基于马尔科夫模型的直流断路器可靠性评估方法

Reliability Evaluation Method of DC Circuit Breaker Based on Markov Model

直流断路器控制电流通断过程的成败取决于整体的可靠性。基于机械式、混合式和全固态直流断路器的拓扑结构,采用故障树梳理各支路的故障事件。利用马尔科夫评估模型描述直流断路器组成部件与整体,以及不同故障状态间的转移过程,提出基于故障率和可用率特征参量评价不同拓扑结构直流断路器平稳运行状态概率的方法。最后对±7.5kV中压直流配电网的三种不同拓扑结构直流断路器进行可靠性计算,辨识影响其整体可靠性的薄弱环节,并对可靠性随冗余设计的变化趋势进行预测。结果表明,目前机械式直流断路器可用率最高,机械开关、IGBT模块是制约断路器可靠性提升的主要因素。随着电力电子器件技术发展,通过合理的冗余设计,全固态直流断路器可用率将超过机械式,在未来直流配电网发展中更具应用优势。

The success or failure of a DC breaker control current on-off depends on the overall reliability. Based on the topology of mechanical, hybrid and all solid state DC circuit breakers, fault trees are used to sort out the fault events of each branch. A Markov evaluation model is used to describe the transfer process between the components of the DC circuit breaker and the whole and different fault states. A method based on fault rate and availability characteristic parameters to evaluate the steady-state operation state probability of different topology DC circuit breakers is proposed. Finally, the reliability calculation of three different topology DC breakers in ±7.5kV medium voltage DC distribution network is carried out, the weak links affecting the overall reliability are identified, and the trend of reliability with redundancy design is predicted. The results show that the mechanical DC circuit breaker has the highest availability at present, and mechanical switch and IGBT module are the main factors restrict the reliability of circuit breakers. With the development of power electronic device technology, the availability of all solid state DC circuit breaker will exceed that of mechanical type by reasonable redundancy design, which will have more application advantages in the future development of DC distribution network.