Revitalization And Operation Analysis Of Tianshengqiao-Guangzhou HVDC Project

Tianshengqiao-Guangzhou HVDC project is the first long distance, high-power andultra-high voltage DC power transmission project of China Southern Power Grid. SinceTianshengqiao-Guangzhou HVDC project was put into operation，it has been makingoutstanding contributions to the West-East electricity transmission and the economicdevelopment for Guangdong.Due to the impact of design issues and equipment defectors, Tianshengqiao-GuangzhouHVDC project has exposed a great many problems. It was forced to block many times of onepole, and even both pole in succession.During December2009to April2010, Renovation was taken inTianshengqiao-Guangzhou HVDC project, including major improvements from the followingaspects:1) HVDC control and protection system was improved. The new control and protectionsystem was designed and manufactured by NARI-RELAYS, while the original one wasdesigned by SIMENSE.2) HVDC measurement system was improved. The original current transformers wereabsolutely taken place and the terminal boxes of potential transformers were adapted.3) Valve cooling control system was improved. The design flaw of valve cooling controlsystem which has been developed was improved, to avoid the misacting of valve coolingcontrol system which may block pole of HVDC.4) AC filters were improved. The capacitors of AC filters numbered271,281,284wereoverall taken place and connecting wiring between capacitors of double-tuned AC filters wereadapted.5) Low voltage direct current system was improved. The low voltage direct currentsystem after reconstruction was more stable and reliable.6) Control loop of circuit breakers and isolation switches were improved. The harmfulimpact to power grid when closing circuit breaker became smaller than before. Control loopof isolation switches were more concise and more close to the design of new HVDC projectsthan before. This article studied the key elements of improvements of the above six aspects,comparative analyzed of the operation before and after reconstruction, and pointed out theadvantage after it.