系统持续扰动下的电力系统戴维南等值参数在线识别

An On-line Parameter Identification of Thevenin Equivalent Circuit for Power Systems With Persistent Disturbance

提出一种适用于系统侧持续扰动的电力系统戴维南等值参数在线识别方法。该方法将节点电压、电流变化量分解为负荷侧和系统侧的叠加,建立新的考虑系统侧变量的数学模型,并利用系统侧、负荷侧电流变量的相互独立性对模型进行求解。传统最小二乘辨识模型假设戴维南等值电势不变,而该方法没有这一假设,所以更能适用于系统侧持续扰动的情况。仿真及实际工程算例表明:与传统最小二乘辨识模型相比,在系统侧持续扰动较小时该方法能更好地识别出戴维南等值参数,而随着系统侧持续扰动的增大,最小二乘辨识模型逐步失效,所提方法依然能较好地识别出戴维南等值参数。

This paper proposed a novel on-line parameter identification method of Thevenin equivalent circuit that is applicable to the situation when the persistent disturbancesoccur at the system side. Based on the theoretical derivation that the voltage and current variation at a node was taken as the superposition of the variation at the system side and the variation at the load side, a new mathematical model that takes into account the variable at the system side was built. Independence of variables at the system side and the load side was used to solve the model. Compared with the traditional least square method, the new method doesn＇t assume that the equivalent source voltage is constant, so it is more applicable to the situation when persistent disturbances occur at the system side. Simulation and filed tests show that the proposed approach performs better than the traditional least square method when the persistent small disturbances occur at the system side. With the persistent disturbances becoming larger, the traditional least square method is out of work gradually, while the proposed approach can identify the parameters of the Thevenin equivalent circuit as well.