Patent ID: 8773828
Filing Date: 2014-07-08
Classification: H02H

Abstract:
1. A busbar differential protection method, comprises the steps of: (1). sampling the voltage of a busbar continuously and respectively sampling the currents of all intervals on the busbar synchronously at the meantime; (2). respectively fitting the sample values of the busbar voltage and current sample values of the respective intervals to get a fitting curve for the voltage of the busbar and fitting curves for the currents of the respective intervals; (3). determining a zero-crossing point on the fitting curve for the voltage of the busbar; as to the fitting curve for the current of each interval, sampling each fitting curve for the current in turn from the above zero-crossing point according to a given sample time period, to get a sample sequence of each interval, said sample sequence comprising current sample values of sampling points and sample serial numbers corresponding to the sampling points; the sample serial numbers of sampling points at the same time being the same for the sample sequences of the respective intervals; (4). storing the sample sequences of the respective intervals, differentially computing the current values with same sample serial numbers for the sample sequence of respective interval, and conducting a differential protection according to the computation results, characterized in that in said step (1), said busbars are a same busbar, and said voltage of the busbars is the busbar voltage sampled by a potential transformer (PT) cabinet on that busbar.