Development of Synchronized Waveform Measurement and Its Application on Fault Detection

Due to the massive installation of distributed renewables in distribution networks, the power signal may be changed extremely fast when a disturbance occurs, which leads to severe waveform distortion. The traditional phasor measurements are unable to capture and characterize this kind of short-timescale dynamic process. Therefore, an adaptive synchronized waveform measurement method and a waveform-based fault detection method are proposed in this article. For the synchronized waveform measurement, an adaptive sampling method based on the effective component identification is first proposed to perform high-precision measurement with different sample rates in different scenarios. A waveform data compression algorithm based on wavelet transform and Deflate algorithm is then proposed to reduce the data redundancy, and a transmission protocol suitable for compressed data transmission is designed. A synchronized measurement device for waveform (SMD-W) is developed and evaluated. This article also proposes a fault detection method for distribution network, which considers high impedance fault (HIF). The field data show that the amplitude error of the proposed synchronized measurement method is less than 0.2%, and the communication delay is saved by 50% compared with the COMTRADE format. And the proposed fault detection method has higher detection accuracy compared with other existing methods.