Rapid grid-connected and off-grid switching control system applied to mining area medium-voltage system

Abstract

The utility model discloses a rapid grid-connected and off-grid switching control system applied to a mining area medium-voltage system, which is applied to the field of grid-connected and off-grid switching of an energy storage converter, and aims to solve the problem that the current grid-connected and off-grid switching is not suitable for the medium-voltage system. Comprising a battery system, an energy storage converter, an EMS control system and a transformer. The energy storage converter converts direct current provided by the battery system into 690V alternating current, an alternating current outgoing line of the energy storage converter is directly connected to a boosting transformer of the boosting all-in-one machine, the boosting transformer boosts alternating current voltage provided by the energy storage converter to 15kV and provides the alternating current voltage for a load to use, and then the boosting transformer is connected with a 15kV power grid bus through the quick circuit breaker and the bypass circuit breaker. When the power grid is normal, the system operates in a grid-connected manner, and the power grid supplies power to the load and stores energy for charging; when the power grid is abnormal, the quick circuit breaker is disconnected and enters an off-grid mode, and the battery system supplies power to the load.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of energy storage converter and off-grid switching, especially relates to a quick on-grid and off-grid switching control system. BACKGROUND

[0002] At present, with the rapid development of new energy, the energy storage converter (PCS) on-grid and off-grid switching function in new energy microgrid, electrochemical energy storage base station, industrial and commercial energy storage and other scenes is widely concerned, according to the connection relationship with the power grid, PCS has two operating modes of on-grid and off-grid, in different operating modes, PCS needs to work in different control modes. When PCS control switching, the switching of control loop and instruction will cause the output voltage of PCS ac port to mutate, thereby causing system voltage, current serious fluctuation, further possibly causing voltage serious distortion, dynamic regulation time too long even system instability. Moreover, the current on-grid and off-grid switching method is mostly applied to low-voltage systems, and the on-grid and off-grid switching of medium-voltage systems can supply low-voltage systems of different voltage levels at the same time, so that the original multiple low-voltage systems on-grid and off-grid switching becomes only one medium-voltage system on-grid and off-grid switching, greatly reducing the on-grid and off-grid switching control. Therefore, how to control PCS to switch under the medium-voltage system and reduce the control switching time and voltage and current fluctuation in the switching process is particularly important in large power supply system. SUMMARY

[0003] The system can solve the problem of multiple devices required for traditional devices to switch on and off grid for multiple low-voltage systems of different voltage levels by switching on and off grid in a 6-35kV medium-voltage system.

[0004] The utility model discloses a technical scheme for a quick on-grid and off-grid switching control system applied to a mine area medium-voltage system, comprising: a battery system, an energy storage converter, a transformer, a 15kV power grid bus, a quick circuit breaker, a bypass circuit breaker and a load.

[0005] The battery system is connected with the transformer through the energy storage converter.

[0006] The transformer is connected with the load through the energy storage circuit breaker, and the transformer is further connected with the 15kV power grid bus through the energy storage circuit breaker and the quick circuit breaker.

[0007] The utility model discloses a beneficial effect: the utility model discloses in the switching of medium voltage 15kV, apply to the mine area medium voltage distribution room, the multiple voltage grade equipment under the mine area medium voltage distribution room, is under 15kV, 15kV switches, will be through each transformer step-down to different voltage grade, through the utility model discloses in the switching of medium voltage system, can provide 15kV through the system battery system when the power grid loses, simultaneously to the low voltage equipment of different voltage grade power supply, greatly reduced the equipment number of low voltage system and off -grid switching, strengthened the system stability simultaneously, reduced the fluctuation that can produce in the process of off -grid switching. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 It is the system block diagram of the utility model;

[0009] Figure 2 It is the communication connection schematic drawing of the utility model. DETAILED DESCRIPTION

[0010] For the technical content of the utility model of the person skilled in the art, the utility model content is further explained below in conjunction with the drawings.

[0011] Figure 1 It is the system diagram of the utility model, including: battery system, energy storage converter, EMS control system, transformer, 15kV power grid bus, fast circuit breaker and bypass circuit breaker and load.

[0012] The battery system is first composed of the battery management unit 1P16S of high safety, long life, environmental protection and pollution-free LiFePO4 battery cell and high -efficient LiFePO4 battery cell characteristics battery module, and then 25 battery modules are connected in series to form a battery cluster in a high voltage box, and five battery clusters are connected in parallel to a bus cabinet to provide direct current energy for the system, the direct current voltage of the battery system is 1280V, the capacity is 1MWh, and the discharge rate is 2C.

[0013] The bus cabinet direct current side is connected with a converter, the converter is a 2MW energy storage converter, the energy storage converter converts direct current into 690V alternating current, the alternating current output line of the energy storage converter is directly connected to the 0.69kV / 15kV step-up integrated machine step-up transformer, the step-up transformer raises the alternating voltage provided by the energy storage converter to 15kV, and provides the load for use, and then is connected with the 15kV power grid bus through the fast circuit breaker Q1 and the bypass circuit breaker Q2, when the power grid is normal, the energy storage circuit breaker Q3 is closed, the fast circuit breaker Q1 is closed, the system is connected to the grid, the load is powered by the grid, and the battery system is charged through the energy storage converter;When the power grid is abnormal, the fast circuit breaker Q1 is disconnected, the off -grid mode is entered, and the load is powered by the battery system;When, for example, Figure 1The utility model needs to overhaul quick circuit breaker Q1, need to set up double circuit, increase bypass circuit breaker Q2, when overhaul quick circuit breaker Q1, open quick circuit breaker Q1, close bypass circuit breaker Q2, close energy storage circuit breaker Q3, system parallel operation runs, by power grid to load power supply;When battery system fails or overhauls, open energy storage circuit breaker Q3, close quick circuit breaker Q1 and bypass circuit breaker Q2 one of them, do not affect load power supply.

[0014] The energy storage converter is TPCS-2000, the converted DC is 1000V-1500V, and the converted AC is 690V.

[0015] The EMS (energy management system) control system is located in the monitoring cabinet, which takes power at 690V on the AC side of the energy storage converter, and after taking power, it is powered by a 690 / 400 control transformer for the monitoring cabinet secondary power supply. Figure 1 A1, B1 and C1 on the monitoring cabinet represent three-phase AC, which is the phase sequence number.

[0016] The monitoring cabinet is an EMS control system, which communicates with PCS (converter), BMS (battery management system) and booster integrated cabinet, collects information of each subsystem, and controls the equipment to complete the on-off grid switching of the medium voltage system.

[0017] The EMS control system communicates with optical fiber and energy storage converter through CAN bus, and issues control instructions to the energy storage converter; the EMS control system, BMS battery management system, PCS and industrial computer form a local area network, and upload equipment operation data to the EMS; the EMS control system communicates with air conditioner, relay protector and fire fighting system through RS485, collects information of each device and controls them.

[0018] The BMS battery system is a three-level management system, which collects single cell information voltage, temperature and other information of the module to the BCM in the high voltage box, and then the BCM collects the module cell data to the BMS through CAN communication, so as to monitor the running state information of the battery cell.

[0019] Those skilled in the art will realize that the embodiments described herein are to help the reader understand the principles of the utility model, and should be understood as the protection scope of the utility model is not limited to such specific statements and embodiments. The utility model can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the utility model should be included in the scope of claims of the utility model.

Claims

1. A fast parallel and off-grid switching control system applied to the mine area under the medium voltage system, characterized by, Comprise: a battery system, an energy storage converter, a transformer, a 15kV power grid bus, a fast circuit breaker and a bypass circuit breaker, and a load; the battery system is connected with the transformer through the energy storage converter; the transformer is connected with the load through the energy storage circuit breaker; the transformer is further connected with the 15kV power grid bus through the energy storage circuit breaker, the fast circuit breaker in sequence.

2. The fast grid-connected and off-grid switching control system applied to the mine medium-voltage system according to claim 1, characterized in that, close the fast circuit breaker and the energy storage circuit breaker; the transformer is a 0.69kV / 15kV integrated transformer, which is used to convert 15kV AC power of the 15kV power grid bus into 0.69kV AC power, and the energy storage converter converts the 0.69kV AC power into DC power to charge the battery system.

3. The fast grid-connected and off-grid switching control system applied to the mine medium-voltage system according to claim 1, characterized in that, open the fast circuit breaker and close the energy storage circuit breaker; the DC power output by the battery system outputs 0.69kV AC power through the energy storage converter; the transformer is a 0.69kV / 15kV integrated transformer, which provides 15kV AC power for the load.

4. The fast grid-connected and off-grid switching control system applied to the mine medium-voltage system according to claim 1, characterized in that, a bypass circuit breaker is further included, which is connected in series between the 15kV power grid bus and the load.

5. The fast grid-connected and off-grid switching control system applied to the mine medium-voltage system according to any one of claims 1-4, characterized in that, an EMS control system is further included, which is in communication connection with the battery system, the energy storage converter and the transformer respectively.

6. The fast grid-connected and off-grid switching control system applied to the mine medium-voltage system according to claim 5, characterized in that, the battery system comprises a plurality of battery clusters connected in parallel, each battery cluster comprises a plurality of battery modules connected in series, and each battery module comprises a LiFePO4 battery cell and a battery management unit 1P16S.

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