Event Location Identification in Distribution Networks Using Waveform Measurement Units

A new method is proposed to identify the location of events in distribution networks using data from waveform measurement units (WMUs). When an event occurs, WMUs provide GPS-synchronized measurements of voltage and current waveforms in time-domain that are captured during the event. Given such data, the proposed method identifies the bus number where the event occurred. Here, an event is defined rather broadly as any major change in the voltage or current waveforms. An event may have various causes, such as capacitor bank switching, load switching, a minor fault, etc. The first step in the proposed method is to characterize the oscillatory modes of the captured waveform; namely their frequency, damping rate, magnitude, and angle. The next step is to model the underlying circuit at the dominant mode of the event. The final step is to locate the cause of the event based on certain forward and backward calculations on the obtained circuit model. As few as only two WMUs, one at the beginning of the feeder and one at the end of the feeder, are sufficient to identify the location of the event. The performance of the developed method is verified on the IEEE 33-bus test system. The results verify the accuracy and robustness of the proposed method in identifying the location of events in distribution networks.