Study On The Wide Area Protection Under Smart Grid

In order to ensure the safety of power grid, relay protection act as an important role. When the fault occurs, the fast and reliable action of relay protection device can make the grid deteriorating condition improved; And when no action or wrong action, it might make the grid condition worse, even collapse. Along with the development of State Grid intelligent power grid construction, the characteristics of smart grid bring about the technology of microgrid, the distributed generation, network reconfiguration and so on put forward new requirements for relay protection. The conventional way based on local measurement information and a small amount of regional information face greater difficulties in solving these problems, the development and application of optical fiber communication technology, clock synchronization and data synchronization technology, new sensor technology, computer technology and so on provide a broad development space for the development of relay protection. With the development of communication and computer technology in recent years.This paper presents a fault region search algorithm based on SVM (support vector machine) and fault recognition algorithm based on the comparison of fault voltage. SVM is a kind of machine learning, through the training sample to achieve the correct classification results, the fault area selection, which can reduce the measurement of the wide area information, avoid the information block. Based on the regional selection, fault identification algorithm calculate the side voltage fault component. Fault region selection method is different from the traditional method, the fault region search based on SVM is more accurate and is not affected by the transition resistance, also be able to correctly identify the first and end line fault. Fault recognition algorithm based on the comparison of fault voltage is different from the traditional wide-area current differential protection, its requirements for information acquisition and synchronization are not high, also can void the larger unbalance current caused by multi-point measurement accumulative error in grid.First, use IEEE9bus standard model to simulate and validate wide area current differential protection algorithm; Then use IEEE14bus standard model to simulate and validate wide area protection algorithm based on the comparison of fault voltage. The results show that the proposed algorithm, the results show that the proposed algorithm can identify the fault zone and fault components in different fault types, different fault location, different transition resistance and transform fault, show the effectiveness of the algorithm. At the same time also can make up for the defects of wide area differential current can’t identify the fault element.