As the only power source for electric locomotives in rail transit, the safety and reliability of the traction power supply system directly affect the quality and safety of transportation. The main problems of current traction power supply technology in China include uncontrollable power quality, discontinuous train power supply, and difficulty in identifying faults, etc.
Professor Li Qunzhan's research team from Southwest Jiaotong University has been devoting to long-term and in-depth research on the above problems, and won the first prize of the 2020 Sichuan Province Science and Technology Progress Award in the category of technological invention. The major innovations include：
1.Creating the general transformation theory of electrical quantities of traction substations, proposing the comprehensive compensation theory of reactive power, negative sequence and harmonics in traction substations, inventing and applying new connecting wiring traction transformers and new filters, etc., which establish the theoretical foundation for co-phase power supply and comprehensive governance of power quality in traction substation.
2.Inventing the co-phase power supply technology based on three-phase to two-phase transformer, co-phase power supply technology with combined structure, and two-way power supply technology, etc., developing a complete set of co-phase power supply device of 10MW level, which realize the objectives of canceling electrical phase separation, enhancing power quality, improving power supply capability and transportation capability.
Fig. 1. Co-phase power supply device
3.Inventing the technologies of segmentation protecting of traction network, status monitoring of train load, fault positioning of two-side feeding power supply, etc., which reduce the fault outage range of traction network to 25% compared to the traditional technology and the fault removal time to less than 30ms, realizing load status awareness, accurate location and rapid removal of faults.
Fig. 2. Measurement and control device for segmentation protection of traction network
Relevant achievements have been authorized with 39 national invention patents, 4 international invention patents, 41 national utility model patents, 26 software copyrights, 6 treatises and 218 papers.
The achievements have also been applied in heavy-haul railways, high-speed railways, suburban railways, general-speed railways and other rail transits, reducing train power outages, ensuring power supply safety, and promoting energy saving in traction power supply system. As of 2019, the cumulative new output has exceeded RMB 800 million, and the profit and cost savings have exceeded RMB 200 million. Due to the remarkable technical, economic and social benefits, it is evaluated as "an original technology, filling the world gap and reaching the international leading level".
