surge arrester

surge arrester

1. Presented By:- Shubham Kumar Electrical Department

2. Surge Arresters

3. CONTENT Introduction Types of surge arrester Lightning Surge arresters in transformer How do surge arrester protect transformer What exactly does a surge arrester do? Advantage of surge arrester D isadvantage of surge arrester

4. INTRODUCTION SURGE ARRESTER : A device used on power system in high voltage line, to protect electrical equipments from lightning and switching surge . It is also called SPD or TVSS. It is a surge diverter . the surge arrester should have a low impulse ratio.

5. Types of arresters Rod arrester. Horn gap arrester. Multigap arrester. Expulsion type arrester. M etal oxide arrester.

6. ROD ARRESTER Simple type of arrester. Consists of two 1.5 cm length rod bend at right angle. One rod connected to line circuit and other connected to the earth.

7. Horn gap arrester Consists of horn shape two metal rod ,separated by small air gap. Distance gradually increases towards the top. One rod connected to line through resistance and choke coil and other to ground.

8. Multigap arrester Consists of series of metallic cylinder. Insulated from each other and seperated by a small intervals of air gap. First cylinder is connected to lines and other is to ground through series resister. System voltage doesn't exceed 33kV.

9. Expulsion type arrester Consists of air gape series with 2 nd air gap enclosed within fire tube. The gap is formed with the help of two electrodes. Upper electrode is connected to rod gap and lower electrode to earth.

10. Metal oxide arrester Mostly used arrester in present time. Without gaps. Gapless design eliminate the high heat association with the arcing discharge. Utilizing ZnO blocks to provides the best performance.

11. Lightning When lightning strike transmission line then a very high voltage is generated within it .

12. How do surge arresters protect transformer or power system 11000 Volts 230 Volts

13. Typically 11000 Volts 230 Volts

14. Typically 11000 Volts 230 Volts Surge arrester

15. Typically 11000 Volts 230 Volts Surge arrester

16. What exactly does a surge arrester do? It does not absorb the lightning. It does not stop the lightning. It divert the lightning to ground. It limit the voltage produced by lightning. It only protects equipment electrically in parallel with it.

17. At the Heart of all Arresters is the Metal Oxide Varistor (MOV) MOV disk is semiconductor disk which is very sensitive to voltage. At normal voltage the MOV Disk is an insulator and will not conduct current. But at higher voltage caused by lightning it becomes a conductor.

18. The Metal Oxide Varistor (MOV) is a very fast acting electronic switch. It is an open switch to standard system AC voltage and a closed switch to Lightning voltages .

19. Advantage of surge arrester in transformer The surge arrester protects the transformer and other electrical equipment from lighting and switching surge ..

20. Disadvantage of surge arrester Conducting surge arrester blow fuses. Surge arrester has no live line capabilities. The earth connection should be checked periodically.