The Investment Optimization And Integrated Benefit Evaluation For Distribution Power Network Under The Smart Grid Environment

The power industry is an important basic industry in the national economy. As an important means to achieve China’s energy strategy layout, the developmental task of power grid is arduous, and power grid bears an important strategic role of the construction of national energy industry transportation system. Therefore, it has the important strategic significance to build a strong smart grid, especially the smart distribution grid. Various fields of power industry including power generation, transmission, distribution and use will all leap and upgrade through the construction of smart grid, especially the construction of active distribution network, which can further promote the power industry change and progress. The access of distributed generation and micro-grid in the distribution network, can effectively guarantees the grid power supply mode towards an efficient, environmental protection and reliable direction to transform, and the distribution network investment and construction taking into account the distributed generation and micro-grid is an effective means to achieve smart distribution grid. Distributed power generation and micro-grid will gradually expand the access level in the distribution network, and this smart grid technology and new functional model will significantly change the grid structure of distribution network, as well as investment planning of power grid enterprises and project construction management.Distributed power supply has become more and more important in the power system with its many advantages, at the same time also become an important research focus of China’s energy development. However, the large penetration of distributed generation also makes the distribution network face more challenges in the planning operation, meanwhile makes the distribution network urgently need to explore effective decision-making methods,optimization models and management models in the investment and construction. Therefore,based on the perspective of participating parties such as government departments, power grid enterprises and distributed generation investors,this paper builds investment optimization and comprehensive benefit evaluation model of distribution network under the condition of smart grid. The main contents of this paper include the following four aspects:(1) The paper combs the basic theory of distribution network investment planning under the condition of smart grid. Firstly, the paper introduces the basic overview of distribution network and the key technologies of smart grid development, and analyzes the influence of smart grid development on distribution grid. Then, the mathematical programming optimization theory and the modern portfolio theory are introduced. Finally, the paper introduces the technical and economic evaluation program and the construction project evaluation method that are suitable for the evaluation of distribution network investment planning, which lays a theoretical foundation for the later research.(2) The paper constructs the multi-objective optimization model of distribution network investment planning. Firstly, the paper defines DG load flow model and system operation hypothesis, and respectively takes the total grid cost and emission cost as the optimization targets, to establish the mathematical model of distribution network planning. Then, the cloud evolutionary algorithm, particle swarm algorithm, entropy weight method and fuzzy satisfaction theory are introduced to construct a three-stage intelligent algorithm for solving the model. Finally, the paper conducts case analysis on the proposed models and algorithms with the improved 3-feeder test system. The results show that using the model constructed in this paper, the total system cost increases and the emission cost reduces, and the system voltage fluctuation is significantly reduced. This means that the distribution grid has better adaptability to load fluctuation and reduces the system carbon emission.(3) The paper establishes the dynamic decision model for investment planning allocation of distribution network. Firstly, the paper introduces the main contents of the investment decision of distribution network, including the investment decision-making characteristics,ideas and optimization process. Then, the key factors of distribution network investment decision are analyzed, including annual maximum expected income, annual comprehensive cost and annual expected benefit ratio. Finally, making the annual increment of expected benefit as the maximum objective function, the paper builds the objective function of the distribution network investment decision-making and swarm algorithm of chaotic binary particle to solve the model, and the example is analyzed.(4) The paper proposes the comprehensive benefit evaluation model of distribution network investment planning. Firstly, based on the index system construction principle, the evaluation index system of the investment benefit of the distribution network is established,and the evaluation process of the investment income is clarified. Then, the gray clustering algorithm and trigonometric function are introduced. After the indexes are normalized and weighted, the gray clustering trigonometric function is used to evaluate the investment return.From the results of comprehensive evaluation, the score of the model has a greater degree of differentiation, can clearly describe the investment situation of all branches, which proves the validity and superiority of the model, and can be used as the investment planning Decision-making basis for the promotion of scientific development of the power grid is of great significance.