Parallel operation control system of medium and low voltage emergency standby diesel generator set

Abstract

The utility model provides a parallel operation control system for a medium-low voltage emergency standby diesel generating set. The parallel operation control system comprises a medium-low voltage generating set, a medium-low voltage parallel operation cabinet and a feeder line cabinet, the power generation output end of the medium-low voltage generator set is connected to the wire inlet end of the medium-low voltage parallel cabinet through a medium-low voltage cable, a control circuit of the medium-low voltage generator set is connected to the control end of the medium-low voltage parallel cabinet, a control power line of the medium-low voltage parallel cabinet is connected to the UPS, and a control power line of the feeder cabinet is connected to the transformer. A unit voltage sampling line is connected to a unit side cabinet voltage transformer, and a busbar voltage sampling line is connected to a middle-low parallel cabinet voltage transformer; the unit mode switch button of the remote operation panel of the medium-low voltage parallel cabinet is connected with a controller of the unit through a control cable, and the medium-low voltage generator set is connected with the medium-low voltage parallel cabinet through a CAN communication line; according to the utility model, the problem of difficulty in parallel operation control of the medium-low voltage emergency standby diesel generator set can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of power grid equipment, in particular to a parallel control system for medium and low voltage emergency standby diesel generator sets. Background Art

[0002] In power station projects, shipbuilding, mining machinery, and oilfield power supply projects, 690V medium and low voltage distribution systems are widely used. Their advantages and disadvantages lie in improving power transmission efficiency and reducing power loss. As a standby power source, 690V medium and low voltage diesel generators are mostly used alone, and there are certain technical difficulties in parallel operation of multiple generators with rapid load carrying.

[0003] In this case, single-unit use can generally be achieved. In special cases, when multiple generators are in parallel operation with rapid load carrying, for the 690V medium and low voltage system, the selection requirements for electrical components are different from those of the 400V low voltage system. The parallel conditions are relatively harsh, the response time needs to be fast, the control logic of the controller changes, and the concept of closing the switch first and then exciting the magnet is adopted. This technology has certain technical difficulties and risks, such as reverse power or control failure where the circuit breaker cannot be normally tripped.

[0004] The above problems need to be solved. Summary of the Invention

[0005] The utility model provides a parallel control system for medium and low voltage emergency standby diesel generator sets, which can solve the problem of difficult parallel control of medium and low voltage emergency standby diesel generator sets.

[0006] A parallel control system for medium and low voltage emergency standby diesel generator sets includes medium and low voltage generator sets, a medium and low voltage parallel cabinet, and a feeder cabinet; the power generation output end of the medium and low voltage generator sets is connected to the input end of the medium and low voltage parallel cabinet through a medium and low voltage cable, the control line of the medium and low voltage generator sets is connected to the control end of the medium and low voltage parallel cabinet, the control power supply line of the medium and low voltage parallel cabinet is connected to a UPS power supply, the control power supply line of the feeder cabinet is connected to a transformer, the unit voltage sampling line is connected to the voltage transformer of the unit side cabinet, and the busbar voltage sampling is connected to the voltage transformer of the medium and low voltage parallel cabinet; the unit mode switch button on the remote operation panel of the medium and low voltage parallel cabinet is connected to the controller of the unit through a control cable, and the medium and low voltage generator sets are connected to the medium and low voltage parallel cabinet through a CAN communication line.

[0007] The control system is used for controlling medium and low voltage emergency standby diesel generator sets in an emergency standby system; the medium and low voltage emergency standby diesel generator sets include G1 medium and low voltage generator sets, G2 medium and low voltage generator sets, and G3 medium and low voltage generator sets of the medium and low voltage generator sets; the deployment area of the control system includes the medium and low voltage parallel cabinet and the feeder cabinet.

[0008] The power generation output breaker of the G1 medium and low voltage generator set is GB1; the power generation output breaker of the G2 medium and low voltage generator set is GB2; the power generation output breaker of the G3 medium and low voltage generator set is GB3;

[0009] The parallel operation controller group includes a first parallel operation controller connected to the G1 medium and low voltage generator set, a second parallel operation controller connected to the G2 medium and low voltage generator set, and a third parallel operation controller connected to the G3 medium and low voltage generator set; the first parallel operation controller, the second parallel operation controller, and the third parallel operation controller are sequentially connected through a CAN communication line.

[0010] The parallel operation controller group is arranged in the medium and low voltage parallel operation cabinet, and the communication link formed by the CAN communication line in the parallel operation cabinet includes multiple communication connection links.

[0011] The medium and low voltage generator set is a diesel generator set, and the number of its parallel operation controllers is no more than 32.

[0012] The working mode of the emergency standby system includes an automatic operation mode or a manual operation mode.

[0013] When any external normal power supply fails and the emergency standby system receives a remote start signal sent by the grid ATS or the faulty busbar, the emergency standby system switches to the automatic operation mode within three seconds, controls the G1 medium and low voltage generator set, the G2 medium and low voltage generator set, and the G3 medium and low voltage generator set of the medium and low voltage emergency standby diesel generator set to start simultaneously, and closes the breakers of these three generator sets at the same time to connect them to the 690V emergency busbar for synchronous excitation, so as to ensure that the voltage, phase, and frequency of the three generator sets on the emergency busbar reach the synchronous standard.

[0014] When the emergency standby system operates in the automatic operation mode, if the normal power supply is restored and the ATS sends a signal to the emergency standby system after an adjustable time delay, the emergency standby system controls the disconnection of the breaker on the diesel generator side of the medium and low voltage emergency standby diesel generator set, closes the normal power supply breaker, and automatically switches all loads back to the normal power supply; at the same time, it sends a generator shutdown command for the medium and low voltage emergency standby diesel generator set. After receiving the shutdown command, the generator parallel operation control system of the medium and low voltage emergency standby diesel generator set resets to the standby state after cooling and delaying operation for 120 - 180 seconds according to the preset program.

[0015] The generator parallel operation control system is used to enable the generator set to automatically start and operate when the commercial power fails. When the commercial power fails, the generator parallel operation control system achieves the ability of rapid parallel operation with load by controlling the breaker to close first and then excite.

[0016] When a power failure occurs in the commercial power supply, if the generator paralleling control system fails to parallel, it will automatically disconnect, and automatically connect to the power grid system when the system returns to normal; at the same time, the generator paralleling control system automatically stops working when the commercial power supply is restored.

[0017] When the medium and low voltage emergency standby diesel generator set is reset to the standby state, if it is necessary to be equipped with an automatic power restoration function, it will operate in a manual power restoration mode.

[0018] The manual operation mode of the emergency standby system is specifically as follows: when the diesel generator set control panel and the paralleling main control panel are in the manual mode, the buttons on the control module of the diesel generator set control panel are used to manually control the startup, paralleling power supply closing, disconnection power-off opening, and shutdown of the unit.

[0019] When the manual operation mode is the manual mode, the unit is normally started, paralleled, and loaded through the diesel generator set control panel and the paralleling main control panel;

[0020] When the manual operation mode is the test mode: the unit is manually started through the diesel generator set control panel and the paralleling main control panel. In the test mode, the unit can only be started, and the closing function is prohibited. The corresponding switch of the test mode is equipped with a mechanical interlock function to perform double protection to prevent the circuit breaker from accidentally closing, so as to achieve the purpose of testing the startup test.

[0021] The double protection function of the diesel generator set control panel and the paralleling main control panel is effective in both the automatic operation mode and the manual operation mode.

[0022] In view of the paralleling control problem of the medium and low voltage emergency standby diesel generator set, and the existing technology can only solve the problems of single-unit operation or ordinary multi-unit parallel operation, and cannot achieve the situation of emergency standby multi-unit parallel operation. After repeated tests, tests, and verifications, the present utility model proposes a complete control system, which solves the paralleling control problem of the medium and low voltage emergency standby diesel generator set, and can realize a complete set of logical control systems. In the present utility model, multiple 690V units can be started simultaneously, the generator circuit breakers can be closed simultaneously when there is no busbar voltage, and at the same time, when one of the units fails to synchronize, it can be reconnected to the power generation system again in the normal mode without shutting down. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments:

[0024] Attached Figure 1 is a schematic diagram of the principle of the present utility model;

[0025] Attached Figure 2 is a system schematic diagram of the control system of the present utility model;

[0026] Attached Figure 3It is a schematic diagram of the control principle of the present utility model. Specific embodiments

[0027] As shown in the figure, a parallel operation control system for a medium and low voltage emergency standby diesel generator set includes a medium and low voltage generator set, a medium and low voltage paralleling cabinet, and a feeder cabinet; the power generation output end of the medium and low voltage generator set is connected to the incoming line end of the medium and low voltage paralleling cabinet through a medium and low voltage cable, the control line of the medium and low voltage generator set is connected to the control end of the medium and low voltage paralleling cabinet, the control power supply line of the medium and low voltage paralleling cabinet is connected to the UPS power supply, the control power supply line of the feeder cabinet is connected to the transformer, the unit voltage sampling line is connected to the voltage transformer of the unit side cabinet, and the busbar voltage sampling is connected to the voltage transformer of the medium and low voltage paralleling cabinet; the unit mode switch button of the remote operation panel of the medium and low voltage paralleling cabinet is connected to the controller of the unit through a control cable, and the medium and low voltage generator set is connected to the medium and low voltage paralleling cabinet through a CAN communication line.

[0028] The control system is used for controlling the medium and low voltage emergency standby diesel generator set of the emergency standby system; the medium and low voltage emergency standby diesel generator set includes the G1 medium and low voltage generator set, the G2 medium and low voltage generator set, and the G3 medium and low voltage generator set of the medium and low voltage generator set; the deployment area of the control system includes the medium and low voltage paralleling cabinet and the feeder cabinet;

[0029] The power generation output circuit breaker of the G1 medium and low voltage generator set is GB1; the power generation output circuit breaker of the G2 medium and low voltage generator set is GB2; the power generation output circuit breaker of the G3 medium and low voltage generator set is GB3;

[0030] The parallel operation controller group includes a first parallel operation controller connected to the G1 medium and low voltage generator set, a second parallel operation controller connected to the G2 medium and low voltage generator set, and a third parallel operation controller connected to the G3 medium and low voltage generator set; the first parallel operation controller, the second parallel operation controller, and the third parallel operation controller are sequentially connected through a CAN communication line.

[0031] The parallel operation controller group is arranged in the medium and low voltage paralleling cabinet, and the communication link formed by the CAN communication line in the paralleling cabinet includes multiple communication connection links.

[0032] The medium and low voltage generator set is a diesel generator set, and the number of its parallel operation controllers is not more than 32.

[0033] The working modes of the emergency standby system include an automatic operation mode or a manual operation mode.

[0034] When any external normal power supply fails and the emergency standby system receives a remote start signal sent by the grid ATS or the faulty busbar, the emergency standby system switches to the automatic operation mode within three seconds, and controls the G1 medium and low voltage generator set, G2 medium and low voltage generator set, and G3 medium and low voltage generator set of the medium and low voltage emergency standby diesel generator sets to start simultaneously. At the same time, the circuit breakers of these three generator sets are closed to connect them to the 690V emergency busbar for synchronous excitation, so as to ensure that the voltage, phase, and frequency of the three generator sets on the emergency busbar meet the synchronous standard.

[0035] When the emergency standby system operates in the automatic operation mode, if the normal power supply is restored and the ATS sends a signal to the emergency standby system after an adjustable time delay, the emergency standby system controls the circuit breaker on the diesel generator side of the medium and low voltage emergency standby diesel generator set to open, and the normal power supply circuit breaker to close, automatically switching all loads back to the normal power supply; at the same time, a generator shutdown instruction for the medium and low voltage emergency standby diesel generator set is sent. After receiving the shutdown instruction, the generator paralleling control system of the medium and low voltage emergency standby diesel generator set resets to the standby state after cooling and running for 120 - 180 seconds according to the preset program.

[0036] The generator paralleling control system is used to enable the generator set to start and operate automatically when the main power supply fails. When the main power supply fails, the generator paralleling control system achieves the ability to quickly parallel and carry load by controlling the circuit breaker to close first and then excite.

[0037] When the main power supply fails, if the generator paralleling control system fails to parallel, it will automatically trip and automatically connect to the power grid system when the system returns to normal; at the same time, when the main power supply is restored, the generator paralleling control system automatically stops working.

[0038] When the medium and low voltage emergency standby diesel generator set resets to the standby state, if it is necessary to be equipped with an automatic power restoration function, it operates in the manual power restoration mode.

[0039] The manual operation mode of the emergency standby system is specifically as follows: when the diesel generator control panel and the parallel main control panel are in the manual mode, the buttons on the control module of the diesel generator control panel are used to manually control the start, parallel connection, power-on closing, disconnection, and shutdown of the unit.

[0040] When the manual operation mode is in the manual mode, the unit is normally started, paralleled, and loaded through the diesel generator control panel and the parallel main control panel.

[0041] When the manual operation mode is the test mode: The unit is manually started through the diesel generator set control panel and the parallel operation main control panel. In the test mode, the unit can only be started, and the closing function is prohibited. The corresponding switch in the test mode is equipped with a mechanical interlock function to perform double protection to prevent the circuit breaker from closing accidentally, so as to achieve the purpose of testing the startup test.

[0042] The double protection function of the diesel generator set control panel and the parallel operation main control panel is effective in both the automatic operation mode and the manual operation mode.

[0043] In this example, as shown in the Figure 1 schematic diagram of the principle, the parallel operation control system of a medium and low voltage emergency standby diesel generator set includes medium and low voltage generator sets G1, G2, and G3; circuit breakers GB1, GB2, and GB3 of the medium and low voltage parallel operation cabinet. The power generation output cable of the G1 generator set is connected to the lower end of the circuit breaker GB1; the power generation output cable of the G2 generator set is connected to the lower end of the circuit breaker GB2; the power generation output cable of the G3 generator set is connected to the lower end of the circuit breaker GB3; the upper ends of the circuit breakers GB1, GB2, and GB3 of the medium and low voltage parallel operation cabinet are all connected to the common busbar through copper bars; the parallel operation controller group includes a first parallel operation controller, a second parallel operation controller, and a third parallel operation controller; the first parallel operation controller is connected to the second parallel operation controller and the third parallel operation controller through CAN communication lines.

[0044] As shown in the Figure 2 schematic diagram of the system, for the parallel operation control system of a medium and low voltage emergency standby diesel generator set, the parallel operation control system includes a medium and low voltage generator set, a medium and low voltage parallel operation cabinet, a feeder cabinet, a UPS power supply, and a control transformer; the power generation output end of the medium and low voltage generator set is connected to the incoming line end of the medium and low voltage parallel operation cabinet through a medium and low voltage cable, the control line of the medium and low voltage generator set is connected to the control end of the medium and low voltage parallel operation cabinet, the control power supply line of the medium and low voltage parallel operation cabinet is connected to the UPS power supply, the control power supply line of the feeder cabinet is connected to the control transformer, the unit voltage sampling line is connected to the voltage transformer of the unit side cabinet, and the busbar voltage sampling is connected to the voltage transformer of the medium and low voltage parallel operation cabinet; the unit mode switch button on the remote operation panel of the medium and low voltage parallel operation cabinet is connected to the controller of the unit through a control cable, and the controller is installed on the unit side cabinet.

[0045] As shown in the Figure 3As shown in the control schematic diagram, when the ATS controller monitors a power failure of the mains power supply, it issues a remote load-start command; the controller is a diesel generator controller, and the controller receives the remote start command and starts the generator set; the AVR of the generator must have a field suppression port, and the field suppression port is connected to the AC contactor through a cable. The controller controls the on / off of the AC contactor. When the unit starts, the main circuit breaker closes, and the controller controls the AC contactor to open. The AVR controls the generator not to generate electricity. When the speed reaches 1200 revolutions per minute, the controller controls the synchronization of the generator, the controller controls the AC contactor to close, the AVR controls the excitation of the generator, and the generator starts to generate electricity. When synchronization fails, the controller controls the circuit breaker to trip immediately. When the power generation is normal, the controller controls the generator set to synchronize and then close the switch, which will not cause the entire power grid to collapse.

[0046] The operating modes of the generator set are summarized in the following table:

[0047]

Claims

1. A medium and low voltage emergency standby diesel generator set parallel control system, characterized by: It includes medium and low voltage emergency standby diesel generator sets, namely medium and low voltage generator sets, and also includes medium and low voltage parallel cabinets and feeder cabinets; the power generation output end of the medium and low voltage generator set is connected to the incoming line end of the medium and low voltage parallel cabinet through medium and low voltage cables, the control line of the medium and low voltage generator set is connected to the control end of the medium and low voltage parallel cabinet, the control power line of the medium and low voltage parallel cabinet is connected to the UPS power supply, the control power line of the feeder cabinet is connected to the transformer, the unit voltage sampling line is connected to the voltage transformer of the unit side cabinet, and the busbar voltage sampling is connected to the voltage transformer of the medium and low voltage parallel cabinet; the unit mode switch button of the remote operation panel of the medium and low voltage parallel cabinet is connected to the controller of the unit through a control cable, and the medium and low voltage generator set is connected to the medium and low voltage parallel cabinet through a CAN communication line.

2. A medium and low voltage emergency standby diesel generator set parallel control system according to claim 1, characterized in that: The control system is used to control the medium and low voltage emergency standby diesel generator sets of the emergency standby system; the medium and low voltage emergency standby diesel generator sets include the G1 medium and low voltage generator sets, the G2 medium and low voltage generator sets, and the G3 medium and low voltage generator sets of the medium and low voltage generator sets; the deployment area of ​​the control system includes the medium and low voltage parallel cabinets and feeder cabinets; The power output circuit breaker of the G1 medium and low voltage generator set is GB1; the power output circuit breaker of the G2 medium and low voltage generator set is GB2; the power output circuit breaker of the G3 medium and low voltage generator set is GB3; The parallel controller group of the control system includes a first parallel controller connected to the G1 medium and low voltage generator set, a second parallel controller connected to the G2 medium and low voltage generator set, and a third parallel controller connected to the G3 medium and low voltage generator set; the first parallel controller, the second parallel controller, and the third parallel controller are connected in sequence via a CAN communication line.

3. A medium and low voltage emergency standby diesel generator set parallel control system according to claim 2, characterized in that: The parallel controller group is arranged in a medium and low voltage parallel cabinet, and the communication link formed by the CAN communication line in the parallel cabinet includes multiple communication connection links.

4. A medium and low voltage emergency standby diesel generator set parallel control system according to claim 2, characterized in that: The medium and low voltage generator sets are diesel generator sets, and the number of parallel controllers thereof is no more than 32.

5. A medium and low voltage emergency standby diesel generator set parallel control system according to claim 4, characterized in that: The working mode of the emergency backup system includes an automatic operation mode or a manual operation mode.

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