光学电流互感器对线路差动保护的影响

基于Matlab/Simulink和ATP,建立了电网模型、电磁型电流互感器、光学电流互感器以及线路纵联差动保护的仿真模型。引入了一套保护系统测量单元和决策单元的评测指标。对于同一线路差动保护,在相同故障条件情况下,分别安装电磁式电流互感器和光学电流互感器进行了对比仿真。以评测指标为基准,定量分析了光学互感器对线路差动保护的影响。结果表明,光学电流互感器能降低保护测量单元的稳态误差,加速保护动作,减小误动、拒动情况的发生,从而有效提高了线路差动保护的可靠性和快速性。但光学电流互感器却易导致测量单元产生较大的过冲量,其抑制直流分量的能力也较差,这将给保护带来潜在的误动可能性。

Influence of optical current transducer on line differential protection

Based on Matlab/Simulink and ATP,simulation models of power network,electro-magnetic current transducer,OCT(Optical Current Transducer) and line longitudinal differential protection are established,which adopts a set of evaluation indices for the measuring and decision-making units of protective system.For the same fault and same differential protective system,OCT and electro-magnetic current transducers are installed respectively to carry out a comparative simulation.The influence of OCT on line differential protective system is quantitatively analyzed using the adopted indices.Simulation results show that,OCT can decrease the steady-state error of measurement unit and improve the speediness and reliability of line differential protection effectively.However,it causes measurement unit generating relatively big overshoot and has poor DC component restraint capability,which may lead to a improper trip of protective system.