Electric energy quality improvement method of low voltage distribution network distributed energy storage system

Abstract

The embodiment of the invention is to provide an electric energy quality improvement method of a low voltage distribution network distributed energy storage system. A distribution network equivalent model and a locating and sizing optimization model of the distributed energy storage system are established, and a multi-target weight coefficient is determined through an analytic hierarchy process so as to convert the multi-target optimization problem into the single target problem. The optimal access position and the optimal power capacity of the energy storage device in the system are calculated, and finally the optimal operation strategy of the distributed energy storage system is accordingly solved by combining the operation strategy planning model of the distributed energy storage system so that the electric energy quality of the low voltage distribution network can be improved, the economic performance of energy storage investment can also be considered, the risk of investment can be reduced and the utilization rate of equipment can be enhanced. According to the distributed energy storage system planning method, the defects of the existing method are compensated so that the electric energy quality of the low voltage distribution network can be effectively improved.

Description

technical field [0001] The invention relates to the field of low-voltage distribution network energy storage system planning, in particular to a method for improving power quality of a low-voltage distribution network distributed energy storage system. Background technique [0002] With the rapid development of my country's economy, users have higher and higher requirements for power quality, and the equipment level of the existing low-voltage distribution network can no longer meet the user's demand for high-quality power. A large number of studies have shown that almost all power quality problems originate from the distribution network system, among which problems such as low voltage at the end of the distribution network, voltage fluctuations, unbalanced loads, and power supply interruptions often occur. The large load peak-to-valley difference leads to low asset utilization of traditional new or renovated lines, while the energy storage system (ESS) has the advantages of...

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Lee S J, KimJH, Kim C H et al. proposed a method for distributed The coordinated control algorithm of the energy storage system is used to reduce the voltage and frequency deviation of the distribution network. Through the verification of the actual power distribution system, compared with the traditional non-coordinated control scheme, this method can reduce the voltage and frequency deviation and improve the power quality; "Research on improving power quality of wind power system based on flywheel energy storage system" published by Li Junhui, Bi Jianglin, Yan Gangui, etc. in Electricity Distribution, 2016CICED 2016.2016China Internationalconference on IEEE (2016: 1-6) and Sutanto D in Research and Development , 2002.SCORED 2002.Student Conference on IEEE (2002:8-11) published "Energy storage system to improve power quality and system reliability", through the improvement of the charging and discharging control strategy of the energy storage system, it alleviates the impact of the random characteristics of renewable energy on electric energy. However, it is difficult to make a comprehensive evaluation of the planning and application of the energy storage system without considering factors such as the access location of the energy storage system and the operating economy; Yang Yuqing, Niu Liyong, Tian Liting, etc. in "Grid Technology" (2015 , 39(4): 1019-1025) published "Regional Distribution Network Energy Storage Configuration Considering Load Optimal Control" takes the minimum standard deviation of load fluctuation and smooth load as the optimization goal of energy storage system planning, and obtains different load control The optimal capacity and power configuration of ESS under ESS, but the article does not involve the location planning of the energy storage system; Zulpo R S, Chouhy Leborgne R, Suman Bretas A in IEEE, International Conference on Harmonics and Quality of Power.IEEE (2014: 871-875) published "Optimal sitting and sizing of distributed generation through powerlosses and voltage deviation" established a non-linear programming model for energy storage system location and capacity to improve voltage fluctuation and active power loss, taking into account the complete equation and inequality constraints Among them, the KNITRO optimization toolbox is used to solve the problem, but the economy is not taken into account, and the influence of the weight of each part in the objective function is ignored; Wu Xiaogang, Liu Zongqi, Tian Liting, etc. in "Power Grid Technology" (2014, 38 (12): 3405-3411) published "Site Selection and Capacity of Distribution Network Energy Storage Based on Improved Multi-objective Particle Swarm Optimization Algorithm" using improved particle swarm optimization algorithm to solve multi-objective location and determination considering node voltage fluctuation, load fluctuation and energy storage system capacity The capacity model overcomes the shortcomings of the conventional particle swarm algorithm in the lack of guidance on the value of the inertia weight, but considers less cost factors and cannot accurately reflect the economics of the energy storage system

Cau T D H, Kaye R published in IEEE PowerEngineering Society International Conference on Power Industry Computer Applications, 2001.Pica 2001.Innovative Computing for Power-Electric EnergyMeets the Market (2001: 402-407) "Multiple distributed energy storage ragstraging scheduling promotion using T D H, Kaye R J published "Evolutionary optimization method formulstorage hydrothermal scheduling" on IET Proceedings-Generation Transmission and Distribution, respectively using simulated annealing algorithm and genetic algorithm to solve the operation strategy problem of the energy storage system, which ensures the economical operation of the system and is short-term Voltage interruption provides voltage support, but the intelligent algorithm has the disadvantage of being premature, which leads to falling into the local optimal solution and cannot guarantee to converge to the global optimal solution

The above literature has studied the theoretical planning model and solution algorithm of energy storage system to improve power quality from different energy storage planning fields, but the application of energy storage system to improve power quality in rural low-voltage distribution network is rare.

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