Research On Harmonic State Estimation Based On Widearea Measurement System

Electric power as a special commodity, its quality problems is concerned by the powercompany and the users. Several factors that affect the power quality, harmonics problemsparticularly draw attention. In order to improve power quality, governance harmonic is verynecessary. To governance harmonic, we must locate the harmonic source and make sure theharmonic nature. Power system harmonic state estimation technique; use limited measurementdata, and select appropriate estimator to estimate the whole power grid harmonic state, and toidentify the location and nature of the harmonic source, providing a reference for harmonicmonitoring, suppression and treatment.Wide area measurement system based on the synchronized measurement technology, thatmake harmonic state estimation possible practical. Because of measurement value of widearea measurement system is different from that of the traditional state estimation, harmonicstate estimation mathematical model, solving method and observability methods are new. Thisarticle describes the synchronized phasor measurement technology, wide area measurementsystem, the mathematical model of the harmonic state estimation, solving method andobservability analysis method.In the three phases AC balance power system, different order harmonic voltage, current,respectively, were positive, negative and zero sequence characteristics. Single order harmonicvoltage and current circulation in the network, respectively, produced only the correspondingsequence of current and voltage drop. Considering different orders of harmonics presentdifferent phase sequence characteristics, established power component sequence parametermodel, considering the characteristics of the harmonic phase sequence network mathematicalmodel was established. Base on these, proposed considering the characteristics of theharmonic phase sequence harmonic state estimation algorithm. Take IEEE13and IEEE14 examples for the simulation analysis, the overall comparative analysis and detailedcomparative analysis of two aspects of the proposed algorithm estimates characteristics withand unconsidered harmonic phase sequence characteristics estimation results are comparedand analyzed. Validate considered harmonic phase sequence characteristics algorithm.For the harmonic measurement devices are expensive, in the short term, impossible toachieve large redundancy can not even achieve complete observable. This paper use SCADAsystem active power measurement and voltage amplitude measurement current amplitudemeasurements with PMU measurement data mixed measurement datas as the measurementdata of harmonic state algorithm, and taking into account the partial zero injection nodesystem, nonlinear harmonic state estimation algorithm is proposed based on the mixedmeasurement with equation constraint. To IEEE13node example, in five differentconfigurations case studies SCADA measurements on the observability of the system as wellas SCADA measurement accuracy of the harmonic state estimation effects; finally contrastedequality constraints and non equation constrained two algorithms model the estimationaccuracy. Validate constrained nonlinear harmonic mixed with measurement equation toestimate the effectiveness of the algorithm.