JP2000080928A - Gas turbine output control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely hold an operating temperature of a gas turbine within an allowable temperature by calculating the maximum output outputted by a gas turbine on the basis of the outlet temperature of the gas turbine in the case where an operation of the gas turbine is controlled, and holding an output of the gas turbine smaller than the maximum output. SOLUTION: In a gas turbine controller 11, when rotating speed of a gas turbine 1 exceeds predetermined rotating speed, a control signal for permitting power to output from an inverter 4 is supplied to an INV controller 12. After the rotating speed attains the predetermined rotating speed, a rate of fuel supplied to the gas turbine 1 is controlled so as to hold the rotating speed. When an output of the gas turbine 1 exceeds the maximum output even if a fuel supplying rate is increased for holding rotating speed of the gas turbine 1, a fuel supplying rate is restricted to such a rate that the output of the gas turbine 1 does not exceed the maximum output. It is thus possible to beforehand prevent the damage of the gas turbine 1 caused by heat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas turbine output control device.

[0002]

2. Description of the Related Art Gas turbines for driving a generator to obtain electric power are known. In a gas turbine, its output becomes large, and when the temperature of the gas turbine exceeds a certain temperature, there is a possibility that the gas turbine will break down. Therefore, there is a limit to the output that the gas turbine can output. Therefore, in the gas turbine output control apparatus disclosed in Japanese Patent Application Laid-Open No. 8-212264, the maximum value of the output that the gas turbine can output based on the temperature of the cooling water for cooling the generator connected to the gas turbine (hereinafter, maximum output) Is calculated, and control is performed so that the output of the gas turbine does not exceed the maximum output. Here, it is determined that the lower the temperature of the cooling water is, the lower the temperature of the air (hereinafter, intake air) taken into the gas turbine is, and the lower the temperature of the gas turbine is, and the higher the maximum output is calculated.

[0003]

However, even when the temperatures of the intake air are equal, the combustion temperature in the gas turbine varies depending on the amount of fuel supplied to the gas turbine and the number of revolutions of the gas turbine. Therefore, the temperature of the intake air does not exactly correspond to the temperature of the gas turbine. Therefore, the temperature of the intake air is estimated based on the temperature of the cooling water, and the maximum output calculated based on the temperature of the cooling water does not correspond to the output that can be actually output by the gas turbine. Can not be prevented. The object of the present invention is therefore to ensure that the operating temperature of the gas turbine is maintained within the permissible temperature,
An object of the present invention is to sufficiently prevent a failure of a gas turbine. Note that the outlet temperature corresponds to the temperature of the exhaust gas discharged from the gas turbine.

[0004]

According to a first aspect of the present invention, there is provided a gas turbine output control device for controlling the operation of a gas turbine such that a predetermined voltage is obtained from the gas turbine. A maximum output calculating means for calculating a maximum output that can be output by the gas turbine based on an outlet temperature of the gas turbine; and a gas turbine output limit for maintaining an output of the gas turbine smaller than the calculated maximum output. Means. That is, the output of the gas turbine is maintained smaller than the maximum output calculated based on the outlet temperature of the gas turbine.

[0005] According to a second aspect of the present invention, in the first aspect, the gas turbine is based on a difference between the predetermined voltage and a voltage obtained from the gas turbine. Gas turbine output calculation means for calculating a first output to be output and calculating a second output to be output by the gas turbine based on a difference between the maximum output and an output being output from the gas turbine. When,
Gas turbine output comparing means for comparing the first output and the second output when the voltage obtained from the gas turbine is lower than the predetermined voltage, and the first output and the second Gas turbine output control means for controlling the output of the gas turbine to the smaller one of the two outputs. That is, when the voltage obtained from the gas turbine is to be increased, the output to be output by the gas turbine is calculated based on the predetermined voltage and the current voltage and the maximum output and the current output, and the gas turbine is set to the smaller output. Maintain the output of

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a gas turbine system provided with the gas turbine output control device of the first embodiment. In FIG. 1, reference numeral 1 denotes a gas turbine (GT). The gas turbine 1 is connected to a magnet generator (PMG) 2. The generator 2 is driven by the gas turbine 1 and generates three-phase AC power. A rectifier (REC) 3 is connected to the generator 2. Rectifier 3 converts AC power received from generator 2 into DC power. An inverter (INV) 4 is connected to the rectifier 3. Inverter 4 converts DC power received from rectifier 3 into three-phase AC power. In the first embodiment, the inverter 4 has three load bodies (Loa).
d1-3) 5, 6, and 7 are switches 8, 9, and 10, respectively.
Connected via

[0007] The gas turbine output control device of the first embodiment converts a voltage output from a gas turbine controller (GTC) 11 for controlling an output (hereinafter, gas turbine output) output from the gas turbine 1 and an inverter 4 from an inverter 4. And an inverter 4 controller (INVC) for controlling. The gas turbine controller (hereinafter, GT controller) 11 receives a signal from the gas turbine 1 and the inverter 4 as described later, and transmits a control signal to the gas turbine 1 and an inverter controller (hereinafter, INV controller) 12. On the other hand, the INV controller 12 receives signals from the inverter 4 and the GT controller 11, and transmits a control signal to the inverter 4.

Next, the outline of the operation of the gas turbine output control device of the first embodiment will be described. In the first embodiment, the GT controller 11 determines that power is output from the inverter 4 from the start of the gas turbine 1 until the rotation speed of the gas turbine 1 (hereinafter, gas turbine rotation speed) reaches a predetermined rotation speed. A control signal for prohibition is transmitted to the INV controller 12. When the gas turbine speed reaches a predetermined speed, a control signal for permitting the inverter 4 to output power is transmitted to the INV controller 12. Also, the GT controller 11 controls the amount of fuel supplied to the gas turbine 1 (hereinafter, referred to as “gas turbine rotation speed”) so that the gas turbine rotation speed is maintained at the predetermined rotation speed after the gas turbine rotation speed reaches the predetermined rotation speed. , Fuel supply).

On the other hand, the INV controller 12 outputs a voltage output from the inverter 4 (hereinafter referred to as an inverter output voltage).
Control the operation of the inverter 4 so that the voltage of the inverter 4 becomes a predetermined voltage. For example, when the number of load elements connected to the inverter 4 increases, the inverter output voltage tends to decrease. Therefore, the INV controller 12 controls the inverter 4 to maintain the inverter output voltage at a predetermined voltage. Further, when the number of load bodies connected to the inverter 4 increases and the inverter 4 is controlled to maintain the inverter output voltage at a predetermined voltage, the load on the gas turbine 1 increases, and the gas turbine speed increases. Therefore, the GT controller 11 increases the fuel supply amount so that the gas turbine speed is maintained at a predetermined speed. Thus, the inverter output voltage is maintained at the predetermined voltage regardless of the load applied to the inverter 4, and the gas turbine speed is maintained at the predetermined speed.

Next, an outline of the operation of the gas turbine output control device of the first embodiment will be described. In the first embodiment, the maximum value of the output that can be output by the gas turbine 1 (hereinafter, maximum output) is calculated at predetermined intervals based on the temperature of the exhaust gas discharged from the gas turbine 1 (hereinafter, exhaust temperature). I do. It should be noted that the lower the exhaust gas temperature, the lower the temperature of the gas turbine, and thus the higher the maximum output. Since the gas turbine output exceeding the maximum output may cause a failure of the gas turbine, the first embodiment increases the fuel supply amount in order to maintain the gas turbine speed at a predetermined speed. Even if it should, the fuel supply amount is limited to such an amount that the gas turbine output does not exceed the maximum output when the gas turbine output exceeds the maximum output. Of course, at this time, the inverter output voltage becomes lower than the predetermined voltage, and the gas turbine speed is maintained at the predetermined speed. Thus, in the first embodiment, the gas turbine output is controlled based on the exhaust gas temperature so as not to exceed the maximum output, and the gas turbine speed is maintained at a predetermined speed.

Further, in the first embodiment, if the number of loads connected to the inverter 4 is reduced and the inverter output voltage tends to be higher than the predetermined voltage, the current output voltage and the predetermined voltage And the fuel supply amount to be reduced based on the difference between the current gas turbine output and the maximum output (hereinafter referred to as the second reduction amount). ) Is calculated. Here, the fuel supply amount is reduced by the larger one of the first reduction amount and the second reduction amount. Therefore, in the first embodiment, when the gas turbine output is to be reduced, the gas turbine output is surely reduced below the maximum output. Therefore, failure of the gas turbine is reliably prevented.

Next, the operation of the gas turbine output control device of the first embodiment will be described in detail. First, the calculation of the maximum output of the gas turbine will be described with reference to the flowchart of FIG. In step S10, the exhaust gas temperature T1 in the current routine, the gas turbine rotational speed NE1 in the current routine, and the gas turbine output Pdc in the current routine are read. The gas turbine output Pdc
Is calculated based on the inverter output voltage and the inverter output current.

Next, in step S12, the total temperature difference TD
T is calculated based on the following equation 1, and the total rotational speed difference TD
N is calculated based on Equation 2 below.

(Equation 1)

(Equation 2)

In this way, the total amount of change in the exhaust gas temperature during the last ten routines and the total amount of change in the rotational speed during the last ten routines are calculated.

Next, at step S14, the total temperature difference TD
It is determined whether or not the absolute value | TDT | of T is smaller than a predetermined temperature difference KK (| TDT | <KK). | T
When DT | <KK, the change in exhaust temperature during the past ten routines is within a conceivable range of change, and is not due to a detection error or a detection error of a sensor for detecting exhaust temperature. Judge, step S
Proceed to 16. On the other hand, when | TDT | ≧ KK, the change in the exhaust gas temperature during the past ten routines is an unpredictable change, and it is determined that there is a possibility that the change is due to a sensor detection error or a detection error. In the routine, the maximum output of the gas turbine is calculated without calculating the maximum output.
Go to 0.

In step S16, the absolute value of the total rotational speed difference TDN is smaller than a predetermined temperature difference KN (| TDN
| <KN) is determined. When | TDN | <KN, the change in the gas turbine speed during the past ten routines is within the range of possible changes,
It is determined that this is not due to a detection error or a detection error of the sensor for detecting the gas turbine speed, and the process proceeds to step S18. On the other hand, when | TDN | ≧ KN, it is determined that the change in the gas turbine rotational speed during the past ten routines is an inconceivable change, which may be due to a sensor detection abnormality or a detection error, and the like.
In this routine, the process proceeds to step S20 without calculating the maximum output of the gas turbine.

In step S18, the maximum output Pdcmax of the gas turbine 1 is calculated in accordance with the equation Pdc + f (Tmax-T1), and the process proceeds to step S20. Where Tma
x is the temperature that the gas turbine can withstand (hereinafter, the service temperature), and f (Tmax-T1) is the maximum gas turbine output that can be increased in a range where the gas turbine temperature does not reach the service temperature.

At step S20, as preparation for the next routine, the exhaust gas temperature T9 at the time of the routine eight times before is set to T9.
10 and the exhaust gas temperature T at the time of the routine seven times before.
8 is input to T9, and the same processing is sequentially performed. Finally, the exhaust gas temperature T1 in the current routine is input to T2, and the process proceeds to step S22.

In step S22, as a preparation for the next routine, the gas turbine speed NE9 at the time of the routine eight times before is input to NE10, and the gas turbine speed NE8 at the time of the seven times previous routine is input to NE9. The same processing is performed, and finally, the gas turbine speed NE1 at the time of this routine is input to NE2, and the processing is terminated.

Next, referring to the flowchart of FIG.
The calculation of the gas turbine output control signal in the V controller will be described. In step S100, step S in FIG.
Maximum output Pdcma of gas turbine 1 calculated in 18
x and the gas turbine output Pd at the time of this routine
c and the inverter output voltage V at the time of this routine.
ac is read.

Next, at step S102, a control value correction amount (hereinafter referred to as an output base correction amount) ΔDF (P) calculated based on the gas turbine output Pdc is calculated by the equation K1 × (Pd
cmax-Pdc) and a control value correction amount (hereinafter, referred to as a control value correction amount) calculated based on the inverter output voltage Vac
Voltage-based correction amount) ΔDF (V) is given by the equation K2 × (Vacs
et-Vac). Where Vacse
t is a predetermined voltage to be output from the inverter 4, K1 is a coefficient for converting the difference between the maximum output and the gas turbine output in the current routine into an output base correction amount, and K2 is a predetermined value. This is a coefficient for converting the difference between the determined voltage and the inverter output voltage in the current routine into a voltage-based correction amount.

Next, at step S104, the gas turbine output Pdc is smaller than the maximum output Pdcmax (Pdmax).
It is determined whether c <Pdcmax). Pdc <Pd
If it is cmax, the process proceeds to step S106, where the inverter output voltage Vac is set to the predetermined voltage Vacse
It is determined whether it is lower than t (Vac <Vacset). When Vac <Vacset, it is determined that it is necessary to increase the inverter output voltage to a predetermined output voltage, and the process proceeds to step S108. By the way, when the inverter output voltage is increased, the gas turbine output may exceed the maximum output. Therefore, in the first embodiment, in step S108, the voltage-based correction amount ΔDF
(V) is larger than the output base correction amount ΔDF (P) (Δ
DF (V)> ΔDF (P)) to determine whether ΔDF
When (V)> ΔDF (P), the control value correction amount ΔD
The voltage-based correction amount ΔDF (V) is input to F, and IN is obtained according to the control value DFn in the current routine, which is calculated in step S112 according to the expression DFn-1 + ΔDF.
When the V controller 12 controls the inverter output voltage, it is determined that the gas turbine output may exceed the maximum output, and the output base correction amount ΔDF (P) is input to the control value correction amount ΔDF in step S110. . On the other hand, in step S108, ΔDF (V) ≦ Δ
When DF (P), the voltage-based correction amount ΔDF (V) is input to the control value correction amount ΔDF, and the INV controller 12 determines the control value DFn in the current routine which is calculated in step S112 according to the expression DFn-1 + ΔDF. Even if the inverter output voltage is controlled, it is determined that the gas turbine output does not exceed the maximum output, and the voltage-based correction amount ΔDF (V) is input to the control value correction amount ΔDF in step S116.

On the other hand, in step S106, Vac ≧
When it is Vacset, it is determined that it is necessary to reduce the inverter output voltage to a predetermined output voltage, and the process proceeds to step S116, where the voltage-based correction amount ΔDF (V) is input to the control value correction amount ΔDF, and the process proceeds to step S112. . At this time, since the control value DFn in the current routine calculated in step S112 is the voltage base correction amount ΔDF (V) for correcting the inverter output voltage to the predetermined output voltage, the INV controller 1
2 controls the inverter output voltage such that the inverter output voltage is maintained at a predetermined output voltage according to the DFn. In this case, since the gas turbine output is already lower than the maximum output in step S104, even if the inverter output voltage is controlled so that the inverter output voltage is maintained at the predetermined output voltage, the gas turbine output will not exceed the maximum output. Never exceed.

On the other hand, in step S104, Pdc ≧
If it is Pdcmax, it is determined that the gas turbine output Pdc should be reduced to the maximum output, and the routine proceeds to step S110, where the control value correction value ΔDF is added to the output base correction amount ΔDF.
(P) is input, and the process proceeds to step S112. At this time, the control value DFn in the current routine calculated in step S112 is the output base correction amount ΔDF (P) for correcting the gas turbine output to the maximum output.
The NV controller 12 controls the inverter output voltage according to the DFn so that the gas turbine output is maintained at the maximum output.

In step S114, the control value DFn in this routine is set to DFn-1 in preparation for the next routine.
And terminates the process.

Next, a second embodiment of the present invention will be described. In the second embodiment, one load 13 is connected to the inverter 4 instead of the three loads of the first embodiment. The load 13 according to the second embodiment requests a different voltage from the inverter 4 according to various conditions. Therefore, in the second embodiment, the operation of the gas turbine 1 is controlled such that the gas turbine output becomes the maximum output in principle. However, when the maximum output is very small, the rotation speed of the gas turbine becomes very small, and the operation of the gas turbine 1 becomes unstable. Therefore, when the maximum output is smaller than the predetermined output, the gas turbine 1 is controlled so that the gas turbine output becomes the predetermined output. Thus, the voltage required by the load can be supplied reliably and quickly.

Next, the operation of the gas turbine output control device according to the second embodiment will be described in detail. The calculation of the gas turbine maximum output is the same as that of the flowchart of FIG. The flowchart of FIG. 3 shows the calculation of the gas turbine output control value in the second embodiment. First, in step S200, the maximum output Pdcmax calculated in step S18 of FIG. 2 is read.

Next, in step S202, the maximum output P
It is determined whether or not dcmax is larger than a predetermined output Pdc0 (Pdcmax> Pdc0). Pd
If cmax> Pdc0, the process proceeds to step S204, and the control value correction amount ΔDF (Pdcmax) calculated based on the maximum output Pdcmax is calculated by the formula K1 × (Pdcm
ax-Pdc), and proceeds to step S206. In this case, in step S206, the expression DFn-1
The INV controller 12 controls the inverter output voltage such that the gas turbine output is maintained at the maximum output by the control value DFn in the current routine calculated according to + ΔDF.

On the other hand, in step S202, Pdcm
When ax ≦ Pdc0, the process proceeds to step S210, and the control value correction amount ΔD calculated based on the output Pdc0
F (Pdc0) is calculated according to the formula K1 × (Pdc0−Pdc), and the process proceeds to step S206. In this case, the control value DFn in the current routine calculated according to the expression DFn-1 + ΔDF in step S206 is used to obtain I
The NV controller 12 controls the inverter output voltage so that the gas turbine output is maintained at a predetermined output higher than the maximum output.

In step S208, the control value DFn in this routine is set to DFn-1 in preparation for the next routine.
And terminates the process.

[0031]

According to the first and second aspects of the invention, the output of the gas turbine is kept smaller than the maximum output calculated based on the outlet temperature of the gas turbine. The outlet temperature of the gas turbine corresponds exactly to the temperature of the gas turbine.
Therefore, by keeping the output of the gas turbine smaller than the maximum output calculated based on the gas turbine outlet temperature, the temperature of the gas turbine is prevented from exceeding the maximum allowable temperature. Thus, failure of the gas turbine due to heat is prevented.

According to the second aspect, when the voltage obtained from the gas turbine is to be increased, the output to be output by the gas turbine is calculated based on the predetermined voltage and the current voltage, and the maximum output and the current output. Thus, the output of the gas turbine is maintained at the smaller output. Therefore, it is possible to reduce the possibility that the output of the gas turbine exceeds the maximum output when the voltage is increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing a gas turbine system according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating a gas turbine maximum output calculation according to the first embodiment.

FIG. 3 is a flowchart illustrating calculation of a gas turbine output control value according to the first embodiment.

FIG. 4 is a diagram showing a gas turbine system according to a second embodiment of the present invention.

FIG. 5 is a flowchart illustrating calculation of a gas turbine output control value according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Gas turbine 2 ... Generator 3 ... Rectifier 4 ... Inverter 5, 6, 7, 13 ... Load body 11 ... Gas turbine controller 12 ... Inverter controller

Claims (2)

[Claims] 1. A gas turbine output control device for controlling the operation of a gas turbine so that a predetermined voltage is obtained from the gas turbine, wherein a maximum output of the gas turbine based on an outlet temperature of the gas turbine is provided. A gas turbine output control device, comprising: a maximum output calculating means for calculating an output; and a gas turbine output limiting means for maintaining an output of the gas turbine smaller than the calculated maximum output. 2. A first output to be output by the gas turbine based on a difference between the predetermined voltage and a voltage obtained from the gas turbine, wherein the first output to be output by the gas turbine is calculated based on a difference between the maximum output and the gas turbine. Gas turbine output calculation means for calculating an output to be output by the gas turbine based on a difference between the second output and the second output being output from the gas turbine, and a voltage obtained from the gas turbine is calculated based on the predetermined voltage. Gas turbine output comparing means for comparing the first output and the second output when the output is low, and controlling the output of the gas turbine to the smaller output of the first output and the second output The gas turbine output control device according to claim 1, further comprising gas turbine output control means.