A high precision calibrator for metal oxide surge arrester on-line monitor

A high-precision calibrator for metal-oxide surge arrester on-line monitor based on DSP and CPLD was developed to verify the accuracy of on-line monitor. This calibrator can generate standard voltage and current to simulate the actual leakage current of metal-oxide surge arrester. The high spatial resolution digital phase-shifting technology and feedback control technology are utilized in design of the calibrator to achieve high precision. The calibrator was tested by mid-south national center of metrology, and the result shows that it can meet the requirements for verifying metal-oxide surge arrester on-line monitor with 0.1% output amplitude error of voltage and current signals and 0.04degphase error between voltage and current signals.