基于自适应制动补偿系数的有源配电网电流纵联差动保护

为了解决传统的三段式电流保护难以适用于有源配电网的问题，通过分析含不同类型分布式电源的配电网正序电流故障分量在区内外故障时的幅相特征差异，提出一种基于自适应制动补偿系数的电流纵联差动保护新方法。该方法采用改造后的e指数函数构建制动补偿系数，根据线路两侧正序电流故障分量的相位差和幅值比自适应决定补偿制动电流的程度。为有效应对不可测负荷分支给保护可靠性带来的消极影响，利用比幅式方向阻抗继电器的动作方程构造辅助判据。仿真结果表明，与传统电流纵联差动保护相比，该方法能够满足各种故障场景下有源配电网的保护需求，且灵敏度高，可靠性、耐受过渡电阻能力和抗时间同步误差能力强。

A current longitudinal differential protection method based on adaptive braking compensation coefficient for active distribution networks

It is difficult to apply traditional three-stage current protection to active distribution networks. This problem is addressed first by analyzing the magnitude and phase characteristic differences of the positive sequence current fault components (PSCFCs) when faults occur inside and outside distribution network protected feeders with different distributed generator types. A new method of current longitudinal differential protection based on adaptive braking compensation coefficient is proposed. The method uses the modified e-exponential function to construct the braking compensation coefficient. From the phase difference and amplitude ratio of PSCFC on both sides of the line, the compensation degree of the braking current is adaptively determined. To effectively cope with the negative impact of unmeasurable load branches on protection reliability, an additional criterion is constructed using the action equation of amplitude-comparison directional impedance relay. The simulation results show that compared with the traditional current longitudinal differential protection, this method can meet active distribution network protection needs in various fault scenarios with high sensitivity, reliability, ability to withstand transition resistance and resistance to time synchronization errors.