The Analysis Of Optimal PMU Placement In Wams

With the gradual expansion of the national electrical network structure in recent years,interconnected power grid is an inevitable trend.It is a necessary process that a large number of power transmission and transformation system is put into practical power grid every year,which makes the characteristics of the power grid and the electrical connection between the major power grids become more and more complex.In this case,the wide area measurement system(WAMS)of power grid has attracted the attention of the academic circles because of its advantages such as uniform time scale and high precision.Synchronous phasor measurement unit(PMU)is the most basic unit of data measurement in WAMS.However,due to the economic and technical reasons,it is not necessary to install PMU on all the nodes in the grid,so in this context,the optimal PMU placement problem(OPP)is proposed.This paper discusses the problem from the following aspects:1.Research background and significanceThis paper first describes the background,structure,characteristics and functions of WAMS.And according to the current research hot spot,according to the actual situation,the OPP problem is introduced,and the four main directions of OPP research are introduced.And the research direction of this paper is put forward,which is based on the mixed measurement model for multi-objective OPP strategy.2.Measurement principle and structure of PMUIn this paper,the basic composition and measurement principle of PMU equipment are discussed,the reason why PMU is better than traditional measurement equipment in measurement is understood,the principle of measuring the phase angle and the power angle is given by means of mathematical method,and the function and significance of the PMU equipment for WAMS are discussed.3.OPP model based on whole network observabilityTo meet the full network observability of the WAMS in this paper,the power system is studied from two aspects,algebra and topology,for a description of the goal of the power grid to establish the corresponding mathematical model.Simutaneously,according to the actual situation of the grid,some other factors are considered to enrich the basic model.Finally,the model is solved and the corresponding configuration strategy is obtained.4.OPP model for improving the accuracy of state estimationIn this paper,in order to meet a specific target in WAMS model,we can establish the corresponding model by OPP,so that the higher corresponding performance can be got with the same number of PMU in this configuration.In order to improve the accuracy of state estimation,a mixed integer semidefinite programming(MISDP)is used to model the OPP problem in this paper,and the corres-ponding placement strategy can be obtained.5.Multi-objective OPP strategyThe power system application function of the optimal configuration requirements and constraints are not consistent,each application function of the points are different,so the OPP problem is put forward the concept of multi-objective optimization configuration.Considering the full network observability,zero injection node and improve the precision of state estimation of multiple target proposed multi-objective optimization strategy in this article.Then,the establishment of a joint optimization model and the optimal allocation strategy to meet the conditions of PMU are obtained.