New Polarization Distance Relay

Relay protection is one of device to respond the fault and abnormal circulate situation of electric power system, to make the breaker action and to send out the signal. With great development, the power system is more and more strict with relay-protection especially in super high voltage and large capability power system. In the power system which is very complex in configuration, the protection device whose function is perfect should be adopted, and distance protection is just one of this types. Although distance protection is the main protection in the protection of transmission lines in complex power network for it is not affected by the structure of the power network and the changing network conditions, its performance is not perfect and not appropriate to high voltage transmission lines. Some problems exist in the traditional protection method. In order to solve these problems, many researchers are working hard all the times. This paper analyzes a new criterion to ground distance relay's action during power system swing under single-phase grounding fault.This paper discusses the basic principle and composing of distance protection. At the same time, this paper analyzes the criterion and principle to domestic some distance relays actually, and summarizes the advantage and disadvantage of those. In all faults, the frequency of earth failure is high. Existing distance protection equipments all have ability to break earth failure, but this ability is not mightly still. According to this paper, the late-model distance relay that was once mentioned can act exactly and be not affected by the transition resistance. This paper analyzes a new criterion and the action characteristic to ground distance relay's action during power system swing under single-phase grounding fault. The study shows the relay can measure the point of the fault correctly during power swing. Its performance is not affected...