METHOD AND ARRANGEMENT FOR DETECTING AN INTERNAL FAILURE IN H-BRIDGE CONNECTED CAPACITOR BANK

摘要

A method for detecting an internal failure in a capacitor bank connected in one phase or more phases respectively to a power system. The capacitor bank includes a plurality of capacitor units. Each of the capacitor units includes a plurality of capacitor elements connected in parallel and/or series. The capacitor units are further divided into two strings and a current transformer is arranged in the midpoints of the two strings so that the capacitor units are further divided into four quadrants and the internal failure(s) may occur in one or more capacitor elements or units and involves one or more capacitor quadrants. The method includes initiating an alarm and/or a trip signal when the determined total number of internal elements failures exceeds a first or a second threshold value.