小干扰稳定约束下联络线输送极限在线估计方法研究

准确估计区间联络线输送功率极限对于指导互联电网安全运行具有重要意义。文章在深入研究Hopf分岔理论的基础上,提出了用于评估系统阻尼水平的改进Hopf分岔指数。该指数与状态变量间具有良好的线性关系,且易于计算,能够真实反映状态变量与系统阻尼比之间的关系。以区间联络线功率随机波动数据为基础,利用随机子空间辨识算法(Stochastic Subspace Identification,SSI)辨识得到以联络线有功功率为状态变量的状态矩阵,进而根据所提出的改进Hopf指数对联络线运行状态进行评估,实现了小扰动稳定约束下联络线输送极限在线估计。仿真计算结果表明本文提出方法能够准确估计出联络线输送极限,且具有计算过程简单、计算速度快的优点,适于在线应用。

Research on the method of on-line estimation of contact line transmissionlimit under small disturbance stability constraints

Accurate estimation of the transmission power limit of the interval tie line is of great significance for guiding the safe operation of the interconnected power grid.Based on the deep study of Hopf bifurcation theory,an improved Hopf bifurcation index is proposed for evaluating the damping level of the system.The exponential and the state variables have good linear relationship,and easy to calculate and also can truly reflect the relationship between the state variables and the system damping ratio.Based on the random fluctuation data of the power of the interval tie line,the subspace identification stochastic (SSI) identification algorithm is used to identify the state matrix of the active power of the contact line as the state variable.According to the proposed improved Hopf index to evaluate the running state of the contact line,and the limit line estimation of the contact line transport under small disturbance stability constraints is realized.The simulation results show that the proposed method can accurately estimate the transmission limit of the tie line,and has the advantages of simple calculation process and fast calculation speed,which is suitable for the on-line application.