JPH09329037A - Gas turbine limit-temperature controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent excess throttling control of fuel when the measured temperature value of a gas turbine is below its limit value. SOLUTION: A gas turbine limit-temperature controller comprises a subtracter 1 for subtracting a measured temperature value 5 from a preset limit- temperature value 3 to output a deviation 7, a deviation limiter 9 for receiving the output from the subtracter 1, a proportional plus integral controller 13 for receiving and then processing the output from the deviation limiter 9, and an output unit for processing the processed output from the proportional plus integral controller 13 with a fuel control signal and a bias 15 taken into consideration therefor to generate a limit-temperature control output signal 17.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a device for controlling the working gas temperature of a gas turbine.

[0002]

2. Description of the Related Art Generally, in a gas turbine, fuel is burned in a combustor to generate high temperature combustion gas,
This is sent to a turbine to rotate the rotor blades and convert thermal energy into rotational power. As a result, the rotor blades and stator blades of the turbine are directly exposed to the high temperature combustion gas, and thus are under severe heat conditions. In this type of heat engine, since the efficiency is improved by increasing the inlet gas temperature, the inlet gas temperature is set as high as possible within the range permitted by the material of the turbine blade. Therefore, even if the inlet gas temperature abnormally rises due to excessive fuel injection, the turbine may be damaged. Under such circumstances, the turbine inlet gas temperature is measured as the blade pass temperature or the exhaust gas temperature, and the combustion or fuel supply amount is controlled so as not to exceed the limit value by comparing with the temperature limit set value. There is. Specifically, the deviation between the limit set value and the measured value is adjusted by proportional-plus-integral adjustment, and the output is limited by a value obtained by adding a bias to the fuel control signal so that the control can always be entered. As described above, the reason why the fuel control signal is limited by the biased value is to prevent the output from being saturated to the upper limit when the above deviation is maintained positive.

[0003]

However, in the above-mentioned conventional control system, when the proportional gain is set too large to obtain the quick response, a sudden temperature change occurs even if the measured temperature value is within the limit value, as shown in FIG. If there is a rise, the control output signal will fluctuate significantly, and as a result of the control action based on it, the fuel will be excessively narrowed down, which may result in a decrease in load or a misfire. Therefore, the present invention does not have the above-mentioned inconvenience, that is, if the temperature measurement value is equal to or less than the limit set value, the temperature limit control device for the gas turbine does not cause an excessive fluctuation in the control output signal even if there is a large temperature rise. The challenge is to provide.

[0004]

In order to solve the above problems, according to the present invention, a gas turbine temperature limit control device includes a subtracter for subtracting a temperature measurement value from a temperature limit set value and outputting a deviation. , A deviation limiter that accepts the output of this subtractor, a proportional-integral regulator that accepts the output of this deviation limiter and performs arithmetic processing, and a temperature limit that takes into account the fuel control signal and bias to the arithmetic output of this proportional-integral regulator. An output device for generating a control output signal is provided, and the characteristic of the deviation limiter is such that the output is below a limit value for a positive deviation input.

[0005]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a temperature limit control circuit in gas turbine control. In FIG. 1, the temperature limit setting value 3 and the temperature measurement value 5 are input to the subtractor 1, the temperature measurement value 5 is subtracted from the temperature limit setting value 3, and the deviation 7 is output. The deviation 7 is input to the deviation limiter 9, but as shown in the figure, the characteristic is set so that the output is limited to a constant value when the deviation 7 is a positive and large value. The output 11 of the deviation limiter 9 enters the proportional-plus-integral adjuster 13 where proportional-integral adjustment is performed, but the output is limited by the fuel control signal + bias 15. That is, in the range where the deviation 7 is restricted by the deviation limiter 9, the temperature limit control output signal follows the fuel control signal + bias 15, and in the range where the deviation 7 is not restricted, that is, the temperature measurement value 5 becomes the temperature limit set value 3. When approaching to some extent, control is performed. Temperature limit setting value 3, temperature measurement value 5 and temperature limit control output signal 1 at this time
The seven relationships are shown in the graph of FIG. As can be seen from this figure, when the temperature measurement value 5 is less than or equal to the temperature limit set value 3 and the temperature measurement value 5 suddenly rises, the output of the deviation limiter 9 fluctuates. It is insensitive and the control is performed after the deviation 7 becomes small to some extent.

[0006]

As described above, according to the present invention, since the deviation limiter having the characteristic that the output is limited when the input deviation is a large positive value is arranged on the input side of the proportional-plus-integral controller, the temperature measurement value is not changed. Even if there is a sharp rise, the output is limited and it is possible to prevent excessive narrowing of the fuel.

[Brief description of drawings]

FIG. 1 is a control circuit diagram of an embodiment of the present invention.

FIG. 2 is a graph showing an example of control according to the embodiment.

FIG. 3 is a graph showing an example of control by a conventional control device.

[Explanation of symbols]

 1 Subtractor 2 Temperature measurement value 3 Temperature limit setting value 5 Temperature measurement area 7 Deviation 9 Deviation limiter 13 Proportional integral controller

Claims (1)

[Claims] 1. A subtractor for subtracting a temperature measurement value from a temperature limit set value to output a deviation, a deviation limiter for accepting the output of the subtractor, and a proportional-plus-integral controller for accepting the output of the deviation limiter for arithmetic processing. And a temperature limit control device having an output device for generating a temperature limit control output signal by adding a fuel control signal and a bias to the operation output of the proportional-plus-integral regulator, and outputting the deviation limiter to a positive deviation input. A temperature limit control device for a gas turbine, wherein the temperature limit control device has a characteristic that makes the temperature equal to or less than a limit value.