基于模型误差的自适应方向元件

Adaptive directional element based on model error

为克服目前快速方向元件动作范围整定的盲目性和保守性,提出了基于模型误差的自适应方向元件。模型误差反映了计算模型与实际模型之间的差别,它与保护计算的相位误差有确定的关系。使用ATP仿真软件建立双端电源超高压输电线路模型。通过R-L模型参数识别的方法判断故障方向,把反映系统网络结构的微分方程产生的归一化误差作为模型误差。通过大量故障仿真计算建立模型误差与相位误差之间的关系。故障后实时地计算模型误差,根据模型误差与相位误差的关系自适应地调整方向元件的动作范围。仿真结果显示该方法能使保护更好地适应系统的状况,提高了方向元件的性能。

An adaptive directional element based on model error is proposed to avoid the conservatism and blindness in the operational range setting of current fast directional elements. The model error describes the differences between calculating model and real model, having a definite relationship with the phase error calculated by the directional element. A double-source EHV system model is built using ATP software. Fault direction is judged by the parameter identification method based on R-L model. The normalized error of the differential equation, which reflects the network structure, is regarded as the model error. The relationship between model error and phase error is found though numerous simulations. When a fault occurs,the model error is calculated in real time and the operational range of directional element is adaptively adjusted according to the relationship between model error and phase error. Simulation results show that, the proposed method enhances the performance of directional element and makes it more suitable for various system conditions.