基于综合能源系统的固态变压器中开关器件故障特性分析与诊断

Fault Characteristics and Diagnosis Strategy Analysis of Power Switch Failures on Solid State Transformer in Integrated Energy System

综合能源系统是主动配电网实现能量综合管理的重要手段与工具,其可靠性与该系统中大量应用的固态变压器的可靠性直接相关。该文针对配电网固态变压器的输入级、中间级和输出级中开关器件开路故障和短路故障开展研究,并对其故障后电压和电流畸变进行分析。以配电网固态变压器中由级联多电平变换器组成的输入级、中间级和输出级的基本工作原理及运行方式为基础,研究了其开关器件在各个故障下电压和电流的畸变,并总结其故障机理和故障特性,通过建立特定波形畸变和故障点位置与类型之间的关系,辨识开关器件故障的位置与种类。最后通过仿真对故障特性进行了验证,并提出了基于故障机理和故障特性的开关器件故障诊断方法。

As the integrated energy system can realize the integrated energy management for active distribution network,its reliability is highly related to the widely applied solid state transformer(SST)which are based on cascaded H-bridge converters.This paper presents research on the voltage and current distortion in the high voltage stage,isolation stage and low voltage stage of SST after the open-circuit and short-circuit faults of its power switches.The operational principles and the control methods for high voltage stage,isolation stage and low voltage stage of SST are introduced.Based on conclusions derived from the performance analysis of SST after the faults,this paper comes up with the effects from its topology design and control scheme on the current and voltage distortion.According to the SST fault characteristics,the abnormality of relevant components heavily depend on the location of the faulty switch,hence it is possible to locate the position of the faulty switch.Finally,the fault characteristics peculiar to SST are analyzed,and further discussed with simulation on the Saber platform,as well as a fault location diagnosis algorithm.