JPS6214695B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a two-shaft gas turbine.

A two-shaft gas turbine is known as a vehicle gas turbine. FIG. 1 is a system diagram showing an outline of a two-shaft gas turbine and its control device, and this diagram will first be explained.

1 is a compressor that compresses the atmosphere to obtain compressed air, and 2 is a gas generator turbine. The gas generator turbine 2 and the compressor 1 are connected by a rotating shaft 2a. 3 is a power turbine, and a load 11 is connected to an output rotating shaft 3a of the power turbine 3. 4 is a heat exchanger that heats the compressed air from the compressor 1 with the exhaust gas of the power turbine 3; 5 is a combustor that mixes fuel supplied by a fuel pump 8 through a fuel regulating valve 6 with the compressed air; The combustion gas is used to drive the gas generator turbine 2. 7 is a fuel adjustment valve drive mechanism for driving the fuel adjustment valve 6. 9 is a variable vane for connecting the gas general turbine 2 and the power turbine 3 and adjusting the amount of output supplied from the gas general turbine 2 to the power turbine 3; 10 is a mechanism for driving the variable vane 9; be.

The two-shaft gas turbine is configured as described above, and next, a control device for controlling the above-mentioned two-shaft gas turbine will be described.

Reference numeral 20 is a fuel/variable vane controller that plays a central role in controlling the two-shaft gas turbine, the details of which will be described later. Various data indicating the operating status of the two-shaft gas turbine are input to this controller.
Control signals for controlling fuel and variable vanes are output.

That is, reference numeral 12 denotes an accelerator pedal, and a setting signal N _G ^* is sent from the gas generator turbine rotation speed setting device 13 to the controller 20 in accordance with the amount of depression of the accelerator pedal 12 during acceleration/deceleration operation. Also, 14
15 is a rotation speed detector that detects the rotation speed of the gas general turbine 2, and 15 is a rotation speed detector that detects the rotation speed of the output rotating shaft of the power turbine 3. The gas general turbine rotation speed measurement value N _G and output are respectively The rotational shaft rotational speed measurement value N _OS is sent to the controller 20 . Furthermore,
16 is a temperature detector that detects the inlet temperature of the gas general turbine 2, and 17 is a temperature detector that detects the intake air temperature of the compressor 1, and the measured value of the gas general turbine inlet temperature T〓 ₇ and the compressor intake air temperature measurement value T, respectively. ₁ is sent to the controller 20. This fuel
The variable vane controller 20 calculates the startup and acceleration/deceleration of the two-shaft gas turbine by processing the set value N _G ^* and the measured values N _G , N _OS , T ₇ , and T ₁ that are supplied. Fuel flow command value G during operation, etc.
Outputs _f and variable vane opening command value V _G.
The fuel flow rate command value G _f from the controller 20 is converted into an operation signal for operating the fuel adjustment drive mechanism 7 by the converter 18, and the variable vane opening command value V _G is converted by the converter 19 into an operation signal for operating the fuel adjustment drive mechanism 7. It is converted into an operation signal for operating 10.

Now, conventional fuel/variable vane controller 2
Details of 0 are shown in FIG. The set value N _G ^* from the gas general turbine rotation speed setting device 13 and the intake air temperature measurement value T 〓 ₁ from the compressor intake air temperature detector 17 are supplied to the gas general turbine set rotation speed correction circuit 21, where the intake air temperature is Perform correction based on T ₁ and set the corrected gas general turbine rotation speed setting value N _GC ^* N. And this correction value N _GC
The comparator 22 compares ^* with the measured value _N
fN and supplies it to the fuel flow rate command calculation circuit 31. Further, the compressor intake air temperature measurement value T 〓 ₁ and the gas general turbine rotation speed measurement value N _G are supplied to the function generator 24, and a planned value T ₇ ^* of the inlet temperature of the gas general turbine 2 is set. This planned value T ₇ ^* is
The comparator 26 compares the measured value _T7C of the gas general turbine inlet temperature measured by the detector 16 with the compensated gas general turbine inlet temperature _T7C , which compensates for the detection delay of the sensor 16 by the compensation circuit 25. An overheat prevention signal ΔG _fT is provided to the fuel flow rate command calculation circuit 31. Furthermore, the output shaft rotation speed measurement value N _OS from the detector 15 and the output N _OS ^* from the setting device 28 for setting the output shaft limit rotation speed N _OS ^* are compared in a comparator 29, and the result is adjusted. vessel 30
The output shaft over-rotation prevention signal ΔG _fOS is then supplied to the fuel flow rate command calculation circuit 31. Note that the arithmetic circuit 31 contains a gas generator turbine rotational speed measurement value N _G
will also be supplied.

In this way, in the fuel flow rate command calculation circuit 31,
Introduced gas general turbine rotation speed adjustment signal ΔG
_fN , gas generator turbine rotation speed measurement value N _G , overheat prevention signal ΔG _fT , and output shaft overspeed prevention signal ΔG _fOS , a fuel flow rate command signal G _f for supplying fuel suitable for the operating condition to the combustor 5. For example, the gas general turbine rotation speed adjustment signal ΔG _fN is sent out so that the gas general turbine is constantly operated at the planned gas general turbine inlet temperature and low fuel consumption is maintained.
Based on this, the fuel flow rate is adjusted to control the rotation speed of the gas generator turbine 2, and the fuel is reduced by the overheat prevention signal ΔG _fT to prevent overheating of the gas turbine material due to excessive fuel injection, and to prevent output shaft overheating. The fuel is reduced by the rotation prevention signal ΔG _fOS to prevent the rotating parts from overspeeding due to power imbalance.

On the other hand, the gas general turbine rotation speed measurement value N _G from the detector 14 is compared with the corrected gas general turbine rotation speed setting value N _GC ^* from the correction circuit 21 in the comparator 32 , and the result is added to the regulator 33 . It is supplied to the variable vane opening command calculation circuit 36 as a variable vane opening adjustment signal _VGN during deceleration. In addition, a comparator 34 compares the gas general turbine inlet temperature planned value T ₇ ^* from the function generator 24 with a compensated gas general turbine inlet temperature T _7C from the compensation circuit 25, and the result is adjusted to a steady state by a regulator 35. It is supplied to the variable vane opening command calculation circuit 36 as a variable vane opening adjustment signal V _GT during operation. The variable vane opening command calculation circuit 36 then opens the variable vane 9 to suit the operating condition based on the variable vane opening adjustment signal _VGN during acceleration/deceleration and the variable vane opening adjustment signal _VGT during steady operation. For example, when the variable vane opening adjustment signal _VGN is used to suddenly drive the variable vane drive mechanism 10 during acceleration/deceleration, the variable vane 9 is suddenly opened and closed _. Improves acceleration/deceleration performance, and also provides variable vane opening adjustment signal V during steady operation.
_{The GT} adjusts the opening degree of the variable vane 9 during steady operation, so that the load on the gas generator turbine 2 does not become excessive, and steady operation is performed while maintaining low fuel consumption on the fuel plan line. There is.

By the way, such a controller 20 may be used, for example, if the output shaft 3 is turned off due to some reason while the gas turbine is operating with the accelerator pedal depressed.
When a becomes over-rotated, the output shaft over-rotation prevention signal ΔG
The fuel is throttled based on _fOS , and the gas general turbine rotational speed measurement value N _G decreases, and as the power generated by the gas general turbine decreases, the output shaft rotational speed N _OS also decreases. At this time, accelerator pedal 1
2 remains depressed, so N _GC ^* _−NG >
0, the regulator 23 determines that it is an acceleration, and the fuel is increased by the gas generator turbine rotation speed adjustment signal ΔG _fN , and the variable vane 9 is opened to the acceleration position by the variable vane opening adjustment signal _VGN during acceleration/deceleration, and the gas generator The turbine 2 is accelerated again to increase its rotational speed measurement N _G . When this rotational speed measurement value N _G increases, the power generated by the gas generator turbine 2 increases, so the output shaft rotational speed N _OS becomes overspeed again, and the output shaft overspeed prevention signal ΔG _fO
S will be working. From then on, the above operation is repeated, and as shown by the broken line in Fig. 4, the gas gene turbine rotation speed N _G , the output shaft rotation speed N _OS , the fuel flow rate command signal G _f , and the variable vane opening command signal V _G are respectively set. This had the disadvantage that hunting occurred and the turbine could not be operated stably.

The present invention has been made with the aim of eliminating such drawbacks.

An embodiment of the present invention will be described below with reference to FIG. Note that FIG. 3 is a system diagram showing the main parts of an embodiment of the control device for a two-shaft gas turbine according to the present invention, and the same parts as in FIGS. 1 and 2 are given the same reference numerals. It is shown.

That is, the present invention detects whether or not the output shaft 3a is in an over-rotation state, and when the output shaft 3a is in an over-rotation state, the variable vane opening degree adjustment signal V at the time of acceleration/deceleration is
The present invention is characterized in that _{the GN} is shut off and the opening degree of the variable vane 9 is adjusted by the signal V _GT based on the gas generator turbine inlet temperature T ₇ .

Therefore, in the present invention, the output of the comparator 29 is branched and supplied to the output shaft over-rotation determination circuit 51 that determines over-rotation of the output shaft, and the output of the regulator 33 is controlled to open the variable vane according to the output of this determination circuit 51. A gate circuit 52 for supplying or blocking the supply to the degree command calculation circuit 36 is added to the conventional controller 20, and the other configurations are as shown in FIGS.
It is similar to that shown in the figure. That is, the determination circuit 51 determines the output signal of the comparator 29 (N _OS ^* - _NO
S ) is used to determine whether the output shaft 3a is over-rotated or not, and the gate circuit control flag F _OS has a logical value of "1" when the output signal is N _OS ^* ≦ N _OS .
On the other hand, the output signal of the comparator 29 is N _OS ^* >
When N _OS , a gate circuit control flag F _OS whose logical value is "0" is output. Therefore, F _OS =0
In this case, the gate circuit 52 is opened and the output V _GN of the regulator 33 is supplied to the arithmetic circuit 36 . And F
When _OS = 1, the gate circuit 52 is closed, so the output V _GN of the regulator 33 is not supplied to the arithmetic circuit 36 . More specifically, the output shaft 3 of the power turbine 3
If the rotation speed of a is normal and not over-rotated, the output F _OS of the determination circuit 51 is "0" and the gate circuit 52 is opened, so the variable vane opening command signal V
_G is calculated from the output V _GN of the regulator 33 and the output V _GT of the regulator 35, but if the output shaft rotation speed of the power turbine 3 is over-rotated, the output F _OS of the determination circuit 51 is “1”. ” and closes the gate circuit 52, so the variable vane opening command signal V _G is calculated only from the output V _GT of the regulator 35. Therefore, while the output shaft 3a is over-rotating,
Regardless of the amount of depression of the accelerator pedal 12, the opening degree of the variable vane 9 is adjusted based only on the inlet temperature of the gas generator turbine 2. At this time, since the variable vane opening command signal V _G is based on the gas generator inlet temperature, there is no large variation, and therefore the gas turbine 2 also has its rotational speed N _G
Therefore, the fuel flow rate command signal G _f obtained from this rotational speed N _G does not vary greatly either. Therefore, as shown by the solid lines in FIG. 4, the various signals N _GC ^* , N _OS , G _f , N _G , and V _G change as shown by the solid lines, and hunting does not occur.

As described in detail above, according to the present invention, it is detected whether or not the output shaft is over-rotated, and when the output shaft is over-rotated, the variable vane opening adjustment signal for acceleration/deceleration is sent regardless of whether or not the accelerator pedal is depressed. _VGN
Since the opening degree of the variable vane 9 is adjusted based only on the gas gene turbine inlet temperature, it is possible to quickly correct the over-speed condition and return to the normal condition, and also to prevent problems such as hunting. A control device for a two-shaft gas turbine is provided which is extremely effective in preventing unstable operating conditions.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing an outline of a two-shaft gas turbine and its control device, and Fig. 2 is a system diagram showing in detail the conventional structure of the fuel/variable vane controller shown in Fig. 1. , FIG. 3 is a system diagram showing the main parts of an embodiment of the control device for a two-shaft gas turbine according to the present invention, and FIG. 4 is a diagram showing changes over time in various signals between the device of the present invention and the conventional device. It is a diagram showing a comparison of differences. 1...Compressor, 2...Gas generator turbine, 3...Power turbine, 4...Heat exchanger, 5
... Combustor, 6 ... Fuel adjustment valve, 7 ... Fuel adjustment valve drive mechanism, 8 ... Fuel pump, 9 ... Variable vane, 10 ... Variable vane drive mechanism, 11 ... Load, 12 ... Accelerator pedal,
13...Gas gene turbine rotation speed setting device, 14...
...Gas general turbine rotation speed detector, 15...Output shaft rotation speed detector, 16...Gas general turbine inlet temperature detector, 17...Compressor intake air temperature detector, 18, 19...Converter, 20...Fuel・
Variable vane controller, 21... Gas generator turbine set rotation speed correction circuit, 22, 26, 29, 3
2, 34... Comparator, 23, 27, 30, 33,
35...Adjuster, 24...Function generator, 25...
Compensation circuit, 28... Output shaft limit rotation speed setting device, 3
DESCRIPTION OF SYMBOLS 1...Fuel flow rate command calculation circuit, 36...Variable vane opening command calculation circuit, 51...Output shaft overspeed determination circuit, 52...Gate circuit.

Claims (1)

[Claims] 1 A two-shaft gas turbine having a gas generator turbine driven by combustion gas from a combustor and a power turbine to which the output of the gas generator turbine is supplied via variable vanes to drive a load is operated at an idling speed. During steady operation, the opening degree of the variable vane is adjusted based on the inlet temperature of the gas generator turbine, and during acceleration/deceleration operation above idling speed, the opening degree of the variable vane is adjusted based on at least the operating amount of the accelerator. In the control device for a two-shaft gas turbine, the controller includes: over-rotation detection means for detecting over-rotation of the output shaft of the power turbine and generating a detection signal; and operation of the accelerator based on the detection signal from the means. 1. A control device for a two-shaft gas turbine, comprising means for inhibiting an opening adjustment operation of a variable vane based on a variable vane amount.