Research and Application of Transient Step Current Source for DC Current Transformer On-Site Transient Performance Calibration

The development of high-voltage direct current(HVDC) transmission system to determine the transient performance calibration of DC current transformer is described. A set of transient step current source based on signal resampling and pre-distorting adjustment is devised to carry out the on-site transient performance test. By the root mean square error(RMSE) revision, the source produces the step current up to 300A with 500kHz sampling speed to restore the initial transient waveform. With the transient step current source, the transient performance of DC transformers for the pole and converter valve current measuring in Sunan 500kV UPFC Project was tested, and the rising time, maximum overshoot and transient delay of the transformers were measured and analyzed. The transient step current source provides great feasibility and good application prospect for the DC current transformer on-site transient performance calibration.