Analysis Of A Multi-phase Compensation Distance Relay Free From Power Swing

Oscillation blocking has been one of the most complex and difficult problems in the application of distance protection. However, at present,oscillation blocking method is generally more complex, but also not perfect. Therefore, the oscillation blocking has been a topic that often discussed by closed area of expertise.This paper presents a multi-phase compensation distance relay free from power swing, and sequence components and the phase diagram method analysis are used to analyze the operating characteristics of the relay in different operating conditions. Then PSCAD simulation results verify the conclusions of the analysis.The purpose of the analysis is to play to the advantages of relay and overcome its shortcomings. Through analysis, it easily can be seen that the relay is free from the impact of power swing and overload. In a variety of asymmetric metallic short circuit situation, the action of the relay has a clear area,which in the local failure the relay can reliably move, and outside the region and reverse faults it can reliably not work. However, the relay itself does not reflect the three-phase short circuit fault,therefore, it needs a special three-phase fault distance relay. The impact of the transition resistance on relay is great.The ability to withstand transient resistance in the transition region line is weak, so it is a great need to take some measures to overcome its effects, or used in conjunction with other protection. Non-phase runs a greater impact on the distance relay. In non-phase oscillation case, the possible malfunction of the relay will need to latch protection.Considering characteristics of multi-phase compensation distance relay cann't reflect the three-phase short circuit fault, this paper analyzes a three-phase fault distance relay,and the relay has a clear action areas when it occurs three-phase short circuit fault. Taking the ability to withstand transient resistance of the relay is week into account, the paper proposes a measure to overcome it, and demonstrated the effectiveness of the measures by theoretical analysis and simulation. For non-phase operation, the paper analyzes the factors on impacting multi-phase compensation distance relay misoperation, and gives the conditions that protection will not malfunction.