计及安全稳定约束的多直流送出电网新能源极限渗透率估计方法

Estimation method of maximum renewable energy penetration rate for multi-send HVDC system considering security and stability constraints

基于电网换相换流器的高压直流系统是大型能源基地电力外送的重要技术手段,然而新能源渗透率的提高会降低送端电网的安全稳定性.为保证多直流送出电网的安全稳定运行,提出一种计及安全稳定约束的多直流送出电网可承受新能源极限渗透率估计方法.推导各类安全稳定约束的表达式,包括短路电流约束、多直流短路比约束以及频率稳定约束;在考虑安全稳定约束的情况下建立多直流送出电网优化调度模型;给出优化调度模型分段线性求解方法,并基于该方法提出新能源极限渗透率估计方法.修改的IEEE 39节点系统仿真结果验证了所提方法的有效性.

The line commutated converter based high voltage direct current(HVDC)system is an important technical means for sending power generated by large energy bases.However,the increase of renewable energy penetration will reduce the security and stability of sending-end power grid.In order to guarantee the safe and stable operation of multi-send HVDC system,an estimation method of maximum renewable energy penetration rate affordable by the multi-send HVDC system is proposed considering the security and stability constraints.The expressions of various security and stability constraints are derived,including short circuit current constraint,multi-HVDC short circuit ratio constraint,and the frequency stability constraint.An optimal scheduling model for multi-send HVDC system is established considering the security and stability constraints.A piecewise linearization method for optimal scheduling model is presented,based on which an estimation method for the maximum renewable energy penetration rate is proposed.The simulative results of a modified IEEE 39-bus system verify the effectiveness of the proposed method.