Patent ID: 8289668
Filing Date: 2012-10-16
Classification: H02H

Abstract:
1. A method for current differential protection using charging current compensation for a power apparatus, wherein individual terminals dynamically determine their respective contributions, if any, to the charging current compensation as availability of one or more voltage sources dynamically changes within the power apparatus, the method comprising: calculating, at respective terminals of the power apparatus, local contributions to a charging current compensation value, each local contribution based on a local voltage measurement, a line capacitance value, and a multiplier corresponding to a total number of terminals contributing to the charging current compensation value; determining a change in the number of terminals contributing to the charging current compensation value as availability of one or more voltage sources dynamically changes within the power apparatus; in response to the change in the number of terminals contributing to the charging current compensation value, automatically adjusting the multiplier so that a sum of the local contributions represents a total charging current; and selectively tripping the power apparatus based on line current differential protection and the charging current compensation value.