Reliability modelling and analysis on MMC for VSC-HVDC by considering the press-pack IGBT and capacitors failure

Abstract

Modular multi-level converter (MMC) with press-packing IGBT devices is the popular and key equipment of VSC-HVDC system, its reliability is directly related to the equipment safe operation. However, it is difficult to analyse the reliability using the failure statistical approach due to less fault data. In order to improve the reliability analyses accuracy, it is necessary to use the physical failure method by considering the main components fatigue failure mode. The reliability analysis models are presented for the MMC sub-module with the press-packing IGBT device and metallised film capacitors. First, based on the MMC-HVDC simulation model, the losses and the junction temperatures of the IGBT devices were derived by the temperature field model, which the failure rates can be calculated. Furthermore, based the corrosion failure mode, the failure rate calculation of the metallised film capacitor was investigated using the voltage stress and thermal stress, the reliability calculation of the MMC sub-module was presented by combining the main components failure rates. Finally, the reliability of the VSC-HVDC based MMC was also presented with the different operation mode. The achievement is helpful to assess and improve the reliability of the VSC-HVDC.

Keywords

• HVDC power convertors
• fatigue
• failure analysis
• insulated gate bipolar transistors
• HVDC power transmission
• thermal stresses
• power transmission reliability
• voltage-source convertors
• power capacitors
• statistical analysis
• reliability analysis models
• press-packing IGBT device
• film capacitors
• MMC-HVDC simulation model
• IGBT devices
• temperature field model
• corrosion failure mode
• failure rate calculation
• metallised film capacitor
• reliability calculation
• modular multilevel converter
• VSC-HVDC system
• equipment safe operation
• failure statistical approach
• physical failure method
• capacitor failure
• reliability analysis accuracy
• main component failure rates
• fault data
• main component fatigue failure mode
• MMC sub-module
• junction temperatures
• voltage stress
• thermal stress