Liyazhuang 35kV Substation Computer Protection System Design And Implementation

Microcomputer-based Protection System is a critical component of modernsubstation secondary system, and it is also the foundation and prerequisite ofsubstation integrated automatization.35kV substation is the main force ofcolliery power supply, which occupies an important position in the mine grid.The power supply reliability of colliery which has been known as the first-rateload is paramount important to safety of production. More to the point, with theupgrading of enormous old substations and operating of some new,microcomputer-based protection system is widely used in colliery substationwith35kV. Thus, strengthening the research of microcomputer-based protectionsystem and its application in colliery substation is of great significance, not onlyin principal but practical, to the safety, reliability and economic operation ofcolliery power system.Combined with the Liyazhuang new35kV substation project, this thesisaccomplished the research, design and implementation of themicrocomputer-based protection system and substation integrated automationsystem. Firstly, according to the current running conditions of Liyazhuang oldsubstation, with the demand of future development, the thesis formulated thecorresponding new stations upgrade scheme, and fulfilled the design and typeselection of substation integrated automation system. Secondly, the thesis hascarried on the detailed research and analysis at the demand for liyazhuangsubstation relay protection. On this basis, to determine the main equipment suchas transformers, circuit, capacitor relay protection function, and select thecorresponding microcomputer protection device. In addition, the thesis hascarried on the research and analysis at the construction environment, theinterference sources and the other sources that will make the microcomputerprotection misoperation of Liyazhuang substation, and designed thecorresponding construction scheme. Finally, on the analysis of the principles andcriterions of secondary harmonic restraint, the thesis tests the rationlity itsquotient through no-load closing transformer experiment, thus, to ensure the reliability of transformer differential protection.Liyazhuang35kV substation has been put into operation. The runningresults shows that the system runs stably and the microcomputer protectionaction correctly, the response time, information refresh rate and other indicatorsof substation integrated automation system have reached the expected designrequirements.