JPS6048620B2 - gas turbine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas turbine control device, and more particularly to a gas turbine control device that controls air purge of a combustor when ignition fails or when a gas turbine trips.

Generally, gas turbine power generation equipment is constructed as shown in FIG.

That is, the gas turbine 11 is connected to an air compressor 12 and a generator 13 on the same shaft, and is further connected to a starter 15 via a clutch 14 . The gas turbine 11 and air compressor 12 are then housed within the combustor 16. The gas turbine 11 is started by connecting the generator 13 and the starter 15 with the clutch 14 and starting the starter 15. That is, when the starter 15 is started, the air compressor 12 connected thereto rotates, pressurizes and compresses the outside air P, and sends it into the combustor 16 as compressed air P. Hereinafter, the starting characteristics of the gas turbine 11 will be explained with reference to FIGS. 1 and 2.

When the rotational speed N of the gas turbine 11 reaches a certain rotational speed ACrμm as shown in FIG. 2, a pilot flame for igniting the gas in the combustor 16 is ignited (at a given time). Then, the rotation speed N further increases to a predetermined rotation speed BCrμm]
When the fuel Q reaches the combustor 16, the fuel Q is injected into the combustor 16. This gas mixture of fuel Q and compressed air P is ignited by the pilot flame. The high-temperature, high-pressure combustion gas Po generated in the combustor 16 is introduced into the turbine 11, and its energy is converted into rotational energy of the turbine 11. Then, the gas Po is exhausted to the exhaust path. released as. When the fuel Q injected into the combustor 16 is increased, the energy in the combustion gas P2 increases, so that at a certain rotation speed C[R
pm], the gas turbine 11 itself can drive the air compressor 12. At this point, the starter 15 becomes unnecessary, so the clutch 14 is disengaged, and the gas turbine 11 reaches the rated speed FCrpm on its own (time Ta). A:
These will be referred to as ignition rotation speed, B: ignition rotation speed, and C: reference rotation speed. The above is a case where the gas turbine starts up smoothly, but in reality, the ratio between the amount of compressed air P and the amount of fuel Q may not be as set due to a difference in the ignition timing at the time of ignition. . In such cases, ignition often fails. If ignition fails, the gas turbine 11 will not be able to rotate up by itself. In addition, unburned fuel Q is inside the combustor 16 and the turbine 1.
1 and flow out into the exhaust passage, creating an extremely dangerous situation. For this reason, a fire detector 17 is attached to the combustor 16 to detect infrared rays and ultraviolet rays generated during combustion, and constantly monitors whether or not fuel is burning. It is the clutch 14 that determines ignition failure during startup of the gas turbine 11.
is turned off at a rotation speed D [Rpm] lower than the reference rotation speed C [Rpm], but at that time T
, when the fire detector 17 does not operate, the gas star pin valve, ie, the fuel stopper valve 18, is immediately fully closed, and the starter 15 is also stopped. The gas turbine 11 may trip not due to ignition failure, but may also occur due to a drop in lubricating oil pressure, excessive vibration, or the like. When a gas turbine pin trip occurs, the fuel Q is briefly cut off as described above, the starter 15 is also stopped if it is being operated, and the gas turbine 11 continues to rotate. The source of energy is cut off. Therefore, the air compressor 12 blows air into the combustor 16 using only inertial energy. FIG. 2 is a characteristic diagram showing changes in the rotational speed of the gas turbine.

The characteristic curve (1) is the characteristic curve (1) of the gas turbine 21. This is the characteristic curve when the startup is performed smoothly, and the characteristic curve (2) is the characteristic curve when the gas turbine 11 trips for some reason. As shown in characteristic curve (2), when the rotation speed N of the gas turbine reaches E [Rpm] (time T,),
When tripped for any reason, the gas turbine 11 is decelerated until its inertial energy disappears.

At this time, the amount of air blown by the air compressor 12 is a function determined by the rotational speed N and time t, so it is proportional to the area surrounded by A, C, and C of the characteristic curve (2). ing. Assuming that the amount of air corresponding to the area surrounded by A, mouth, and C is the minimum required for complete air purging, the gas turbine 11 will have an air purge rotation speed of ECrpm.
] If a trip occurs below this, sufficient air purge will not be performed. In such a case, to perform an air purge, connect the clutch 14, operate the starter 15,
The air compressor 12 must be driven, in this case,
The gas turbine is operated manually so as not to ignite even when the rotational speed of the gas turbine reaches the ignition rotational speed A [Rpm], and not to inject fuel into the combustor 16 even when the rotational speed reaches the ignition rotational speed BCrpm].

When the rotation speed reaches the air purge rotation speed EC rpm, the clutch 14 is disengaged, the starter 15 is stopped, and the air purge is completed. After the air purge is completed, a normal starting operation is performed to restart the gas turbine 11. If the engine is restarted without sufficient air purging after the gas star pin trip, there is a risk that the unburned fuel Q remaining in the combustor 16 will catch fire when the engine is ignited during the restart.

In the worst case, this could cause an explosion, causing the combustor 16
This is extremely dangerous as it may destroy the turbine 11. Therefore, in order to prevent this, if an air purge is necessary, a warning is issued to the operator and the restart is not possible until after the air purge is completed, greatly increasing the safety of the apparatus.

Also, during air purge operation, the fuel valve and shutoff valve are automatically closed.
If the ignition system can be locked, the burden on the operator will also be reduced.
In view of the above, an object of the present invention is to provide a gas turbine which determines whether or not air purge is necessary when a gas turbine pin trip occurs, issues an alarm if necessary, and prevents the next startup until the air purge is completed. The purpose of this invention is to provide a control device for

An embodiment of the present invention will be described below with reference to FIG.

FIG. 3 is an air purge control circuit of the gas turbine control device of the present invention. Contact 1 is a limit switch that closes when the gas turbine rotation speed N is equal to or higher than the ignition rotation speed BCrpm, and contact 2 is a limit switch that closes when the gas turbine rotation speed is equal to or higher than the air purge rotation speed ECr.
pm] Contact 3 is a limit switch that is used when the fire detector 17 confirms ignition, and contact 4 is a contact that closes when the turbine trips. Relay 5 is an air purge relay that operates when air purge operation is required, relay 6 is a fuel shutoff relay that issues a command to close fuel shutoff valve 18 in accordance with the operation of relay 5, and relay 7 is an ignition relay. This is the ignition relay that operates the device. Also, the rotation speed of contact 8 is the air purge rotation speed E.
The contact 9 is a limit switch that closes at [Rpm] or more, the contact 9 is a limit switch that closes at a rotational speed, and the relay 10 is an air purge completion relay that determines the completion of air purge.

Further, the relay 20 is an air purge start relay. Whether or not air purge is necessary is determined as follows.

That is, the rotational speed of the gas turbine 11. Combustor 1 for ignition
The rotation speed B [Rpm] at which fuel is injected within 6 or more,
When the gas turbine 11 is operated in a rotational speed range lower than the rotational speed ECrpm which does not require air purge, and when the gas turbine 11 cannot be confirmed to be ignited by the fire detector 17, or due to vibrations, etc. When the gas turbine 11 trips under the mechanical emergency stop condition of
In these cases, it is determined that air purge is necessary. In Fig. 2, the rotational speed N of the gas turbine is the ignition rotational speed BCrp.
m], contact 1 closes.

Further, if the rotational speed N of the gas turbine does not reach the rotational speed E [Rpm] at which air purge is unnecessary, the contact 2 is closed.

If ignition fails in this state, contact 3 closes and relay 5 operates. Further, if vibration or the like occurs in the gas turbine, the contact point 4 will close in this case as well, so the relay 5 will cause the activated gas turbine to come to an emergency stop.
At this time, the relay 5 is energized and is self-held by the contact 5a of the relay 5, and the contact 5b of the relay 5 issues a warning that "air purge operation is required". In addition, contact 5c of relay 5
The relay 6 is energized, and the contact 6a of the relay 6 issues a command to close the fuel sheath valve 18. Since the contact 5d of the relay 5 is open at this time, even if the ignition command contact 21 is closed,
Relay 7, which provides the ignition command, is not energized. In other words, the contact 7a of the relay 7 is not closed and the operation of the ignition device is locked. When the "air purge operation required" condition occurs, air purge operation is performed as described above, and the rotational speed of the starter is reduced to ECr.
pm], contact 8 closes and relay 20 is energized.

This starts the air purge, and the contact 20a of the relay 20 self-holds it. At this time, since the rotational speed of the gas turbine is not constant, contact 9 is engaged and relay 10 is not energized. During air purge operation, the starter 15 stops when the rotational speed reaches ECrpm, and the clutch 14 is also disengaged. The gas turbine continues to rotate due to the residual inertial energy, but the gas turbine gradually decelerates as the driving source disappears. In other words, the air compressor 12 maintains a rotational speed atmosphere while continuing air purging. When the rotational speed reaches ambient temperature, contact 9 closes and relay 10 is energized. That is, the self-holding of the relay 5 is released by engaging the contact 10a of the relay 10. Therefore, the relay 5 continues to be energized until the air purge is completely completed. In other words, the contact 5b of the relay 5 issues an alarm, the contact 5c of the relay 5 excites the relay 6, the contact 6a of the relay 6 continues to issue a command to close the fuel valve 18, and locks the ignition device. continue. When restarting after the air purge is completed, relay 5 becomes de-energized due to the completion of the air purge.
Since the contact 5d is closed, when the ignition command contact 21 is present, the relay 7 is activated, and the contact 7a of the relay 7 is ignited, and the contact 7b of the relay 7 is engaged to release the self-holding of the relay 20, and the second All of the circuits in FIG. 3 are in their initial state.

As described above, according to the present invention, there is a function to determine whether air purge operation is necessary in the event of a gas star pin trip or ignition failure, and a function to determine whether air purge operation is completely performed. When the air purge operation is required, it will issue an alarm, and during the air purge operation, the fuel valve and valve will be closed, the ignition system will be locked, and this state will continue until it is determined that the air purge is complete. A control device can be obtained which can significantly increase safety for gas turbines.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a gas turbine generator, FIG. 2 is a characteristic diagram showing changes in the rotational speed of the gas turbine, and FIG. 3 is a diagram showing an embodiment of the present invention. 11... Gas turbine, 12... Air compressor, 13
... Generator, 14... Clutch, 15... Starter, 16... Combustor, 17... Fire detector, 18...
- 5 fuel valves.

Claims (1)

[Claims] 1. A gas turbine, an air compressor that is directly connected to the same shaft and supplies compressed air, a combustor that houses the air compressor and the gas turbine and burns fuel internally, and an air compressor that is connected to the outside of the combustor. Starting a gas turbine power generation facility comprising a generator arranged and directly connected to the air compressor, and a starter connected to the generator via a clutch and providing driving force until the gas turbine reaches a reference rotation speed. An air purge relay that operates when there is a gas turbine trip or ignition failure when the rotational speed of the gas turbine is in a range exceeding the ignition rotational speed and less than the air purge rotational speed, and detects that air purge operation has started. a fuel cut-off relay that cuts off the fuel supplied to the combustor when the air purge relay operates; and a fuel cut-off relay that cuts off the fuel supplied to the combustor when the rotation speed of the gas turbine exceeds the air purge rotation speed, and cuts off the clutch to shut off the starter. an air purge start relay that prevents the driving force from being transmitted to the gas turbine, and an air purge completion relay that detects the completion of the air purge operation when the rotational speed of the gas turbine reaches approximately atmospheric. Gas turbine control device.