Study On Fault Diagnosis Method For Smart Substation Secondary System

Recently, the construction of smart grid is in the rapid development in China. With the deepening construction, as the core part of smart grid, smart substations are being built rapidly. At the same time, higher requirements of the management and maintenance of smart substations are put forward also. Therefore, research on fault diagnosis method of smart substations has become one of the key topics of smart grid in the near future.Traditional substation fault diagnosis method can be classified into two types: one is based on the information of protective relays and circuit breakers, considering substation as a whole, and the fault diagnosis results are fault lines and failure equipment, including the information of protective relaying equipment and the switch, that was failed to run normally. The other is based on the station alarm information of a device (such as a transformer station) to evaluate its state and carry out its fault diagnosis, and its output is whether its performance is good or bad. However, the main feature of smart substation is the intelligent primary equipment and the networking secondary system, and he networking secondary system is the most significant feature. Fault diagnosis methods above are failed to take into account the impact of abnormal function of communication network to the stable operation of smart substation. In view of the problems mentioned above, this paper uses the rule reasoning method to carry on fault diagnosis and condition evaluation of communication system of smart substations. The specific work related is as follows:(1) The establishment of basic fault diagnosis model of smart substation. The secondary system diagnosis is grounded on the fault feature information, according to the logical relationship among various information, by virtue of the inference of intelligent algorithm, to determine the fault equipment and the fault reason. Based upon the basic fault diagnosis process and characteristics of Smart Substation, the paper establishes the fault diagnosis model and maps the basic flow diagram. (2) Comprehensive introduction of the fault features of intelligent substation information. By virtue of advanced computer technology and communication technology in smart substation, it is basically realized to the comprehensively real-time monitoring and anomaly detection of the secondary network. When a fault occurs, there will be a large number of warning information, alarm information and accident information. Information classification should be first to fault diagnosis system, and then the processing of original alarm information, the representation by general structure, and lastly, diagnostic rules matched according to the fault feature information of different classes.(3) Proposing the device or equipment fault diagnosis method for intelligent substation. Based on alarm information of substation automation system, utilizes self-check alarm information to determine device’s program running state; makes use of the monitoring alarm information to defer the equipment’s working state.(4) Presentation of the communication network fault diagnosis method. Based on message monitoring alarm information from communication network monitoring device to determine the function of information transfer station, and then deduce the work state of the communication network and network equipment.(5) Research on fault diagnosis method, in the case of lack of alarm information. The supervision system in the substation could not detect all faults of equipment and communication network, one hundred percent and the alarm information can not be uploaded precisely. Therefore, in some cases, when fault characteristic information is not complete, other relevant alarm information would be used to go on fault diagnosis, and also, the paper tries to infer the alarm information that was lost, as an auxiliary evidence to diagnosis results.(6) The establishment of a distribute fault diagnosis system. The paper designs a distributed structure, according to the fault feature information, to infer status of primary equipment, the secondary device, the secondary communication network, and the network devices. Then, makes a comprehensive analysis of intermediate result, outputs the comprehensive diagnosis result, and gives the related diagnostic explanation.