Research On Optimal Placement Method Of Voltage Sag And Harmonic Resonance Monitoring Sites

Voltage sag and parallel harmonic resonance are two extremely serious power quality problems,and power quality monitoring is an important part and prerequisite for their analysis and control.However,due to the large number of nodes in the power system,it will cost a lot to install power quality monitoring devices in all nodes,so it is of great significance to optimize the placement of monitoring sites.In this paper,firstly,the optimal placement methods of voltage sag and harmonic resonance monitoring sites are studied respectively,based on which the unified optimal placement method of voltage sag and harmonic resonance monitoring sites is studied.In the aspect of optimal placement of voltage sag monitoring sites,this study presents an approach to the optimal voltage sag monitor placement considering the uncertainties of transition resistance.Firstly,the influence of transition resistance on the magnitude of voltage sags is analyzed.Then,based on the established transition resistance interval set array for voltage sags and the random vector model on voltage sag observability,the optimal voltage sag monitor placement method is established,and the related particle position updating rules of discrete particle swarm optimization algorithm are improved to solve the optimal placement programme.Finally,the proposed method is carried out on IEEE30 bus test system.Simulation results show that the proposed method can effectively detect the voltage sags caused by faults of random type originating from random position under the condition of any given number of monitors,compared with the traditional method.In the aspect of optimal placement of harmonic resonance monitoring sites,an optimal placement method of harmonic resonance monitoring sites considering the uncertainties of system parameters is proposed in this paper.Firstly,the probabilistic model of different kind of system parameter is constructed,and the probabilistic resonance monitoring matrix is constructed based on Resonance Modal Analysis Approach and Monte Carlo Technique so as to describe the potential harmonic resonance observability of each bus.Then,the resonance observability index is defined and quantified,and the optimal placement method of harmonic resonance monitoring sites is proposed.Finally,the proposed method is applied to the IEEE30 bus test system.The simulation results show that the proposed method can more effectively monitor the actual potential harmonic resonances of the power system under the condition of any given number of monitoring devices,compared with the existing method.In the aspect of unified optimal placement of voltage sag and harmonic resonance monitoring sites,the voltage sag and harmonic resonance observability as well as the economy of investment cost are comprehensively considered in this paper,and the evaluation index set of placement programme comprehensive performance is established,based on which the quantitative analysis method of the comprehensive performance is proposed applying the Analytic Hierarchy Process Method and Fuzzy Comprehensive Evaluation Method.Then,with the goal of the highest comprehensive score of the placement programme and the constraint that the number of monitoring devices required does not exceed the limit value,a unified optimal placement method of voltage sag and harmonic resonance monitoring sites is proposed.Finally,the unified optimal monitor placement is carried out for the IEEE30 bus test system,and the simulation results verify the feasibility of the proposed method.