System for starting large-scale power load in micro-grid

Patent metadata

Field	Value
Publication number	US-2016294187-A1
Application number	US-201415038714-A
Country	US
Kind code	A1
Filing date	Jun 24, 2014
Priority date	Nov 22, 2013
Publication date	Oct 6, 2016
Grant date	—

Abstract

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 K 1 -K 3 , 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.

First claim

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 K 1 -K 3 , 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 K 3 and main contact pins 1 and 2 of the contactor K 1 sequentially; the current-limiting resistor R is connected in parallel with main contact pins 1 and 2 of the contactor K 1 ; 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 K 2 , 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 I 1 and a second control input terminal I 2 of the power relay board respectively; a first power output terminal E 1 - 1 of the power relay board is connected to a common output terminal E 1 - 01 of the power relay board through power supply coil terminals A 1 and A 2 of the contactor K 3 and normally closed auxiliary contact pins 5 and 6 of the contactor K 2 sequentially; a second power output terminal E 1 - 2 of the power relay board is connected to the common output terminal E 1 - 01 of the power relay board through power supply coil terminals A 1 and A 2 of the contactor K 2 , normally closed auxiliary contact pins 5 and 6 of the contactor K 3 , and normally closed auxiliary contact pins 5 and 6 of the contactor K 1 sequentially; a third power output terminal E 1 - 3 of the power relay board is connected to the common output terminal E 1 - 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 K 3 sequentially; a fourth power output terminal E 1 - 4 of the power relay board is connected to the common output terminal E 1 - 01 of the power relay board through power supply coil terminals A 1 and A 2 of the contactor K 1 and normally open contact pins 3 and 4 of the time relay KT sequentially.

2 : The system for starting a large-scale power load in a micro-grid according to claim 1 , wherein, the power relay board comprises resistors R 1 -R 2 , photoelectric couplers OC 1 -OC 2 , relays J 4 -J 5 , DC power sources DC 1 -DC 2 , and AC power source E 1 ;
the first input control terminal I 1 of the power relay board is connected to the positive electrode pin 1 of an LED of the photoelectric coupler OC 1 through the resistor R 1 ; the negative electrode pin 2 of the LED of the photoelectric coupler OC 1 is grounded; a collecting electrode pin 4 of the photoelectric coupler OC 1 is connected to the positive electrode of a coil J 4 - 1 of the relay J 4 , and an emitting electrode pin 3 of the photoelectric coupler OC 1 is connected to the negative electrode of the coil J 4 - 1 of the relay J 4 through the DC power source DC 1 ; a normally open stationary contact of the relay J 4 is connected to the first power output terminal E 1 - 1 of the power relay board, and a normally open moving contact of the relay J 4 is connected to a terminal E 1 - 02 of the AC power source E 1 ; the second input control terminal I 2 of the power relay board is connected to the positive electrode pin 1 of an LED of the photoelectric coupler OC 2 through the resistor R 2 ; the negative electrode pin 2 of the LED of the photoelectric coupler OC 2 is grounded; a collecting electrode pin 4 of the photoelectric coupler OC 2 is connected to the positive electrode of a coil J 5 - 1 of the relay J 5 , and an emitting electrode pin 3 of the photoelectric coupler OC 2 is connected to the negative electrode of the coil J 5 - 1 of the relay J 5 through the DC power source DC 2 ; a normally open stationary contact of the relay J 5 is connected to the second power output terminal E 1 - 2 of the power relay board, and a normally open moving contact of the relay J 5 is connected to the terminal E 1 - 02 of the AC power source E 1 ; the third power output terminal E 1 - 3 of the power relay board and the fourth power output terminal E 1 - 4 of the power relay board are connected to the terminal E 1 - 02 of the AC power source E 1 respectively; the terminal E 1 - 01 of the AC power source E 1 is the common output terminal E 1 - 01 of the power relay board 3 .

3 : The system for starting a large-scale power load in a micro-grid according to claim 2 , wherein, both of the photoelectric couplers OC 1 -OC 2 are of model TLP521-1; both of the relays J 4 -J 5 are of model MY2NJ-12 VDC.

4 : The system for starting a large-scale power load in a micro-grid according to claim 1 , wherein, the rectifier circuit of converter is a three-phase full-wave bridge circuit composed of rectifier diodes D 1 -D 6 .

5 : The system for starting a large-scale power load in a micro-grid according to claim 4 , wherein, all of the rectifier diodes D 1 -D 6 are of model SKD110/12E.

6 : The system for starting a large-scale power load in a micro-grid according to claim 1 , wherein, the filter circuit of converter is a LC filter circuit composed of an inductor L and a capacitor C.

7 : The system for starting a large-scale power load in a micro-grid according to claim 1 , wherein, the inverter circuit of converter is a three-phase full-bridge inverter circuit composed of IGBT modules Q 1 -Q 6 and diodes D 7 -D 12 ; the power storage inverter is a three-phase full-bridge inverter circuit composed of IGBT modules Q 7 -Q 12 and diodes D 13 -D 18 .

8 : The system for starting a large-scale power load in a micro-grid according to claim 7 , wherein, all of the IGBT modules Q 1 -Q 12 are of model FS450R12KE3 from Infineon.

9 : The system for starting a large-scale power load in a micro-grid according to claim 1 , wherein, the time relay KT is of model JS14P from Chint; the micro-grid main control system is of model NMC1000; the PCC grid-connection switch is of model MG2312; the active power filter (APF) is of model SPA3-100A/0.4.

10 : The system for starting a large-scale power load in a micro-grid according to claim 2 , wherein, the time relay KT is of model JS14P from Chint; the micro-grid main control system is of model NMC1000; the PCC grid-connection switch is of model MG2312; the active power filter (APF) is of model SPA3-100A/0.4.

11 : The system for starting a large-scale power load in a micro-grid according to claim 3 , wherein, the time relay KT is of model JS14P from Chint; the micro-grid main control system is of model NMC1000; the PCC grid-connection switch is of model MG2312; the active power filter (APF) is of model SPA3-100A/0.4.

12 : The system for starting a large-scale power load in a micro-grid according to claim 4 , wherein, the time relay KT is of model JS14P from Chint; the micro-grid main control system is of model NMC1000; the

Assignees

• State Grid Corp China
• State Grid Hebei Electric Power Res Inst
• Hebei Electric Power Commissioning Inst

Inventors

• Gao Zhiqiang
• Meng Liang
• Hu Wenping
• Wang Wenxin
• Fan Hui
• Jing Hao
• Liang Bin

Classifications

• H02J3/381

  Dispersed generators · CPC title

• Y02P80/14

  District level solutions, i.e. local energy networks · CPC title

• H02J3/01 Primary

  Arrangements for reducing harmonics or ripples · CPC title

• H02M7/44

  by static converters · CPC title

• H02M1/12

  Arrangements for reducing harmonics from AC input or output · CPC title