JPH11229899A - Gas turbine ignition detection unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect ignition reliably and reduce the time taken for detecting the ignition by detecting the exhaust gas temperature. SOLUTION: An ignition detection unit 10 is formed of ignition detectors 1, 2 for detecting ignition based on an exhaust gas temperature signal 21. The signal passes through OR circuit 3 and either of those detection signals enters into a set/reset circuit 5, and the circuit 5 is set to output an ignition detection signal 22. When an insufficient ignition detection unit 6 detects insufficient ignition state upon ignition detection through AND circuit 4, the circuit 5 is reset to make sure the ignition detection signal is output. Since the ignition detector 1 detects the temperature rise when using the gas fuel, and the ignition detector 2 detects the temperature rise when using the oil fuel, the ignition state can be reliably determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition detection device for detecting ignition of a gas turbine combustor by detecting exhaust gas temperature.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram of a gas turbine flame detector currently used. The flame detector employed in the gas turbine includes an ultraviolet detector 52 and a pressure-resistant glass 53 attached to the main body of the gas turbine combustor 51, and a flame switch 54 installed in the control room.

[0003] A vacuum tube 55 is used for the ultraviolet ray detector 52. When ultraviolet rays 60 generated from a flame 70 in the combustor 51 are received through a lens 61, a discharge starts between the electrodes and a current flows. . This current is amplified in an electronic circuit 56 provided in the flame switch 54, and the presence of a flame is output to the outside by performing a relay operation.

The principle of operation of the ultraviolet detector 52 is that the ultraviolet detector 52 responds to ultraviolet light having a wavelength of 1900 to 2600 angstroms, and this ultraviolet light is emitted from any ordinary flame. No reflection or radiation occurs. The detection unit is formed of a special glass container, and has electrodes therein, and a pure gas is sealed in the glass container. An AC voltage is applied to the electrodes, and a current flows when the electrodes sense ultraviolet photons in the above wavelength band. The amount of current pulse per unit time is proportional to the intensity of the light beam. The signal pulse is sent from the ultraviolet detector 52 to the cable 5.
The signal is input to an electronic circuit 56 in the flame switch 54 by 7 and sent to an amplifier where it is filtered, integrated and amplified. The amplified signal activates the relay and outputs a contact output 58. This contact output 58
Is "ON", there is a flame, it is determined to be misfire, and "O"
At the time of "FF", it is determined that there is no flame. Reference numeral 59 denotes a jack for checking. The flame detector has the above-described components and operating principle. By attaching the detector 52 to the combustor main body 51, the flame is monitored by oil combustion, gas combustion, or oil / gas mixed combustion.

[0005]

The above-mentioned flame detector is an important measuring instrument for detecting misfire by the light of the flame, and particularly for detecting misfire during gas turbine startup. However, the installation environment of the flame detector is inferior and there are the following problems.

(1) At present, the life of the sensor portion is short, and the sensor is treated as a consumable. (2) Also, among the instrumentation components, the cost is relatively high, and the proportion of the total maintenance cost is large.

(3) There is a concern that erroneous flame detection due to self-discharge of the flame detector may occur. (4) If the flame cannot be detected for some reason, fuel that has not yet been burned may cause an explosion, which may cause man-made disaster.

[0008] In general, fuels for gas turbines are various, but ignition in the combustor needs to be detected regardless of the type of fuel. In addition, it is desirable that the ignition detection method be constant regardless of the type of fuel.

The rising pattern of the temperature of the exhaust gas at the time of ignition is largely classified into two types of A type and B type shown in FIG. 6, and it is almost A type for gas fuel, and either A type or B type for oil fuel. Become. Further, it is necessary to detect the ignition as soon as possible and surely. This is because the ignition detection time needs to be shortened as much as possible in order to avoid excessive injection of unburned fuel.
This is particularly necessary for gas fuels.

When the temperature rise pattern is the B type, the ignition detection is performed by the A type detection method, and the B type α shown in FIG.
There is a case where ignition is not detected due to counting up in the section.

The present invention solves the above-mentioned problems of the ignition detection method due to the difference in the type of fuel in normal gas turbine control, and can reduce the time required for ignition detection. It is an object to provide a device.

[0012]

The present invention provides the following means for solving the above-mentioned problems.

A first ignition detection device for detecting ignition using a predetermined rise rate and a rise width of an exhaust gas temperature signal due to combustion of gas fuel; a predetermined rise rate and a rise width of an exhaust gas temperature signal due to combustion of oil fuel; A second ignition detection device that detects ignition by using a circuit; a circuit that outputs a detection signal of one of the first and second ignition detection devices; and a predetermined increase width based on the exhaust gas temperature signal. A circuit for detecting a state of insufficient ignition immediately after ignition due to a decrease in the rate of increase of the temperature; and outputting a detection signal of the first ignition detection circuit or the second ignition detection circuit based on a detection signal of the circuit for detecting the state of insufficient ignition. And a circuit for resetting the circuit.

According to the ignition detection device of the present invention, the temperature rise pattern (A) mainly due to gaseous fuel is detected by the first ignition detection device.
Type), monitor the rise of the average blade path temperature,
Detect ignition. In this case, the temperature of the A-type exhaust gas changes from the fuel injection to the ignition point, and the temperature rapidly decreases after the ignition. In the first ignition detection device, the temperature range after ignition is set with respect to the average blade pass temperature when fuel is turned on. This temperature set value is, for example, the average blade pass temperature at the time of fuel supply + 10 ° C. (BPT1),
Within 30 seconds, a temperature rise of + 30 ° C. is further set (BPT2). If the actual average blade path temperature rises more than the set temperature, “ignition detection” is set. This is because the blade pass temperature before ignition is HOT START or COLD ST
Since the temperature at the time of fuel supply is stored because it cannot be unconditionally determined by conditions such as ART, BPT1, BPT2
Is set, and "ignition" is performed when the actual average blade pass temperature reaches. When the temperature rise pattern is the A type, the first ignition detection device detects the ignition detection BP.
The time from T1 to the ignition detection BPT2 is several hundred msec, and the ignition detection time can be shortened as much as possible.

On the other hand, when the temperature rise pattern is mainly oil fuel, the temperature rises gradually to a certain degree, and then the temperature rises sharply (B type). Ignition detection is difficult. Therefore, ignition detection is performed by the second ignition detection device. In this case, the rise rate of the average blade path temperature is set to a predetermined value, for example, 10 ° C./sec, and if 10 ° C./sec continues for 3 seconds or more, ignition is considered. As described above, the first and second ignition detection devices are provided side by side, and an ignition detection signal is output by a circuit that outputs one of the detection values, thereby improving the accuracy of the ignition detection.

Furthermore, in the present invention, a circuit for detecting a state of insufficient ignition is provided. Alternatively, it is considered that ignition is insufficient, an insufficient ignition signal is output to the reset circuit, and the ignition detection signal is reset, so that the reliability of ignition detection is improved. As described above, according to the present invention, it is possible to shorten the ignition detection time and improve the reliability of the ignition detection.

[0017]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a block diagram of a gas turbine ignition detection device according to the present invention. In the figure, reference numeral 10 denotes an ignition detection device main body, which receives a gas turbine exhaust gas temperature signal 21 and outputs an ignition detection signal 22,
It is used for monitoring oil and gas combustion or oil and gas mixed combustion flames.

Reference numeral 10 denotes an ignition detection device main body, which is provided with an ignition detection device 1 and an ignition detection device 2, and its signal is input to a set / reset circuit 5 by an OR circuit 3. 4
Is an AND circuit, and 6 is an insufficient ignition detection device.
The AND circuit 4 is configured to receive the insufficient ignition detection device 6 and the output signal of the set / reset circuit 5, and to input the output to the reset side of the set / reset circuit 5.

In the ignition detection device having the above configuration, the ignition detection devices 1 and 2 are used in combination, and the temperature rise pattern is as shown in FIG.
In the case of the A type as shown in FIG.
In the case of the temperature rise pattern B type, the ignition is detected by the ignition detection 2, the signal is sent from the OR circuit 3 to the set / reset circuit 5, and the ignition detection signal 22 is output.

Further, after the ignition is detected, the rise rate of the exhaust gas temperature is continuously monitored for a certain period of time. Insufficient ignition detection device 6
To shorten the ignition detection time and realize reliable ignition detection. That is, if the insufficient ignition detection device 6 detects insufficient ignition while the ignition detection signal 22 is being output, AND
The set / reset circuit 5 is reset by a signal from the circuit 4 to increase the reliability of ignition detection.

FIG. 2 is a diagram for explaining the operation of the ignition detection device 1. In the figure, the solid line indicates the average blade pass temperature of A type (average B
PT) and the actual average BPT ignition detection (setting) B
If the temperature rises beyond the ignition detection (set) BPT2 within 3 seconds after reaching PT1, it is regarded as ignition and an ignition signal is issued.
Ignition detection (setting) BPT1 is 1 from FLON (with fuel)
The temperature is increased by 0 ° C., and the ignition detection (setting) BPT2 is set to a temperature further increased by 30 ° C. from BPT1.

The average BPT sharply rises after the ignition point after FLON (fuel input), reaches BPT1, and then 3
If the temperature rises to BPT2 within the second, ignition is detected. Thus, ignition is reliably detected when the temperature rise pattern is the A type.

FIG. 3 is a diagram for explaining the operation of the ignition detection device 2. In the figure, the solid line indicates the average blade pass temperature of B type (average B
PT), ΔBPT / Δt is set to 10 ° C./sec, and ignition is performed if ΔBPT> 10 ° C./sec continues for 3 seconds or more. In this way, the ignition of the temperature rise pattern B type is reliably detected.

FIG. 4 is a diagram for explaining the operation of detecting insufficient ignition immediately after the detection of ignition in the case of the temperature rise pattern A type. In the figure, it is assumed that the average blade pass temperature is continuously increased at> 10 ° C./sec for 2 seconds immediately after ignition detection, otherwise, misfire or insufficient ignition is assumed.

FIG. 5 is a diagram for explaining the operation of detecting misfire and insufficient ignition after detecting the ignition of the temperature rise pattern B type. In the figure, if ΔBPT / Δt <10 ° C./sec within 2 seconds after ignition is confirmed immediately after ignition detection, misfire or insufficient ignition is determined.

The insufficient ignition detection device 6 shown in FIG. 1 detects a misfire or insufficient ignition by the method shown in FIG. 4 for the temperature rise pattern A type and the method shown in FIG. 5 for the type B temperature rise. Then, the ignition detection signal is ensured.

In a gas turbine, the ignition detection time must be as short as possible in order to avoid over-charging of unburned fuel. In addition, it is possible to prevent ignition detection by counting up ignition detection, and to detect ignition as soon as possible. You need to make sure.

Therefore, the ignition detecting device 1 monitors the rise of the average blade path temperature of the temperature rise pattern A type to detect the ignition. As shown in FIG. 2, the average blade pass temperature at the time of FLON (with fuel) is compared with the temperature after ignition [in this case, the average blade pass temperature at the time of (fuel input) is increased to + 10 ° C .; Temperature rise] is set, and if the actual average blade path temperature rises more than the set value, it is determined that "ignition is detected".

This is because the blade pass temperature before ignition is HOT.
The temperature at the time of FLON (fuel injection) is stored because it cannot be determined unconditionally by the conditions such as START or COLD START, and the setting is performed based on the temperature. Things.
Thus, when the temperature rise pattern is the A type, the time from the ignition detection BPT1 to the ignition detection BPT2 in the detection circuit of the ignition detection device 1 is several hundred msec, and the ignition detection time can be shortened as much as possible. .

On the other hand, when the temperature rise pattern is the B type, the temperature gradually rises to a certain degree and then rises sharply, so that the ignition detection device 1 cannot detect the temperature. For this purpose, an ignition detection device is provided, and the temperature rise width immediately after the detection of ignition is monitored by the detection device 2.

In the present embodiment, the two types of ignition detection devices 1 and 2 are used together to improve the accuracy of ignition detection.
Further, by installing a device for detecting insufficient ignition after detection of ignition, it is possible to shorten the time for ignition and detection and to improve the reliability of ignition detection.

[0032]

According to the gas turbine ignition detection device of the present invention,
A first ignition detection device for detecting ignition using a predetermined rise rate and a rise width of an exhaust gas temperature signal due to combustion of gaseous fuel;
A second ignition detection device for detecting ignition using a predetermined rise rate and a rise width of an exhaust gas temperature signal due to combustion of the oil fuel; and outputting any one of the first and second ignition detection devices. A circuit for detecting an insufficient ignition state immediately after ignition due to a decrease in the rate of increase at a predetermined increase width based on the exhaust gas temperature signal; and a first signal based on a detection signal of the circuit for detecting the insufficient ignition state. And a circuit for resetting a circuit for outputting a detection signal of the ignition detection circuit or the second ignition detection circuit. With such a configuration, the following effects can be obtained.

(1) By replacing the flame detection with the detection of the average blade path temperature, the detection method can be softwareized (elimination of the sensor) and the procurement cost and maintenance cost can be reduced.

(2) The ignition detection method is fixed irrespective of the type of fuel, and ignition is detected as quickly and reliably as possible.
Avoid over-charging of unburned fuel and counting up of ignition detection to ensure ignition determination. Therefore, reliability in gas turbine operation is further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a gas turbine ignition detection device according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of an operation of the ignition detection device 1 shown in FIG.

FIG. 3 is an explanatory diagram of an operation of the ignition detection device 2 shown in FIG.

FIG. 4 is an explanatory diagram of an operation of the insufficient ignition detection device in a temperature rise pattern in the gas turbine ignition detection device according to one embodiment of the present invention.

FIG. 5 is an explanatory diagram of the operation of the insufficient ignition detection device in another temperature rise pattern in the gas turbine ignition detection device according to one embodiment of the present invention.

FIGS. 6A and 6B are general exhaust gas temperature rise pattern diagrams according to fuel types of a gas turbine, wherein FIG.
Is the pattern for oil fuel.

FIG. 7 is a configuration diagram of a current flame detector.

[Explanation of symbols]

 1, 2 ignition detector 3 OR circuit 4 AND circuit 5 set reset circuit 6 insufficient ignition detection device 10 entire ignition detection device 21 ignition detection signal 22 exhaust gas temperature signal

Claims (1)

[Claims] A first ignition detection device for detecting ignition using a predetermined rise rate and a rise width of an exhaust gas temperature signal due to combustion of gas fuel; and a predetermined rise rate of an exhaust gas temperature signal due to combustion of oil fuel. A second ignition detection device that detects ignition using the rise width; a circuit that outputs a detection signal of one of the first and second ignition detection devices; and a predetermined rise based on the exhaust gas temperature signal. A circuit for detecting an insufficient ignition state immediately after ignition due to a decrease in the rate of increase in the width; and a detection signal of the first ignition detection circuit or the second ignition detection circuit based on a detection signal of the circuit for detecting the insufficient ignition state. A circuit for resetting a circuit for outputting, the ignition detection device for a gas turbine.