摘要:本篇论文主要描述的是针对区域电网所产生的不对称短路故障的分析及为避免故障所安装的保护措施，即线路的三段式电流保护。及故障的排除的方法。

　　　根据对称分量的基本原理，即是将整个网络分解为正序网络、负序网络、零序网络三个对称序网，再利用线性电路的叠加原理，对这三组对称分量分别按对称三相电路进行求解，然后将其结果进行叠加。其过程需要将各序网络图分别进行化简，通过化简结果计算三种不对称短路故障的电流，并根据其电流对线路进行三段式电流保护的计算（即：电流速断保护、限时电流速断保护、定时限过电流保护），包括其整定和校验。本设计主要选取了5个短路点，分别选取在线路L5，L6的两侧及变压器T7和T8的两侧，并对其进行正序、负序、零序网络的化简，并对线路进行相应的保护计算。

　　　通过对电力系统的了解，应在系统线路上装设线路保护装置，使其满足校验的条件。当电力系统发生短路故障时，根据不同不对称短路故障的特点，能够选择合适的电力线路检查的方法，并及时快速的检查计算出短路故障点的地点及短路类型。根据短路情况，运用相应的方法对短路故障进行解除。

关键词：不对称网络；短路故障；故障排除

ABSTRACT:This paper mainly describes the regional power grid generated by asymmetric fault analysis and in order to avoid failure of the installation of protective measures, that line the three-section current protection. And trouble shooting method.

　　According to the basic principle of symmetrical components, that is, the entire network into network network of positive sequence, negative sequence and zero sequence three symmetric sequence network network, and then using the superposition principle for linear circuits, on the three sets of symmetrical components to solve breakdowns on the symmetrical three-phase circuit and its result stack. Process the sequence needs to be to simplify network respectively, by simplifying the results calculated three asymmetrical short-circuit fault current, and lines based on their current calculation of three-section current protection (that is, current fast-tripping protection time limits, limited to current fast-tripping protection, over current protection), including its tuning and calibration. Choose 5 main characteristics of the design, choose line L5,L6, respectively on either side and T7 and T8 on either side of the transformer, and make positive sequence, negative sequence and zero sequence network simplification and appropriate protection for line calculation.

　　Through the understanding of power systems, installation of transmission line protection device on the line, to meet a validation condition. When the power system short-circuit fault occurs, depending on asymmetrical short-circuit fault characteristics, ability to select appropriate methods for checking of electrical wiring, and quick check in time to calculate the short circuit short circuit type and location of the point of failure. Under short circuit conditions, use the appropriate method to lift the fault.

Key words: asymmetric network fault; troubleshooting