A Low Group Delay Phasor Estimation Algorithm for Distribution Network

As the most effective technical means to record the dynamic process of power system, synchronous phasor estimation technology can provide reliable data for the protection and control of power system. Therefore, synchronous phasor estimation of power signals is the basis for ensuring safe and reliable operation of power systems. However, with the increasing proportion of distributed renewable energy connected to the distribution network, traditional synchronous phasor estimation methods are no longer applicable to new distribution network systems. Therefore, a low group delay phasor estimation algorithm for distribution networks is proposed, which can provide fast and accurate data for protection control. This paper first analyzes the principle of phasor estimation algorithm based on FIR filter, reveals its group delay characteristics, and compares and selects the filter design methods. Further, the group delay requirements of the power signal synchronous phasor estimation for the filter passband and blockband are analyzed. Based on this, a low-latency synchronous phasor estimation algorithm based on nonlinear phase FIR filter is proposed. Simulation tests show that the proposed algorithm effectively reduces the estimation delay, and the estimation accuracy in the single test specified by PMU is higher than the standard requirement by more than one order of magnitude, which can provide a fast and reliable data base for the protection control of the distribution network.