SYSTEM FOR STARTING LARGE-SCALE POWER LOAD IN MICRO-GRID

摘要

A system for staring a large-scale power load in a micro grid comprises a PCC grid connection switch, a micro grid alternating-current bus, an active power filter (APF), an energy storage inverter, an energy storage battery, a current-limiting resistor R, contactors K1-K3, a time relay KT, a power supply relay board, a micro grid maser control system, a frequency converter rectifying circuit, a frequency converter filter circuit, and a frequency converter inverter circuit. There are the advantages: an output torque of a power load can be effectively improved by using a variable frequency starting apparatus, and a starting current is also small; the provided method can effectively reduce a harmonic current when a variable frequency starting apparatus starts a power load, the phenomenon that two power sources supply power on a direct-current side of the variable frequency starting apparatus at the same time is avoided, thereby improving the stability and the economy of a micro grid.

主权项

1: A system for starting a large-scale power load in a micro-grid, comprising: PCC grid-connection switch, a micro-grid AC bus, an active power filter (APF), a battery storage inverter, an energy storage battery, a current-limiting resistor R, contactors K1-K3, a time relay KT, a power relay board, a micro-grid main control system, a rectifier circuit of converter, a filter circuit of converter, and an inverter circuit of converter, wherein, the micro-grid AC bus is bi-directionally connected with a bulk grid through the PCC grid-connection switch; the active power filter (APF) is bi-directionally connected with the micro-grid AC bus;
the energy storage battery comprises two branches, wherein one branch is bi-directionally connected with the micro-grid AC bus through the battery storage inverter, and the other branch is connected to the input terminal of the filter circuit of converter through main contact pins 1 and 2 of the contactor K3 and main contact pins 1 and 2 of the contactor K1 sequentially; the current-limiting resistor R is connected in parallel with main contact pins 1 and 2 of the contactor K1; the micro-grid AC bus is connected to the large-scale power load through the rectifier circuit of converter, main contact pins 1 and 2 of the contactor K2, the filter circuit of converter, and the inverter circuit of converter sequentially; a first control output terminal and a second control output terminal of the micro-grid main control system are connected to a first control input terminal I1 and a second control input terminal I2 of the power relay board respectively; a first power output terminal E1-1 of the power relay board is connected to a common output terminal E1-01 of the power relay board through power supply coil terminals A1 and A2 of the contactor K3 and normally closed auxiliary contact pins 5 and 6 of the contactor K2 sequentially; a second power output terminal E1-2 of the power relay board is connected to the common output terminal E1-01 of the power relay board through power supply coil terminals A1 and A2 of the contactor K2, normally closed auxiliary contact pins 5 and 6 of the contactor K3, and normally closed auxiliary contact pins 5 and 6 of the contactor K1 sequentially; a third power output terminal E1-3 of the power relay board is connected to the common output terminal E1-01 of the power relay board through power terminal pins 1 and 2 of the time relay KT and normally open auxiliary contact pins 7 and 8 of the contactor K3 sequentially; a fourth power output terminal E1-4 of the power relay board is connected to the common output terminal E1-01 of the power relay board through power supply coil terminals A1 and A2 of the contactor K1 and normally open contact pins 3 and 4 of the time relay KT sequentially.