Reactive Power And Harmonic Detection Method For Electrified Railway

Electrical railway has been developed greatly in latest thirty years, which make great contribution to traffic communication. However, with the development of electrical railway, power quality such as reactive power, harmonic current, negative sequence is a serious problem. The solution is gradually focused to dynamic compensation. It is very important and for solving the problem to acquire the compensated component precisely at the environment of single phase power supply system, distorted voltage and frequently varied loadTransient reactive power detection method by constructing phase and the one by isolating active power have been studied by theory analysis and computer simulation in this paper. The first detection method can use three phase transient reactive power theory, but, detection circuits has time delay and become complex because of the added constructing phase. This method can be more proper for electrical railway detection by improving the added phase .The detection method by isolating reactive power is proper in electrical railway detection. research results shows that the phase lock loop (PLL) and low passing filter (LPF) used in detection method has negative effort for detection. Those detection method without PLL and LPF is more proper for electrical railway detection.