Parameter Estimation For Distribution Grids Based On The Measurement Data Sequential Collection

In the related analysis and calculation of distribution grids, the model and parameter ofthe components in power grid was based on data which obtained nameplate calculation. Butthe actual operation parameters of the equipment would be changed by the influence ofenvironmental factors and result in the actual parameters of components deviated from itsrated value. In such circumstances, if still use the rated value to calculating, it will make thedeviation that between theoretical value and actual value bigger. In addition, the change of theparameters reflecting actually is equipment deficiencies. If the equipment exist defects, itwould lead to the equipment run in abnormal state for a long time, and cause the hiddentrouble. Equipment parameters estimation for distribution network can solve these problemswell.Firstly, this paper discusses the principle and algorithm of hierarchical model fordistribution, describe the mathematical model of electric components in distribution grids. Onthis basis, research the method of parameters estimation based on sequential data collection. Inthe parameter estimation, firstly, this paper build the measurement nonlinear equation based onthe relationship between start node and end node of a branch in single time section. Secondly,according to the sequential sampling principle, use the time for space to sample the measuringdata in different time sections, form the system of measurement equation, meet theobservability of parameter estimation. At last, use the Levenberg-Marquarate algorithm tosolve the measurement equation group and realize the parameters recursive estimating ofdistribution grids based on hierarchical model. With the above algorithm as the core, compilethe general program of parameter estimating.In addition, in order to analyse and test the accuracy of parameter estimation methodbased on sequential collection, this paper research the method of three-phase power flow ofdistribution grids and compile the program of three-phase power flow. Then discuss the method of forming test scene. Points out that, the forming test scene need to follow two basicprinciples. Based on this, provide the scenario of forming test scene. At last, use an example totest the accuracy of parameter estimation in different scenes and the results show that theparameter estimation method researched by this paper is feasible and effective.