Three-stage Voltage And Reactive Power Optimization Strategy For Regional Power Grid Based On Voltage Qualification Rate Model

In the traditional voltage regulation strategy,the regional voltage reactive power optimization only needs to consider keeping the bus voltages within the qualified range,and the various levels of the power grid under the buses perform voltage regulation according to the upper voltage.However,in actual operation,the voltage regulation capability of the low-voltage distribution network is often insufficient to ensure its voltage qualification rate,and the upper-level power grid needs to adjust its voltage according to the actual requirements of the lower-level power grid.Therefore,when the medium voltage buses voltage is qualified,there are still many unqualified voltages in the lower voltage distribution network.There is a lack of coordination mechanism between regional grid voltage reactive power optimization and station voltage qualification rate optimization,and the bus voltage is basically a blind adjustment.Therefore,in order to fully increase the voltage qualification rate in Taiwan,it is necessary to perform three-stage voltage and reactive power optimization in the Taiwan region,the middle-pressure district,and the regional power grid.Three-level optimization of regional power grids requires repeated calculations of combined power flows in the transmission and distribution networks.In order to shorten the convergence time required for load flow calculation,this paper first proposes a method for global power flow calculation of transmission and distribution networks based on equivalent fitting of distribution network power flow characteristics.Firstly,the principle of equivalent fitting of distribution network is analyzed in detail,and the distribution netw ork power flow fitting function is established.Then,the power flow calculation model of the transmission and distribution network with master-slave splitting and master-slave merging is established.In this method,the fitting result of the distribution and the exact result of the master-slave iterations are taken as the boundary condition for the coordination information.It does not need the master-slave iteration for each power flow calculation,reduces the amount of the current flow,accelerates the convergence of the power flow and has high accuracy.The simulation example verifies the feasibility and effectiveness of the proposed method.It is applicable to the current large-scale distribution network global power flow calculation and the voltage reactive power optimization scenario that requires repeated calculation of the distribution network global power flow.Based on the distribution network global power flow distribution algorithm with equivalent distribution,a voltage and reactive power optimization model for transmission and distribution network coordination is established.The artificial intelligence algorithm is studied,and the optimal trajectory characteristics of multiple algorithms are analyzed.Network Collaborative Regional Grid Voltage Reactive Optimization.Based on the above research,this paper proposes a regional voltage reactive power optimization strategy based on the voltage qualification rate evaluation function.By establishing the voltage qualification model of the low-voltage distribution network platform and the voltage qualification rate model of the medium-voltage area,the three-level voltage reactive power optimization strategy for the low-voltage platform,medium-pressure area and regional power grid is formed.The voltage qualification rate evaluation function established step by step makes regional voltage and reactive power optimization strategies well consider the impact on the voltage qualification rate of the lower-level power grid and solve the problem of voltage and reactive power coordination and optimization of the upper and lower three-level power grid.The simulation results show that this strategy greatly improves the comprehensive voltage qualification rate of the regional power grid and has high ec onomic benefits.