Switching device of energy storage system in micro-grid

Abstract

The utility model discloses a switching device of an energy storage system in a micro-grid. The switching device comprises an energy storage device; the energy storage converter is connected with energy storage equipment and is provided with two ports, one port is connected with a power grid through a power grid port of the first line, and the other port is connected with a load through a load port of the second line; the grid-connected contactor is arranged on the first line; the bypass circuit breaker is arranged between the power grid port and the load port; the load circuit breaker is arranged between the load port and the energy storage converter; wherein the bypass circuit breaker is mechanically interlocked with the load circuit breaker, and the bypass circuit breaker is electrically interlocked with the grid-connected contactor. The switching device ensures that the power supply of the load is uninterrupted under the condition that the energy storage system is in a grid-connected state, an off-grid state and an overhaul state.

Description

Technical Field

[0001] The utility model relates to the field of microgrid energy storage, in particular to the technical field of switching devices of energy storage systems in microgrids. Background Art

[0002] A microgrid is a small power generation and distribution system formed by integrating distributed power sources, energy storage devices, energy conversion devices, related loads, and monitoring and protection devices. Most of the power sources in a microgrid are distributed power sources with small capacities, that is, small units with power electronic interfaces, including micro gas turbines, fuel cells, photovoltaic cells, small wind turbines, and energy storage devices such as supercapacitors, flywheels, and storage batteries. Since they are connected to the user side and have the characteristics of low cost, low voltage, and low pollution, they have been widely used.

[0003] A microgrid is an autonomous system that can achieve self-control, protection, and management. As a complete power system, it relies on its own control and management to supply energy to achieve functions such as power balance control, system operation optimization, fault detection and protection, and power quality management.

[0004] As an important part of the microgrid, the energy storage system plays a decisive role in the stability of the microgrid. In order to ensure the power supply reliability of important loads, it is often placed at the back end of the energy storage system in the power grid. However, when the energy storage system is installed, debugged, or repaired, the backup important loads have to be powered off together with the energy storage system, and it is very likely that they cannot be restored in a short time, which instead reduces the power supply reliability of important loads.

[0005] Therefore, in the prior art, there is an urgent need for a reliable load switching device. Content of the Utility Model

[0006] In view of this, the purpose of the utility model is to provide a switching device for an energy storage system in a microgrid.

[0007] To achieve the above purpose, the utility model provides a switching device for an energy storage system in a microgrid, including:

[0008] Energy storage equipment;

[0009] An energy storage converter, which is connected to the energy storage equipment and has two ports. One port is connected to the power grid through the power grid port of the first line, and one port is connected to the load through the load port of the second line;

[0010] A grid-connected contactor, which is arranged on the first line;

[0011] A bypass circuit breaker, which is arranged between the power grid port and the load port;

[0012] A load breaker, which is arranged between a load port and an energy storage converter;

[0013] Wherein, the bypass breaker is mechanically interlocked with the load breaker, and the bypass breaker is electrically interlocked with the grid-connected contactor.

[0014] Optionally, it further includes a voltage detection unit and a control unit. The voltage detection unit is connected to the control unit. The voltage detection unit is used to detect whether the grid voltage is abnormal and send a feedback signal to the control unit, and the control unit is used to control the grid-connected contactor and the bypass breaker.

[0015] Optionally, the load breaker is arranged on the second line.

[0016] Optionally, the control unit realizes grid connection / disconnection conversion control, power-on control, and bypass control by controlling the grid-connected contactor and the bypass breaker.

[0017] Optionally, the bypass breaker is mechanically interlocked with the load breaker and has opposite states.

[0018] Optionally, the bypass breaker is electrically interlocked with the grid-connected contactor and has opposite states.

[0019] Optionally, the energy storage device is a storage battery.

[0020] Optionally, the energy storage converter is any one of centralized, string-type, and cascaded types.

[0021] Optionally, it further includes a manual switch, and the manual switch is connected to the bypass breaker.

[0022] Compared with the prior art, the beneficial effects of the present utility model are:

[0023] The switching device of the present utility model can ensure uninterrupted power supply to the load when the energy storage system is in the grid-connected state, off-grid state, and maintenance state. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is a schematic diagram of the switching device of the present utility model;

[0026] Figure 2 It is a schematic diagram of the interlocking method of the present utility model.

[0027] The reference numerals in the accompanying drawings are as follows:

[0028] 101, energy storage converter; 103, energy storage device; 107, voltage detection unit; 109, control unit; QF1, bypass circuit breaker; QF2, load circuit breaker; KM1, grid-connection contactor. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] Figure 1 The schematic diagram of the switching device of the energy storage system in the microgrid of the present invention is shown, as Figure 1 shown, the switching device of the energy storage system in the microgrid includes: an energy storage device 103, an energy storage converter 101, a grid-connection contactor KM1, a bypass circuit breaker QF1, a load circuit breaker QF2, a voltage detection unit 107, and a control unit 109.

[0031] Among them, the energy storage converter 101 (PCS) is connected to the energy storage device 103, and it is provided with two ports. One port is connected to the grid through the grid port of the first line, and one port is connected to the load through the load port of the second line; the grid-connection contactor KM1 is arranged on the first line; the bypass circuit breaker QF1 is arranged between the grid port and the load port; the load circuit breaker QF2 is arranged between the load port and the energy storage converter; among them, the bypass circuit breaker QF1 and the load circuit breaker QF2 are mechanically interlocked, and the bypass circuit breaker QF1 and the grid-connection contactor KM1 are electrically interlocked.

[0032] The voltage detection unit 107 is connected to the control unit 109. The voltage detection unit is used to detect whether the grid voltage is abnormal and send a feedback signal to the control unit. The control unit is used to control the grid-connection contactor and the bypass circuit breaker. Voltage detection can judge whether the grid is abnormal through the principle of delay detection, and at the same time can prevent the energy storage system from disconnecting from the grid in the case of voltage sag.

[0033] Optionally, the load circuit breaker QF2 is arranged on the second line.

[0034] Optionally, the control unit realizes grid connection / disconnection conversion control, power-on control, and bypass control by controlling the grid-connection contactor KM1 and the bypass circuit breaker QF1.

[0035] Figure 2 shows a interlocking mode, such as Figure 2 shown, the bypass circuit breaker QF1 and the load circuit breaker QF2 are mechanically interlocked and have opposite states. The purpose is that the load port can only be powered by one of the power grid or the energy storage device 103 at the same time, to avoid the connection between the off-grid state of the energy storage device 103 and the power grid.

[0036] The bypass circuit breaker and the grid-connected contactor are electrically interlocked and have opposite states. The purpose is that in the bypass state, the energy storage device 103 needs to be separated from the power grid to ensure the safety of maintenance personnel. The switching device also includes a manual switch, and the manual switch is connected to the bypass circuit breaker.

[0037] Optionally, the energy storage device is a storage battery. For example, it is a lithium battery.

[0038] Optionally, the energy storage converter is any one of centralized, string-type, and cascaded types.

[0039] The present utility model can achieve the following states;

[0040] Normal operation state: The grid-connected and off-grid switching of the energy storage system can be realized by controlling the grid-connected contactor KM1, and important loads can be continuously powered by the power grid or the energy storage.

[0041] Fault, maintenance, and debugging states: The energy storage system can be separated from the power grid through the manual bypass switch to ensure that important loads are powered by the power grid, and at the same time, the energy storage system can perform safe maintenance work.

[0042] The switching device of the present utility model can ensure uninterrupted power supply to the load when the energy storage system is in the grid-connected state, off-grid state, and maintenance state.

[0043] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A switching device for an energy storage system in a microgrid, characterized in that, Comprising: Energy storage device; Energy storage converter, which is connected to the energy storage device, has two ports, one port is connected to the power grid through the grid port of the first line, and one port is connected to the load through the load port of the second line; Grid-connected contactor, which is arranged on the first line; Bypass circuit breaker, which is arranged between the grid port and the load port; Load circuit breaker, which is arranged between the load port and the energy storage converter; Wherein, the bypass circuit breaker is mechanically interlocked with the load circuit breaker, and the bypass circuit breaker is electrically interlocked with the grid-connected contactor.

2. The switching device of the energy storage system in the microgrid according to claim 1, wherein It further includes a voltage detection unit and a control unit. The voltage detection unit is connected to the control unit. The voltage detection unit is used to detect whether the grid voltage is abnormal and send a feedback signal to the control unit, and the control unit is used to control the grid-connected contactor and the bypass circuit breaker.

3. The switching device of the energy storage system in the microgrid according to claim 1, characterized in that, The load circuit breaker is arranged on the second line.

4. The switching device of the energy storage system in the microgrid according to claim 2, characterized in that, The control unit realizes grid connection / disconnection conversion control, power-on control, and bypass control by controlling the grid-connected contactor and the bypass circuit breaker.

5. The switching device of the energy storage system in the microgrid according to claim 1, characterized in that, The bypass circuit breaker is mechanically interlocked with the load circuit breaker, and their states are opposite.

6. The switching device of the energy storage system in the microgrid according to claim 1, characterized in that, The bypass circuit breaker is electrically interlocked with the grid-connected contactor, and their states are opposite.

7. The switching device of the energy storage system in the microgrid according to claim 1, characterized in that, The energy storage device is a storage battery.

8. The switching device of the energy storage system in the microgrid according to claim 1, wherein, The energy storage converter is any one of centralized, string-type, and cascade-type.

9. The switching device of the energy storage system in the microgrid according to claim 1, characterized in that, It further includes a manual switch, which is connected to the bypass circuit breaker.

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