JPS63302733A - Frequency control method for maritime generator - Google Patents

Abstract

PURPOSE:To shorten time necessary for synchronous throw-in, by interrupting an air circuit breaker when a stand-by Diesel generator operating in parallel is stopped and set frequency of the Diesel generator to be approximately the same as a predetermined frequency of maritime power supply system. CONSTITUTION:A propeller shaft 2 to be driven through a main machine 1 is provided with an AC shaft generator 3 to be driven through the propeller shaft 2 and a Diesel generator 6 comprising a Diesel engine 4 and an AC generator 5. Distribution of load between the shaft generator 3 and the Diesel generator 6 is controlled through an automatic synchronous load bearing unit 15. When the Diesel generator 6 operating in parallel with the shaft generator 3 is stopped, load on the Diesel generator 6 is transferred to the shaft generator 3, then an air circuit breaker is interrupted and the frequency of the Diesel generator 6 is set to be same as the frequency of maritime power supply system. When actual frequency is matched with the set frequency, the Diesel generator is stopped.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a frequency control method for marine generators, and particularly improves synchronization of diesel generators when operating a regular generator and a standby diesel generator in parallel. This is what I am trying to do.

[Prior art]

Conventionally, energy-saving ships use exhaust gas turbo generators (
(hereinafter referred to as TG) or a shaft generator (hereinafter referred to as TG) that generates electricity from the main engine power (
(hereinafter referred to as SG) is often used as a regular generator.

Both the TG and SG mentioned above generate electricity using energy from the main engine, so when the main engine output decreases, the amount of power generated by the TG and SG also decreases, so they are used to reduce power shortages when the main engine output is low, such as when the ship departs or decelerates. In order to provide this power, a standby diesel generator (hereinafter referred to as DG) is generally provided, and the TG or SG and DG are operated in parallel.

By the way, when the main engine output decreases, such as when the ship decelerates, the DG is activated and the TG or SG and DG are operated in parallel.Since these are alternating current generators, the following conditions are required to start parallel operation. Conditions are necessary.

(a) The difference between the frequency of the onboard power supply system receiving power from the TG or SG (generally 60 Hz) and the frequency of the DC output power is sufficiently small, about 0.5 tlz or less.

(b) The difference between the voltage of the power supply system (generally 450V) and the output voltage of the DG is sufficiently small, being 2 to 10% or less.

(C) The difference between the phase of the voltage of the power supply system and the phase of the output voltage of the DG is extremely small.

Therefore, when starting parallel operation of the DG with respect to the TG or the SG, the synchronization is manually performed by the following operation.

(1) Start the DG diesel engine.

(2) Using a frequency meter, operate the diesel engine governor motor so that the difference in frequency is sufficiently small.

(3) Confirm that the frequency difference and voltage difference have become sufficiently small.

(4) While watching the synchronization tester for phase verification, turn on the DC ACB (air circuit breaker) when the phases are synchronized.

On the other hand, automatic other ships are equipped with an automatic synchronization device, and when using this device to synchronize the DC, the above (1)
The operations from (4) to (4) will be performed automatically.

That is, in the above-mentioned automatic synchronization device, a governor drive signal corresponding to the magnitude of the frequency of the DG is output to the governor motor of the DG to control the rotation speed of the diesel engine, and thereby,
When the frequency difference becomes smaller than the set value, after confirming that the voltage difference is smaller than the set value, when the phase difference matches, the DG A
Outputs ACB input signal to CB.

In this case, the governor drive signal is output at a cycle of approximately 5 seconds, and when the frequency difference is large, the drive time is lengthened (and when the frequency difference is small, the drive time is shortened, thereby preventing hunting and ensuring safe speed uniformity). It makes you do an action.

[Problem that the invention seeks to solve]

When the automatic synchronization device is used to synchronize the DC as described above, the cabana drive signal is output at intervals of approximately 5 seconds, so if the frequency difference is large, the governor drive signal may be lengthened. It only takes about 8 seconds to eliminate the frequency difference of I Hz, but when the frequency difference becomes small, the speed equalization operation is performed slowly to prevent hunting, so it often takes about 1 minute to synchronize the DC. (do not have.

In the case of an energy-saving ship where the onboard power during normal voyages is provided only by SG, a decrease in main engine output directly leads to a decrease in the amount of power generation, so it is necessary to synchronize the DC input before the ship can decelerate or move astern. (The ship is moved backwards by reversing after stopping the main engine.) Therefore, it is desirable to synchronize the DC in as short a time as possible.

In addition, in the case of a ship equipped with a TG, there is not enough power generation capacity in the TG, and when the main engine is decelerated, a blower (approximately 50K) is used to supply scavenging air.
Since it is necessary to operate two electric motors of about W, T
Unless the G and DG are operated in parallel, the ship cannot be decelerated or reversed, and it is desirable to synchronize the DG in as short a time as possible.

Therefore, for example, if DG synchronization is not completed within a set time, some ships seem to abandon synchronization, forcibly shut off the SC ACB, and switch to DG by switching BLACK OUT. OU
T should be avoided as much as possible.

After the parallel operation of TG or SG and DC is started, frequency, voltage, phase control and load sharing control are automatically performed by an automatic synchronization load sharing device including the automatic synchronization input device.

Conventionally, when stopping DCs that were running in parallel, the load on DG is transferred to TG or SG, and the load on DC is reduced to several tens of thousands.
When the power level reached approximately KW, the ACB was shut off, and at the same time, control of the DG by the automatic synchronized load sharing device was stopped, and a stop command was then output to the DC drive engine.

In this state immediately before the DC stops, the cabana of the DCKK power engine is set to have an output of several tens of kilowatts and 60IIg, and the engine stops in a sluggish state.

However, since the load on the DG driving engine is no load before the DG is synchronized, the frequency of the DC output power is 6011z.
, and as mentioned above, it takes time to synchronize.

[Means for solving problems]

A frequency control method for a marine generator according to the present invention is a parallel operation control method in which a regular generator that generates electricity using energy from a main engine and a standby diesel generator are operated in parallel by controlling an automatic synchronized load sharing device. When stopping a backup diesel generator in operation, after cutting off the ACB of the diesel generator, the frequency setting means of the diesel generator is manually or automatically set to a frequency approximately equal to a predetermined frequency in the onboard power supply system. It is something.

[Effect]

In the frequency control method for a marine generator according to the present invention,
When stopping a standby diesel generator running in parallel,
After cutting off the ACB of the diesel generator, the frequency setting means of the diesel generator is manually or automatically set to a frequency approximately equal to a predetermined frequency in the onboard power supply system, so that after the diesel generator is started and before synchronization is started,
The output frequency when the diesel generator is in a no-load state is approximately equal to the predetermined frequency.

Therefore, for synchronization, the output frequency of the diesel generator can be controlled to match the frequency of the onboard power supply system in a short time and reliably.

〔Effect of the invention〕

According to the frequency control method for a marine generator according to the present invention, as explained above, the operation time required for the synchronization control of the standby diesel generator can be significantly reduced, and the control time by the automatic synchronization load sharing device after ACB shutoff can be reduced significantly. Since the frequency setting means can be set with only a slight extension, the present invention can be easily implemented without providing any special equipment, and the present invention can be easily applied to existing automatic synchronization load sharing devices. .

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

First, a description will be given of a marine power generator and its control device for implementing the frequency control method for a marine power generator according to the present invention.

As shown in Fig. 1, a propeller shaft 2 driven by a diesel engine 1 (hereinafter referred to as the main engine) for propulsion of an automatic ship is connected to an AC shaft generator 3 (common generator) driven by the propeller shaft 2. Diesel power generation consisting of a diesel engine 4 and an alternating current generator 5 driven by this engine! 16 (which is a standby generator) is provided.

The output line 7 of the shaft generator 3 is connected to the bus bar 8a of the main switchboard 8, and the output line 7 is interposed with a shaft generator control panel 9 that converts the frequency using a thyristor. ACBlo (air circuit) in 8
A breaker) is installed. The output line 11 of the diesel generator 6 is connected to the bus bar 8a of the main switchboard 8, and an ACB 12 (air circuit breaker) is interposed in the main switchboard 8 to this output line 11. A power supply line 14 extends from the motherboard i&1i8a to a plurality of onboard electrical loads.

An automatic synchronization load sharing device 15 (hereinafter referred to as a control unit) that controls the shaft generator 3 and the diesel generator 6 is provided.

The output line 7 includes a current transformer 16 (hereinafter referred to as CT) that detects the current flowing through the output line 7 and an instrument transformer 17 (hereinafter referred to as CT) that detects the voltage of the power flowing through the output line 7.
PT) is attached, and the output line 11 is similarly connected to C.
'I'18 and P'T'19 are attached, and these, C'
The detection signals from l'16-18 and P'T'17 and 19 are output to the control unit 15, and from the control unit 15, the AC of the ACB 10 of the output line 7 is output.
B input circuit lOa and output line 11 ACB 12 AC
Drive signals can be output to the B input circuits 12a, respectively.

At the same time, the control unit 15 outputs drive signals to the shaft generator control panel 9, the governor motor 4b that operates the cabana 4a of the diesel engine 4, and the electromagnetic valve 4C for cutting fuel supply, respectively.

Note that a circuit breaker 20 (MCB) is installed in each power supply line 14 connected to the bus bar 8a in the main distribution board 8.

The control unit 15 includes a microcomputer, an input/output interface, and an ACB input circuit 10a/1.
2a, shaft generator control panel 9, governor motor 4b, and solenoid valve 4
It is composed of drive circuits that output drive signals to C, etc., respectively, and the ROM (read,
Only memory) has shaft generator 3 and diesel generator I/
A control program for synchronization control to synchronize the diesel generator 6 to the shaft generator 3 in order to operate the Ii6 in parallel, a control program for load sharing control to perform load sharing control during parallel operation, and a parallel operation as described below. A control program for frequency control when stopping the diesel generator 6 that has been running is stored in advance.

To briefly explain the synchronization control described above, first, during normal navigation, the power required for the ship is covered by the power of the shaft generator 3, which is a regular generator, but when the ship is decelerated, etc., when the main lll is decelerated, the shaft generator 3 outputs Therefore, prior to the deceleration, it is necessary to start and synchronize the diesel generator 6, which is a backup generator. In this case, ACB 12
The diesel generator 6 is started in the cut-off state of CTlB.
- The rotation speed of the diesel engine 4 is controlled via the governor motor 4b so that the frequency detected by the PT 19 approximately matches the predetermined frequency of the onboard power supply system (generally 60 Hz), and the frequency difference is approximately 0.511 Hz or less. After the voltage difference has decreased to approximately 10% or less, connect the re-output lines 7 and 1.
When the phases of voltages 1 and 1 match, the ACB input circuit 12a
A drive signal is output to the ACB 12 and the ACB 12 is turned on.

In other words, the ACB 12 must be turned on only when the frequency, voltage difference, and phase difference are within predetermined allowable ranges, and this is what is called synchronous turning on of the alternator.

Next, when the diesel generator 6 is synchronously turned on as described above and the shaft generator 3 and the diesel generator 6 are operated in parallel, the main engine 1 starts to decelerate, and the shaft generator 3
Load sharing control is performed so that the amount of power generated by the diesel power generator m6 increases in accordance with the decrease in the amount of power generated by the diesel power generator m6. In this case, the shaft generator 3 is controlled by the control unit 15.
The frequency is controlled by outputting a drive signal to the panel 9, and the frequency of the diesel generator 6 is controlled by outputting a drive signal from the control unit 15 to the motor 4b.

By the way, the frequency control according to the present invention reduces the frequency required for synchronization by bringing the frequency of the diesel generator 6 as close as possible to the predetermined frequency of the power supply system when the diesel generator 6 is started and cycled as described above. In order to shorten the required time as much as possible, the following frequency control is performed in advance when stopping the diesel generator 6.

Hereinafter, frequency control performed by the control unit 15 on the shaft generator 3 and the diesel generator 6 will be explained with reference to the flowchart in FIG. 2.

31 to S8 in FIG. 2 show each step of the frequency control routine when the diesel generator 6 is stopped, and the shaft generator 3 and the diesel generator 6 are operated in parallel.
When the diesel generator stop command switch on the operation panel of the control unit 15 is turned on, frequency control for stopping the diesel generator is started, and load transfer control is performed to shift the load of the diesel generator a6 to the shaft generator 3 in S2. This load transfer control is similar to existing control, and while reducing the rotation speed of the diesel engine 4, the shaft generator 3
A drive signal is output to the governor motor 4b and the control panel 9 respectively to increase the frequency of the output, and then
Based on the detection signals from i', CT16/18 and P'r'17/19, it is determined whether the load of the diesel generator 6 has become less than a set value (for example, 30 KW), and if it is larger than the set value, The process returns to S2 and when the value falls below the set value, the process proceeds to S4 where the output line 1 of the diesel generator 6 is
1Q) ACBI2 is shut off. This is done by outputting a drive signal to the ACB input circuit 12a.

As mentioned above, the load of the diesel generator 6 is, for example, 30K.
Since the ACB 12 is cut off in the W state and the diesel engine 4 enters a no-load state, the number of revolutions of the diesel engine 4 increases, and the frequency that fluctuates in response to this number of revolutions also becomes greater than 60 Hz.

Next, in S5, a drive signal instructing to set the frequency of the output of the diesel generator 6 to 60Hz is output to the governor motor 4b, and then in 86, the frequency of the output of the diesel generator 6 is set to a value within a predetermined tolerance range. For example 60
~60.511z is determined, 60~60
．． If it is not within the range of 511z, return to S5,
When the frequency falls within the range of 60 to 60°5 Hz, the process moves to S7, in which a stop command is output to the diesel generator 6, and when the diesel generator 6 is stopped in S8, the frequency control is stopped in step 39.

In conventional diesel generator stop control, steps S5 and S6 are not provided, and after the ACB 12 is shut off, a stop command is output and the diesel engine 4 is stopped.

In that case, the governor of diesel engine 4 is, for example, 30
The diesel engine 4 is stopped in a state where the rotation speed is set to correspond to 6011z under a load of KW. Therefore, in the no-load state after the start-up of the diesel generator 6 and before synchronization (at this time, the ACB 12 is cut off), the rotation speed of the diesel engine 4 increases above the rotation speed corresponding to 60 flz, The frequency of the output of the diesel generator 6 is higher than 6011z, and the time required for the synchronization control becomes longer.

As in the present invention, steps S5 and S6 are provided, and ACB
By presetting the frequency of the diesel generator 6 in the range of 60 to 60°5 Hz under the same no-load condition as when the synchronization was turned on after the shutdown of the diesel generator 6, the frequency after the start-up of the diesel generator 6 before the synchronization is can match the specified frequency of the power supply system, reducing the time required for synchronization control by approximately 1/2.
It can be shortened to ~l/3.

Although the above control is automatically performed according to a control program inputted into the control unit 15 in advance, it may also be performed manually by operating switches on the operation panel of the control unit 15.

Although the above embodiment is an example in which an SG is provided, the present invention can be similarly applied to a case in which a turbo generator is provided in place of the SG.

[Brief explanation of drawings]

The drawings relate to an embodiment of the present invention, and FIG. 1 is a block diagram of a marine power generation system, and FIG. 2 is a flowchart showing a frequency control routine when the diesel generator is stopped. 3... Shaft generator, 4b... Governor motor, 6... Diesel generator, 11... Output line, 12... A
CB, 15...Automatic synchronous load sharing device. Patent applicant Kawasaki Heavy Industries, Ltd. Figure 2

Claims (1)

[Claims] (1) In a parallel operation control method in which a regular generator that generates electricity using energy from the main engine and a standby diesel generator are operated in parallel by controlling them with an automatic synchronized load sharing device, the standby diesel generator that is operating in parallel is stopped. Occasionally,
A method for controlling the frequency of a marine generator, characterized in that after shutting off the ACB of the diesel generator, the frequency setting means of the diesel generator is manually or automatically set to a frequency substantially equal to a predetermined frequency in the ship's power supply system.