Study On The Condition Based Maintenance Decision-Making For Distribution Equipment In Jinxiang Distribution Networks

Equipment maintenance in distribution network is an important part of production and operation management for county power enterprises. In recent years, power network construction focus on solving of “two-side weakness” problems, with rapid development of distribution network construction, smart network was gradually used in county power enterprises. With the continuous economic and social development, the size of power network is expanding and new technologies such as distributed generation are emerging while customers' demand on power supply reliability and power quality is increasing, these changes present a new challenge to distribution equipment maintenance model. The traditional maintenance model such as Time Based Maintenance(TBM) and Corrective Maintenance(CM) has not met the current demand of power network development, Condition Based Maintenance(CBM) which is well-directed and effective can extend equipment's lifetime, reduce maintenance cost, raise equipment's operation level and improve the network reliability. CBM contains three parts: equipment information collection, operation state evaluation and maintenance polices selection. Equipment information collection is the premise of CBM, operation state evaluation is the basis of CBM and maintenance polices selection is the core of CBM. Currently, CBM in provincial and municipal power enterprises focus on transmission equipment maintenance, equipment maintenance in county power enterprises has not received enough attention, and there still has not an effective maintenance decision-making model. Thus, the paper targets at the benefit of maintenance decision, use state evaluation results, combines with the actual Jinxiang power network, conducts research on network distribution equipment maintenance polices which focusing on the decision–making of optimal maintenance mode and time of distribution equipment.Compared with the reliability index and economic index,the objectives which are derived from risk theory would be more reasonable. In this paper, the health index of Jinxiang power network distribution equipment was calculated based on the scoring system of distribution equipment state evaluation, and failure rate which refers the probability of equipment failure in a short period was derived from equipment operation status such as the load, temperature and insulation of distribution equipment. Combining the failure rate and the losses such as equipment-self loss, environment loss, safety loss and social loss caused by equipment failure, the risk of equipment failure can be obtained.In terms of maintenance mode selection, we proposed a maintenance mode selection model based on effectiveness and cost analysis. We measured maintenance benefit index via decreases of equipment-self loss and environment loss after maintenance, and proposed the composition of maintenance cost and the method of calculation, we also proposed a maintenance mode selection model which aimed at maximum benefits via adding in failure risk constraint. Base on mass data analysis, the maintenance mode selection model was applied to Jinxiang power network distribution equipment maintenance, and formed Jinxiang annual distribution equipment maintenance project.In terms of maintenance time selection, we proposed a maintenance time selection model based on risk assessment. We measured equipment importance by risk increment caused by current equipment status, simulated the operation risk of power network, and made maintenance decision which minimizes the sum of power network risks before, in and after maintenance. The calculation process considered the characteristics of Jinxiang annual network load, and restrictions such as maintenance time constraint, the maintenance relations and maintenance resources was also taken into account.