Optimal Placement Of Micro-PMU In Distribution System

With the increasing penetration of distributed generation(DG)in distribution system,the measurement and monitoring function of distribution system has higher requirements.Micro-PMU(?PMU)is a new type of PMU measuring device with higher precision,stronger function and more suitable for distribution network.The use of ?PMU can effectively improve the measurement and monitoring capacity of distribution system and ensure the safe and stable operation of the distribution system.Starting from the key technologies and theories such as the structure and function of the device,the theory of information entropy,the dual-use line relay device(DULR)with measuring and relay protection function and the loss coefficient of network outage after considering the line fault,the optimal placement of ?PMU in distribution system is studied in this paper.The main research contents of this paper are as follows:(1)Study on the characteristics of ?PMU placement in complex configuration of distribution networkThis paper studies on the characteristics of ?PMU placement in complex configuration of distribution network.First of all,the basic structure,characteristic,function of ?PMU device and basic principle of synchronous phasor measurement method are introduced.Then the concept and the discriminant method of network completely observable are introduced in detail.In the next part,the characteristics of ?PMU placement under different network structures and measurement environments in distribution network are analyzed.(2)Study on optimal ?PMU placement considering the uncertainty of distribution networkThis paper proposes a new method to determine the set of candidate ?PMU locations based on information entropy evaluation strategy considering the uncertainty of distribution network.Firstly,Shannon's information entropy theory and formula are introduced.Secondly,after the comprehensive consideration of dynamic characteristics of uncertain nodes such as DG and the measurement error of measurement data,the probabilistic state estimation of distribution system is calculated by two-point estimation method,and the uncertainty of network can be evaluated by information entropy.Finally,the greedy algorithm is combined to select the ?PMU placement based on the information entropy evaluation,the effectiveness of the method is demonstrated by case studies.(3)Study on joint optimal placement of ?PMU and DULR considering the load loss of line outageThis paper proposes a new method of joint optimal placement of ?PMU and DULR considering the load loss of line outage.Firstly,the DULR device with both measuring function and relay protection function is introduced.Secondly,the joint optimal model of ?PMU and DULR is established to consider the load loss of line outage based on the relay protection function of DULR.This model can not only guarantee the observability of distribution network,but also ensure to satisfy the maximum load loss coefficient limit and guarantee the operation of distribution system after the single branch outage.Finally,the genetic algorithm is proposed to solve this model and the results of test cases show the effectiveness of the method.