New algorithm for protection of capacitor banks exposed to harmonic overvoltages

Conventional relays based on voltage peak detection exhibit serious shortcomings with respect to capacitor banks overvoltage protection. A harmonic simulation case study is presented, the purpose of which is to evaluate the performance of capacitor overvoltage relays in a static VAr compensator (SVC) installation. The concept of a computer-based digital relay, designed to reduce the overprotection trend found in conventional relays, is introduced. The major concern is to properly evaluate the time stresses applied on the capacitor according to the NEMA (ANSI/IEEE) standard.<
>