JP2000220474A - Gas turbine start-up control method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In a start control of a gas turbine driving a generator connected to the gas turbine as a starter motor,
When a high-voltage generator having a low controllable upper limit rotation speed within the battery voltage is used, ignition occurs in a combustion failure region of the combustor, so that there is a problem that ignition determination becomes difficult. SOLUTION: When the rotation speed of a turbine shaft reaches an ignition rotation speed N1, the rotation speed is maintained substantially constant, and ignition and fuel supply are started in a combustor of the gas turbine 1 to make a minimum at a combustor outlet. By detecting the temperature and comparing the minimum temperature at the outlet of the combustor with the outlet temperature during combustion to determine ignition, even when ignition occurs in the combustion failure region of the combustor using a high-voltage generator, a predetermined By checking the temperature rise, it is possible to make a reliable ignition determination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine start-up control method used for starting a gas turbine by driving a generator connected to the gas turbine as a starter motor.

[0002]

2. Description of the Related Art A starting control device for a gas turbine includes:
For example, the one shown in FIG. 5 has been proposed. The start control device for a gas turbine shown in FIG.
0 is driven as a starter motor, and the generator 101 is driven by the starting rotation control means 102, and when the rotation speed of the turbine shaft reaches a predetermined ignition rotation speed, the rotation speed is reduced. The fuel is supplied from the fuel supply system 104 to the combustor while maintaining and maintaining ignition in the combustor of the gas turbine 100 and adjusting the fuel flow rate by the ignition fuel control means 103. Then, after confirming ignition by a temperature sensor or the like in the combustor, acceleration of the turbine shaft is started by the starting rotation control means 102,
When the turbine shaft is accelerated to a predetermined number of revolutions, the startup is terminated, and the generator 101 is switched to power generation control.

[0003] The above-described start control apparatus for a gas turbine is provided with an ignition fuel control means 103 for adjusting a fuel flow rate, thereby realizing good ignitability. Such a start control device for a gas turbine is disclosed in, for example,
No. 64766.

[0004]

However, in recent years,
The number of permanent magnet type generators that are small and have high efficiency is increasing, and in a gas turbine start-up control device for the purpose of cost reduction, sharing with a high voltage, for example, 100%
The adoption of a high-voltage generator for sharing V and 200V is being considered.

However, a high-voltage generator sharing 100V and 200V has about twice the voltage characteristics of a 100V-dedicated generator, but has a 100V rotation range that can be driven by a battery of the same voltage (for example, 24V). It is about half of the dedicated generator. For this reason, if a high-voltage generator is used for the start control device of the gas turbine, the upper limit rotational speed that can be controlled within the voltage of the battery is too low, and ignition occurs in a combustion failure region of the combustor, and as a result, However, since the temperature rise required for the ignition determination cannot be obtained despite the ignition, there is a problem that the ignition determination becomes difficult, and it has been a problem to solve such a problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. In starting control of a gas turbine, a gas which can reliably determine ignition even when a high-voltage generator is used. An object of the present invention is to provide a method for controlling startup of a turbine.

[0007]

According to a first aspect of the present invention, there is provided a method for controlling the start of a gas turbine, wherein a generator connected to the gas turbine is driven as a starter motor to start the gas turbine. When the rotation speed of the shaft reaches the ignition rotation speed, the rotation speed is maintained substantially constant, ignition and fuel supply are started in the combustor to detect the lowest temperature at the combustor outlet, and the lowest temperature at the combustor outlet is detected. The ignition is determined by comparing the temperature with the outlet temperature during combustion. According to a second aspect, the acceleration of the turbine shaft is started after a predetermined standby time has elapsed while maintaining the ignition rotation speed of the turbine shaft. According to a third aspect of the present invention, when the minimum temperature at the combustor outlet is higher than a reference value, the standby time is set shorter. As a fourth aspect, a generator connected to a gas turbine When the gas turbine is started by driving as a starter motor, ignition and fuel supply are started in the combustor when the rotation speed of the turbine shaft reaches the ignition rotation speed, and then the ignition rotation speed is maintained and the turbine shaft is accelerated. Is repeatedly performed in a short time, and the above configuration is used as means for solving the conventional problems.

[0008]

In the gas turbine start-up control method according to the first aspect of the present invention, when starting the gas turbine by driving the generator connected to the gas turbine as a starter motor, the number of rotations of the turbine shaft is reduced. When the ignition speed is reached, the speed is maintained substantially constant, and ignition and fuel supply are started in the combustor. At this time, if the generator is, for example, a high-voltage generator sharing 100 V and 200 V, the ignition speed is also low because the upper limit speed that can be controlled within the battery voltage is low. As a result, ignition occurs in the combustion failure region of the combustor, and the temperature at the combustor outlet is lower than that in normal ignition. Therefore, in the start control method of the gas turbine, when ignition and fuel supply are started in the combustor, the lowest temperature (initial temperature) at the combustor outlet is detected, and then the lowest temperature at the combustor outlet and the outlet during combustion are detected. The ignition is determined by comparing the temperatures. That is, by confirming the predetermined temperature rise after the start of ignition, even if the temperature of the combustor outlet is low due to the ignition in the combustion failure region of the combustor, the ignition determination becomes reliable. Thereafter, the starting acceleration of the turbine shaft is performed, and when the rotation reaches a predetermined number of revolutions, the startup is terminated, and the generator is switched to the power generation control.

In the gas turbine startup control method according to a second aspect of the present invention, when the rotation of the turbine shaft reaches the ignition rotation speed, the ignition rotation speed is maintained for a predetermined standby time. That is, when the ignition speed is low and the combustion is performed in the combustion failure region of the combustor, if the turbine shaft is accelerated immediately after the ignition, the fire may blow out. Therefore, by providing a predetermined standby time, the blowout of fire is prevented. Further, by starting acceleration of the turbine shaft after the elapse of the standby time, a temperature rise at which ignition can be determined is likely to occur.

[0010] In the start control method for a gas turbine according to the third aspect of the present invention, when a high-voltage generator having a low upper limit rotational speed which can be controlled within the battery voltage is used, ignition occurs in a combustion failure region of the combustor. In other words, the higher the initial temperature of the combustor, the less likely it is for the fire to blow out,
In addition, if combustion is performed for a long time at a low ignition rotation speed, soot is deposited near the fuel injection valve, or a partial hot spot that causes deformation of parts is generated. By setting the standby time short when the minimum temperature at the outlet is higher than the reference value, the combustion time at a low ignition speed is shortened while preventing the blowout of fire.

[0011] In the gas turbine start-up control method according to a fourth aspect of the present invention, when the generator connected to the gas turbine is driven as a starter motor to start the gas turbine, the rotation speed of the turbine shaft is set to the ignition rotation. After the ignition and fuel supply are started in the combustor when the number reaches the limit, the upper limit rotational speed that can be controlled within the battery voltage can be controlled by repeatedly switching the maintenance of the ignition rotational speed and the acceleration of the turbine shaft in a short time. For low high voltage generators,
The rotation speed of the turbine shaft is secured to a higher rotation speed range suitable for ignition than the lower ignition rotation speed, whereby the ignition is performed favorably and the ignition determination becomes easy.

[0012]

According to the start control method of the gas turbine according to the first aspect of the present invention, when the generator connected to the gas turbine is driven as a starter motor to start the gas turbine, ignition is performed in the combustor. After the fuel supply is started, the minimum temperature at the combustor outlet is compared with the outlet temperature during combustion to confirm a predetermined temperature rise.Therefore, the upper limit rotational speed that can be controlled within the battery voltage, that is, the ignition rotational speed is low. By using the high-voltage generator, the ignition can be reliably determined even when ignition occurs in the combustion failure region of the combustor. Thus, a start control device for a gas turbine using a low-cost high-voltage generator can be realized, and the gas turbine can be started smoothly.

[0013] According to the gas turbine startup control method of the second aspect of the present invention, the same effect as that of the first aspect can be obtained, and the ignition speed of the turbine shaft is maintained for a predetermined standby time. It is possible to prevent the blowout of fire when igniting in the poor combustion area of the combustor,
In addition, by starting acceleration of the turbine shaft after a predetermined standby time has elapsed, it is easy to generate a rise in temperature at which ignition can be determined, and a comparison is made between the lowest temperature at the combustor outlet and the outlet temperature during combustion. The ignition determination can be made more reliable.

[0014] According to the gas turbine startup control method of the third aspect of the present invention, the same effect as in the second aspect can be obtained, and when the minimum temperature at the combustor outlet is higher than the reference value. By setting the standby time short, especially when the initial temperature of the combustor is high, it is possible to prevent the blowout of fire when ignited in the combustion failure area of the combustor, and to prevent soot accumulation and hot spots For example, the combustion time in the low-speed rotation range in which problems such as the above tend to occur can be shortened as much as possible.

According to the method for controlling the start of a gas turbine according to a fourth aspect of the present invention, when the generator connected to the gas turbine is driven as a starter motor to start the gas turbine, the rotation speed of the turbine shaft is reduced. When the ignition speed is reached, the ignition and fuel supply are started in the combustor, and then the switching between the maintenance of the ignition speed and the acceleration of the turbine shaft is repeatedly performed in a short time, whereby the upper limit that can be controlled within the battery voltage is obtained. Even when a high-voltage generator with a low rotation speed is used, the combustion speed in the combustor can be satisfactorily set by setting the rotation speed of the turbine shaft to a high rotation speed range suitable for ignition. The determination can be facilitated, and the gas turbine can be started smoothly.

[0016]

FIG. 1 is a block diagram for explaining a gas turbine start control apparatus to which a gas turbine start control method according to the present invention is applied.

The start control device for the gas turbine drives the generator 2 connected to the turbine shaft of the gas turbine 1 as a starter motor, and includes a start rotation control means 3 for controlling the start rotation of the generator 2; An ignition fuel control means 4 for controlling a fuel flow rate in accordance with a command from the start rotation control means 3 and a fuel supply system 5 communicating with a fuel injector of a combustor in the gas turbine 1 are provided.

The generator 2 is a small-sized and highly efficient permanent magnet type.
This is a high-voltage generator that shares 00V and 200V.
For this reason, the generator 2 has a characteristic that the voltage rises almost in proportion to the number of revolutions, but the controllable upper limit number of revolutions at the same voltage is about half compared to, for example, a 100 V-only type generator. , The ignition speed is low. Further, the generator 2 has a first mode in which a predetermined ignition speed is set within a controllable range within a battery voltage (for example, 24 V), and a second mode in which starting acceleration is performed with constant electric power (the rotation speed depends on the rotation speed). ).

The start rotation control means 3 has a function of switching the generator 2 between a starter drive mode and a power generation control mode, and in the starter drive mode, drives the generator 2 by supplying power from a battery (not shown). However, at this time, when the rotation speed of the turbine shaft is maintained at the predetermined ignition rotation speed, the generator 2 is driven within the battery voltage via the first mode, that is, the rotation speed control means 6,
When starting and accelerating the turbine shaft, the generator 2 is driven via the second mode, that is, the constant electric power accelerating means 7.

The start control device for the gas turbine includes a temperature detecting means 8 for detecting the outlet temperature (gas temperature) of the combustor in the gas turbine 1. The temperature detecting means 8 detects the lowest temperature (initial temperature) after ignition, and compares the minimum temperature input from the lowest temperature detecting means 9 with the outlet temperature of the combustor during combustion. A determination unit 10 is provided. The ignition determination means 10
A predetermined ignition determination temperature ΔT is set, and it is determined whether the outlet temperature during combustion is higher than the minimum temperature by the ignition determination temperature ΔT or not. The judgment is input to the starting rotation control means 3.

The starting rotation control means 3 has a function of setting a predetermined standby time Th for maintaining the rotation speed after the rotation speed of the turbine shaft reaches the ignition rotation speed. If the lowest temperature detected in step 9 is higher than a predetermined reference value, the standby time Th is set to be shorter. In addition, it is also possible to add a function of extending the standby time Th when the minimum temperature is lower than the reference value.

In the start control apparatus for a gas turbine having the above configuration, the start control is performed according to a flowchart shown in FIG.

That is, when the start switch of the start rotation control means 3 is turned on in step S1 and the start rotation control means 3 is set in the starter drive mode in step S2, the electric power is generated via the rotation speed control means 6 which is the first mode. The machine 2 is driven, and the turbine shaft of the gas turbine 1 starts rotating. Then, when the rotation of the turbine shaft is set to the predetermined ignition rotation speed N1 in step S3,
In step S4, the ignition device of the combustor is turned on, and further, in step S5, fuel supply from the fuel supply system 5 to the combustor is started.

At this time, in the startup control method of the gas turbine, as shown in FIG. 3, when the rotation of the turbine shaft reaches the ignition rotation speed N1, the rotation speed is maintained, and step S
In 6, the lowest temperature detecting means 9 detects the lowest temperature at the combustor outlet, and in step S7, measurement of the standby time Th is started. The ignition speed N1 is maintained during the standby time Th.

Here, since the gas turbine start-up control device shown in FIG. 1 uses the high-voltage type generator 2,
The upper limit rotational speed that can be controlled within the battery voltage is low, and the ignition rotational speed N1 is also low. As a result, ignition occurs in the combustion failure region of the combustor, so that the temperature of the combustor outlet is lower than that of normal ignition. It is low. In addition, since ignition occurs in the combustion failure region of the combustor, if the turbine shaft is accelerated immediately after ignition, fire may be blown out.

Therefore, in the start control method of the gas turbine, the wiping of fire is prevented by setting the standby time Th for maintaining the ignition rotation speed N1. Then, in step S8, the minimum temperature at the combustor outlet is compared with the current outlet temperature during combustion, and when it is determined that the current outlet temperature is not higher than the minimum temperature by the ignition determination temperature ΔT (No). Determines in step S9 whether or not it is within the standby time Th, and if it is determined that it is within the standby time Th (Yes), the process returns to step S8. If it is determined in step S9 that the standby time Th has elapsed (No), the control proceeds from step S10 to the control of the first mode by the rotation speed control means 6 in the second mode by the constant power acceleration means 7 in step S10. Switching, constant power acceleration means 7
, The acceleration of the turbine shaft at a constant power is started, and the process returns to step S8.

If it is determined in step S8 that the current outlet temperature has risen from the minimum temperature by the ignition determination temperature ΔT (Yes), in step S11, the starting acceleration after the ignition determination is performed, and the turbine shaft is turned off. When the engine is accelerated to a predetermined number of revolutions, the startup is terminated, and the generator 2 is switched to the power generation control mode.

As described above, in the start control of the gas turbine, by confirming a predetermined temperature rise after the start of ignition, the temperature at the combustor outlet is low due to ignition in the combustion failure region of the combustor. However, the ignition determination is reliable, and the startup of the gas turbine 1 is performed smoothly. Also,
By starting the acceleration of the turbine shaft after the predetermined standby time Th has elapsed, the wiping of the fire is prevented, and the temperature rise at which ignition can be determined is more likely to occur, so that the ignition determination is more reliable. Becomes Therefore, in the normal case, the ignition determination (ignition confirmation) is performed after the acceleration of the turbine shaft as shown in FIG.

Furthermore, in this start control device for a gas turbine, the higher the initial temperature of the combustor, the less likely it is for the blowout of fire to occur. Therefore, when the lowest temperature is detected in step S6 and the lowest temperature is higher than the reference value, the standby time Th is set short in step S7. In other words, if combustion is performed for a long time at a low ignition speed, soot is deposited in the vicinity of the fuel injection valve, or a partial hot spot that causes deformation of parts is generated. If it is high, a short standby time Th 'is set as shown in FIG. 3 to obtain the function of preventing extinction of fire and shorten the combustion time at low speed. In addition, when the temperature of the combustor of the gas turbine 1 is high at the time of startup, when the turbine shaft is rotated, the amount of air flowing in increases with the increase in the number of revolutions, which may lower the temperature of the combustor. Control for canceling the decrease is also performed.

FIG. 4 is a diagram for explaining another embodiment of the gas turbine startup control method according to the present invention. The activation control device shown in FIG. 1 can be used.

In this method for controlling the start of the gas turbine, the generator 2 connected to the gas turbine 1 is driven as a starter motor, and when the gas turbine 1 is started, the rotation speed of the turbine shaft reaches the ignition rotation speed. After the start of ignition and fuel supply in the combustor, the switching between the maintenance of the ignition speed and the acceleration of the turbine shaft is repeated in a short time. That is, switching between the control in the first mode via the rotation speed control means 6 and the control in the second mode via the constant power acceleration means 7 is repeatedly performed in a short time.

Thus, in the start-up control of the gas turbine using the high-voltage generator 2 having a low upper limit rotational speed which can be controlled within the battery voltage, the rotational speed of the turbine shaft is increased along with the repetition of the first and second modes. Repeat increasing and decreasing,
The rotation speed N2 of the turbine shaft becomes a higher rotation speed range suitable for ignition than the lower ignition rotation speed, and the ignition is performed satisfactorily. Therefore, as in the previous embodiment, the temperature rise is confirmed by comparing the lowest temperature of the combustor outlet with the current outlet temperature, it is easy to make an ignition determination, and the temperature at which the temperature rise is not detected is determined. The ignition determination by the temperature detecting means such as a sensor can also be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a start-up control device to which a start-up control method for a gas turbine according to the present invention is applied.

FIG. 2 is a flowchart illustrating a start control process of the gas turbine.

FIG. 3 is a graph illustrating a relationship between a time and a rotation speed of a turbine shaft in startup control of a gas turbine.

FIG. 4 is a graph illustrating a relationship between time and a rotation speed of a turbine shaft in another embodiment of the gas turbine startup control method according to the present invention.

FIG. 5 is a block diagram illustrating a conventional startup control device for a gas turbine.

[Explanation of symbols]

 1 gas turbine 2 generator

Claims (4)

[Claims] When starting the gas turbine by driving a generator connected to the gas turbine as a starter motor, when the rotation speed of the turbine shaft reaches an ignition rotation speed, the rotation speed is maintained substantially constant. And starting ignition and fuel supply in the combustor to detect the lowest temperature at the combustor outlet, and comparing the lowest temperature at the combustor outlet with the outlet temperature during combustion to determine ignition. Startup control method for turbine. 2. The start control method for a gas turbine according to claim 1, wherein the acceleration of the turbine shaft is started after a predetermined standby time has elapsed while maintaining the ignition rotation speed of the turbine shaft. 3. The method according to claim 2, wherein the standby time is set shorter when the minimum temperature at the combustor outlet is higher than a reference value. 4. When starting the gas turbine by driving a generator connected to the gas turbine as a starter motor, ignition and fuel supply are started in the combustor when the rotation speed of the turbine shaft reaches the ignition rotation speed. After doing
A startup control method for a gas turbine, wherein the switching between the maintenance of the ignition speed and the acceleration of the turbine shaft is repeatedly performed in a short time.