Analysis in the Effect of Co-phase Traction Railway HPQC Coupled Impedance on Its Compensation Capability and Impedance-Mapping Design Technique Based on Required Compensation Capability for Reduction in Operation Voltage

Abstract

Railway hybrid power quality conditioner (HPQC) is one of the newly proposed devices for power quality compensation in co-phase high speed traction power supply for its benefit in reduction of operation voltage over conventional railway power quality conditioner (RPC). However, initial Railway HPQC design is developed based on minimum operation voltage at pre-defined fixed rated load. This may not be applicable in practical condition when load varies. In order to solve this problem, a Railway HPQC design with increased operation voltage has been investigated to enhance the compensation capability. Nevertheless, the compensation capability is even larger than that required during load variations such that the operation voltage is higher than it actually requires. A lower operation voltage can actually be used to provide required compensation capability when the coupled impedance is different from the designed rated one. In this paper, the effect of coupled impedance on the compensation capability in Co-phase Railway HPQC is being analyzed. An impedance-mapping design technique based on required compensation capability is then proposed based on the analysis. The proposed method is advantageous for lower operation voltage and smaller capacitance value. The effectiveness of impedance-mapping technique is verified via simulation and experimental results.Index Terms-Railway hybrid power quality conditioner, high-speed railway, power quality, co-phase traction power supply, impedance mapping Manuscript

Third harmonic injection control for co‐phase traction power supply system using direct AC/AC full‐bridge modular multilevel converter

“…All of these can cause accidents such as tripping and ramp stopping which endanger the safe and stable operation of trains and traction systems. The other is the power quality problems such as negative sequence current, reactive power, and harmonics due to the single-phase, non-linear, and random fluctuation characteristics of the locomotive load, which endanger the safe operation of the public grid and cause a series of electrical equipment failures [3][4][5].…”

A Novel Co-Phase Power-Supply System Based on Modular Multilevel Converter for High-Speed Railway AT Traction Power-Supply System

“…However, it can only eliminate the neutral section at the substation but cannot eliminate the neutral section in the entire traction network. This kind of co-phase power-supply schemes includes China's first co-phase power-supply unit, which is put into operation at the Mershan substation in 2010 [10] and the first single three-phase combined co-phase power-supply unit at the Shangyu substation in 2014 [15], as well as the Active Power Compensator (APC) [16], the Railway Power Conditioner (PRC) [17,18], the Hybrid Power Quality Conditioner (HPQC) [19][20][21][22], and the Hybrid Electrical Magnetic Power Quality Compensator (HEMPQC) [23]. The through co-phase power-supply schemes can simultaneously and completely solve the power quality problems and eliminate all neutral section of the whole traction network, making the traction network whole line through, e.g., the schemes based on the Cascaded H-Bridge (CHB) converter in [24,25] and the schemes based on the Modular Multilevel Converter (MMC) in [26].…”

Hybrid railway power quality conditioner based on half‐bridge converter and asymmetric balanced traction transformer with deadbeat current control

“…All ARPQCs follow the base performance of the RPC, which is the bilateral transfer of the active and reactive powers between the ERS feeders. Examples of ARPQCs are active PQ compensator [7, 8], half‐bridge RPC (HBRPC) [9, 10], hybrid PQ conditioner [11], Z ‐source RPC [12, 13] etc. Among these ARPQCs, the HBRPC has only four power switches and exhibits the very same compensating capability compared to other ARPQCs, but at a lower cost and hardware complexity [1, 10, 14].…”

“…On the other hand, the proper control system design of the ARPQCs is another challenge to be dealt with. Hysteresis current control is widely used in current control stage of the ARPQCs [11, 21] although other approaches such as PI current control [3, 22], proportional resonant (PR) control [23] etc. have also been used in current control stage.…”