CN108847690B - Micro-grid operation mode seamless switching control device and method - Google Patents
Micro-grid operation mode seamless switching control device and method Download PDFInfo
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- CN108847690B CN108847690B CN201810906255.2A CN201810906255A CN108847690B CN 108847690 B CN108847690 B CN 108847690B CN 201810906255 A CN201810906255 A CN 201810906255A CN 108847690 B CN108847690 B CN 108847690B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
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Abstract
The invention discloses a micro-grid operation mode seamless switching control device and method based on time sequence control, wherein the device comprises a grid-connected point signal acquisition module, a grid abnormity discrimination module, a switching value output module and a switching control module; the device judges the abnormality of an external power grid by acquiring the switching value and the analog quantity of the grid-connected point in real time, receives an external planned grid connection/disconnection command at the same time, and realizes the switching of the switching state and the energy storage mode of the grid-connected point through the switching value output module according to an abnormality judgment result or the planned grid connection/disconnection command. Meanwhile, the method sets a delay time interval between sending the on/off command of the grid-connected point switch and sending the energy storage mode switching command, and finishes the switching of the grid-connected point switch and the energy storage mode at the same time, so that the grid connection and off-grid switching of the microgrid is smooth and rapid, the impact on a large power grid in the switching process of the operation mode of the microgrid can be reduced, and the seamless switching without power interruption can be realized.
Description
Technical Field
The invention relates to the technical field of micro-grid operation mode control, in particular to a micro-grid operation mode seamless switching control device and method based on time sequence control.
Background
The inside of the microgrid adopts a power electronic technology to realize the access of a distributed power supply, and adopts a set of complete energy management system platform to realize the protection, measurement and control of each element in the microgrid so as to realize the safe, stable and economic operation of the microgrid.
Under normal conditions, the micro-grid connection point is connected with the power distribution network, and the method is called a grid-connected operation mode. When the power grid fails or the power quality does not meet the requirements, the micro-grid connection point is disconnected from the power grid and operates independently, and the operation mode is called as an off-grid operation mode. To reduce the impact during the switching process, the switching between the two must be smooth and fast. The ideal state of switching is the moment when the grid-connected point switch is switched on (off), and the energy storage control mode is switched off.
At present, the micro-grid in China is in a starting stage, and domestic micro-grid projects are mostly exemplary projects and are used for researching and solving problems existing in the actual operation process of the micro-grid. In order to ensure the safe and stable operation of the microgrid and improve the power supply reliability, the seamless switching of the operation modes of the microgrid is always a research hotspot, but still in the research and exploration stage.
Noun interpretation
PQ: the PQ control is applied to the control of the energy storage converter in a grid-connected operation mode, and in the control mode, the energy storage converter is controlled to be constant in power output, and reactive power and active power of the energy storage converter are controllable.
V/f: the V/f control is applied to an off-grid operation mode, and in the control mode, the energy storage converter is controlled to be in voltage and frequency to meet the requirements of loads in the micro-grid.
Disclosure of Invention
The invention aims to provide a micro-grid operation mode seamless switching control device and method based on time sequence control, which can reduce the impact on a large power grid in the micro-grid operation mode switching process and realize seamless switching without power failure.
The microgrid operation mode comprises a grid-connected mode and an off-grid mode, the grid-connected point switch is located at a closed position in the grid-connected mode, the microgrid energy storage control mode is PQ, the grid-connected point switch is located at a separated position in the off-grid mode, and the microgrid energy storage control mode is V/f.
The technical scheme of the invention is as follows:
a seamless switching control device for micro-grid operation modes comprises a grid-connected point signal acquisition module, a grid abnormity discrimination module, a switching value output module, a switching control module and a network interface for receiving an external switching command;
the grid-connected point signal acquisition module acquires analog quantity on a circuit where a grid-connected point is located and on-off state signals of a grid-connected point switch;
the switching value output module comprises a first switching value output node and a second switching value output node, wherein the first switching value output node is used for outputting a switching command of a switching-on/switching-off state of a grid-connected point switch, and the second switching value output node is used for outputting a switching command of an energy storage control mode;
the power grid abnormity judging module judges whether an external power grid accessed by the micro-grid is abnormal or not according to the signals collected by the grid-connected point signal collecting module;
the switching control module sends a switching command of a switching on/off state of a grid-connected point switch to an existing grid-connected point switch control circuit through a first switching value output node in the switching value output module according to an abnormity judgment result of the grid abnormity judgment module and a received external switching command, and simultaneously sends a switching command of an energy storage control mode to the energy storage converter through a second switching value output node, so that the micro-grid is controlled to be switched between a grid-connected operation mode and an off-grid operation mode.
In the seamless switching control device for the micro-grid operation mode, the grid abnormity discrimination module and the switching control module can be combined and realized by adopting the existing microcontroller CPU. The analog quantity collected by the grid-connected point signal collecting module is the voltage and the current of the grid-connected point, and the switching value is the on-off state of the grid-connected point.
In the prior art, the switching on and off of the grid-connected point switch nodes is realized by a grid-connected point switch control circuit, the switching of the energy storage control mode of the microgrid is realized by an energy storage converter, and the energy storage converter is provided with an input interface for receiving an input signal for switching the energy storage control mode. According to the invention, the switching value output of the switching instruction is realized by setting the switching value output node of the grid-connected point on-off state switching and the switching value output node of the energy storage control mode switching, so that the grid-connected point switching control circuit and the energy storage converter receive corresponding switching value output. And changing the on-off state of the grid-connected point switch and changing the energy storage control mode.
Preferably, when the network interface receives an external switching command, the switching control module switches the switching-on/off state of the grid-connected point switch and the energy storage control mode through the first switching value output node and the second switching value output node according to the external switching command. The external switching commands comprise grid-connected to grid-disconnected and grid-disconnected commands, and the switching control module performs operation mode switching control according to the specific external switching commands.
Preferably, when the power grid abnormality judgment result indicates that abnormality occurs, the switching control module switches the switching-on/off state of the grid-connected point switch and the energy storage control mode through the first switching value output node and the second switching value output node, so that the micro-power grid is switched from a grid-connected operation mode to an off-grid operation mode.
Preferably, the first switching value output node is an auxiliary contact of a relay, and is connected to the grid-connected point switch control circuit, and the on-off state of the first switching value output node changes, so that the grid-connected point switch control circuit controls the on-off state change of the grid-connected point switch. The control circuit in the specific implementation is designed as the prior art.
Preferably, the first switching value output contact and the second switching value output contact respectively comprise two hard contacts; two hard contacts of the first switching value output node are connected to a grid-connected point switch control loop and are respectively used for driving the grid-connected point switch to be switched on and off; and a driving circuit is arranged between the two hard contacts of the second switching value output node and the input interface of the energy storage converter, and the two hard contacts of the second switching value output node are conducted to respectively enable the driving circuit to output switching value driving signals to the energy storage converter, so that the energy storage control mode is switched between V/f and PQ. The drive circuit comprises a power supply, and can be set as follows in specific implementation: when the hard contact corresponding to the PQ mode is conducted, the power supply is connected with the corresponding open interface, the corresponding open interface is set to be 1, the other open interface is set to be 0, the current energy storage control mode is controlled to be the PQ mode, when the hard contact corresponding to the V/f mode is conducted, the power supply is connected with the corresponding open interface, the corresponding open interface is set to be 1, the other open interface is set to be 0, and the current energy storage control mode is controlled to be switched to be the V/f mode. The specific circuit can adopt the prior art.
Preferably, the grid-connected point signal acquisition module, the power grid abnormity discrimination module, the switching control module and the network interface are positioned on the same circuit board to form an acquisition control unit, the switching value output module is an independently arranged plug-in, and the switching control module and the switching value output module are communicated through a CAN bus. Namely, when the switching value output node adopts the relay auxiliary contact, the corresponding relay and the corresponding contact are arranged in the plug-in unit. According to the invention, the first switching value output node for switching and driving the on-off state of the grid-connected point switch and the second switching value output node for switching and driving the energy storage control mode are arranged on the same DO plug-in unit, so that the communication delay between the CPU (central processing unit) of the switching control module and the DO plug-in unit can be ensured to be fixed.
As a result of research, the method has the following advantages: the time required by the grid-connected point switch to complete the switch-on/switch-off operation is longer than the time required by the energy storage mode switching, so that the delay time interval is set between the sending of the grid-connected point switch on/off command and the sending of the energy storage mode switching command, the grid-connected point switch switching and the energy storage mode switching are simultaneously completed, and the grid connection and the grid disconnection of the microgrid are smooth and rapid.
The invention also discloses a microgrid operation mode seamless switching control method based on the microgrid operation mode seamless switching control device, which comprises the following steps:
s1, collecting analog quantity and switching value of the grid-connected point;
s2, judging whether the external power grid connected with the micro-grid is abnormal or not according to the collected analog quantity and the collected switching value; when the external power grid is abnormal, the micro-grid unplanned off-grid control operation is executed;
s3, acquiring an external microgrid planned operation mode switching command, and executing microgrid planned off-grid or on-grid control operation according to the acquired command;
when the planned or unplanned off-grid control operation of the microgrid is executed: switching the control module at a preset delay time interval delta t1Sequentially transmitting a grid-connected point switching command and an energy storage control mode switching command to a switching value output module to be a V/f command;
when the planned grid-connected control operation of the microgrid is executed: switching the control module by a preset delay interval delta t2And transmitting a combined net point switching command and switching the energy storage control mode into a PQ command to the switching value output module in sequence.
The delay time interval deltat of the invention1And Δ t2The setting can be carried out according to the difference value between the time required by switching the switching state of the actual grid-connected point switch and the time required by switching the energy storage mode.
The analog quantity of the grid-connected point, namely the current and the voltage of the grid-connected point, and the switching quantity of the grid-connected point, namely the switching-on and switching-off state quantity of the grid-connected point switch.
Advantageous effects
According to the invention, in the switching process of the micro-grid operation mode, the time delay matching between the switching command of the grid-connected point switch output by the CPU and the energy storage mode switching command is set, so that the time sequence matching of the conduction of two switching value output nodes is realized, the aim that the energy storage control mode is just switched at the moment of switching on (off) of the grid-connected point switch is achieved, the impact on a large power grid in the switching process of the micro-grid operation mode is reduced, and the seamless switching without power failure is realized.
Meanwhile, the invention realizes the time sequence coordination control through a microcomputer device, namely a micro-grid operation mode seamless switching control device, the module design of the microcomputer device ensures that the microcomputer device has higher real-time performance, the control of the time sequence in ms level can be realized when the micro-grid operation mode is switched, and the error can reach the level less than 1 ms.
Drawings
FIG. 1 is a schematic diagram of a micro-grid operation mode seamless mode switching based on micro-computer device timing control;
FIG. 2 is a schematic diagram illustrating a microcomputer device off-grid command interval time constant value setting principle;
FIG. 3 is a schematic diagram illustrating a microcomputer device grid-connection command interval time constant value setting principle;
in fig. 1: 1-a microcomputer device; 2-a grid-connected point switch; 3-an energy storage converter;
in fig. 2: t 1-dividing the point on-off command generation time of the microcomputer device CPU; t 2-switching the energy storage control mode to V/f command generation time by the CPU of the microcomputer device; t 3-the microcomputer device divides the on time of the hard node of the point switch; t 4-switching the energy storage control mode to V/f hard node conduction time by the microcomputer device; t5/t 6-the time when the switching of the micro-grid operation modes is completed;
in fig. 3: t 1-the CPU of the microcomputer device merges the dot on-off command occurrence time; t 2-switching the energy storage control mode to PQ command generation time by the CPU of the microcomputer device; t 3-the microcomputer device merges the hard node conducting time of the dot switch; t 4-switching the energy storage control mode to the PQ hard node conducting time by the microcomputer device; t5/t 6-time of completion of switching of operation modes of the microgrid.
Detailed Description
The following further description is made in conjunction with the accompanying drawings and the specific embodiments.
In the prior art, switching on and off of the grid-connected point switch nodes is realized by a grid-connected point switch control circuit, switching of the microgrid energy storage control mode is realized by an energy storage converter, the energy storage converter is provided with an input interface, and two pairs of input nodes are used for receiving input and output instructions for switching the energy storage control mode.
According to the invention, the switching value output of the switching instruction is realized by setting the switching value output node of the grid-connected point on-off state switching and the switching value output node of the energy storage control mode switching, so that the grid-connected point switching control circuit and the energy storage converter receive corresponding switching value output. And changing the on-off state of the grid-connected point switch and changing the energy storage control mode.
Because the time required by the grid-connected point switch to complete the switching-in/switching-off operation is longer than the time required by the energy storage mode switching, when the micro-grid operation mode is controlled to be switched, the delay time interval is set by controlling the switching value output node to be conducted in the switching-on/switching-off state of the grid-connected point and controlling the switching value output node to be conducted in the energy storage control mode, so that the time sequence coordination control is realized, the grid-connected point switch switching and the energy storage mode switching are completed simultaneously, and the grid-connected and off-grid switching of the micro-grid is smooth and rapid.
Example 1
Referring to fig. 1, the present embodiment is a seamless switching control device for micro grid operation, that is, a microcomputer device 1 in fig. 1, which includes a grid-connected point signal acquisition module, a grid abnormality determination module, a switching value output module, a switching control module, and a network interface for receiving an external switching command;
the grid-connected point signal acquisition module acquires analog quantity on a circuit where a grid-connected point is located and on-off state signals of a grid-connected point switch;
the switching value output module comprises a first switching value output node and a second switching value output node, wherein the first switching value output node is used for outputting a switching command of a switching-on/switching-off state of a grid-connected point switch, and the second switching value output node is used for outputting a switching command of an energy storage control mode;
the power grid abnormity judging module judges whether an external power grid accessed by the micro-grid is abnormal or not according to the signals collected by the grid-connected point signal collecting module;
the switching control module sends a switching command of a switching on/off state of a grid-connected point switch to an existing grid-connected point switch control circuit through a first switching value output node in the switching value output module according to an abnormity judgment result of the grid abnormity judgment module and a received external switching command, and simultaneously sends a switching command of an energy storage control mode to the energy storage converter through a second switching value output node, so that the micro-grid is controlled to be switched between a grid-connected operation mode and an off-grid operation mode.
In this embodiment, when the network interface receives an external switching command, the switching control module switches the switching-on/off state of the grid-connected point switch and the energy storage control mode through the first switching value output node and the second switching value output node according to the external switching command. The external switching command comprises switching from grid connection to grid disconnection and switching from grid connection to grid connection.
When the power grid abnormity judgment result indicates that abnormity occurs, the switching control module switches the on-off state of the grid-connected point switch and the energy storage control mode through the first switching value output node and the second switching value output node, so that the micro-power grid is switched from a grid-connected operation mode to an off-grid operation mode.
In this embodiment, the first switching value output node may be an auxiliary contact of a relay, which is connected to the grid-connected point switch control circuit, and the on-off state of the first switching value output node changes, so that the grid-connected point switch control circuit controls the on-off state change of the grid-connected point switch. The control circuit in the specific implementation is designed as the prior art.
In the microcomputer device, a power grid abnormity judging module and a switching control module can be combined and realized by adopting the existing microcontroller CPU.
The grid-connected point signal acquisition module, the power grid abnormity discrimination module, the switching control module and the network interface are positioned on the same circuit board to form an acquisition control unit, the switching value output module is an independently arranged plug-in, and the switching control module is communicated with the switching value output module through a CAN bus. Namely, when the switching value output node adopts the relay auxiliary contact, the corresponding relay and the corresponding contact are arranged in the plug-in unit. According to the invention, the first switching value output node for switching and driving the on-off state of the grid-connected point switch and the second switching value output node for switching and driving the energy storage control mode are arranged on the same DO plug-in unit, so that the communication delay between the CPU (central processing unit) of the switching control module and the DO plug-in unit can be ensured to be fixed.
Example 2
Referring to fig. 2 and fig. 3, this embodiment is a method for controlling seamless switching of an operation mode of a microgrid based on the device for controlling seamless switching of an operation mode of a microgrid according to embodiment 1, and the method includes:
s1, collecting analog quantity and switching value of the grid-connected point;
s2, judging whether the external power grid connected with the micro-grid is abnormal or not according to the collected analog quantity and the collected switching value; when the external power grid is abnormal, the micro-grid unplanned off-grid control operation is executed;
s3, acquiring an external microgrid planned operation mode switching command, and executing microgrid planned off-grid or on-grid control operation according to the acquired command;
when the planned or unplanned off-grid control operation of the microgrid is executed: switching the control module at a preset delay time interval delta t1Sequentially transmitting a grid-connected point switching command and an energy storage control mode switching command to a switching value output module to be a V/f command;
when the planned grid-connected control operation of the microgrid is executed: switching the control module by a preset delay interval delta t2And transmitting a combined net point switching command and switching the energy storage control mode into a PQ command to the switching value output module in sequence.
The delay time interval deltat of the invention1And Δ t2The setting can be carried out according to the difference value between the time required by switching the switching state of the actual grid-connected point switch and the time required by switching the energy storage mode.
According to the invention, in the switching process of the micro-grid operation mode, the time delay matching between the switching command of the grid-connected point switch output by the CPU and the energy storage mode switching command is set, so that the time sequence matching of the conduction of two switching value output nodes is realized, the aim that the energy storage control mode is just switched at the moment of switching on (off) of the grid-connected point switch is achieved, the impact on a large power grid in the switching process of the micro-grid operation mode is reduced, and the seamless switching without power failure is realized.
Meanwhile, the invention realizes the time sequence coordination control through a microcomputer device, namely a micro-grid operation mode seamless switching control device, the module design of the microcomputer device ensures that the microcomputer device has higher real-time performance, the control of the time sequence in ms level can be realized when the micro-grid operation mode is switched, and the error can reach the level less than 1 ms.
Example 3
In this embodiment, referring to fig. 1, the first switching value output contact and the second switching value output contact respectively include two hard contacts; two hard contacts of the first switching value output node are connected to a grid-connected point switch control loop and are respectively used for driving the grid-connected point switch to be switched on and off; and a driving circuit is arranged between the two hard contacts of the second switching value output node and the input interface of the energy storage converter, and the two hard contacts of the second switching value output node are conducted to respectively enable the driving circuit to output switching value driving signals to the energy storage converter, so that the energy storage control mode is switched between V/f and PQ. The drive circuit comprises a power supply, and can be set as follows in specific implementation: when the hard contact corresponding to the PQ mode is conducted, the power supply is connected with the corresponding open interface, the corresponding open interface is set to be 1, the other open interface is set to be 0, the current energy storage control mode is controlled to be the PQ mode, when the hard contact corresponding to the V/f mode is conducted, the power supply is connected with the corresponding open interface, the corresponding open interface is set to be 1, the other open interface is set to be 0, and the current energy storage control mode is controlled to be switched to be the V/f mode.
According to the actual switching-off and switching-on time of a grid-connected point switch and the control mode switching completion time of the energy storage converter, setting an off-grid command interval time fixed value and a grid-connected command interval time fixed value on an engineering site according to the principles of the graph 2 and the graph 3.
The grid-connected operation of the microgrid is switched to off-grid operation, and the operation is divided into two types: planned off-grid, unplanned off-grid.
Planned off-gridThe microcomputer receives the off-grid command issued by energy management, and sets the interval time constant value delta t according to the off-grid command set by the device1And sequentially conducting the grid-connected point switch hard contact and switching the energy storage control mode to be a V/f hard node.
When the system is unplanned off-grid, the microcomputer device identifies the abnormality of the external power grid, and after the hard node of the point-to-point switch (protection trip) is switched on, the interval time delta t is set1And switching the energy storage control mode to be V/f hard node conduction.
Because the delay from the CPU command to the DO plug-in is fixed, the conduction time interval of the two hard nodes is delta t1。
Because the time required by the grid-connected point switch to complete the switching-off operation is longer than the time required by the energy storage mode switching, the grid-connected point switch node is firstly conducted, so that the switching of the grid-connected point switch state and the switching of the energy storage mode can be completed at the same time.
And when the off-grid operation of the microgrid is switched to the grid-connected operation, the energy management system issues a grid-connected command. The microcomputer device sets the interval time constant value delta t according to the preset off-grid command2And sequentially switching on the combined network point switch hard contact and switching the energy storage control mode to be a PQ hard node.
Because the delay from the CPU command to the DO plug-in is fixed, the conduction time interval of the two hard nodes is delta t2。
Because the time required by the grid-connected point switch to complete the closing operation is longer than the time required by the energy storage mode switching, the grid-connected point switch node is firstly conducted, so that the switching of the grid-connected point switch state and the switching of the energy storage mode can be completed at the same time.
The existing technology is to discriminate the abnormality of the external power grid based on the analog quantity and the light output quantity acquired by the grid-connected point.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (4)
1. A seamless switching control device for a micro-grid operation mode is characterized by comprising a grid-connected point signal acquisition module, a grid abnormity discrimination module, a switching value output module, a switching control module and a network interface for receiving an external switching command;
the grid-connected point signal acquisition module acquires analog quantity on a circuit where a grid-connected point is located and on-off state signals of a grid-connected point switch;
the switching value output module comprises a first switching value output node and a second switching value output node, wherein the first switching value output node is used for outputting a switching command of a switching-on/switching-off state of a grid-connected point switch, and the second switching value output node is used for outputting a switching command of an energy storage control mode;
the power grid abnormity judging module judges whether an external power grid accessed by the micro-grid is abnormal or not according to the signals collected by the grid-connected point signal collecting module;
the switching control module sends a switching command of a switching on/off state of a grid-connected point switch to an existing grid-connected point switch control circuit through a first switching value output node in the switching value output module according to an abnormity judgment result of the grid abnormity judgment module and a received external switching command, and simultaneously sends a switching command of an energy storage control mode to the energy storage converter through a second switching value output node, so that the micro-grid is controlled to be switched between a grid-connected operation mode and an off-grid operation mode;
when the external power grid is abnormal, the switching control module executes the unplanned off-grid control operation of the microgrid and executes the planned off-grid or grid-connected control operation of the microgrid according to the acquired external switching command;
when the planned or unplanned off-grid control operation of the microgrid is executed: switching the control module at a preset delay time interval delta t1Sequentially transmitting a grid-connected point switching command and an energy storage control mode switching command to a switching value output module to be a V/f command;
when the planned grid-connected control operation of the microgrid is executed: switching the control module by a preset delay interval delta t2Transmitting combined network point switching command and switching to switching value output module in sequenceThe energy storage control mode is a PQ command;
the delay time interval Δ t1And Δ t2And setting according to the difference between the time required by switching the switching state of the actual grid-connected point switch and the time required by switching the energy storage mode.
2. The seamless switching control device for the operation modes of the microgrid according to claim 1, wherein the first switching value output node is an auxiliary contact of a relay, which is connected to the grid-connected point switch control circuit, and the on-off state of the first switching value output node is changed, so that the grid-connected point switch control circuit controls the on-off state change of the grid-connected point switch.
3. The seamless switching control device for the operation mode of the microgrid according to claim 2, wherein the first switching value output contact and the second switching value output contact each comprise two hard contacts; two hard contacts of the first switching value output node are connected to a grid-connected point switch control loop and are respectively used for driving the grid-connected point switch to be switched on and off; and a driving circuit is arranged between the two hard contacts of the second switching value output node and the input interface of the energy storage converter, and the two hard contacts of the second switching value output node are conducted to respectively enable the driving circuit to output switching value driving signals to the energy storage converter, so that the energy storage control mode is switched between V/f and PQ.
4. The seamless switching control device for the micro-grid operation mode according to claim 1, wherein the grid-connected point signal acquisition module, the grid abnormality discrimination module, the switching control module and the network interface are located on the same circuit board to form an acquisition control unit, the switching value output module is an independently arranged plug-in unit, and the switching control module and the switching value output module are communicated through a CAN bus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810906255.2A CN108847690B (en) | 2018-08-10 | 2018-08-10 | Micro-grid operation mode seamless switching control device and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201810906255.2A CN108847690B (en) | 2018-08-10 | 2018-08-10 | Micro-grid operation mode seamless switching control device and method |
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| Publication Number | Publication Date |
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| CN108847690A CN108847690A (en) | 2018-11-20 |
| CN108847690B true CN108847690B (en) | 2020-06-23 |
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