JPS6042339B2 - How to start a load on a diesel generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for starting a load on a diesel generator used as an emergency generator in a nuclear power plant.

A conventional method for applying a load to a diesel generator will be described with reference to FIGS. 1 and 2.

In FIG. 1, when a command to start a diesel engine 2 is issued from a controller 1, a solenoid valve 3 is opened and the diesel engine 2 is
Compressed air is supplied to the speed governor amplifier 4 from the air tank 5 .

The compressed air supplied to this diesel engine 2 is distributed through the distribution valve (
(not shown) is appropriately distributed within the cylinders of the diesel engine 2, thereby causing the diesel engine 2 to rotate.
On the other hand, oil pressurized from the speed governor widening device 4 by the compressed air supplied to the speed governor widening device 4 is supplied to the speed governor 7 via the oil pipe 6. The fuel adjustment shaft 8 is moved to the position where the fuel injection amount of the fuel injection pump 9 is maximized. As a result of the above, the rotational speed of the diesel engine 2 rapidly increases.

The rotation speed of diesel engine 2 is 20% of the specified rotation speed.
When this happens, the solenoid valve 3 is closed by a signal from the controller 1, and compressed air is no longer supplied to the diesel engine 2 and governor amplifier 4.

However, there is no problem because the diesel engine 2 is supplied with fuel from the fuel tank 11 via the fuel oil pipe 10 and shifts to fuel operation. Furthermore, since the rotational speed is in the process of increasing, the governor 7 operates to continue to hold the fuel adjustment shaft 8 at the position where the fuel is at its maximum. When the rotational speed increases and reaches a specified value, the governor 7 returns the fuel adjustment shaft 8 to a position where the rotational speed is maintained at the specified rotational speed. In this way, the frequency and voltage of the generator 12 directly connected to the diesel engine 2 also reach the specified values. The rotational status of the generator 12 and the permanent magnet pilot generator 13 directly connected to the generator 12 is sent to the controller 1 as a signal. When the values of these signals reach the specified values, the generator breaker 15 installed between the generator 12 and the bus bar 14 is turned on, and the motor breaker 16 is also turned on to disconnect the load. The electric motor 17 will be driven. A pump (not shown) or the like is connected to this electric motor 17, and the pump or the like can supply cooling water or the like into the core of the nuclear reactor. At this time, the pilot generator 13 is used to confirm what percentage of the specified speed the diesel engine 2 is operating at. Next, the operation will be explained based on the characteristic diagram shown in FIG.

In Figure 2, the horizontal axis shows the time from the start command, line A is the rotational speed (frequency), line B is the movement of the fuel adjustment axis, and line C is the voltage generated by the generator. D shows the time course of the load current. As can be seen from the figure, when a start command is issued, the movement of the fuel adjustment axis shown by line B immediately shifts to the position where the fuel is at its maximum and maintains that state for a predetermined period of time. When the maximum amount of fuel is supplied to the diesel engine 2 by this movement of the fuel adjustment shaft, the rotational speed of the diesel engine 2 gradually increases as shown by line A, and the voltage generated by the generator 12 also increases as shown by line C. It will gradually rise after a predetermined period of time so that the In this way, when the frequency is established at time T2, the fuel adjustment axis 8 rapidly moves in the direction of decreasing fuel, and after time T2, the generated voltage is established at the specified voltage. When frequency establishment t1 and voltage establishment! are confirmed, at time T3, the load is turned on, that is, the generator shield breaker 15 and the motor shield breaker 16 are turned on, and the motor 1 is turned on.
7 will be driven. As a result, the load current suddenly increases as shown by line D, and then settles down to a steady state at point P. When the electric motor 17 as a load is turned on, the diesel engine 2 is rapidly braked, so the rotational speed, that is, the frequency, temporarily decreases by the frequency drop f.
Descends by 1.

Sensing this change in rotational speed, the speed governor 7 moves the fuel adjustment shaft 8 again to a position where the fuel supply is increased in order to return the rotational speed to the specified value. In this case, since the speed governor 7 performs this operation using the hydraulic pressure generated by itself, its response is delayed. FIG. 2 is an example of actual machine measurement, and the fuel adjustment axis movement time T1 is about 1. Therefore, the time F1 required for the frequency to recover is as long as about 3 seconds, and the amount of frequency drop f1 is also large. Incidentally, the frequency fluctuation and recovery time of the generator 12 are kept small, especially in an emergency diesel generator of a nuclear power plant.

Furthermore, the time Tp from the starting command for the diesel engine 2 to the completion of starting the electric motor 17 is kept small, but in the conventional technology, the electric motor 17 is inevitably started after the process shown in FIG. Can't make it shorter. For this reason, in the prior art, the problem has been dealt with by increasing the output of the diesel engine 2, which has the disadvantage of increasing manufacturing costs. An object of the present invention is to provide a load starting method for a diesel generator that can shorten the time from a diesel engine starting command to the completion of starting the electric motor as a load.

When a load is applied to a diesel generator, the present invention makes it possible to turn on a shear cutter and start the load before the fuel reaches the lowest position by the fuel adjusting shaft to the diesel engine, and the load is started. This is what we are trying to achieve.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 7. Here, the same or equivalent components as in the conventional example are given the same reference numerals to simplify the explanation. Figure 3 shows the frequency fluctuation (see line A) when starting according to the method of the present invention.
Voltage fluctuation (see line C), movement of fuel adjustment axis (see line B)
This figure shows the behavior of the load current (see line D) over time.

As can be seen in FIG. 2, the fuel adjustment shaft suddenly drops in the decreasing direction as soon as the rotational speed reaches the specified value, and is not sufficiently prepared to respond to the next load application.

When a load is suddenly applied, it is necessary to suddenly raise the fuel adjustment axis to the maximum increase position, but there is a delay in response time, and since it is a mechanical system, it cannot respond quickly enough to rapid load changes. Therefore, as shown in FIG. 3, when the diesel engine is increasing in speed after the diesel engine start command is issued, the movement of the fuel adjustment axis is increased until the speed reaches the specified value. By focusing on the fact that the diesel engine is held at the position of This reduces the time required from the starting command to the completion of starting the motor. That is, in Fig. 3, the fuel adjustment axis is at the maximum increase position B, and the rotational speed (frequency) is A.
The load is applied at time ζ after self-sustaining operation (operation using fuel). In this way, as shown in FIG. 3, the frequency fluctuation, that is, the frequency drop amount F2 and the voltage fluctuation after the completion of starting can be made sufficiently small, and the specified values can be sufficiently satisfied. Further, the time Tp until the completion of starting the electric motor can be reduced by about 40% compared to the case of the coupling shown in FIG. As described above, according to this embodiment, whereas the conventional closing condition for the breaker is the establishment of the voltage and frequency of the generator, this embodiment Since the breaker is turned on when the speed reaches approximately 50% or more and before the fuel returns to the lowest position, the time from the starting command to the completion of starting the motor is reduced by T.
p can be sufficiently shortened. Also, the amount of frequency drop F
2 and voltage fluctuations can also be made sufficiently small. Next, main parts of a specific apparatus for carrying out the present invention will be explained based on FIGS. 4 to 7.

In FIG. 4, a first fuel adjustment shaft 8A is connected to the speed governor 7 via a link mechanism 21 and a lever/pin mechanism 22, and the movement of the leakage mechanism 21 in the direction of increasing fuel as indicated by the arrow G or the arrow H The movement in the fuel decreasing direction shown by is made to be the movement in the rotational direction of the first fuel adjusting shaft 8A. One end of an actuating piece 23 is fixed in the middle of this first fuel adjustment shaft 8A, and the other end of this actuating piece 23 is
A limit switch 24 is provided which is operated by. At this time, the actuating piece 23, as shown in FIG.
A first position 23 in which no fuel is supplied to the diesel engine.
A1 can be moved between a second position 23B where fuel is supplied to a certain extent and a third position 23C where the maximum fuel is supplied, and the limit switch 24 is activated at the third position 23C. A second fuel adjustment shaft 8A is connected to the other end of the first fuel adjustment shaft 8A via a lever pin mechanism 25.
The fuel adjustment shaft 8B is connected so that the movement of the first fuel adjustment shaft 8A in the rotational direction is converted into the axial movement of the second fuel adjustment shaft 8B.

In the middle of this fuel adjusting shaft 8B, the amount of oil in the fuel oil pipe 10 can be adjusted by adjusting the opening degree of a gate valve provided in the fuel injection pump 9. Also, in Figure 6, the horizontal axis shows the actuating piece position, and the vertical axis shows the amount of fuel.
When the actuating piece 23 is in the first position 23A, no fuel is supplied, when in the third position 23C, the maximum amount of fuel is supplied, and when in the second position 23B, no fuel is supplied. It can be seen that the following is supplied.

FIG. 7 shows a sequence electrical circuit diagram in which the electric motor as a load is turned on when the diesel engine is started.

Here, between the busbars 14A and 14B, the limit switch Sl, 24, a switch S2, which is turned on when the speed of the diesel engine reaches 50% or more of the specified speed,
26 and a coil Rl, 27 which is excited when the limit switch 24 and switch 26 are closed are connected in series. The coil R2 of the generator shield breaker 15 is connected in series to the auxiliary contact 28 of this coil 27, and the self-holding auxiliary contact 29 of the generator shield breaker 15 is connected in parallel with the auxiliary contact 28. It is connected. Furthermore, the coil R3 of the motor sheath breaker 16 is connected in series to the auxiliary contact 30 of the generator sheath breaker 15. In such a configuration, when the diesel engine is started,
Since the first fuel adjusting shaft 8A is located at the third position 23C, when the limit switch 24 is closed and the speed of the diesel engine exceeds 50% of the specified speed, the auxiliary contact 26 is closed and the coil 27 is closed. Energized and auxiliary contact 28
is closed, and the generator sheath breaker 15 is turned on.

By turning on the generator breaker 15, the auxiliary contact 29
, 30 are closed, and the coil R2 of the generator sheath breaker 15 is closed.
is self-maintained, and the motor disconnector 16 is turned on to energize the generator 12. At this time, the reason why the generator sheath breaker 15 is self-retained is when the first fuel adjusting shaft 8A is in a state other than the third position 23C, the limit switch Sl, 24 is opened and the coil coil 27 becomes de-energized, thereby preventing the generator shield and disconnector 15 from being disconnected. Note that the self-holding of the generator breaker 15 can be released by disconnecting the stop switch of the entire device.

Further, if the limit switch 24 is not provided, the self-holding auxiliary contact 29 is not necessarily required. but,
If the limit switch 24 is provided, the first fuel adjustment axis 8
This has the advantage that the position of A can be detected reliably. In addition,
In the embodiment described above, the load is turned on after the diesel generator is operated in a self-sustaining manner, but the load may be turned on before the self-sustaining operation, for example, simultaneously with the start command.

However, in this case, the diesel engine cannot be started unless the amount of air blown from the air tank is increased, so there is a disadvantage that the capacity of the air tank etc. must be increased. As described above, according to the present invention, it is possible to provide a load starting method for a diesel generator that can shorten the time from a diesel engine starting command to the completion of starting the electric motor as a load.

[Brief explanation of the drawing]

Fig. 1 is a starting system diagram of a general diesel generator, Fig. 2 is a line diagram showing a load starting method in a conventional diesel generator, and Fig. 3 is a line diagram showing a load starting method of a diesel generator according to the present invention. 4 is a schematic perspective view of a fuel control unit for carrying out the load starting method according to the present invention, FIG. 5 is an enlarged view taken along the line V-■ in FIG. 4, and FIG. 6 is an operating piece position. FIG. 7 is a sequence electrical circuit diagram of a surface section for carrying out the load starting method of the present invention. 1...Controller, 2...Diesel engine, 7...Governor, 8...Fuel adjustment shaft, 9...
... Fuel injection pump, 12 ... Generator,
15・・・・Shin breaker for generator, 16・・・・・・
Electric motor disconnector, 17...Electric motor as a load.

Claims (1)

[Claims] 1 In a load starting method for a diesel generator, in which a load is connected to a generator connected to a diesel engine via a breaker, and the load is started by turning on the breaker, the load is applied to the generator. When starting the diesel generator, the load is started by turning on the above-mentioned shutoff switch before the fuel supply to the diesel engine reaches a position where it returns to the lowest level for the first time after the diesel generator is in self-sustaining operation. How to start the load on the machine.