Electrical device for parallel operation of photovoltaic system and diesel generating set and control method

Abstract

The invention discloses an electrical device for parallel operation of a photovoltaic system and a diesel generating set and a control method, and relates to the technical field of power control, and the electrical device is characterized by comprising a dual-power change-over switch TS, a photovoltaic system grid-connected switch QA3 and a controller C1; and the dual-power change-over switch TS is composed of a first switch QA1, a second switch QA2 and a controller C. For a building or a park provided with a diesel generating set as a standby / emergency power supply of a fire-fighting and security load, a special guarantee bus section is arranged, the bus section is powered by the mains supply when the mains supply is normal, and the bus section is powered by the diesel generating set when the mains supply fails. The photovoltaic system is connected to the section of bus, and the photovoltaic system and the diesel generating set can operate in parallel when the commercial power is switched to be supplied with power by the diesel generating set. By arranging the controller, the working condition of the front-end power supply is monitored in real time, and the dual-power change-over switch TS is controlled to be accurately switched according to the working condition and the control steps.

Description

Technical Field

[0001] The present invention relates to the technical field of power control, and more specifically, to a control device and method for parallel operation of a photovoltaic system and a diesel generator set. Background Art

[0002] As photovoltaic systems are increasingly used in civil buildings, the existing photovoltaic system grid-connected technology cannot meet the needs of all application scenarios, and new equipment and technical support are needed to improve the utilization efficiency of photovoltaic systems.

[0003] When the city power outage occurs, the grid-connected photovoltaic system will exit operation due to island protection. Under this condition, all the electricity generated by the photovoltaic system will be abandoned, resulting in a large amount of abandoned light, and the photovoltaic system cannot be effectively used. Especially in some extreme climates, such as extremely high temperatures in summer, which cause a large increase in air conditioning loads, the municipal power grid will take power-limiting measures such as local power outages due to insufficient power supply capacity, which will cause the photovoltaic system to be unusable. This is an unreasonable phenomenon that needs to be solved urgently. For a large number of civil buildings, diesel generator sets are set up as self-contained standby / emergency power supplies according to fire protection needs. After the city power outage, the diesel generator sets will be put into operation to supply electricity to important loads when not in fire protection. Under this condition, if the photovoltaic system can be connected to the power supply system powered by diesel generator sets, the absorption rate of the photovoltaic system can be improved.

[0004] Currently, there is no equipment that can be used in the above application scenarios. Therefore, how to study and design a control device and method for the parallel operation of photovoltaic systems and diesel generator sets that can overcome the above defects is an urgent problem to be solved. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide an electrical device and a control method for the parallel operation of a photovoltaic system and a diesel generator set. By setting a controller, the front-end power supply condition is monitored in real time, and the dual power conversion switch TS is controlled to be accurately switched according to the condition and control steps.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] In the first aspect, an electrical device for parallel operation of a photovoltaic system and a diesel generator set is provided, including a dual power conversion switch TS, a photovoltaic system grid-connected switch QA3 and a controller C1;

[0008] The dual power conversion switch TS is composed of a first switch QA1, a second switch QA2 and a controller C; the inlet end of the first switch QA1 is used to connect to the mains power supply, and the inlet end of the second switch QA2 is used to connect to the power output end of the diesel generator set; the signal end of the controller C is connected to the internal signal output end 6 of the controller C1, and the outlet end of the dual power conversion switch TS is connected to a dedicated protection bus section;

[0009] The dedicated busbar section is connected to the incoming line end of the photovoltaic system grid-connected switch QA3, and the dedicated busbar section is extended to the outgoing line circuit of the load connected outside the device;

[0010] The outgoing line terminal of the photovoltaic system grid-connected switch QA3 is connected to the photovoltaic system outside the device, and the control signal terminal of the photovoltaic system grid-connected switch QA3 is connected to the internal signal output terminal 7 of the controller C1;

[0011] A first current transformer BC1 and a second current transformer BC2 are respectively provided on the outgoing line end of the photovoltaic system grid-connected switch QA3 and the extended section of the dedicated protection bus section; the output end of the first current transformer BC1 is connected to the internal signal input end 1 of the controller C1, and the output end of the second current transformer BC2 is connected to the internal signal input end 2 of the controller C1;

[0012] The internal signal input terminal 5 of the controller C1 is connected to the dedicated protection bus section, the external signal input terminal 8 of the controller C1 is connected to the signal output terminal of the photovoltaic system reverse power detection equipment outside the device, the external signal output terminal 9 of the controller C1 is a reserved port, and the external signal output terminal 10 of the controller C1 is connected to the control signal input terminal of the photovoltaic inverter outside the device.

[0013] Furthermore, the first switch QA1 and the second switch QA2 of the dual power conversion switch TS have a mechanical locking function;

[0014] When the first switch QA1 is closed, the second switch QA2 is not allowed to be closed;

[0015] When the second switch QA2 is closed, the first switch QA1 is not allowed to be closed.

[0016] Furthermore, the dual power transfer switch TS is provided with an electric operating mechanism, and has three positions: a normal position, a standby position and a power-off position;

[0017] The common position is that the first switch QA1 is closed and the second switch QA2 is open;

[0018] The standby position is that the first switch QA1 is open and the second switch QA2 is closed;

[0019] The power-off position is that the first switch QA1 is open, and the second switch QA2 is open;

[0020] Furthermore, the dual power conversion switch TS can receive an external control signal to automatically convert.

[0021] Furthermore, the photovoltaic system grid-connected switch QA3 has the functions of grid connection and island protection, and has the functions of reverse connection between the power supply end and the load end and cutting off the neutral line;

[0022] The photovoltaic system grid-connected switch QA3 can receive the control signal from the internal signal output terminal 7 of the controller C1 to perform opening and closing actions to achieve connection and disconnection between the photovoltaic system and the device.

[0023] Furthermore, the first current transformer BC1 collects the current data of the output end of the photovoltaic system grid-connected switch QA3 in real time, and transmits it to the internal signal input end 1 of the controller C1.

[0024] Furthermore, the second current transformer BC2 collects the current data of the extended section of the dedicated protection bus section in real time, and transmits it to the internal signal input terminal 2 of the controller C1.

[0025] Furthermore, the controller C1 detects the voltage data of the dedicated protection bus section through the internal signal input terminal 5.

[0026] Furthermore, the controller C1 receives the line terminal voltage signals of the first switch QA1 and the second switch QA2 through the internal signal input terminal 3 and the internal signal input terminal 4 to determine the working conditions of the mains power supply and the diesel generator set power supply.

[0027] Furthermore, the controller C1 receives the output signal of the reverse power detection device outside the device through the external signal input terminal 8. When the photovoltaic system does not allow reverse power to be connected to the grid, the controller C1 outputs a control signal from the external signal output terminal 10 to the photovoltaic inverter to control the output power or outputs a control signal from the internal signal output terminal 7 to control the photovoltaic system grid-connected switch QA3 to open.

[0028] In a second aspect, a control method for parallel operation of a photovoltaic system and a diesel generator set is provided, the method being used to implement an electrical device for parallel operation of a photovoltaic system and a diesel generator set as described in any one of the first aspects, comprising the following steps:

[0029] Step 1: Install the electrical device, the dual power switch TS is in the normal position, and the dedicated bus section is powered by the mains power supply;

[0030] Step 2: When the photovoltaic system grid-connected switch QA3 detects that the power supply of the dedicated protection bus section meets the grid-connected conditions, it automatically closes the switch to realize the grid-connected operation of the photovoltaic system; the controller C1 receives the reverse power detection device signal of the photovoltaic system in real time, and outputs a control signal to control the output power of the photovoltaic inverter or control the opening or closing of the photovoltaic system grid-connected switch QA3 according to whether the photovoltaic system allows reverse power access to the grid, so as to realize reverse power protection;

[0031] Step 3: When the mains power supply is cut off, the photovoltaic system grid-connected switch QA3 is automatically opened to realize the island protection of the photovoltaic system;

[0032] Step 4: After the city power outage, the diesel generator set starts and runs stably according to the design requirements. After the controller C of the dual power conversion switch TS detects that the output voltage of the diesel generator set meets the requirements, it automatically switches to the standby position, and the dedicated protection bus section is powered by the diesel generator set;

[0033] Step 5: In non-firefighting conditions, when the photovoltaic system grid-connected switch QA3 detects that the power supply of the dedicated busbar section meets the grid-connected conditions, it automatically closes the switch to realize the parallel operation of the photovoltaic system and the diesel generator set; in firefighting conditions, the fire alarm signal controls the shunt release of the photovoltaic system grid-connected switch QA3 to operate, realizing the disconnection of the photovoltaic system and the device;

[0034] Step 6: When the controller C1 detects that the mains power is restored, the controller C1 outputs a control signal to the controller C of the dual power conversion switch TS to control the dual power conversion switch TS to switch to the power-off position, and the photovoltaic system grid-connected switch QA3 automatically opens to realize the photovoltaic system island protection;

[0035] Step 7: After a delay of 2 to 15 seconds, the dual power switch TS automatically switches to the normal position, and step 3 is repeated.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The electrical device for the photovoltaic system and the diesel generator set running in parallel provided by the present invention monitors the front-end power supply working condition in real time by setting the controller C1 and the dual power conversion switch TS, and controls the dual power conversion switch TS to be switched accurately according to the working condition and control steps;

[0038] 2. The present invention realizes reliable grid connection or parallel operation and anti-islanding protection of the photovoltaic system by setting a photovoltaic system grid connection switch QA3;

[0039] 3. The present invention sets a controller C1 to collect signals such as voltage, frequency, and current of the dedicated bus section under the condition of mains power supply or diesel generator power supply in real time, monitor the power quality data, and realize power quality management by controlling the photovoltaic system inverter or communicating with the power quality management device outside the device;

[0040] 4. The present invention provides a controller C1 to monitor the reverse power detection device signal of the photovoltaic system in real time, and implements reverse power protection when the photovoltaic system does not allow reverse power access to the grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0042] Figure 1 It is a schematic diagram of the internal structure of the control device in Example 1 of the present invention. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0044] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to the other component.

[0045] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0046] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0047] Example 1: An electrical device for a photovoltaic system and a diesel generator set running in parallel, such as Figure 1 As shown, it includes a dual power conversion switch TS, a photovoltaic system grid-connected switch QA3 and a controller C1.

[0048] The dual power conversion switch TS consists of a first switch QA1, a second switch QA2 and a controller C; the incoming end of the first switch QA1 is used to connect to the mains power supply, and the incoming end of the second switch QA2 is used to connect to the power output end of the diesel generator set; the signal end of the controller C is connected to the internal signal output end 6 of the controller C1, and the outgoing end of the dual power conversion switch TS is connected to a dedicated protection bus section.

[0049] The dedicated protection bus section is connected to the incoming line end of the photovoltaic system grid-connected switch QA3, and the outgoing line end of the dedicated protection bus section is extended to the outgoing line circuit connected to the load outside the device.

[0050] The outgoing line terminal of the photovoltaic system grid-connected switch QA3 is connected to the photovoltaic system outside the device, and the control signal terminal of the photovoltaic system grid-connected switch QA3 is connected to the internal signal output terminal 7 of the controller C1.

[0051] The first current transformer BC1 and the second current transformer BC2 are respectively arranged on the outgoing line end of the photovoltaic system grid-connected switch QA3 and the extended section of the dedicated protection bus section; the output end of the first current transformer BC1 is connected to the internal signal input terminal 1 of the controller C1, and the output end of the second current transformer BC2 is connected to the internal signal input terminal 2 of the controller C1.

[0052] The internal signal input terminal 5 of the controller C1 is connected to the dedicated protection bus section, the external signal input terminal 8 of the controller C1 is connected to the signal output terminal of the photovoltaic system reverse power detection equipment outside the device, the external signal output terminal 9 of the controller C1 is a reserved port, and the external signal output terminal 10 of the controller C1 is connected to the control signal input terminal of the photovoltaic inverter outside the device.

[0053] In this embodiment, the first switch QA1 and the second switch QA2 of the dual power conversion switch TS have a mechanical locking function; when the first switch QA1 is closed, the second switch QA2 is not allowed to be closed; when the second switch QA2 is closed, the first switch QA1 is not allowed to be closed; and the dual power conversion switch TS is equipped with an electric operating mechanism, having three positions: a normal position, a standby position and a power-off position, wherein the normal position is that the first switch QA1 is closed and the second switch QA2 is open; the standby position is that the first switch QA1 is open and the second switch QA2 is closed; the power-off position is that the first switch QA1 is open and the second switch QA2 is open; the dual power conversion switch TS can receive an external control signal for automatic conversion.

[0054] In this embodiment, the photovoltaic system grid-connected switch QA3 has the functions of grid connection and island protection, and has the functions of reverse connection of the power supply end and the load end and cutting off the neutral line. The photovoltaic system grid-connected switch QA3 can receive the control signal of the internal signal output terminal 7 of the controller C1 to perform opening and closing actions to realize the connection and disconnection between the photovoltaic system and the device.

[0055] In this embodiment, the first current transformer BC1 collects the current data of the output end of the photovoltaic system grid-connected switch QA3 in real time, and transmits the current data to the internal signal input end 1 of the controller C1.

[0056] In this embodiment, the second current transformer BC2 collects the current data of the extended section of the dedicated protection bus section in real time and transmits it to the internal signal input terminal 2 of the controller C1.

[0057] In this embodiment, the controller C1 collects voltage data on the dedicated protection bus section in real time.

[0058] In this embodiment, the controller C1 determines the working conditions of the mains power supply and the diesel generator set power supply by receiving the line-in terminal voltage signals of the first switch QA1 and the second switch QA2.

[0059] In this embodiment, the controller C1 receives the output signal of the reverse power detection device outside the device through the external signal input terminal 8. When the photovoltaic system does not allow reverse power to be connected to the grid, the control signal is output from the external signal output terminal 10 to control the output power of the photovoltaic inverter or the control signal is output from the internal signal output terminal 7 to control the photovoltaic system grid-connected switch QA3 to open.

[0060] Embodiment 2: A control method for the parallel operation of a photovoltaic system and a diesel generator set, the method is used to realize an electrical device for the parallel operation of a photovoltaic system and a diesel generator set as described in Embodiment 1, comprising the following steps:

[0061] Step 1: Install the above electrical device, the dual power transfer switch TS is in the normal position, and the dedicated protection bus section is powered by the mains power supply;

[0062] Step 2: When the photovoltaic system grid-connected switch QA3 detects that the power supply of the dedicated busbar section meets the grid-connected conditions, it automatically closes to realize the grid-connected operation of the photovoltaic system;

[0063] The controller C1 receives the reverse power detection device signal of the photovoltaic system in real time, and outputs a control signal to control the output power of the photovoltaic inverter or control the opening or closing of the photovoltaic system grid-connected switch QA3 according to whether the photovoltaic system allows reverse power access to the grid, so as to realize reverse power protection;

[0064] Step 3: When the mains power is cut off, the photovoltaic system grid-connected switch QA3 automatically opens to realize the island protection of the photovoltaic system.

[0065] Step 4: After the city power outage, the diesel generator set starts and runs stably according to the design requirements. After the controller C of the dual power conversion switch TS detects that the output voltage of the diesel generator set meets the requirements, it automatically switches to the standby position, and the dedicated protection bus section is powered by the diesel generator set;

[0066] Step 5: In non-firefighting conditions, when the photovoltaic system grid-connected switch QA3 detects that the power supply of the dedicated busbar section meets the grid-connected conditions, it automatically closes the switch to realize the parallel operation of the photovoltaic system and the diesel generator set; in firefighting conditions, the fire alarm signal controls the photovoltaic system grid-connected switch QA3 shunt release to operate, realizing the disconnection of the photovoltaic system and the device;

[0067] Step 6: When the controller C1 detects that the mains power is restored, the controller C1 outputs a control signal to the controller C of the dual power conversion switch TS to control the dual power conversion switch TS to switch to the power-off position, and the photovoltaic system grid-connected switch QA3 automatically opens to realize the island protection of the photovoltaic system;

[0068] Step 7: After a delay of 2 to 15 seconds, the dual power conversion switch TS automatically switches to the normal position and repeats step 3.

[0069] Working principle: The electrical device for the parallel operation of the photovoltaic system and the diesel generator set provided by the present invention monitors the front-end power supply condition in real time by setting the controller C1 and the dual power conversion switch TS, and controls the dual power conversion switch TS to be accurately switched in and out according to the condition and the control steps; the present invention realizes the connection and disconnection between the photovoltaic system and the device by setting the photovoltaic system grid-connected switch QA3, and realizes the reliable grid-connected or parallel operation and anti-islanding protection of the photovoltaic system; the present invention realizes the real-time monitoring and collection of the voltage, frequency, current and other signals of the dedicated guarantee bus section under the mains power supply condition or the diesel generator set power supply condition by setting the controller C1, monitors the power quality data, and realizes the power quality management by controlling the photovoltaic system inverter or communicating with the power quality management device outside the device; the present invention realizes the reverse power protection when the photovoltaic system does not allow reverse power to be connected to the grid by setting the controller C1.

[0070] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0071] The present application is described with reference to the flowcharts and / or block diagrams of the methods, device systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0072] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0073] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0074] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An electrical device for the parallel operation of a photovoltaic system and a diesel generator set, characterized in that: It includes a dual power conversion switch TS, a photovoltaic system grid-connected switch QA3 and a controller C1; The dual power conversion switch TS is composed of a first switch QA1, a second switch QA2 and a controller C; the inlet end of the first switch QA1 is used to connect to the mains power supply, and the inlet end of the second switch QA2 is used to connect to the power output end of the diesel generator set; the signal end of the controller C is connected to the internal signal output end 6 of the controller C1, and the outlet end of the dual power conversion switch TS is connected to a dedicated protection bus section; The dedicated busbar section is connected to the incoming line end of the photovoltaic system grid-connected switch QA3, and the dedicated busbar section is extended to the outgoing line circuit of the load connected outside the device; The outgoing line terminal of the photovoltaic system grid-connected switch QA3 is connected to the photovoltaic system outside the device, and the control signal terminal of the photovoltaic system grid-connected switch QA3 is connected to the internal signal output terminal 7 of the controller C1; A first current transformer BC1 and a second current transformer BC2 are respectively provided on the outgoing line end of the photovoltaic system grid-connected switch QA3 and the extended section of the dedicated protection bus section; the output end of the first current transformer BC1 is connected to the internal signal input end 1 of the controller C1, and the output end of the second current transformer BC2 is connected to the internal signal input end 2 of the controller C1; The internal signal input terminal 5 of the controller C1 is connected to the dedicated protection bus section, the external signal input terminal 8 of the controller C1 is connected to the signal output terminal of the photovoltaic system reverse power detection equipment outside the device, the external signal output terminal 9 of the controller C1 is a reserved port, and the external signal output terminal 10 of the controller C1 is connected to the control signal input terminal of the photovoltaic inverter outside the device.

2. The electrical device for parallel operation of a photovoltaic system and a diesel generator set according to claim 1 is characterized in that: The first switch QA1 and the second switch QA2 of the dual power conversion switch TS have a mechanical locking function; When the first switch QA1 is closed, the second switch QA2 is not allowed to be closed; When the second switch QA2 is closed, the first switch QA1 is not allowed to be closed.

3. The electrical device for parallel operation of a photovoltaic system and a diesel generator set according to claim 2 is characterized in that: The dual power transfer switch TS is equipped with an electric operating mechanism and has three positions: a normal position, a standby position and a power-off position; The common position is that the first switch QA1 is closed and the second switch QA2 is open; The standby position is that the first switch QA1 is open and the second switch QA2 is closed; The power-off position is that the first switch QA1 is open, and the second switch QA2 is open; Furthermore, the dual power conversion switch TS can receive an external control signal to automatically convert.

4. The electrical device for parallel operation of a photovoltaic system and a diesel generator set according to claim 1 is characterized in that: The photovoltaic system grid-connected switch QA3 has the functions of grid connection and island protection, and has the functions of reverse connection between the power supply end and the load end and cutting off the neutral line; The photovoltaic system grid-connected switch QA3 can receive the control signal from the internal signal output terminal 7 of the controller C1 to perform opening and closing actions to achieve connection and disconnection between the photovoltaic system and the device.

5. The electrical device for parallel operation of a photovoltaic system and a diesel generator set according to claim 1 is characterized in that: The first current transformer BC1 collects the current data of the output end of the photovoltaic system grid-connected switch QA3 in real time, and transmits it to the internal signal input end 1 of the controller C1.

6. The electrical device for parallel operation of a photovoltaic system and a diesel generator set according to claim 1, characterized in that: The second current transformer BC2 collects the current data of the extended section of the dedicated protection bus section in real time, and transmits it to the internal signal input terminal 2 of the controller C1.

7. The electrical device for parallel operation of a photovoltaic system and a diesel generator set according to claim 1, characterized in that: The controller C1 detects the voltage data of the dedicated protection bus section through the internal signal input terminal 5.

8. The electrical device for parallel operation of a photovoltaic system and a diesel generator set according to claim 1, characterized in that: The controller C1 receives the line terminal voltage signals of the first switch QA1 and the second switch QA2 through the internal signal input terminal 3 and the internal signal input terminal 4 to determine the working conditions of the mains power supply and the diesel generator set power supply.

9. The electrical device for parallel operation of a photovoltaic system and a diesel generator set according to claim 1, characterized in that: The controller C1 receives the output signal of the reverse power detection device outside the device through the external signal input terminal 8. When the photovoltaic system does not allow reverse power to be connected to the grid, the controller C1 outputs a control signal from the external signal output terminal 10 to the photovoltaic inverter to control the output power or outputs a control signal from the internal signal output terminal 7 to control the photovoltaic system grid-connected switch QA3 to open.

10. A control method for the parallel operation of a photovoltaic system and a diesel generator set, the method being used to implement the electrical device for the parallel operation of a photovoltaic system and a diesel generator set as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Install the electrical device, the dual power switch TS is in the normal position, and the dedicated bus section is powered by the mains power supply; Step 2: When the photovoltaic system grid-connected switch QA3 detects that the power supply of the dedicated protection bus section meets the grid-connected conditions, it automatically closes the switch to realize the grid-connected operation of the photovoltaic system; the controller C1 receives the reverse power detection device signal of the photovoltaic system in real time, and outputs a control signal to control the output power of the photovoltaic inverter or control the opening or closing of the photovoltaic system grid-connected switch QA3 according to whether the photovoltaic system allows reverse power access to the grid, so as to realize reverse power protection; Step 3: When the mains power supply is cut off, the photovoltaic system grid-connected switch QA3 is automatically disconnected to realize the island protection of the photovoltaic system; Step 4: After the city power outage, the diesel generator set starts and runs stably according to the design requirements. After the controller C of the dual power conversion switch TS detects that the output voltage of the diesel generator set meets the requirements, it automatically switches to the standby position, and the dedicated protection bus section is powered by the diesel generator set; Step 5: In non-firefighting conditions, when the photovoltaic system grid-connected switch QA3 detects that the power supply of the dedicated busbar section meets the grid-connected conditions, it automatically closes the switch to realize the parallel operation of the photovoltaic system and the diesel generator set; in firefighting conditions, the fire alarm signal controls the shunt release of the photovoltaic system grid-connected switch QA3 to operate, realizing the disconnection of the photovoltaic system and the device; Step 6: When the controller C1 detects that the mains power is restored, the controller C1 outputs a control signal to the controller C of the dual power conversion switch TS to control the dual power conversion switch TS to switch to the power-off position, and the photovoltaic system grid-connected switch QA3 automatically opens to realize the photovoltaic system island protection; Step 7: After a delay of 2 to 15 seconds, the dual power switch TS automatically switches to the normal position, and step 3 is repeated.

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