. 2. A gas filled surge arrester as claimed in claim 2 wherein said insulating tube is terminated in metallic flanges (4) with openings (5, 6) for gas circulation (A). 3. A gas filled surge arrester as claimed in claim 1 wherein said arrester elements are made of silicon carbide (Sic) and/or metal oxide and/or Zinc oxide. 4. A gas filled surge arrester as claimed in claim 1 wherein the stacks are arranged in a multi hair pin like fashion and is connected by means of a connector (6). 6. A gas filled surge arrester as claimed in claim 1 wherein the arrester elements are provided with a high voltage shield (7) with special window (8) towards the enclosure (9). 7. A gas filled surge arrester as claimed in claims 1, 5 to 7 wherein the hair pin assembly is housed in an oval shaped enclosure (9). 8. A gas filled surge arrester with fast response time as herein described and illustrated with reference to the accompanying drawings. |
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171-del-2000-correspondence-others.pdf
171-del-2000-correspondence-po.pdf
171-del-2000-description (complete).pdf
| Patent Number | 215560 | |||||||||
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| Indian Patent Application Number | 171/DEL/2000 | |||||||||
| PG Journal Number | 11/2008 | |||||||||
| Publication Date | 14-Mar-2008 | |||||||||
| Grant Date | 27-Feb-2008 | |||||||||
| Date of Filing | 25-Feb-2000 | |||||||||
| Name of Patentee | BHARAT HEAVY ELECTRICALS LTD., | |||||||||
| Applicant Address | BHEL HOUSE, SIRI FORT, NEW DELHI-110 049, INDIA. | |||||||||
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| PCT International Classification Number | NA | |||||||||
| PCT International Application Number | N/A | |||||||||
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