Reliability analysis and condition based maintenance cycle on control protection system in HVDC convertor station

Without considering the economy and the reliability difference between various kinds of equipments, the prophylactic maintenance mode may lead to excess or deficiency repair. Some studies has been done in the condition maintenance of AC relay devices, still involving nothing in the condition based maintenance of HDVC control protection equipment. However, the structure of the protection system in convertor station is also very different of that in AC protection system, which could not imitate the foreign research results. The paper adopt Fault Tree analysis method to build the failure model and study each reliability indicator on control protection system, based on the redundancy structure characteristic of HDVC control protection system. Then, the paper investigated the economy of condition maintenance and set up the optimal condition maintenance time interval model subjected to reliability indicators, based on maintenance costs. Finally, the case study of real convertor station data can show the proposed method can get the optimal maintenance time interval in the device life-time cycle. The results can provide the theory basis for the control protection system in HDVC convertor station.