Method for fast recovery of power supply after total power failure of a diesel-electric plant ship

Abstract

The application provides a method for quickly restoring power supply after the whole ship loses power in a diesel power station ship, which comprises the following steps: setting the judgment logic of the power monitoring device, starting the standby unit and making the unit with the first closing condition automatically close to supply power, if there is a normally running generator unit not connected to the network at this time, then the normally running generator unit is closed according to the pre-set priority, so that at least one power station in multiple power stations restores power supply within a predetermined time, and the power supply is quickly restored under the condition of the whole ship losing power. The application pre-sets factors that may affect the quickness of the unit starting, eliminates various possible interferences under the condition of the whole ship losing power, including the control mode of automatically issuing the starting unit instruction, the number of standby units, the starting frequency, the starting instruction pulse width, the interval time between the two starting instructions of the standby unit and the energy guarantee, etc., so that the power supply is restored at the first time, and the navigation safety of the ship and the completion of the task are ensured.

Description

Technical Field

[0001] This invention belongs to the field of marine power station design technology, specifically relating to a method for quickly restoring power supply to a diesel engine power station ship after a complete power outage. Background Technology

[0002] Shipboard electrical systems provide power to various electrical equipment used for navigation and missions. System design must consider diverse operating conditions and special circumstances, such as system failures or even a complete shipboard power outage. This intellectual property provides a method for rapidly restoring power in the event of a shipboard power outage.

[0003] Modern shipboard electrical systems are generally highly reliable. Ships typically have two (or more) power stations, each equipped with two (or more) generator sets. The interconnected networks between power stations, generator sets, and electrical equipment, along with robust power system protection designs, effectively limit faults to a minimal area, preventing power outages to equipment outside the fault zone. Therefore, a complete shipboard power outage is virtually impossible. However, a complete shipboard power outage remains a concern that designers must consider. Cases of complete shipboard power outages still occur, and the causes are complex. These could be due to malfunctions of internal protection devices triggered by specific reasons, or a chain reaction following a fault in parallel generator sets. For ships, a complete power outage can have a fatal impact on safety and mission performance if power cannot be restored quickly. Therefore, shipboard electrical systems are typically designed with automatic power restoration strategies in mind. Generally, in automatic mode, a command is issued to automatically start backup generators (in semi-automatic mode, manual command is required), starting them sequentially or all at once. If backup generators are started according to a pre-set priority order, the startup performance requirement is two successful starts out of three attempts. If the first backup generator fails before starting the second, power cannot be restored immediately. Therefore, to quickly restore power, a strategy of simultaneously starting all backup generators can be adopted, with the first successfully started unit connecting to the grid. However, since generator startup requires resources such as oil, water, gas, and electricity, and shipboard resources are limited, simultaneous startup may cause resource contention, leading to insufficient resources for all generators and startup failures, thus delaying power restoration. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for quickly restoring power supply to a diesel engine power station ship after a complete power failure, for starting the standby unit under the condition of a complete power failure.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a method for rapidly restoring power supply to a diesel engine power station ship after a complete power loss, comprising the following steps:

[0006] S0: Sets a threshold for the energy required to start the generator set, which is used to supplement energy when the energy level is below the threshold.

[0007] S1: When a ship-wide power failure occurs, the power stations operating in parallel are disconnected, and the power monitoring equipment switches to automatic control mode.

[0008] S2: The power monitoring equipment starts n-1 generator sets that meet the starting conditions for each power station, where n is the number of generator sets for each power station;

[0009] S3: Start twice according to an interval not less than the sum of the pulse width of the start command and the recovery time after the generator set starts consuming energy, and switch on the generator set that first meets the closing conditions to supply power.

[0010] According to the above scheme, in step S1, by default, the mode of the power monitoring equipment includes automatic control mode or semi-automatic control mode.

[0011] According to the above scheme, in step S2, if the number of generator sets that meet the starting conditions at time T0 is greater than or equal to n-1, the power monitoring equipment sends a starting command to n-1 generator sets; if the number of generator sets that meet the starting conditions is less than n-1, the power monitoring equipment sends a starting command to the generator sets that meet the starting conditions.

[0012] According to the above scheme, the specific steps in step S3 are as follows:

[0013] The system first checks if a generator set has started successfully. If no generator set has started successfully, the power monitoring equipment sends a second start command at time T0+T2 and checks again if a generator set has started successfully. If no generator set has started successfully, an alarm is triggered to prompt manual intervention.

[0014] If a generator set starts successfully on the first or second time, the generator set that first meets the conditions for closing will be automatically closed to supply power, and it will be determined whether there is a generator set on the grid.

[0015] If a generator set is on the grid, power will be restored; if no generator set is on the grid, the generator set will be put on the grid.

[0016] If grid connection fails, an alarm will be triggered to prompt manual intervention; if grid connection is successful, power supply will be restored.

[0017] Furthermore, in step S3, let the pulse width of the start command sent by the power monitoring equipment be T1, where T1 is the shortest time set according to the start performance requirements of the diesel generator set, and the time required for the energy supplied to start the generator set to recover after using the T1 time is ΔT. Then, the start command interval time T2 = T1 + ΔT.

[0018] According to the above scheme, the following steps are also included in the execution of step S2:

[0019] S4: The power monitoring equipment sends closing commands to the generator sets that are currently operating normally but not connected to the grid, according to priority.

[0020] Furthermore, in step S4, the specific steps are as follows:

[0021] The power monitoring equipment sends a closing command to the highest priority generator set that is currently operating normally but not connected to the grid; if the grid connection is successful, power supply is restored; if the grid connection fails, it sends a closing command to the next highest priority generator set that is currently operating normally but not connected to the grid according to priority; the priority is gradually reduced until the lowest priority generator set that is currently operating normally but not connected to the grid, and if the grid connection is successful, power supply is restored.

[0022] According to the above scheme, step S0 further includes the following steps:

[0023] For ships equipped with two or more power stations, undervoltage release devices shall be installed in the cross-connection circuit breakers between the power stations.

[0024] According to the above scheme, in step S0, the set threshold must be sufficient to start n-1 generator sets twice.

[0025] A computer memory storing a computer program executable by a computer processor, the computer program executing a method for rapidly restoring power to a diesel engine power station vessel after a complete power outage.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. The present invention provides a method for rapidly restoring power supply to a diesel engine power station vessel after a total power outage. By setting the judgment logic of the power monitoring equipment, the standby generator set is started and the generator set that first meets the closing conditions is automatically closed to supply power. If there are generator sets that are operating normally but not connected to the grid at this time, the generator sets that are operating normally but not connected to the grid are closed according to the preset priority, ensuring that at least one of the multiple power stations restores power supply within a predetermined time, thereby achieving rapid power restoration in the event of a total power outage.

[0028] 2. This invention pre-sets factors that may affect the speed of unit startup, eliminating various possible interferences in the event of a complete power outage on board. These include the control method for automatically issuing startup commands, the number of standby units to be started, the number of startups, the pulse width of the startup command, the interval between two startup commands for standby units, and energy security, etc. This ensures that power is restored as soon as possible, guaranteeing the safety of the ship's navigation and the completion of the mission. Attached Figure Description

[0029] Figure 1 This is a single-line diagram of a ship's diesel engine power station according to an embodiment of the present invention.

[0030] Figure 2 This is a flowchart of an embodiment of the present invention.

[0031] In the diagram: G1: Diesel generator set No. 1; G2: Diesel generator set No. 2; G3: Diesel generator set No. 3; G4: Diesel generator set No. 4; G5: Diesel generator set No. 5; G6: Diesel generator set No. 6; MBS1: Front main distribution board; MBS2: Rear main distribution board; QF1: Circuit breaker for generator set No. 1; QF2: Circuit breaker for generator set No. 2; QF3: Circuit breaker for generator set No. 3; QF4: Circuit breaker for generator set No. 4; QF5: Circuit breaker for generator set No. 5; QF6: Circuit breaker for generator set No. 6; QF7: First bus tie circuit breaker; QF8: Second bus tie circuit breaker; QF9: Third bus tie circuit breaker; QF10: Fourth bus tie circuit breaker; QF11: First jumper circuit breaker; QF12: Second jumper circuit breaker; QF13: Third jumper circuit breaker; QF14: Fourth jumper circuit breaker. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] Embodiments of the present invention include the following steps:

[0035] Regardless of whether the power monitoring equipment (or power station controller) is in automatic or semi-automatic control mode, the control mode will switch to automatic mode when a total power loss occurs.

[0036] For vessels equipped with two (or more) power stations, an undervoltage release device should be installed in the jumper circuit breaker between the power stations. This step is not required if only one power station is configured.

[0037] The power monitoring equipment (or power station controller) automatically starts n-1 generator sets (if any) that meet the starting conditions for each power station, where n is the number of generator sets in a single power station. After two consecutive starts, the generator set that first meets the closing conditions automatically closes the circuit to supply power.

[0038] The pulse width T1 of the start command sent by the power monitoring equipment (or power station controller) needs to be set to the shortest time according to the start performance requirements of the diesel generator set. The start command interval time T2 is set to T1+△T, where △T is the time required for the energy supplied for starting the diesel engine to be restored after using the T1 time.

[0039] When a unit is operating normally (not in the shutdown process) and not connected to the grid, the power monitoring equipment (or power station controller) first sends a closing command to the unit, and at the same time starts other standby units.

[0040] A threshold needs to be set for the energy supplied to start the diesel engine. When the energy level falls below the threshold, it needs to be supplemented. The set value of this threshold must meet the energy requirements for the two starts mentioned above.

[0041] Example 2

[0042] Assume a ship has two power stations, one at the bow and one at the stern, each equipped with three diesel generator sets. The power station configuration and connection diagram are as follows: Figure 1 As shown. The procedure for restoring power in the event of a total ship power failure is as follows. Figure 2 The process flow for Power Plant #1 and Power Plant #2 is shown in the diagram; the process flow for Power Plant #1 and Power Plant #2 is the same and will not be shown in this diagram.

[0043] According to the method provided by this invention:

[0044] 1. The power monitoring system needs to be equipped with the function of "automatically switching the control mode to automatic when the whole ship loses power". This setting can ensure that once the whole ship loses power, the power monitoring system can automatically execute the corresponding strategy without being limited by the control mode.

[0045] 2. The jumper circuit breakers QF11 to QF14 are equipped with undervoltage trip. When the entire ship loses power, the jumper circuit breaker will disconnect due to the undervoltage. This operation isolates the power stations when the entire ship loses power, so that each power station can start and close the circuit breaker successfully, avoiding the situation where only one unit of the entire ship can start and close the circuit breaker successfully. If problems such as starting failure occur, the time for power restoration will be delayed.

[0046] 3. The power monitoring system automatically sends start commands to the adjacent power stations for two generator sets that meet the start-up conditions (if any). The generator sets are started twice consecutively (if both fail to start on the first attempt, a second start command is issued). The generator set that first meets the closing conditions automatically closes the circuit and supplies power. The pulse width T1 of the start command sent by the power monitoring equipment (or power station controller) is the minimum time required for the diesel generator set's starting performance, such as 5 seconds. Since the diesel engine in this power station uses a pneumatic motor for starting, and the starting energy is compressed air from a compressed air cylinder, it is necessary to determine the time required for the compressed air to release for 5 seconds and for the pressure to recover after a pressure drop, for example, 3 seconds. Therefore, the interval T2 between the second and first start commands should be 8 seconds (i.e., 5 seconds + 3 seconds).

[0047] 4. While automatically starting the standby unit, if it is detected that a unit in the power station is running but not closed, the corresponding generator circuit breaker will be closed according to the pre-set priority of the power station until the power station restores power supply or fails to restore power supply.

[0048] 5. The ship's diesel generator sets use compressed air from gas cylinders as starting power. Considering factors such as pipeline losses on site, to ensure that after venting air for 5 seconds during the initial startup of both generator sets, the compressed air cylinder outlet pressure can still provide starting air pressure for the second startup of the diesel engines after the air pressure recovers, actual ship testing shows that the compressed air cylinder outlet pressure must not be lower than 2.2 MPa. An automatic air replenishment device is installed to automatically replenish air when the air cylinder pressure drops to 2.2 MPa, ensuring the compressed air cylinder pressure is sufficient for both generators to start twice.

[0049] This invention pre-sets all factors that may affect the speed of unit startup. For example, the control mode setting can avoid the inability to automatically issue the start command because the control mode is not in automatic mode; the setting of the number of standby units can avoid excessive consumption of starting energy; the setting of the start command pulse time can avoid excessive consumption of starting air, which would affect the second startup; the automatic air replenishment setting parameters of the air cylinder can ensure that both units can start twice; since the requirement for diesel engine starting characteristics is that two out of three startups must be successful, this invention sets two startups.

[0050] like Figure 2The flowchart illustrates that when a total power loss occurs, the jumper circuit breakers QF11 to QF14 disconnect due to voltage loss, transforming the two power stations that were originally operating in parallel into independent entities. At this point, the control mode is automatic, and the power monitoring system automatically sends commands to start the two generator units at each power station. The generator unit that first meets the closing conditions automatically closes and supplies power. If both generator units in a single power station fail to start successfully under the first start command, a second start command is issued, and the generator unit that first meets the closing conditions automatically closes and supplies power. After the above operations, both power stations can restore power within 20 seconds. Even if other unforeseen reasons occur, it can be guaranteed that at least one power station can restore power.

[0051] If, during the above process, the power monitoring system detects that two power stations have units that are operating normally but have tripped due to special reasons, it will automatically issue a closing command according to the pre-set priority order. If the closing is successful, power supply can be restored.

[0052] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0053] The above embodiments are only used to illustrate the design concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made based on the principles and design ideas disclosed in the present invention are within the protection scope of the present invention.

Claims

1. A method for fast recovery of power supply after a total loss of power on a diesel-electric plant ship, characterized in that: Includes the following steps: S0: Sets a threshold for the energy required to start the generator set, which is used to supplement energy when the energy level is below the threshold. S1: When a ship-wide power failure occurs, the power stations operating in parallel are disconnected, and the power monitoring equipment switches to automatic control mode. S2: The power monitoring equipment starts n-1 generator sets that meet the starting conditions for each power station, where n is the number of generator sets in each power station; if the number of generator sets that meet the starting conditions at time T0 is greater than or equal to n-1, the power monitoring equipment sends a start command to n-1 generator sets; if the number of generator sets that meet the starting conditions is less than n-1, the power monitoring equipment sends a start command to the generator sets that meet the starting conditions. S3: Start twice at an interval not less than the sum of the pulse width of the start command and the recovery time after the generator set starts consuming energy, and switch on the generator set that first meets the closing conditions to supply power; the specific steps are as follows: Let the pulse width of the start command sent by the power monitoring equipment be T1, where T1 is the shortest time set according to the start performance requirements of the diesel generator set, and the time required for the energy supplied to start the generator set to recover after using the T1 time is ΔT. Then the start command interval time T2 = T1 + ΔT. The first check determines whether a generator set has started successfully. If no generator set has started successfully, the power monitoring equipment sends a second start command at time T0+T2 and checks again whether a generator set has started successfully. If the generator set still fails to start successfully, an alarm will be triggered to prompt manual intervention. If a generator set starts successfully on the first or second time, the generator set that first meets the conditions for closing will be automatically closed to supply power, and it will be determined whether there is a generator set on the grid. If a generator set is on the grid, power will be restored; if no generator set is on the grid, the generator set will be put on the grid. If grid connection fails, an alarm will be triggered to prompt manual intervention; if grid connection is successful, power supply will be restored.

2. The method for fast recovery of power supply after a total power failure of a diesel-electric ship according to claim 1, characterized in that: In step S1, by default, the power monitoring equipment is in either automatic control mode or semi-automatic control mode.

3. The method for rapidly restoring power supply to a diesel engine power station vessel after a complete power outage, as described in claim 1, is characterized in that: The execution of step S2 also includes the following steps: S4: The power monitoring equipment sends closing commands to the generator sets that are currently operating normally but not connected to the grid, according to priority.

4. The method for fast recovery of power supply after a total power failure of a diesel-electric ship according to claim 3, characterized in that: The specific steps in step S4 are as follows: The power monitoring equipment sends a closing command to the highest priority generator set that is currently operating normally but not connected to the grid; if the grid connection is successful, power supply is restored; if the grid connection fails, it sends a closing command to the next highest priority generator set that is currently operating normally but not connected to the grid according to priority; the priority is gradually reduced until the lowest priority generator set that is currently operating normally but not connected to the grid, and if the grid connection is successful, power supply is restored.

5. The method for fast recovery of power supply after a total power failure of a diesel-electric ship according to claim 1, characterized in that: Step S0 further includes the following steps: For ships equipped with two or more power stations, undervoltage release devices shall be installed in the cross-connection circuit breakers between the power stations.

6. The method for fast recovery of power supply after a total power failure of a diesel-electric ship according to claim 1, characterized in that: In step S0, the set threshold must be sufficient to start n-1 generator sets twice.

7. A computer memory, characterized by: It contains a computer program that can be executed by a computer processor, which performs a method for rapidly restoring power to a diesel engine power station ship after a total power loss, as described in any one of claims 1 to 6.

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