Safety quantitative evaluation method for active power distribution network connected with large-scale charging facility

Abstract

The invention provides a safety quantitative evaluation method for an active power distribution network connected with a large-scale charging facility. The safety quantitative evaluation method is a quantitative evaluation method based on a probability statistics method, and comprises establishing a power distribution network safety evaluation index system aiming at operation characteristics of a distributed photovoltaic unit and an electric car, establishing a probability model for each index by means of the probability statistics method, a Monte Carlo sampling method and a three-point estimation method, calculating the composite weight by means of a precedence chart method and an entropy weight method, and combining the index model with the composite weight to determine the safety evaluation final result by means of a safety quantitative evaluation method based on a fuzzy matter-element analysis method. According to the invention, randomness and fluctuation problems caused by grid connection of the distributed device are solved; the constructed probability model is more suitable for processing practical problems; the calculating efficiency is greatly improved; the result of safety evaluation analysis is quantified into a concrete numerical value, and is more visual , and is convenient for subsequent analysis and optimization.

Description

technical field [0001] The invention relates to the technical field of active distribution network safety monitoring, in particular to a security quantitative evaluation method for large-scale charging facilities connected to an active distribution network. Background technique [0002] The traditional distribution network is a passive power grid, and the flow direction flows from the distribution transformer bus to each load node in one direction. The flow calculation, equipment protection, system monitoring and adjustment are relatively simple. After the distributed photovoltaic power supply is connected to the power distribution side from the fixed node, the system becomes an active ring network, and the load receives the electric energy transmitted from the distribution transformer and photovoltaic nodes at the same time, and the voltage of each node varies with the access photovoltaic capacity. Corresponding changes will occur, and line power may appear backflow phenome...

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Problems solved by technology

At present, the security analysis of the transmission side is relatively mature, but the security analysis of the distribution network is not perfect enough, and the security assessment of the distribution network after accessing distributed devices (including photovoltaics, large-scale charging facilities, etc.) methodological research is even more lacking

The common safety analysis of the distribution side usually focuses on establishing a safety analysis index system, and cannot propose a relatively comprehensive evaluation method; and the common evaluation methods usually can only statically analyze the safety degree of the distribution network at a certain moment, without Considering the dynamic and time-varying nature of security issues, such static evaluation results cannot provide practical suggestions for power grid planning

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