基于电压灵敏度的交直流电力系统静态电压安全域评估方法

Evaluation Method of Static Voltage Security Region of AC/DC Power System Based on Voltage Sensitivity

特高压直流可能导致近区电网潮流分布不合理,造成电压越限。针对这一问题,提出了一种基于灵敏度分析的交直流混联系统静态电压安全域的快速评估方法。首先结合直流系统准稳态模型得到交直流系统潮流方程,通过对系统功率方程求偏导数得到节点注入功率和支路导纳对电压的灵敏度,进一步给出基于灵敏度的节点电压变化量计算方法。然后设置预想故障集,并将其中的事故等值为节点功率扰动与支路导纳的变化,计算出各种事故后节点电压的变化量。最后基于电压变化量最大值和最小值评估静态电压安全域,给出具体的节点电压安全运行范围。通过对四机两区域的交直流系统及江西500 kV电网的仿真,验证了所提出的评估方法的可行性。

UHV DC may cause unreasonable power flow distribution of power grid near UHVDC and the volatge may exceed its limitation.To solve this problem,a fast evaluation method of static voltage safety region of AC/DC hybrid system based on sensitivity analysis is proposed.Firstly,the power flow equation of AC/DC system is obtained by combining with the quasi steady state model of DC system,the sensitivity of node injection power and branch admittance to voltage is obtained by taking the partial derivative of system power equation,and the calculation method of node voltage deviation based on the sensitivity is proposed.A preconceived accident set is established and all accidents are equivalent to the change of node power disturbance and branch admittance,so the deviation of node voltage after each accident can be calculated.Finally,the static voltage safety region is evaluated based on the minimum and maximum of voltage deviation,the safety range of node voltage is proposed.The feasibility of the proposed evaluation method is verified by the simulation of the AC/DC system with four machines and two regions and Jiangxi 500 kV power grid.