Time error correction in East China Grid

The deregulation of power industry led to some new features of power quality.Power grid time is one of the symbols of power quality.Power grid frequency is normally scheduled at 50.00 Hz and controlled to that value.The automatic generation control is imperfect and over time,the average frequency will be slightly above or below 50.00Hz resulting in mechanical electric clocks developing an error compared with true time.This paper specifies the procedure to be used for reducing the power grid time error to within acceptable limits of true time.The purpose of this correction is to ensure that time error corrections are conducted in a manner that does not adversely affect the reliability of the interconnection.By means of the analysis of the frequency of East China Grid,the results indicate that is necessary to draw a standard of time error corrections in East China Grid in the future.Finally,some suggestions are put forward.