Instrument for in-service assessment of surge arrestors

Though there are several studies on the causes of transformer failure and each one gives different weight to the different causes, all agree that one of the causes of failure is overvoltage, whether of atmospheric origin or due to maneuvering. Therefore, it is important that surge arresters are tested periodically.  IEC 61099-5 standard details and compares different methods of verifying surge arresters, being method B2 the simplest and providing the best results for evaluating and comparing status of arresters

Surge arresters degrade over time. The causes of failure are multiple and range from partial discharges, sealing problems, discharges due to surface contamination, aging, overload, among others. Typically, arrester failure can cause a ground fault, less overvoltage limitation, and even explosion of arrester itself.

The LCM500 uses the third harmonic compensated leakage current measurement method, B2 method, measuring the total leakage current and separating the capacitive third harmonic leakage current to display the voltage compensated resistive third harmonic leakage current as in temperature thanks to its built-in instrument thermometer.