MODELING MOV-PROTECTED SERIES CAPACITORS FOR SHORT-CIRCUIT STUDIES

This paper proposes a procedure to adequately model series capacitors protected by metal oxide varistor (MOV) in a conventional short-circuit program. The procedure uses a quasi-linear model to represent the non-linear characteristic of the MOVs combined with a compensation technique to represent the intersequence coupling during unbalanced faults. The effectiveness of the proposed method, which is valid for unbalanced faults as well as balanced faults, is demonstrated by comparing the results obtained with this technique against those obtained using time-domain simulations (EMTP). The results show that the proposed procedure can adequately and efficiently model MOV-protected series capacitors in a standard short-circuit program, thus improving on a flexible and familiar engineering tool.