Invention patent|A method for controlling AC/DC hybrid microgrid
Applicant Beijing Sifang Jibao Automation Co., Ltd.
State Grid Zhejiang Electric Power Company Electric Power Research Institute
Inventor Wu Heng Liu Yun Wu Jiahong Lin Da Feng Yibin
Technical field
The present disclosure relates to the field of micro-grid control technologies, and in particular, to an AC-DC hybrid micro-grid control method.
Background technique
With the informationization and intelligence of social development, there are an increasing number of AC and DC equipment, such as LED (Light Emitting Diode), computers, printers, video recorders, televisions, etc., which have formed a large number of AC equipment and DC equipment coexisting. Situation. Multiple AC/DC conversions are required in independent AC microgrids or DC microgrids to meet the needs of distributed power and load access.
In the related art, the operation mode and the control algorithm of the main converter and the DC partial energy storage converter need to configure a large-capacity energy storage in the DC part, and can bring up the entire AC-DC hybrid micro-grid in the off-network condition. At present, the DC part is constructed with distributed photovoltaics, and generally distributed with small-capacity distributed energy storage. The AC part is often equipped with large-capacity energy storage, which is not conducive to the promotion and application of AC-DC hybrid micro-grid.
In the related art, the operation mode and the control algorithm of the main converter and the DC partial energy storage converter need to configure a large-capacity energy storage in the DC part, and can bring up the entire AC-DC hybrid micro-grid in the off-network condition. At present, the DC part is constructed with distributed photovoltaics, and generally distributed with small-capacity distributed energy storage. The AC part is often equipped with large-capacity energy storage, which is not conducive to the promotion and application of AC-DC hybrid micro-grid.
Summary of the invention
In view of this, the present disclosure proposes an AC/DC hybrid microgrid control method to solve the problem of high maintenance difficulty caused by the low degree of automation of the AC/DC hybrid microgrid in the related art.
According to an aspect of the present disclosure, an AC/DC hybrid microgrid control method is provided for use in an AC/DC hybrid microgrid, where the AC/DC hybrid microgrid includes an islandable operating grid, the method comprising:
Detecting the operating condition of the canal island operating grid when the equipment in the grid operation grid is in a shutdown state;
Adjusting the working mode of the device according to the operating condition of the canal island operating grid.
In a possible implementation manner, the device is an inverter in the canal island operating system, and the working mode of the device is adjusted according to the operating condition of the canal island operating network, including:
The inverter is switched from a shutdown state to a constant power operation mode when the island is operated without faults, there is no overhaul setting, and both the DC portion and the AC portion have voltages.
In a possible implementation manner, the device is an inverter in the canal island operating system, and the working mode of the device is adjusted according to the operating condition of the canal island operating network, including:
Adjusting the converter from the shutdown state to the constant voltage constant frequency when the grid is fault-free, there is no maintenance setting, and the DC portion has voltage but the AC boundary switch is disconnected to cause the AC portion to have no voltage. In an operating mode, the inverter is configured to provide a voltage to the alternating current portion.
Adjusting the converter from the shutdown state to the constant voltage constant frequency when the grid is fault-free, there is no maintenance setting, and the DC portion has voltage but the AC boundary switch is disconnected to cause the AC portion to have no voltage. In an operating mode, the inverter is configured to provide a voltage to the alternating current portion.
When the canal island operation grid is fault-free and there is no maintenance setting, the energy storage unit is adjusted to be switched from the shutdown state to the droop control operation mode.
In a possible implementation, the AC/DC hybrid microgrid further includes a grid switch, the grid switch is provided with a first island protection device, and the protection time set by the first island protection device is the first time. The first time is greater than a reclosing time of the circuit breaker of the AC distribution network; the method further includes:
When the disconnection time of the circuit breaker of the AC distribution network reaches the protection time set by the first island protection device, the grid-connected switch is disconnected, so that the AC-DC hybrid micro-grid and the AC-matching The grid is off the grid.
In a possible implementation manner, the islandable operation network includes an AC demarcation switch, the AC demarcation switch is provided with a second island protection device, and the second island protection device sets a protection time of a second time; The method also includes:
When the AC/DC hybrid microgrid and the AC distribution network are off-grid, the AC demarcation switch is disconnected, triggering the converter in the island-connected power grid to switch to a constant voltage constant frequency operation mode, An inverter is used to supply a voltage to the alternating portion such that the alternating portion operates independently.
In a possible implementation, the canal-island operating system further includes a DC demarcation switch, and the DC demarcation switch is associated with the AC demarcation switch; the method further includes:
When the AC demarcation switch is turned off, the DC demarcation switch is turned off to allow the DC section to operate independently.
In a possible implementation, after the grid-connected switch and the AC demarcation switch are disconnected, the method further includes:
When the grid-connected switch is closed and the AC portion has a voltage, the AC demarcation switch is turned on during the same period, and the inverter in the island-connected power grid is triggered to switch to a constant power operation mode, so that the AC-DC hybrid micro The grid is connected to the AC distribution network.
The AC/DC hybrid microgrid control method of the present disclosure is used in an AC/DC hybrid microgrid, and the AC/DC hybrid microgrid includes an islandable operation grid, and the island can be detected when the equipment in the grid is in a shutdown state. The operating status of the power grid, and the operating mode of the equipment can be adjusted according to the operating conditions of the grid operation, thereby being able to identify the self-healing conditions after the AC/DC hybrid microgrid failure, and realize the handover through the self-starting control of the equipment. The self-recovery of the DC hybrid microgrid in the original working mode improves the automation level of the AC/DC hybrid microgrid, reduces the maintenance difficulty of the AC/DC hybrid microgrid, and increases the stability, reliability and economy of the AC/DC hybrid microgrid.
Other features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments. , features and aspects, and are used to explain the principles of the present disclosure.
FIG. 1 shows a schematic diagram of an AC-DC hybrid microgrid according to an embodiment of the present disclosure.
2 shows a flow chart of an AC-DC hybrid microgrid control method in accordance with an embodiment of the present disclosure.
FIG. 3 illustrates a flow chart of an AC/DC hybrid microgrid control method in accordance with an embodiment of the present disclosure.
FIG. 4 illustrates a flow chart of an AC/DC hybrid microgrid control method in accordance with an embodiment of the present disclosure.
List of reference signs
100: AC/DC hybrid microgrid; 10: can operate the grid on an island;
20: first converter; 30: grid switch;
101: AC part; 102: DC part;
103: AC demarcation switch; 104: DC demarcation switch;
105: Second inverter.
Brief Analysis of the Main Points of Invention Patent
An AC/DC hybrid microgrid control method, characterized in that, in an AC/DC hybrid microgrid, the AC/DC hybrid microgrid includes an island-connectable power grid, and the method includes:
When the device in the power grid is in the shutdown state, detecting the running condition of the islandable operating grid; adjusting the working mode of the device according to the operating condition of the canal operating grid.
The method according to claim 1, wherein the device is an inverter in the island operation grid, and the working mode of the device is adjusted according to an operation state of the island capable operation network, include:
The inverter is switched from a shutdown state to a constant power operation mode when the island is operated without faults, there is no overhaul setting, and both the DC portion and the AC portion have voltages.
The method according to claim 1, wherein the device is an inverter in the island operation grid, and an operation mode of the device is adjusted according to an operation state of the island capable operation network, include:
Adjusting the converter from the shutdown state to the constant voltage constant frequency when the grid is fault-free, there is no maintenance setting, and the DC portion has voltage but the AC boundary switch is disconnected to cause the AC portion to have no voltage. In an operating mode, the inverter is configured to provide a voltage to the alternating current portion.
The method according to claim 1, wherein the device is an energy storage unit in the canal island operating grid, and the working mode of the device is adjusted according to an operating condition of the canal island operating grid, include:
When the canal island operation grid is fault-free and there is no maintenance setting, the energy storage unit is adjusted to be switched from the shutdown state to the droop control operation mode.
The method according to claim 1, wherein the AC/DC hybrid microgrid further comprises a grid connection switch, wherein the grid connection switch is provided with a first island protection device, and the first island protection device is provided. The protection time is the first time, and the first time is greater than the reclosing time of the circuit breaker of the AC distribution network; the method further includes:
When the disconnection time of the circuit breaker of the AC distribution network reaches the protection time set by the first island protection device, the grid-connected switch is disconnected, so that the AC-DC hybrid micro-grid and the AC-matching The grid is off the grid.
The method according to claim 5, wherein the islandable operating grid comprises an AC demarcation switch, the AC demarcation switch is provided with a second island protection device, and the protection time set by the second island protection device For the second time; the method further includes:
When the AC/DC hybrid microgrid and the AC distribution network are off-grid, the AC demarcation switch is disconnected, triggering the converter in the island-connected power grid to switch to a constant voltage constant frequency operation mode, An inverter is used to supply a voltage to the alternating portion such that the alternating portion operates independently.
The method of claim 6, wherein the islandable operating grid further comprises a DC demarcation switch, the DC demarcation switch being associated with the AC demarcation switch; the method further comprising:
When the AC demarcation switch is turned off, the DC demarcation switch is turned off to allow the DC section to operate independently.
The method according to claim 6, wherein after the grid-connecting switch and the AC demarcation switch are disconnected, the method further comprises:
When the grid-connected switch is closed and the AC portion has a voltage, the AC demarcation switch is turned on during the same period, and the inverter in the island-connected power grid is triggered to switch to a constant power operation mode, so that the AC-DC hybrid micro The grid is connected to the AC distribution network.
Finish And Wood Working Staple
Wood Working Staple,T-Head Staple,Hardware Decoration Staple,18 Gauge Brad Nail
Zhejiang Best Nail Industrial Co., Ltd. , https://www.beststaple.com