A Hierarchic Control Strategy for Reliability Enhancement of PFCs in Co-phase TPSS

As the core component of co-phase traction power supply system (TPSS), the reliability evaluation and reliability optimization of power flow controllers (PFCs) are crucial to its safe operation. In this paper, the failure rate calculation model is adopted to evaluate the reliability of the PFCs. To enhance the reliability of PFCs, a novel hierarchic control of PFCs under the third compensation strategy is proposed in this paper. In the high-load area, all of the PFCs are operated simultaneously by the average-current sharing control while in the light-load area part of the PFCs unit is operated by turns to decrease the total power loss of converters. Taking the co-phase PFCs of the Shayu traction substation as an example, the effectiveness of proposed strategy is demonstrated. Results are shown that the failure rate of IGBT modules is reduced by 42.16% and the power loss is decreased by 11.75%.