基于阻尼比的小干扰安全域多项式近似边界及其可信域

应用隐函数求导法,提出了基于阻尼比的小干扰安全域(D-SSSR)边界多项式近似算法。该算法在传统小干扰安全域(SSSR)理论的基础上,通过坐标旋转建立D-SSSR边界的计算模型;进一步基于隐函数求导法,将D-SSSR边界多项式近似的系数求解问题转化为线性方程组求解问题。与传统的描点法相比,所提算法可以求取D-SSSR边界的解析表达式且运算量小,因此具有广泛的应用前景。除此之外,提出一种基于优化方法的可信域计算方法,以确定D-SSSR边界多项式近似的有效范围。最后,通过IEEE-118节点系统上的仿真计算,验证了D-SSSR边界的多项式近似算法和可信域求解算法的正确性。

Polynomial Approximation of Damping-ratio-based Small-signal Security Region Boundaries and Its Credible Region

A polynomial approximation method is proposed to construct an analytical expression of the boundaries of the damping-ratio-based small-signal security region(D-SSSR) by using the implicit function approach.Because this method gives the explicit polynomial expression,it has broad perspectives in applications.This method establishes the calculation model of the D-SSSR boundary by rotating the coordinate axis of the traditional small-signal security region(SSSR) boundary model.Then,the calculation of the coefficients of the polynomial approximation can be converted into the problem of solving a group of linear equations by using the implicit function approach.Further more,in order to handle the problem of local validity due to the polynomial approximation,an optimization formula is proposed to estimate the credible region of the approximation with a given accuracy.The correctness and effectiveness of the proposed methods are verified through the case studies on IEEE 118-bus system.