Wang W.-A.,Central South University |
Wang W.-A.,CSR Zhuzhou Electrical Locomotive Research Institute Co. |
Gui W.-H.,Central South University
Tiedao Xuebao/Journal of the China Railway Society | Year: 2013
In order to solve the negative sequence current problem caused by high-speed and heavy-load locomotives for two phase traction power supply systems and to surpress harmonics and compensate reactive power, considering the advantage of a Modular Multilevel Converter (MMC) able to be directly applied in middle and high voltage systems without the need for an input transformer, the multilevel railway static power conditioner (MRPC) of half bridge modules-cascaded type was put forward, which consisted of two back-to-back power converters to achieve two phase transmission of active power. Appropriate power conversion eliminated or reduced negative sequence currents in the high voltage system and compensated the reactive power and harmonics in the feeding lines that connected to the converters. The presence of high voltage and small current on the DC side of the converter avoided the difficulty of heat dissipation caused by large direct currents. In the context of a traction substation installed with the Scott transformer, the structure, the operating principle and detection and control of active power, reactive power and harmonics of the MRPC system were analyzed. A five-level prototype was established. The effectiveness and feasibility of the proposed MRPC system was proved by experiment results.
Jing H.,Central South University |
Nian X.,Central South University |
Luo W.,CSR Zhuzhou Electrical Locomotive Research Institute Co.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012
DC side of VSC-HVDC station is connected directly, and the dc voltage regulating is also inter coupling with power control. The situation of transmission line icing is existed simultaneously. Based on the analysis of the existing VSC-HVDC station, a VSC-HVDC chopping converter station with ice-melting function was proposed. The converter station adopted the style of cascade VSC units, and used a chopper to control the voltage difference between two-terminal converter station in DC side to control the transmission power. It can be used as DC ice-melting power on transmission line. On the basis of the analysis of converter station's circuit topology with chopping transmission function in DC side, the mathematical model and equivalent circuit of a converter unit was obtained; with the operation states classification, the control strategy of the VSC-HVDC chopping converter station was researched. The control method under different operation modes was discussed, and the test prototype was manufactured. The test results show that the converter station can be applied to the middle and small VSC-HVDC and ice-melting of the power line respectively; the station can achieve the function of DC-chop transmission and DC ice-melting. The results also verify the correctness and effectiveness of the theoretical analysis and the system. ©2012 Chin. Soc. for Elec. Eng.
Lu Y.,Wuhan University of Technology |
Yi J.,CSR Zhuzhou Electrical Locomotive Research Institute Co. |
Lv Z.,Wuhan University of Technology
ICTIS 2015 - 3rd International Conference on Transportation Information and Safety, Proceedings | Year: 2015
Based on the safety evaluation model, risk offsetting factors of the dangerous cargo ship are analyzed. Correlation algorithm of the control factors of the maximum accident rate offset and algorithm of comprehensive offsetting factors are given. Combined with statistical analysis of inland ship accidents, the differences between the value of the inherent risk evaluation and the real risk evaluation have been compared. According to data analysis, the curves between each offsetting factors and safety evaluation values are obtained. The ship risk evaluation is determined accurately. The negative feedback mechanism of the ship safety management to the risk has been obtained. © 2015 IEEE.
Jing H.,CSR Zhuzhou Electrical Locomotive Research Institute Co. |
Jing H.,Central South University |
Nian X.,Central South University
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013
In light of the lower performance-price ratio of the ice-melting device and the relatively strong periodicity in its application, a hybrid high power DC ice-melting source with static synchronous compensator (STATCOM) function is put forward. Based on analysis of topology operation principle and operation switching process, the equivalent circuit and mathematical model of power unit and main circuit are deduced on the condition of STATCOM and DC ice-melting application. Modulation strategy, unit operation mode and control method are studied under STATCOM and DC ice-melting mode, and a new way for the unit balance is given. Simulation and test results show that this hybrid high power DC ice-melting source has better reactive power compensation and DC ice-melting effects. Consistent with the analysis, the results also verify the correctness of topology and control method. © 2013 State Grid Electric Power Research Institute Press.
Li J.,CSR Zhuzhou Electrical Locomotive Research Institute Co. |
Wu X.,CSR Zhuzhou Electrical Locomotive Research Institute Co. |
He X.,Central South University |
Li Z.,Central South University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014
For reducing the harmonic and reactive power of the grid after being filtered with reactive network, a LCL-APF system is applied to decrease the remain harmonic and reactive power of the grid for concentrated compensation in the transformer substation. The direct power control method is adopted which omits the detection and calculation of harmonic and reactive current and improves the distortion of grid current which is decreased to 3.78% from 26.86%. Moreover, through the analysis of the mathematical model and bode figure, the active damping method is applied in the power control loop for suppressing the resonance of three-phase LCL, which promotes the dynamic performance of LCL-APF. Simulation results show that the proposed method is correct and feasible. ©, 2015, Power System Protection and Control Press. All right reserved.