含电压源换流器的交直流混联电网状态估计快速解耦法

Fast Decoupling Algorithm of State Estimation for Hybrid AC/DC Power Systems with Voltage Source Converters

多端柔性直流输电技术的发展迫切需要改进和完善现有的状态估计算法以支撑调度系统应用。根据含多端柔性直流的交直流混联系统状态估计模型的结构特点,提出了一种含电压源换流器的交直流电网快速解耦状态估计算法。在传统交流状态估计模型上扩展了柔性直流电网模型,并根据交直流系统的稳态物理特性按有功、无功类对交直流量测和状态量进行分类,在保留系统耦合关系的基础上忽略雅可比矩阵中的某些次要因素,通过正常工况下的矩阵元素常数化,从而实现交直流系统的快速解耦估计计算。通过含3端柔性直流系统的IEEE 14和IEEE 118节点交直流系统算例仿真,验证了算法的有效性和实用性。

With the rapid development of voltage source converter based multi-terminal direct current（VSC-MTDC）technology,the existing state estimation algorithms need to be improved to support the application of dispatching systems.According to the structural features of a hybrid AC/DC with VSC-MTDC power system,a fast decoupling algorithm of state estimation for AC/DC system with VSC is proposed.The model of VSC-based DC system is extended on the basis of conventional AC state estimation.In this modified decoupling algorithm,the AC/DC current measurement and states are classified into active and reactive ones according to the steady-state physical characteristics of this unified AC/DC unit.A few minor factors in Jacobian matrix are neglected while the coupling relation between hybrid systems is preserved.The matrix elements are set with appropriate constant values to realize the fast decoupling estimation calculation of AC/DC system.Two cases are adopted for the validation of current algorithm,including a modified IEEE 14-bus and IEEE 118-bus AC/DC system with three-terminal VSC-HVDC.It is confirmed that the proposed algorithm is practical and effective with good convergence performance and estimation accuracy.