考虑边界母线电压无功特性的地区电网无功优化

地区电网的电源是连接上下级电网的变电站,将REI等值用于地区电网无功优化,以解决常规模型中无法反映边界母线(即连接上下级电网的母线)间电压无功特性(边界母线电压幅值受自身以及其他边界母线下级电网无功变化的影响情况)等问题。推导了能有效反映电压无功特性的等值电抗与边界母线电压无功灵敏度矩阵的关系,分析了等值电抗的变化特性以及潮流状态在等值前后的一致性,提出首先根据等值前后电压无功特性保持一致的原则利用本地数据求取等值参数,然后在优化计算中根据优化前后电压偏差的不变性对优化电压进行修正。通过对四川某地区电网的仿真计算,验证了该方法可以有效反映边界母线间的电压无功特性,使优化潮流计算电压更加准确。

Reactive Power Optimization of Regional Power Grid Considering Voltage and Reactive Power Characteristics of Boundary Buses

The power supply of regional power network is a substation that connects the network in upper voltage class with that in lower voltage class.To solve the problem that in conventional models the boundary buses,namely the buses of a network in a certain voltage class connecting with networks in lower voltage class,cannot reflect the voltage-reactive power characteristics among boundary buses,namely the influenced extent of voltage amplitude of a boundary bus due to the reactive power variation from network in lower voltage class connected with the boundary bus itself and reactive power variations from networks in lower voltage class connected with other boundary buses in the very network,the radial,equivalent and independent(REI) equivalence is applied to reactive power optimization of regional power network.The relation between equivalent reactance that can effectively reflect voltage-reactive power characteristics and voltage-reactive power sensitivity matrix of boundary buses is derived,and the time-varying characteristics of equivalent reactance and the consistency of power flow before and after the equivalence are analyzed.It is proposed that firstly according to the principle that the voltage-reactive power characteristics keep consistent before and after the equivalence the equivalent parameters are obtained by local data,and then during the optimization calculation according to the invariance of voltage deviation before and after the optimization the optimized voltage is modified.The proposed method is verified by simulation of a certain regional network in Sichuan power grid,and simulation results show that the proposed method can effectively reflect voltage-reactive power characteristics among boundary buses and make the calculated voltage for optimal power flow more accurate.