Analysis On The Influence Of AC Power Supply System To DC Power Supply System In The AC/DC Hybrid Power Supply Section

In recent years, with the development of high-speed railway and urban rail transit, there are many situations in city establishment about how the high-speed railway and urban rail transit are laid closely or parallel on the overhead to each other, especially near the high-speed railway station or the hub station, such as Guangzhou South Railway Station (Wuhan-Guangzhou high-speed railway, the Guangzhou-Zhuhai intercity, Guangzhou-Shenzhen-Hong Kong Express Rail and Metro Line 2 transfer), Wuhan station (Wuhan-Guangzhou high-speed railway and subway line 4 transfer), Nanjing South Station (Beijing-Shanghai high-speed railway, Shanghai Nanjing Intercity and transfer Metro line 1 parallel to the ground segment), Chengdu Metro line 2 and ChengGuan high-speed railway laid closely to each other in the XiPu station, and Yangtze river bridge reserved for metro line 12 (DC system) to co-operation on the bridge with the Beijing-Shanghai high-speed railway and the Shanghai-Wuhan-Chengdu passenger dedicated. Furthermore, in some factory where are mainly in producing AC multiple units and DC urban rail train in this country, such as Zhuzhou Electric Locomotive Factory, There are also AC locomotives test line and urban rail vehicle test line (DC 1500V catenary, third rail) laid parallel to the ground close to the (line spacing of about 4m), etc. Actual application process is also reflected in the AC line electric locomotive during dynamic debugging, there have been high on the DC line induced voltages.Most of Urban Rail Transit (MRT) apply the DC traction power supply system, while high-speed rail apply AC traction power supply system. Because the DC rail traction power supply system can not be completely insulation, there would have a unavailable stray current, which is a risk to nearby infrastructure or other high-speed rail system to produce corrosion. AC system will produce induced voltage to DC system voltage by electromagnetic coupling.Due to the interaction of DC and AC electric traction power supply system, hazardous voltages and currents may lead to the damage on human body or equipment. For example, when the capacitive and inductive are coupling, the influence of AC rail to DC rail is always bigger than usual. While when the resistance (conductance) is coupling, AC system short-circuit may generate peak voltage in the structure of the connection with DC circuit connected to the railway, as well as more risk of stray current corrosion in the connect of the DC circuit and AC railway grounding circuit.The paper has firstly introduced some typical cases in the overseas of AC power supply system interacts with DC power supply system, which used to illustrate the AC-DC power supply system in the upper power system PCC point, the access order of two systems have effects on the power system, the two parallel sections traction net, feeder cables parallel,AC and DC systems hybrid running section separation zone, etc. all have interaction. Then the theoretical analysis of Dashengguan Bridge AC power supply system with DC power supply system has been researched as a case, which focused on the discussion of the combination of AC and DC traction power supply system parallel section’influences to the electromagnetic field, and electromagnetic induction of AC system to DC system,at last, a series of disincentives are proposed.