Unified modeling and operation strategy for long-distance co-phase cable traction power supply system with novel compensation scheme

• Compensation is crucial for enhancing power quality and power supply capacity. • A multi-objective unified model for various compensation schemes is developed. • A novel power flow calculation model with power flow controller is established. • The operation characteristics with power flow controller are revealed. • The proposed scheme has stronger compensation capability than the existing scheme. Compensation with a power flow controller (PFC) is crucial for enhancing power quality and power supply capability of the long-distance co-phase cable traction power supply system (TPSS). The integration of PFC introduces new demands on the power flow calculation methods, operation strategies, and analysis. Firstly, a compensation scheme with stronger power supply capability is proposed, and a multi-objective unified model for various schemes is developed based on the port connection angle. Secondly, a power flow calculation method based on network transformation and unified iteration is proposed, enabling efficient power flow calculation for asymmetric networks with PFC. Then, an operation strategy based on mathematical analysis to minimize PFC capacity is proposed, aiming to achieve the economic operation of TPSS. Finally, the accuracy of the compensation scheme and models is verified, and the different operation characteristics of the TPSS with PFC are demonstrated based on the Xining to Golmud Plateau Railway in China. The research shows that the voltage compensation capability of the proposed scheme is eight times that of the existing scheme with the same capacity. In contrast to the 45 ∼ 104 iterations needed for the alternating iteration method, the proposed method converges in merely 5 ∼ 7 iterations, achieving the same accuracy.