Lightning Arresters. Construction and Condition Monitoring . LA Characteristics. Arrester Fundamentals. Need for High Resistance to limit Discharge Current Need Low Resistance during flow of lightning current to limit Surge Voltage . A non-linear resistance material required.
Construction and Condition Monitoring
A non-linear resistance material required
Concept of Leakage Current
temperature and voltage
During single phase to ground fault, voltage on healthy phase may go upto 1.4 to 1.5 times
230 x 1.4/1.5= 323 – 346
Temporary O/V= 1.5 pu = 336kV
LAs are available at 336kV, 360kV, 372kV and 390kV
Higher ratings are selected taking into consideration of ageing of LA elements
Meter Terminal Fixing:
Meter Enclosure :
1.TOTAL LEAKAGE CURRENT MEASUREMENT
2.WATT LOSS MEASUREMENT
3.INSULATION RESISTANCE MEASUREMENT
4.THIRD HARMONIC RESISTIVE CURRENT MONITORING.
5.THIRD HARMONIC RESISTIVE CURRENT (THRC) MONITORING WITH COMPENSATION FOR THIRD HARMONICS IN SYSTEM VOLTAGE.
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