Research On The Technology Of Voltage Regulation For10kV All-cable Power Through Line In High-speed Railways

With the continuous development of China’s high-speed electrified railways, high-speed railway and power system are increasingly inseparable. Railway power through line to provide power for the railway signaling, communications and other railway integrated electrical equipment, its normal voltage is important for high-speed railway operation safely. The cable has a series of advantages such as a little influence from environment, does not occupy space on the ground, not to expose, good safety, high reliability and so on, the proportion of railway power through line continues to rise. High-speed railway in China,10kV power through line widely apply all-cable line.The distributed capacitance of the cable is larger, the system in normal or fault will have larger capacitance current flows through, such bringing the all-cable line a series of problems must be solved. Cable capacitive current is big, the capacitance effect can make the voltage end of the line higher and the voltage distribution is not reasonable, beyond the scope allowed. The system capacitive current make excess capacitive reactive power, lead to the line power factor lower cannot meet the requirements. Through theoretical analysis of the operation of the cable, combined with the cable in practical engineering applications, this paper studied the voltage regulating strategy of all-cable power through line, making voltage reach the standard of power supply.This paper discusses the application of the cable for railway10kV power through line, analyses the parameters calculation method of the cable in railway environment. The lumped parameter model and distributed parameter model of the cable are both discussed and illustrates the reason of its voltage rise from the two models perspective respectively. According to the principle of voltage regulating all-cable through line’s voltage regulation technology is studied, and established the regulating strategy through on-load voltage regulator matching the reactive power compensation for the all-cable power through line. Reactive power compensation should combined fixed reactor compensation along the railway and the concentrated compensation in substations and distribution substations. Introduced the compensation principle of shunt reactor, SVC and SVQ and established the way of reactive power compensation and the degree of compensation through the derivation.Tianjin-qinhuangdao passenger dedicated line is designed as high as350km per hour standard passenger dedicated line and its power through line adopts the model of the all-cable. This paper make simulation through the PSCAD/EMTDC software and field measurement for the section of the power through line between Binhai north distribution substation and Tangshan distribution substation. By simulating the effect of various regulating methods under different load factor, established the optimal voltage regulating scheme., the test of various regulating methods is hold with the permit of engineering field and it demonstrate the validity of the voltage regulating technique.