Analysis And Strategy To Prevent Maloperation Of Zone ? Distance Protection Due To Overload

Power system is the most important method for resorce and energy optimization.Remote transimiting electricity and power system interconnectionthe theme of modern power system evolution.But the interconnecttion lead to partial fault evolving to extensiveness,and lead to the blackout.After line tripping happens in power system,loading flows in system.The load in the tripped line may transfer to other lines,leading overloading with the characteristic of low-voltage and over-current.The transformation of measured impedance in impedance ichnography for overloading and the one for fault are similar,which results in the maloperation of distance protection ? and chain tripping.So the analysis and countermeasure to distance protection maloperation in overloading,and the improvement to the performance of distance protection answering overloading are important to prevent distance protection maloperation.The artical firstly analyze generic overloading model,set up PSCAD overloading model basing on the difference of the voltage of two sides of system,and analyze the character of measured impedance.In case of the difference of the voltage of two sides of system,the distance protecion ? may maloperate for overloading.Experiment with alternate impedance relay and grounding impedance relay andverifies the results of PSCAD model.erOn the basis of PSCAD and experiment,the artical puts forward voltage limitation and voltage limitation,analyze the area of inpedance relay maloperation in impedance ichnography.Then the artical put forward a self-adaption inpedance protection project to remove the maloperating area,to solve the distance protection maloperation in overloading.