Synchronous Waveform Measurements to Locate Transient Events and Incipient Faults in Power Distribution Networks

Abstract

A new method is proposed to identify the location of transient events, including incipient faults, in power distribution systems, by using synchronized measurements from an emerging class of sensors, called waveform measurement units (WMUs). WMUs capture the voltage and current waveforms in time domain. The proposed method consists of three steps. The first step is to characterize the oscillatory modes of the transient components of all the captured synchronized voltage and current waveforms from all WMUs, by conducting a multi-signal modal analysis. The second step is to construct a circuit model for the underlying distribution feeder at the identified dominant mode(s) of the transient event. The final step is to identify the location of the transient event with the means of a method that involves certain forward and backward analyses of the constructed circuit model. The proposed method requires installing as few as only two WMUs. It can also utilize several synchronized waveform measurements when several WMUs are available. The performance of the proposed method is assessed on the IEEE 33-bus test system; for different cases of transient events, such as sub-cycle incipient faults, multi-cycle incipient faults, permanent faults, as well as benign yet informative events such as capacitor bank switching. Both the accuracy and the robustness of the proposed method are verified. The analysis and results in this paper provide new insights on possible applications of synchronized WMU measurements; while they also address a highly challenging problem in power distribution networks.

A Synchronized Lissajous-Based Method to Detect and Classify Events in Synchro-Waveform Measurements in Power Distribution Networks

“…The basic ideas and comparison with supervisory control and data acquisition (SCADA) measurements and PMU measurements are discussed in [1]. Methods based on modal analysis at damping frequencies are presented in [2], [3] to identify the location of power quality events and incipient faults using synchrowaveform measurements. A analysis based on eliminating the fundamental frequency component is done in [15] to identify sub-synchronous resonance.…”

“…The very high reporting rate of WMUs, such as 256 samples per cycle, and the fact we have access to synchronized waveform measurements, can significantly enhance situational awareness and operational intelligence in power distribution networks [8], [9]. So far, WMUs have been used in only a few number of applications, such as to study harmonics in transformers [1] or to identify the source location of power quality events [2] and incipient faults [3].…”

“…It is worth clarifying that the term WMU is relatively new. While phasor measurement units (PMUs) are used to measure synchro-phasors [10], WMUs are used to measure synchrowaveforms [3], [11], [12]. The term WMU is gradually starting to appear in the academic literature, e.g., see [2], [7], and also in the industry reports, e.g., see [13], [14].…”

“…Given the much higher reporting rate of WMUs than PMUs, and also because WMUs have much less internal filtering than PMUs, WMUs are capable of capturing several details about the voltage waveforms and current waveforms that are inherently impossible for PMUs to capture. Illustrative examples on the details that can be captured by WMUs but cannot be captured by PMUs are available in Section I-A in [3].…”

Impact Analysis and Mitigation of Losing Time Synchronization at Micro-PMUs in Event Location Identification

“…Our focus in this paper is on the application of micro-PMUs in event location identification. Different methods are used in the literature for event or fault location, including impedancebased methods [2], [5], [6], traveling wave [7], and methods based on machine learning [8]. Of particular interest is the work in [2], which uses synchrophasors from two or more micro-PMUs on a power distribution feeder.…”