NEW ALGORITHM FOR PROTECTION OF CAPACITOR BANKS EXPOSED TO HARMONIC OVERVOLTAGES

Conventional relays based on voltage peak detection exhibit serious sh ortcomings with respect to capacitor banks overvoltage protection. Thi s paper presents a harmonic simulation case study, the purpose of whic h is to evaluate the performance of capacitor overvoltage relays in st atic var compensator (SVC) installation. The paper introduces the new concept of a computer based digital relay, designed to reduce the over protection trend found in conventional relays. The major concern is to properly evaluate the time stresses applied on the capacitor accordin g to the NEMA (ANSI/IEEE) standard.