Maintenance Procedures and Verification of Mixed Connection of DC Power System Grounding for Electrical Substation

• Main Authors: WANG,MING-TZONG, 王明宗
• Other Authors: PAI,FU-SHeng
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/5vev92

碩士 === 國立臺南大學 === 電機工程學系碩博士班 === 106 === In the power plant and substation, the DC power system is used in the logic control loops of protective relay and power distribution panel. The DC power system is an insulation system with insulation resistance of millions of ohms. When the DC power system works normally, the insulation resistance of the positive/negative line is almost equal, and the line-to-ground voltage is also relatively balanced. However, during the line fault, the voltage of DC power system will change. The voltage in the fault line side will decrease, possibly affecting its power supply. In severe cases, the line fault of DC power system may affect the safety of the overall system. In order to improve the operational reliability of ultra-high voltage system, two or more independent DC power supplying loops have been designed in the substation of the Taiwan power company. Then, each power apparatus in the substation equips the independent DC power supply and circuit breaker for line insulation. In this case, when the line fault occurs in the DC power system, the corresponding switch can automatically trips or manually turns off. However, because of system expansion, reconstruction, and the effect of climate reason, there is still line fault event occurring in the DC power system. Therefore, in this thesis, a maintenance procedures of mixed connection of DC power system grounding for electrical substation is proposed. The method has been applied to the practical case study of Chia-Min UHV substation of Taiwan power company. The test results show that the method proposed in this thesis can position the fault area, and eliminate the line mixed-connection condition. Test results confirm the effectiveness of the method, thereby demonstrating that the method is beneficial for power industry applications.