The Reliability And Related Issues Of Secondary System Of Intelligent Substation

In recent years, most of the large blackouts that occurred in the worldhad a direct or indirect relationship with the incorrect action of thesecondary system of the substation. For a reliable power system, thereliability of the secondary system plays a crucial important role.Therefore, the reliability of the power system must contain the secondarysystem reliability management.With the developing of the intelligent switching equipment,unconventional transformer, and the application of high-speedcommunication networks, all-digital and intelligent substation is theinevitable trend. The smart substation is different from the traditionalsubstation in structure of the system and the elements contained. Thetraditional secondary system of substation consisted with simple protectionrelays and automatic safety devices, as well as the necessary means ofcommunication has been developed an complex integrated intelligentsubstation secondary system which contain wide-area protection systems,wide-area measurement systems, wide-area communication systems, andwide-area supervision system, characterized by standardizedcommunication protocol and the information model, intelligent equipment,transmission of information by network.The reliability of the power system management is an importantguarantee for the safe operation of the power system. The reliability of thesecondary system with a system reliability are equally important, thereliability of the power system must include the reliability of the secondarysystem for ensuring the operation of the system safe and stable. Thereliability of the secondary system is ultimately manifested through the primary system, therefore, for more practical significance, the reliability ofthe secondary system must be combined with the reliability of the primarysystem.In summary, this study is divided into four parts:1A depth understanding of the system structure and characteristics ofintelligent substation, analysis the different of smart substation, traditionalsubstation and digital substation; summarize the research of the intelligentsubstation construction and equipment technology.2Based on the structural features of the intelligent substationsecondary system, the network evaluation reliability model of theintelligent substation secondary system is established in which acommunication link to the intelligent substation secondary system slip as abranch and an intelligent substation secondary equipment as a node. Thecalculation model of the node, branch and system are built, and finally,according to the series and parallel relationship of equipment, thesecondary system reliability is calculated.3Reliability of the secondary system eventually is reflected throughthe primary system, according to the efficacy of the secondary system tothe system components, Analysis the unreliable operation of the secondarysystem affected to the components of the primary system, a Markovmodel of the component considering the secondary system is built, andfinally, the state space method is used to calculate considering the role ofthe secondary system the probability of system components work properly.4Considered the reliability of the components is closely related totheir failure rate, repair rate which are used to correct the availablecapacity of the component (for examples: lines and transformers), thereliability analysis model of complex systems is established. Finally,calculate the draw system reliability indicators.