JP2798533B2 - Start control device for gas turbine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a start control device for a gas turbine installed in, for example, a power generation facility.

[0002]

2. Description of the Related Art A general example of a gas turbine power generation system according to the prior art is, for example, as shown in FIG.
The gas turbine 1, the air compressor 2, and the generator 3 are coaxially connected, and the opening of the fuel control valve 8 is controlled by each signal output from each of the control devices 4 to 6. The fuel supplied and the compressed air supplied from the air compressor are mixed and burned in the combustor 9, and the high-temperature and high-pressure gas generated by the mixed combustion is supplied to the gas turbine 1 to rotate the shaft, thereby generating the electric power from the generator 3 It is configured to extract power from the

When the gas turbine 1 is started,
The supply of fuel to the combustor 9 is increased in anticipation of an increase in the rotation speed of the gas turbine 1, but when the actual rotation speed of the gas turbine 1 is lower than the expected increase rate,
Alternatively, when the rotation speed does not rise above a certain value, the fuel becomes excessive, causing the temperature of the air supplied to the gas turbine 1 to rise, which adversely affects the gas turbine 1.

In order to avoid such a rise in the temperature of the supplied air, a known technique disclosed in Japanese Patent Application Laid-Open No. 1-182531 has disclosed a target rotation speed or a deviation value between a target rotation speed equivalent value and an actual rotation speed. Is detected to exceed a predetermined value, the control is shifted from the gas turbine acceleration control to the gas turbine holding control. Then, when it is detected that the deviation has recovered to a predetermined value or less, the process returns to the acceleration control.On the other hand, when a predetermined time has elapsed without the deviation recovering to the predetermined value or less,
The control is returned from the gas turbine holding control to the warming-up control, and is again shifted to the gas turbine acceleration control.

[0005]

However, in the gas turbine start control method described above, when the deviation between the target rotation speed or the target rotation speed equivalent value and the actual rotation speed exceeds a predetermined value, the gas turbine is already controlled. Often the temperature of the air supplied to the air is considerably increased.

In that case, since the deviation is fixed,
It is not possible to cope with the fact that there is a considerable difference in the air temperature between low and high speeds, and the temperature of the combustion air supplied to the turbine also depends on the atmospheric temperature supplied to the compressed air. However, there is a problem to be solved in that this cannot be adequately dealt with.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a start control apparatus for a gas turbine which achieves a quick and smooth start while preventing an increase in the temperature of air supplied to the gas turbine and eliminating an adverse effect on the gas turbine. It is in.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and therefore, a feature of the gas turbine start control device according to the first aspect of the present invention is that the ignition is performed. A starting control device for a gas turbine that gradually increases supply fuel following operation and performs acceleration control of the gas turbine, and controls a preset control amount that increases with an increase in the rotation speed and an exhaust temperature or a turbine inlet temperature. A fuel control circuit that selects a low value of a control amount to suppress the temperature to a value that is slightly lower than a temperature set in advance by a rotation speed at that time and that is a fuel control amount, and a gradually increasing acceleration rate of the rotation speed If the time during which the acceleration rate is equal to or less than the set value exceeds a predetermined time and the rotation speed at that time is within a preset range, the fuel output by the fuel control circuit is output. Constant control amount Only there is to made and a acceleration control circuit to increase.

A feature of the start control apparatus for a gas turbine according to a second aspect of the present invention is that the supplied fuel is gradually increased following the ignition operation, and the acceleration control of the gas turbine to which the air compressor is axially coupled. A control amount that is set in advance as the rotation speed increases, and the exhaust temperature or the turbine inlet temperature is slightly smaller than the temperature that is set in advance by the rotation speed. A fuel control circuit that selects a low value from a control amount for suppressing the difference to a low value and sets the fuel control amount, and calculates an acceleration rate of the rotational speed that gradually increases, and the acceleration rate is equal to or less than a set value. An acceleration control circuit that increases the fuel control amount output by the fuel control circuit by a fixed amount if the time exceeds a predetermined time and the rotational speed at that time is within a preset range; Entrance, exit The amount of air flowing into the compressor is calculated from the temperature and the number of revolutions, a fuel flow rate that causes surging for the number of revolutions at that time is obtained, and the fuel flow rate and the fuel control quantity output by the fuel control circuit are calculated. And a surging prevention control circuit that selects a low value of and sets a fuel control amount.

[0010]

According to the starting control apparatus for a gas turbine according to the first aspect of the present invention, since the starting is performed while controlling the temperature of the exhaust or the inlet of the turbine, the temperature of the supply air can be prevented from rising. In addition, even when the acceleration rate of the rotational speed decreases, the rotational speed can be increased by increasing the fuel control amount by a certain amount, and as a result, the exhaust gas temperature decreases. Is stable.

According to the starting control apparatus for a gas turbine of the present invention, the amount of air flowing into the compressor is calculated, and the fuel flow rate at which surging occurs with respect to the rotational speed at that time is obtained. A surging prevention control circuit that selects a low value of the fuel flow rate and the fuel control amount output from the fuel control circuit and sets the selected fuel control amount as a fuel control amount, thereby preventing surging due to excessive supply of fuel. Can be.

[0012]

FIG. 1 is a control circuit diagram of a gas turbine start control device according to one embodiment of the present invention, and FIG. 2 is a control circuit of a gas turbine start control device according to another embodiment of the present invention. FIG. In FIGS. 1 and 2, FIG.
The same reference numerals are given to the same corresponding or corresponding parts, and the following description will be given.

In FIG. 1, a signal from a rotation speed detector 11 for detecting the rotation speed (N) of the gas turbine 1 is set in advance as a control amount corresponding to a fuel supply amount that increases as the rotation speed increases. An acceleration schedule setting device 13 and an exhaust gas preset with a limit value as an upper limit of the exhaust gas temperature (or turbine inlet temperature) of the gas turbine 1 detected by the exhaust gas temperature detector 12 corresponding to the relationship with the rotation speed. It is input to the temperature limit setting device 14.

When the gas turbine 1 is started, the deviation between the limit temperature from the exhaust temperature limit setting unit 14 corresponding to the signal of the rotational speed detector 11 and the signal of the exhaust temperature detector 12 is proportional to
The processing is performed by the integrator 15. Then, this processing signal and the control amount corresponding to the rotation speed from the acceleration schedule setting unit 13 are input to the low value selection circuit 21, and the output thereof is the fuel control amount in the normal case.

On the other hand, the rotation speed N of the gas turbine 1 is input to an acceleration rate calculator 16, and the output dN / dt of the acceleration rate calculator 16 is input to a comparator 17 where the acceleration rate is compared with a set value α. If the acceleration rate is equal to or smaller than the set value α, the timer 18 is operated. The number of rotations N is determined by the comparator 1
9 and the number of revolutions N is equal to the number of revolutions N ₁ and N ₂
(N ₁ <N <N ₂ ), the comparator 19 outputs a 0N signal. Then, the output of the timer 18 and the output of the comparator 19 are input to an AND circuit 20. When the AND circuit 20 becomes 0N, the selection circuit 22 operates to add a fixed amount Δw to the output of the low value selection circuit 21. Is done.

With the above-described starting control circuit configuration,
The operation at the time of starting the gas turbine 1 is as follows. That is, when the acceleration rate of the rotation speed of the gas turbine 1 decreases at the time of startup and the exhaust temperature of the gas turbine 1 increases, the fuel control amount decreases to prevent the exhaust temperature from increasing. When the decrease in the acceleration rate continues for a predetermined time or more, the fuel control amount is increased by a fixed amount Δw and the fuel supply amount is increased, so that the rotation speed of the gas turbine 1 is increased. Due to the increase in the number of revolutions, the amount of air flowing into the combustor 9 increases, so that when the exhaust gas temperature falls and falls within a predetermined range, the fuel control is performed by the fuel control amount governed by the acceleration schedule of the acceleration schedule setting unit 13. Since the opening of the valve 8 is controlled, the rotation speed of the gas turbine 1 is increased until it reaches the rated rotation speed.

In FIG. 2, the amount of air flowing into the compressor 2 is calculated from the temperatures of the inlet and outlet of the compressor 2 and the number of revolutions, and the fuel flow rate that causes surging for the number of revolutions is calculated. A surging prevention control circuit that selects a low value between the fuel flow rate and the fuel control amount output from the fuel control circuit and uses the selected value as the fuel control amount is added to the start control circuit in FIG.

That is, based on the inlet pressure of the air compressor 2 detected by the air compressor inlet pressure detector 23, the inlet temperature of the air compressor 2 detected by the air compressor inlet temperature detector 24, and the rotation speed, The air compressor flow rate calculator 25 calculates the flow rate of air flowing into the air compressor 2.

Further, based on the rotation speed at that time and the calculated air flow rate, a fuel flow rate causing surging is calculated by a surging prevention fuel flow rate calculation circuit 26.
A low value between the fuel flow rate and the fuel control amount output from the start control circuit is selected by a low value selection circuit 27 to be used as a fuel control amount.

The surging prevention control circuit shown in FIG. 2 prevents the surging of the air compressor 2 which tends to occur when the amount of air to the air compressor 2 is small and the fuel becomes excessive. Meanwhile, the gas turbine 1 can be started smoothly.

[0021]

As described in detail above, claim 1 of the present invention
According to the start control device for a gas turbine according to the above, since the system is started while controlling the exhaust temperature or the inlet temperature of the gas turbine, regardless of the temperature fluctuation of the air supplied to the gas turbine, the temperature rise can be prevented, In addition, even when the acceleration rate of the rotational speed decreases, the rotational speed increases and the exhaust gas temperature decreases by increasing the fuel control amount by a predetermined constant amount. The rotation speed of the turbine can be increased to the rated rotation speed, and according to the start control apparatus for a gas turbine according to the second aspect of the present invention, the air flow rate to the air compressor directly connected to the gas turbine is small and the fuel is reduced. In the event of an excessive condition, the fuel supply can be limited to prevent surging of the air compressor, so that the life of the gas turbine can be extended by optimizing the temperature, There is a very significant effect on the speed or the like of the motion.

[Brief description of the drawings]

FIG. 1 is a control circuit diagram of a start control device for a gas turbine according to one embodiment of the present invention.

FIG. 2 is a control circuit diagram of a start control device for a gas turbine according to another embodiment of the present invention.

FIG. 3 is an apparatus system diagram of a conventional gas turbine power generation facility.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Gas turbine, 2 ... Air compressor, 3 ... Generator, 8 ...
Fuel control valve, 9: combustor, 11: rotational speed detector, 12 ...
Exhaust gas temperature detector, 13 ... Acceleration schedule setting device, 14
... Exhaust gas temperature limit setter, 15 ... Proportional / integrator, 16 ... Acceleration rate calculator, 17 ... Comparator, 18 ... Timer, 19 ... Comparator, 20 ... AND circuit, 21 ... Low value selection circuit, 22 ...
Selection circuit, 23 ... Air compressor inlet pressure detector, 24 ... Air compressor inlet temperature detector, 25 ... Air compressor flow rate calculator, 26 ... Surging prevention fuel flow rate calculation circuit, 27 ...
Low value selection circuit.

Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) F02C 7/26 F02C 9/26-9/28

Claims (2)

(57) [Claims] 1. A starting control device for a gas turbine that performs acceleration control of a gas turbine by gradually increasing supply fuel following an ignition operation, wherein the control amount is a preset control amount that increases with an increase in rotation speed; A fuel control circuit for selecting a low value of the control amount for suppressing the exhaust gas temperature or the turbine inlet temperature to a value slightly lower than the temperature set in advance by the rotation speed at that time as the fuel control amount, and gradually increasing the fuel control circuit; If the time during which the acceleration rate is equal to or less than the set value exceeds a predetermined time, and the rotation speed at that time is within a preset range, the fuel rate is calculated. A start control device for a gas turbine, comprising: an acceleration control circuit that increases the fuel control amount output by the control circuit by a fixed amount. 2. A starting control device for a gas turbine for controlling the acceleration of a gas turbine to which an air compressor is axially connected by gradually increasing the supply fuel following an ignition operation, and increasing with an increase in the number of revolutions. Select a low value between a preset control amount and a control amount for suppressing the exhaust temperature or the turbine inlet temperature to a value that is slightly lower than the temperature preset by the rotational speed at that time, and select a fuel control amount. A fuel control circuit,
Calculate the acceleration rate of the gradually increasing rotation speed, if the time during which the acceleration rate is less than or equal to the set value exceeds a predetermined time, and if the rotation speed at that time is within a preset range, the An acceleration control circuit that increases the fuel control amount output by the fuel control circuit by a fixed amount; and calculates the amount of air flowing into the compressor from the inlet and outlet temperatures of the compressor and the number of rotations, and calculates the number of rotations at that time. A surging prevention control circuit that determines a fuel flow rate that causes surging, selects a low value of the fuel flow rate and a fuel control amount output by the fuel control circuit, and sets the low value as a fuel control amount. Characteristic gas turbine start control device.