电力系统动态安全域线性近似方法比较

Comparison of Linear Approximations for the Dynamic Security Region of Power Systems

分析比较了网络约化模型下电力系统动态安全域的3种线性近似方法的综合效能,分别为: 基于稳定域二次近似的动态安全域线性近似(Q线性近似)、基于稳定域线性近似的动态安全域线性近似(L线性近似)和基于稳定域边界法向量恒定假设的动态安全域近似(L0线性近似)。其共同之处为在事先搜索而得的处于动态安全域边界的临界点处应用相应的近似刻画方法。文中以最小二乘拟合搜索得到的临界点所获得的线性近似为基准,分析比较了上述3种线性近似对安全域边界刻画的准确程度;特别是对于低维的动态安全域,以搜索获得的真实动态安全域为基准,采用图示方法直接比较不同线性近似的近似程度。仿真分析表明:在具有事先搜索的临界点时,3种线性近似方法均能准确地近似动态安全域的局部边界;同时,L0线性近似和L线性近似计算量小,更适用于大型电力系统。

This paper compares the performance of three types of linear approximations for the dynamic security region of power system with network-reduction model. The three types of linear approximations are the Q-linear approximation based on the quadratic approximation of stability region, the L-linear approximation based on the linear approximation of stability region and the L0-1inear approximation based on the invariant assumption of the normal vector of stability region. The linear approximations are obtained with a critical point just on the boundary of dynamic security region. In the comparison, the linear approximation obtained by the least square curve fitting method is used as the benchmark. Furthermore, for the dynamic security region in low dimension, the figure with the searched critical point is used to directly compare the accuracy of different approaches. Simulations in IEEE 3-machine 9-bus system and 10-machlne 39-bus New England system show that, with a given critical point, all the three types of approximations display fairly accurate estimation. Furthermore, from the computational viewpoint, the L-linear and the L0-1inear method with less computational burden are two alternative choices to approximate the dynamic security region.