A Signature-Based Approach to Pinpoint Causes for Poor Performance of Real Time Distribution Power Flow

In modern distribution systems, accurate real-time monitoring is critical for reliable operation and control. A common method used in practice is a power flow-based state estimation called near real-time power flow (RTPF). Limited real-time data makes it challenging to determine the cause when the RTPF provides poor results on a consistent basis with a large mismatch between measured and estimated node voltages. This paper focuses on this issue of poor RTPF performance and proposes a signature-based analysis method to identify the cause for the poor performance. The proposed method first identifies possible causes for the poor performance then utilizes residual spread analysis to identify signatures in the residual between measurements and the respective estimated values. Given a certain signature, a specific cause for the large mismatch in voltages is suspected and can be verified by simulating a corrected model. A sample study using a set of cases from a real system is given to illustrate the effectiveness of the proposed method.