A virtual in-phase power supply system and power supply method

Abstract

The invention discloses a virtual in-phase power supply system and a power supply method, including a railway power quality regulator arranged in a traction substation; one end of the railway power quality regulator is connected to a phase A power supply arm, and the other end is connected to a B phase power supply arm; Multiple battery energy storage modules, one end of the battery energy storage module is connected to the cascaded H-bridge ground over-current phase-splitting device, and the other end is connected to the railway power quality regulator; the cascaded H-bridge ground over-current phase-splitting device is connected to the neutral section; this The invention realizes through power supply for trains and solves the power quality problem of railway traction power supply system through the effective cooperation of railway power quality regulator and battery energy storage cascaded multi-level ground overcurrent phase separation device, and can greatly reduce The capacity of the power electronic device in the same-phase power supply system based on the existing railway power quality regulator is used to save costs.

Description

technical field [0001] The invention relates to a railway traction power supply system, in particular to a virtual in-phase power supply system and a power supply method. Background technique [0002] The single-phase power frequency traction power supply system consists of a traction substation and a traction power supply network. The traction substation steps down the three-phase 110kV or 220kV power supply of the power system to 27.5kV through the traction transformer, and then supplies it to the traction network, such as figure 1 shown. According to the power supply capacity of the substation, the catenary erection environment, and electromagnetic compatibility requirements, the AC traction power supply system can adopt different power supply methods; the traditional traction catenary power supply methods include direct power supply, current-absorbing transformer (Booster-Transformer , BT) power supply mode and parallel autotransformer (Auto-Transformer, AT) power suppl...

AI Technical Summary

Problems solved by technology

[0003] Because electric locomotives are single-phase loads and power electronic devices are commonly used, problems such as reactive power, negative sequence, and harmonics generally exist in power frequency single-phase traction power supply systems; in order to solve these problems, researchers have proposed various methods, among which railway Power quality conditioner (Railway Power Conditioner, RPC) is one of the more effective means; the topology of RPC is as follows figure 2 As shown, the RPC uses two voltage source converters, which form a back-to-back structure by sharing the DC side capacitors. The AC sides of the two voltage source converters are respectively connected in parallel to the two power supply arms through the transformer; Active power is transferred between the two power supply arms, and reactive power and active filtering are independently compensated, so that the loads of the two power supply arms are balanced in real time, thereby eliminating negative sequence current, and realizing reactive power compensation and active filtering; successfully developed in Japan in 2002 The 20MVA / 60kV RPC system applied to the Scott traction transformer and put into operation on the Shinkansen; the operation results show that the RPC can effectively suppress the voltage fluctuation of the traction power supply system, reduce the three-phase voltage unbalance, and has reactive power compensation and active harmonic wave function; however, RPC cannot eliminate the split phases existing in the substation, and it is still necessary to take corresponding measures to ensure that the train passes through the split phases safely.

[0004] Scholars in my country have proposed the use of balanced transformers combined with active filters to achieve the same phase power supply; theoretically it can be proved that the technical solution that saves the most symmetrical compensation capacity is to use balanced transformers and active power compensation devices (Active Power Compensator, APC), such as image 3 As shown, it can cancel the electrical phase separation at the exit of the traction substation; the system uses the APC device to realize the functions of traction transformer current balance, reactive power compensation and filter load harmonics, and can realize the functions of two traction substations Pull the same phase of the voltage of the power supply arm, thereby eliminating the electrical phase split inside the substation; this system has been applied in the power supply section of Meishan in my country, but the electrical split phase between two adjacent substations still exists in this scheme ; In addition, the voltage difference between the two bridge arms of the traction substation in my country is π / 3 or π / 2. When APC is used for compensation, its rated capacity is the capacity of the traction power supply arm, and there is a problem of high cost

Images