Realization of the Reference Composite Voltage Waveforms for Lightning Impulse (LI) Voltages Superimposed Over DC and AC Signals

Composite voltage test according to IEC 60060-1:2010 is a test method where impulse high voltage is applied simultaneously with alternative voltage (AC) or direct voltage (DC) to the same terminal of the test object. The equipment used in the DC and AC high-voltage grids has some special test procedures to be fulfilled under not only DC, AC, and lightning impulse (LI) but also the composite voltages having impulse high voltages superimposed over HVDC and HVAC. In addition, the IEC 61083–1 standard allows low-voltage measuring instruments to be qualified by comparison to approved reference calibrators traceable to the international system of units. The measuring instruments used in this test usually calibrated by the reference systems separately for DC, AC and LI. But there is a metrological gap related to the calibration of these measuring equipment with reference composite signals. In this work, to provide traceability about the composite high-voltage measuring system, reference composite voltage waveforms for LI voltages superimposed over DC and AC signals have been designed up to 300 V for impulse voltage and 1000 V for AC and DC voltage using with passive protection components. On the AC and DC voltage source side of the setup, the reference voltage calibrator with the 10 µV/V uncertainty has been used and a reference calculable impulse voltage calibrator has been used as an impulse voltage source with the 1 mV/V peak voltage uncertainty and 10 ms/s time parameters uncertainty. The simulation results of calibrator design and comparison measurements of the real circuits were presented for LI superimposed on DC and AC.