The evolution of power quality data acquisition systems-triggering to capture power quality events

25 years ago, capturing multiple channels of simultaneous data required multiple oscilloscopes or a very specialized, expensive, and customized data acquisition system. In order to capture power quality events, very sophisticated methods were used to invoke simultaneous triggering across all recording channels. Normally, triggering was accomplished using overvoltage or overcurrent conditions and typically, you only had one shot. In addition, there was no easy way to get an oscilloscope to trigger on an undervoltage event (like a sag, for example). Today, all of that has changed. We are now able to record multiple channels of simultaneous data using many types of triggering mechanisms. This paper discusses the evolution of triggering power quality instrumentation and the advanced triggering systems available for portable and fixed panel mounted meters.