基于网络约化模型的电力系统动态安全域近似

Approximations for the Dynamic Security Region of Network-reduction Power System

基于故障后主导不稳定平衡点所决定的稳定域边界的显式方程及其二次近似,并结合灵敏度分析法,给出了基于网络约化模型的电力系统在给定故障下动态安全域的显式形式及其线性近似(称为“Q线性近似”)和拟二次近似。进一步,与基于稳定域边界线性近似的动态安全域线性近似(称为“L线性近似”)进行了比较分析,所得仿真结果表明:L线性近似精确度较低;拟二次近似局部精确度较高,但依赖于初始参数的选择;Q线性近似不仅精确度高,而且对初始参数选择的变化不敏感,能够满足工程要求,具有较强的适用性。

Based on the explicit analytical equation for the stable manifold of the post fault stability region determined by the controlling unstable equilibrium points, this paper develops the explicit analytical equation for the local dynamic security region of network-reduction power systems. It presents the linear (QL method) and quadratic (QQ method) approximations for the dynamic security region based on the quadratic approximation for stable manifold and sensitivities. Furthermore, this paper compares the proposed methods to the linear approximation (LL method) of the dynamic security region based on the linear approximation for the stability region. The simulations in SMIB and IEEE 9-bus systems show that in the small-scale power systems, the LL method is robust but it may result in relative serious deviation. It is also shown that the QQ method may display fairly accurate estimation but it is sensitive to the initial parameters, and fortunately, the QL method is robust and it may meet the engineering requirements.