采用归一化制动系数的故障分量综合阻抗母线保护新判据

A New Criterion Adopting Normalized Restraint Coefficient for Bus-bar Protection Based on Fault Component Integrated Impedance

基于故障分量综合阻抗母线保护原理,提出了一种采用归一化制动系数的母线保护新判据。通过研究母线区内、外故障电流互感器(TA)饱和对故障分量综合阻抗相角造成的偏移影响,定义了故障分量综合阻抗的相角偏移误差,并将其归一化处理后作为制动系数引入原动作判据,构成一种母线保护新判据。新判据不仅具有基于故障分量综合阻抗母线保护的所有特点,而且大大提高了保护抗TA饱和的能力,当母线区外故障TA饱和时,新判据能可靠制动,当母线区内故障TA饱和时,新判据仍有很高的灵敏度,使保护能迅速动作。EMTP仿真验证了新判据的有效性。

On the basis of the principle of fault component integrated impedance based bus-bar protection,a new criterion adopting normalized restraint coefficient is put forward. According to the angle displacement of the fault component integrated impedance caused by current transformer （CT） saturation,the error of the angle displacement is defined and adopted as restraint coefficient to establish the new criterion. The new criterion has all the advantages of the fault component integrated impedance based bus-bar protection as well as higher security and dependability of tripping when there is CT saturation. EMTP simulation results show that it can immunize the mal-operation when CT saturation occurs outside the protection zone of a bus-bar.