Secondary synchronous switching system for mobile power generation equipment and commercial power

Abstract

The invention provides a secondary synchronous switching system for mobile power generation equipment and commercial power. The secondary synchronous switching system comprises a synchronous control module, a generator synchronous contactor and a generator main circuit breaker, the commercial power input end is connected with the synchronization control module after passing through the synchronization sampling conversion change-over switch; the commercial power input line is provided with a commercial power synchronous contactor which is connected with the synchronization control module through a synchronization sampling conversion change-over switch. The commercial power synchronous contactor is connected with the load end of the user busbar after being converged with an output end line of the generator main circuit breaker; and a busbar parameter acquisition module is arranged between the user busbar load and the synchronous sampling conversion change-over switch. The synchronous control module, the commercial power synchronous contactor, the current transformer and other modules are arranged on existing mobile power generation equipment, field wiring operation is carried out according to a designed circuit, two-time synchronous switching of commercial power supply and generator power supply during maintenance of a commercial power line can be achieved, and loss caused by power failure to a user is avoided; and the field operation is convenient and fast.

Description

Technical Field

[0001] The invention relates to the technical field of power grid maintenance, and in particular to a mobile power generation equipment and a mains secondary synchronous switching system when a mains power grid is maintained. Background Art

[0002] The current city power grid (mainly for residential electricity) generally adopts grid management, and each management grid contains a certain number of users. For example, in rural areas, one production group is a management grid; in urban residential areas, one building is a management grid. The city power supply of the same management grid has a general control node. One of the reasons for this design is to facilitate regular maintenance of the city power network. During maintenance, multiple management grids can be repaired one by one without affecting other users, so as to minimize the impact of maintenance on user electricity consumption.

[0003] Currently, when the mains power grid is being inspected and maintained, in order to ensure the safety of the staff, it is necessary to first cut off the power consumption of a management grid and then carry out the inspection and maintenance, which will inevitably affect the power consumption of users in the management grid; in order to solve this problem, when the mains power is being inspected and maintained, a backup power supply can be provided for the users of the management grid, but obviously, due to economic cost considerations, it is impossible to configure two sets of mains power supply networks for all users.

[0004] Mobile power generation equipment (such as mobile diesel generators) can be widely used in construction sites, large gatherings, disaster relief sites, mines, night activity venues and other places that need to provide temporary power supply at night. It can meet the needs of large-scale and rapid urban construction, the needs of enriching people's cultural life, the needs of mineral exploration and development, and various industrial construction and social life needs. It can also be used as a backup power supply during city power maintenance. Mobile diesel generators can be installed on a frame like a container, or wheels can be installed under the chassis of the mobile diesel generator and moved to the maintenance construction site by a trailer. When it is necessary to repair the city power grid in a certain area, the mobile diesel generator can be easily connected to the city power supply network for power supply, avoiding the impact of the city power grid maintenance on the power consumption of users in the area. Traditional power generators need to be manually adjusted during the grid connection process, which is complicated to operate and has certain safety risks.

[0005] At present, when the mains power grid is under maintenance, even if the backup power supply is used, the usual practice is to first cut off the mains power supply, then connect the backup power supply, and then start the backup power supply to generate electricity; after the mains power grid maintenance is completed, the backup power supply is first cut off, then connected, and then the mains power supply is started. In other words, users need to go through the process of two power outages and two power supplies, and the impact on users still exists, such as power outages of working electrical appliances causing work interruptions and computer file loss.

[0006] Therefore, it is necessary to provide a method that can achieve synchronous switching between the mains power and a backup power source such as a mobile diesel generator when the mains power grid is under maintenance, providing users with zero-perception automatic switching. Summary of the invention

[0007] In response to the application needs of the prior art, the purpose of the present invention is to provide a secondary synchronous switching system between a mobile power generation equipment and the mains, which can automatically complete functions such as frequency comparison, synchronous closing, and automatic adjustment of power generation output between the mobile power generation equipment and the mains, and will not affect the user's electricity consumption when the mains is under maintenance.

[0008] Specifically, to achieve the purpose of the present invention, the present invention adopts the following technical solutions: A mobile power generation equipment and a secondary synchronization switching system for a city power supply, wherein the mobile power generation equipment comprises a generator, and the synchronization switching system comprises a synchronization control module, the generator is connected to the synchronization control module, a generator synchronization contactor is connected to the generator, the generator synchronization contactor is connected to the synchronization control module through a closing and feedback signal line, and the generator main circuit breaker is connected to the generator synchronization contactor; the city power input end is connected to the synchronization control module after passing through a synchronization sampling conversion switch; a city power synchronization contactor is provided on the city power input line, the city power synchronization contactor is connected to the synchronization conversion switch, and is connected to the synchronization control module through a closing and feedback signal line; the city power synchronization contactor is connected to the user busbar load terminal after the output end line of the generator main circuit breaker is merged; a busbar parameter acquisition module is provided between the user busbar load and the synchronization sampling conversion switch; the synchronization control module comprises a working display screen, a generator working state key, a generator stop key, a generator Open / Close key, a manual operation key, a city power working state key, a city power Open / Close key, and a generator start key.

[0009] Preferably, the mobile power generation equipment and the secondary synchronous switching system of the mains power also include a first current transformer, a second current transformer and a third current transformer; the synchronous control module collects the current signal of the mains power end load in real time through the first current transformer, and analyzes and determines the power size of the mains power end; collects the current signal of the upper end of the mains power synchronous contactor through the second current transformer, that is, the current output current of the mains power; collects the current signal of the upper end of the generator synchronous contactor through the third current transformer, that is, the current output current of the generator; the synchronous control module feeds back the control signal to the generator according to the collected signal, and the generator adjusts the output voltage and operating frequency in real time according to the voltage and frequency of the mains power. When the output voltage and frequency of the generator are consistent with the voltage and frequency of the mains power end, the generator synchronous contactor can be closed, and the load is powered by the mains power and the generator to achieve synchronous closing.

[0010] Preferably, the synchronous switching operation process of the mobile power generation equipment and the city power synchronous switching system is as follows: S1. Preparation at the same time: S11, turn the generator start knob switch 102 to the ON state, the generator powers on the synchronous control module 100, and triggers the manual operation button 125 on the synchronous control module 100 to enter the manual operation mode; S12, adjusting the synchronous sampling conversion switch 30 to the "secondary synchronous" mode; S13, first press the mains Close / Open button 113, and the mains synchronous contactor closes; S14. After the mains synchronous contactor is closed, turn off the main switch of the parallel mains incoming cabinet; S15, press the start button 112 to start the generator. After it runs normally, press the generator Close / Open button 123, and the generator will automatically find synchronization and close; S16, after the generator is synchronously closed, the user load is automatically transferred from the mains to the generator; S17. After observing that all loads on the mains end have been transferred and the power is close to zero, immediately press the mains Close / Open button 113 to disconnect the mains synchronous contactor. At this time, the load has been completely transferred to the generator, the mains synchronous contactor and the main switch of the mains incoming cabinet have been disconnected, and the mains maintenance can be carried out. S2. Anti-synchronization preparation: S21. Before supplying power after the mains maintenance, check that the main switch of the mains incoming cabinet is in the off state; S22. Press the AC power Close / Open button 113, the generator will automatically synchronize with the AC power, and the AC power synchronization contactor will automatically close; S23. After observing that the mains synchronous contactor is closed successfully, immediately press the generator Close / Open button 123 to avoid long-term reverse power after synchronization. The generator load begins to transfer to the mains, and the generator synchronous contactor automatically opens and disconnects; S24, after confirming that the synchronous contactor of the generator is open, close the main switch of the incoming line cabinet of the city grid, press the stop button 122 of the generator, and the generator stops; S25. After the generator stops, the module can be powered off directly, and the generator start knob switch 102 is turned to the OFF state. After a delay, the AC synchronous contactor automatically opens. At this time, the load has been completely transferred to the AC power, the AC synchronous contactor and the generator switch have been disconnected, and the quick-connect cable is disconnected to complete the entire maintenance process.

[0011] More preferably, in step S15, the specific process of the generator automatically finding synchronization and closing is: the synchronization control module collects the current signals of the AC power synchronization contactor and the upper end of the generator synchronization contactor; and the current signal of the load busbar end; the synchronization control module feeds back the signal to the generator, and the generator adjusts the output voltage and operating frequency in real time according to the voltage and frequency of the AC power. When the output voltage and frequency of the generator are consistent with the voltage and frequency of the AC power end, the generator synchronization contactor can be closed, and the load is powered by both the AC power and the generator, realizing synchronous closing.

[0012] More preferably, an indicator light is provided corresponding to each button on the synchronous control module.

[0013] More preferably, the synchronous control module is further provided with a plurality of function indication modules, including an alarm indication module, a warning indication module and an operation indication module.

[0014] More preferably, the synchronous control module, AC synchronous contactor, and current transformer are all integrated on the mobile diesel generator. When on-site maintenance is required, the staff can operate after wiring according to the circuit connection diagram of the present invention; when the maintenance is completed, the cables can be removed from the mobile diesel generator.

[0015] More preferably, a cable quick interface with a standardized structure is provided at the interface of each module.

[0016] The mobile power generation equipment and the mains secondary synchronous switching system of the present invention arranges a synchronous control module, a mains synchronous contactor, a current transformer and other modules on the existing mobile power generation equipment, and performs on-site wiring operations according to the designed circuit, so as to realize two synchronous switchings of the mains power supply and the generator power supply during the mains power line maintenance, without any impact on the user, thus avoiding the loss caused to the user by power failure; the on-site operation is convenient and fast, and the mobile diesel generator is suitable for different working environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects, features and advantages of the present invention will become apparent from the following detailed description in conjunction with the accompanying drawings, in which: Figure 1 The figure shows a schematic diagram of the system architecture of the mobile power generation equipment and the secondary synchronous switching system of the mains power of the present invention; Figure 2 The figure shows a schematic diagram of the module composition of the mobile power generation equipment and the secondary synchronization switching system of the mains power of the present invention; Figure 3 It is a schematic diagram showing the circuit connection between the mobile power generation equipment of the present invention and the secondary synchronous switching system of the mains; Figure 4 Shown Figure 3An enlarged schematic diagram of the circuit in the left dashed box shown in FIG. Figure 5 Shown Figure 3 An enlarged schematic diagram of the circuit in the right dashed box shown in FIG. Figure 6 The figure shows a schematic diagram of current signal acquisition for secondary synchronous closing control of the mobile power generation equipment and the secondary synchronous switching system of the mains power of the present invention. DETAILED DESCRIPTION

[0018] According to the purpose of the present invention and actual application needs, the present invention provides a mobile power generation equipment and a secondary synchronous switching system for the mains power, so that when the mains power line is being repaired, the mobile generator can be used for synchronous switching to supply power to the user's load, thereby avoiding affecting the user's electricity consumption.

[0019] Specifically, refer to Figure 1 , Figure 2 As shown, the mobile power generation equipment and the mains secondary synchronous switching system of the present invention include a synchronous control module 100, a mobile generator 20 connected to the synchronous control module 100, a generator synchronous contactor 22 connected to the mobile generator 20, the generator synchronous contactor 22 and the synchronous control module 100 are connected through a closing and feedback signal line, and the generator main circuit breaker 24 is connected to the generator synchronous contactor 22; the input end of the mains 10 is connected to the synchronous control module 100 after passing through a synchronous sampling conversion switch 30; a mains synchronous contactor 12 is provided on the input line of the mains 10, the mains synchronous contactor 12 is connected to the synchronous sampling conversion switch 30, and is connected to the synchronous control module 100 through a closing and feedback signal line; the output end line of the mains synchronous contactor 12 and the generator main circuit breaker 24 is connected to the user busbar load terminal 40 after merging; a busbar parameter acquisition module is provided between the user busbar load and the synchronous sampling conversion switch 30.

[0020] Among them, the synchronous control module 100 is used to receive data information and analyze it; send out voltage and frequency control signals; output opening and closing instructions; output protection alarm instructions; monitor key parameters such as voltage, current, water temperature, and oil pressure; the mobile generator 20 is generally a diesel generator, which can output reliable AC power for load use; the generator synchronous contactor 22 is controlled by the synchronous control module 100 to realize the on and off of the diesel generator output; the generator main circuit breaker 24 is a manual switch on the diesel generator output route, which is connected in series with the generator synchronous contactor. Through the manual switch, an additional safety guarantee is provided when the generator is disconnected; the synchronous sampling conversion switching switch 30, through the conversion switch, switches the sampling positions of different lines, and transmits the sampling information to the synchronous control module, and the synchronous control module determines the synchronous mode based on the sampling information.

[0021] Reference Figure 2 The module composition diagram of the mobile power generation equipment and the mains secondary synchronous switching system of the present invention is shown. The mobile power generation equipment in this embodiment is a diesel generator (referred to as generator); the synchronous control module 100 includes a working display screen 106, a generator working status key 120, a generator stop button 122, a generator Open / Close button 123, a manual operation button 125, a mains working status key 110, a mains Open / Close button 113 and a generator start button 112; the synchronous sampling conversion switch 30 and the generator start knob switch 102 are electrically connected to the synchronous control module 100.

[0022] According to the mobile power generation equipment and the secondary synchronous switching system of the mains of the present invention, when the mains needs to be repaired, the synchronous switching operation process of the mains and the mobile generator (generator) includes positive synchronous preparation and reverse synchronous preparation. The positive synchronous preparation refers to: the mains is in a normal load state, the generator is connected to the grid to accept the load, the mains does not stop the load transfer, and the mains switch is cut off for maintenance; the upper and lower ends of the mains synchronous contactor are respectively connected to the upper and lower ends of the main switch of the mains incoming cabinet, so that the contactor and the main switch of the mains incoming cabinet are connected in parallel, and the neutral line of the mains is connected with the neutral line of the generator; the reverse synchronous preparation refers to transferring the load of the generator to the mains after the mains maintenance is completed; specifically, the synchronous operation process of the present invention is as follows: S1. Preparation at the same time: S11, turn the generator start knob switch 102 to the ON state, the generator powers on the synchronous control module 100, and triggers the manual operation button 125 on the synchronous control module 100 to enter the manual operation mode; S12, adjusting the synchronous sampling conversion switch 30 to the "secondary synchronous" mode; S13, first press the mains Close / Open button 113, and the mains synchronous contactor 12 is closed; S14, after the mains synchronous contactor 12 is closed, turn off the main switch of the parallel mains incoming cabinet. Figure 1 User low voltage load switch in; S15. Press the generator start button 112 to start the generator. After the generator runs normally, press the generator Close / Open button 123, and the generator will automatically find synchronization and close. S16, after the generator is synchronously closed, the user load is automatically transferred from the mains to the generator; S17. After observing that all loads on the mains end have been transferred and the power is close to zero, immediately press the mains Close / Open button 113 to disconnect the mains synchronous contactor. At this time, the load has been completely transferred to the generator, the mains synchronous contactor and the main switch of the mains incoming cabinet have been disconnected, and the mains maintenance can be carried out. S2. Anti-synchronization preparation: S21. Before supplying power after the mains maintenance, check that the main switch of the mains incoming cabinet is in the off state; S22. Press the AC power Close / Open button 113, the generator will automatically synchronize with the AC power, and the AC power synchronization contactor will automatically close; S23. After observing that the mains synchronous contactor is closed successfully, immediately press the generator Close / Open button 123 to avoid long-term reverse power after synchronization. The generator load begins to transfer to the mains, and the generator synchronous contactor automatically opens and disconnects; S24, after confirming that the synchronous contactor of the generator is open, close the main switch of the incoming line cabinet of the city grid, press the stop button 122 of the generator, and the generator stops; S25. After the generator stops, the module can be powered off directly, and the generator start knob switch 102 is turned to the OFF state. After a delay, the AC synchronous contactor automatically opens. At this time, the load has been completely transferred to the AC power, the AC synchronous contactor and the generator switch have been disconnected, and the quick-connect cable is disconnected to complete the entire maintenance process.

[0023] During the above operation, the mains synchronous contactor acts as a mains bypass switch. When the mains synchronous contactor is closed, the main switch of the mains incoming cabinet can be disconnected, and the mains can flow to the user load through the mains synchronous contactor; then after the generator is synchronously closed, when the user load is completely transferred from the mains to the generator, the mains synchronous contactor is disconnected. At this time, the mains and the load are completely separated, and the mains line maintenance work can be carried out.

[0024] In step S15, the specific process of the generator automatically finding synchronization and closing is as follows: Figure 1 , Figure 2 , Figure 4 as well as Figure 6As shown, the synchronous control module 100 collects the current signal of the load at the mains end in real time through the first current transformer 14, analyzes and determines the size of the power at the mains end; collects the current signal at the upper end of the mains synchronous contactor 12 through the second current transformer 16, that is, the current output current of the mains; collects the current signal at the upper end of the generator synchronous contactor 22 through the third current transformer 26, that is, the current output current of the generator; since the lower ends of the mains synchronous contactor 12 and the generator synchronous contactor 22 are connected to the load busbar end together, the synchronous control module can collect the current output current of the generator, the mains output current and frequency, and the current required by the load in real time, and the synchronous control module 100 feeds back the control signal to the generator according to the collected signal, and the generator adjusts the output voltage and operating frequency in real time according to the voltage and frequency of the mains. When the output voltage and frequency of the generator are consistent with the voltage and frequency of the mains end, the generator synchronous contactor can be closed, and the load is jointly powered by the mains and the diesel generator to achieve synchronous closing, and then the load is transferred from the mains to the generator. Similarly, in step S22 of reverse synchronization preparation, the same principle is used to find the synchronous closing of the generator and the mains, and after closing, the load is transferred from the generator to the mains.

[0025] In another preferred embodiment, indicator lights 124 are provided corresponding to each button on the synchronization control module 100, so that the staff can understand the working status of each module of the system and the current operating environment in real time, and avoid safety problems caused by misoperation.

[0026] In another preferred embodiment, the synchronization control module 100 is further provided with a plurality of function indication modules, such as an alarm indication module 103 , a warning indication module 104 , an operation indication module 105 and the like.

[0027] In another preferred embodiment, the synchronous control module 100, the mains synchronous contactor 12, the synchronous sampling conversion switch 30, and the current transformer are all integrated on the mobile diesel generator. When on-site maintenance is required, the staff can operate after wiring according to the circuit connection diagram of the present invention; when the maintenance is completed, the cables can be removed from the mobile diesel generator. In another more preferred embodiment, a standardized cable fast interface is provided at the interface of each module to facilitate on-site wiring and disassembly operations.

[0028] The mobile power generation equipment and the mains secondary synchronous switching system of the present invention arranges a synchronous control module, a mains synchronous contactor, a current transformer and other modules on the existing mobile power generation equipment, and performs on-site wiring operations according to the designed circuit, so as to realize two synchronous switchings of the mains power supply and the generator power supply during the mains power line maintenance, without any impact on the user, thus avoiding the loss caused to the user by power failure; the on-site operation is convenient and fast, and the mobile diesel generator can flexibly adapt to different working environments.

[0029] The present invention is not limited to the described embodiments. Those skilled in the art may make some modifications or changes without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A mobile power generation equipment and a secondary synchronous switching system for a city power supply, the mobile power generation equipment comprising a generator, characterized in that: The synchronous switching system includes a synchronous control module, a generator connected to the synchronous control module, a generator synchronous contactor connected to the generator, the generator synchronous contactor and the synchronous control module are connected through a closing and feedback signal line, and the generator main circuit breaker is connected to the generator synchronous contactor; the mains input end is connected to the synchronous control module after passing through a synchronous sampling conversion switch; a mains synchronous contactor is provided on the mains input line, the mains synchronous contactor is connected to the synchronous conversion switch, and is connected to the synchronous control module through a closing and feedback signal line; the mains synchronous contactor and the generator main circuit breaker are connected to the user bus load terminal after the output end line converges; a bus parameter acquisition module is provided between the user bus load and the synchronous sampling conversion switch; the synchronous control module includes a working display screen, a generator working status key, a generator stop key, a generator Open / Close key, a manual operation key, a mains working status key, a mains Open / Close key and a generator start key.

2. The mobile power generation equipment and mains secondary synchronous switching system according to claim 1, characterized in that: It also includes a first current transformer, a second current transformer and a third current transformer; the synchronous control module collects the current signal of the load at the mains end in real time through the first current transformer, analyzes and determines the power size of the mains end; collects the current signal at the upper end of the mains synchronous contactor through the second current transformer, that is, the current output current of the mains; collects the current signal at the upper end of the generator synchronous contactor through the third current transformer, that is, the current output current of the generator; the synchronous control module feeds back the control signal to the generator according to the collected signal, and the generator adjusts the output voltage and operating frequency in real time according to the voltage and frequency of the mains. When the output voltage and frequency of the generator are consistent with the voltage and frequency of the mains end, the generator synchronous contactor can be closed, and the load is powered by the mains and the generator to achieve synchronous closing.

3. A mobile power generation equipment and mains secondary synchronous switching system as claimed in claim 2, characterized in that: The synchronous switching operation process of the mobile power generation equipment and the city power synchronous switching system is as follows: S1. Preparation at the same time: S11, turn the generator start knob switch to the ON state, the generator powers on the synchronous control module, and triggers the manual operation button on the synchronous control module to enter the manual operation mode; S12, adjust the synchronous sampling conversion switch to the "secondary synchronization" mode; S13, first press the AC Close / Open button, and the AC synchronous contactor will close; S14. After the mains synchronous contactor is closed, turn off the main switch of the parallel mains incoming cabinet; S15. Press the start button to start the generator. After it runs normally, press the generator Close / Open button and the generator will automatically find synchronization and close. S16, after the generator is synchronously closed, the user load is automatically transferred from the mains to the generator; S17. After all the loads on the mains end have been transferred and the power is close to zero, immediately press the mains Close / Open button to disconnect the mains synchronous contactor. At this time, the loads have been completely transferred to the generator, the mains synchronous contactor and the main switch of the mains incoming cabinet have been disconnected, and the mains maintenance can be carried out. S2. Anti-synchronization preparation: S21. Before supplying power after the mains maintenance, check that the main switch of the mains incoming cabinet is in the off state; S22. Press the AC Close / Open button, the generator will automatically synchronize with the AC, and the AC synchronous contactor will automatically close; S23. After observing that the mains synchronous contactor is closed successfully, press the generator Close / Open button immediately to avoid long-term reverse power after synchronization. The generator load begins to transfer to the mains, and the generator synchronous contactor automatically opens and disconnects; S24. After confirming that the synchronous contactor of the generator is open, close the main switch of the incoming line cabinet of the city grid, press the stop button 122 of the generator, and the generator stops; S25. After the generator stops, the module can be powered off directly, the generator start knob switch is turned to the OFF state, and the AC synchronous contactor automatically opens after a delay; at this time, the load has been completely transferred to the AC power, the AC synchronous contactor and the generator switch have been disconnected, and the quick-connect cable is disconnected to complete the entire maintenance process.

4. A mobile power generation equipment and mains secondary synchronous switching system as claimed in claim 3, characterized in that: In step S15, the specific process of the generator automatically finding synchronization and closing is as follows: the synchronization control module collects the current signals of the AC power synchronization contactor and the upper end of the generator synchronization contactor; and the current signal of the load busbar end; the synchronization control module feeds back the signal to the generator, and the generator adjusts the output voltage and operating frequency in real time according to the voltage and frequency of the AC power. When the output voltage and frequency of the generator are consistent with the voltage and frequency of the AC power end, the generator synchronization contactor can be closed, and the load is powered by the AC power and the generator to achieve synchronous closing.

5. A mobile power generation equipment and mains secondary synchronous switching system as claimed in claim 1, characterized in that: The synchronous control module is provided with indicator lights corresponding to each button.

6. A mobile power generation equipment and mains secondary synchronous switching system as claimed in claim 5, characterized in that: The synchronous control module is also provided with a plurality of function indication modules, including an alarm indication module, a warning indication module and an operation indication module.

7. A mobile power generation equipment and mains secondary synchronous switching system as claimed in claim 1, characterized in that: The synchronous control module, AC synchronous contactor and current transformer are all integrated on the mobile diesel generator. When on-site maintenance is required, the staff can operate after wiring according to the circuit connection diagram of the present invention; when the maintenance is completed, the cables can be removed from the mobile diesel generator.

8. A mobile power generation equipment and mains secondary synchronous switching system as claimed in claim 7, characterized in that: At the interface of each module, a cable quick interface with a standardized structure is provided.

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