基于马尔科夫状态空间法的换流变压器继电保护系统可靠性

A Reliability Analysis of Converter Transformer Relay Protection Systems Based on Markov State Space Method

中文关键词:换流变压器  继电保护  隐性故障  风险评估

keywords:converter transformer  relay protection  hidden faults  risk assessment

中文摘要:现有的继电保护风险评估侧重分析线路故障的影响，确定隐性故障概率时多依赖经验数据，未充分考虑换流变压器等一次设备故障对继电保护性能的影响。深入分析了换流变压器的热故障诱因，建立了基于流热耦合模型的换流变压器故障概率模型。同时考虑了设备热故障对保护性能的影响，建立了可能诱发继电保护拒动和误动的隐性故障概率模型，并提出了基于马尔科夫状态空间法的直流系统风险评估方法，探讨了换流变压器热故障以及继电保护隐性故障对直流系统稳定性和安全性的潜在影响。通过建立概率模型和仿真分析，综合考虑设备性能、环境因素和时间变化等多个维度，精确评估换流变热故障下的系统稳定性与风险指标。仿真结果表明，换流变压器故障率随时间呈指数增长，在系统可用度提升的同时，系统风险显著增大，提高了保护装置的故障检出系数，可有效降低系统综合误动率。

Abstract:The current risk assessment of relay protection primarily concentrate on analyzing the effects of line faults. When determining the probability of latent faults，it heavily relies on empirical data，but fails to fully consider the impact of failures in primary equipment，such as converter transformers，on the performance of relay protection. This article investigates the underlying causes of thermal faults in converter transformers and develops a time-varying probability model for converter transformer failures. The model is based on a thermal-flow coupling analysis of converter transformers and further incorporates the impact of equipment thermal faults on the performance of protection systems，establishing a probability model for hidden failures that can lead to relay protection malfunction or misoperation. Additionally，a DC system risk assessment model is proposed，employing the Markov state space method. By exploring the potential effects of converter transformer thermal faults and hidden failures in relay protection on the overall stability and safety of the DC system，this article aims to offer a more comprehensive understanding of these risks. Through the establishment of time-varying models and simulation analyses，the system's stability and risk under converter transformer thermal faults are evaluated with greater accuracy，taking account of factors such as equipment performance，environmental conditions，and temporal variations. Simulation results show that the fault rate of the converter transformer increases exponentially over time，the system availability improves while the system risk increases significantly，and improving the fault detection coefficient of the protection device can effectively reduce the overall false action rate of the system.