Computer Aided Calibration of Voltage and Current Surge Generator in Accordance with IEC 61000-4-5:2014

Reliable electrical and electronic equipment are designed to immense against different kinds of electromagnetic interference such as voltage dip, burst, electrostatic discharge, and surge. Surge is a 'slow transient overvoltage' with frequency contents below 10 MHz which may cause electrical and thermal damages to the equipment. Surges are created by switching events and insulation faults in AC power distribution networks, lightning and others. A combination wave generator which simulates the switching and lightning transients is used to evaluate the immunity performance of equipment under test against high energy surge interference. The Standards and Calibration Laboratory (SCL) has recently set up a system to calibrate 1.2/50 μs - 8/20 μs or 10/700 μs - 5/320 μs combination wave generators by laboratory digital oscilloscope in accordance with the latest international standard IEC 61000-4-5:2014. The new revision has made many significant changes including redefinition of the surge waveforms and the evaluation of measurement uncertainty. The calibration parameters include the front time, duration and voltage surge peak. The principle of the calibration is to convert the high voltage or high current surge pulse waveform to lower signal waveform by calibrated potential divider or burden respectively. System response time including the oscilloscope, divider and the burden must be considered to characterize the surge waveform accurately. The required voltage and timing measurement is taken by computer automatically to reduce human error and to enhance consistency. The best measurement uncertainties of the front time, duration and surge peak are 5%, 2% and 3% respectively with test output voltage of 0.5 to 4 kV.