CN117469037A - Automatic adjustment method for combustion stability of gas turbine - Google Patents

Abstract

The automatic combustion stability adjusting method of the gas turbine obtains the characteristic sensitive to the stability of the combustion chamber, and compares and judges whether the characteristic of the stability precursor sensitive to the stability of the combustion chamber is an unstable precursor in a PLC module or a control system; the method comprises the steps of acquiring the vibration mode and the characteristics of Zhou Xiangbo in a combustion chamber by carrying out real-time judgment on signals of probes arranged at different positions of the combustion chamber, carrying out joint judgment on the vibration mode characteristic detection and the unstable precursor characteristic signals, correcting the on-duty air flow and the TETC value, and correcting the on-duty air flow or the TETC set value by an automatic combustion adjusting system by adopting different gas turbine combustion parameter adjusting methods under different working conditions.

Description

Automatic adjustment method for combustion stability of gas turbine

Technical Field

The invention relates to the technical field of combustion stability adjustment of gas turbines, in particular to an automatic adjustment method for combustion stability of a gas turbine.

Background

The gas turbine is an internal combustion power machine which uses continuously flowing gas as working medium to drive impeller to rotate at high speed and convert the energy of fuel into useful work, and is a rotary impeller type heat engine, and its main components include gas compressor, combustion chamber and turbine. The air compressor sucks air from the external atmospheric environment, the air compressor compresses the air step by step to pressurize the air, and meanwhile, the air temperature is correspondingly increased; compressed air is sent to a combustion chamber under pressure to be mixed with injected fuel for combustion to generate high-temperature and high-pressure gas; then the gas enters the turbine to expand and do work, the turbine is pushed to drive the gas compressor and the external load rotor to rotate together at high speed, so that the chemical energy of the gas or liquid fuel is partially converted into mechanical work, and electric work is output.

The stability of the combustion of fuel in the combustion chamber of a gas turbine is one of the most important factors affecting the reliability and safe operation of the gas turbine. The combustion stability is affected by fluctuation of fuel components, environmental change, rapid load change and normal aging of the unit, so that the range of the new machine can be deviated or exceeded. At this time, equipment manufacturers are generally required to dispatch debugging personnel to perform combustion adjustment on site so as to ensure that the combustion of the gas turbine is always in a stable and low-emission area, and in order to ensure that the gas turbine can stably burn under most working conditions, a large stability margin is reserved for debugging parameters, so that the performance of a unit cannot be completely released, and seasonal combustion adjustment windows are also required to be arranged every year, so that a great deal of manpower and time are consumed.

The combustion adjustment technology is a complex technology which needs to consider multiple influences and multi-objective overall optimization, belongs to a key technology of a gas turbine, and is an important point for researching the gas turbine. During combustion adjustment, parameters such as pressure pulsation, combustion temperature, pollutant emission and the like of a combustion chamber are required to be monitored in real time, a debugger adjusts combustion control parameters according to unit operation characteristics in combination with historical debugging data and self experience, stable and low-emission working boundaries under various load points are searched, and the combustion parameters are set in a reasonable range with sufficient safety margin.

Disclosure of Invention

In view of the above, the present invention aims to provide an automatic adjustment method for combustion stability of a gas turbine, which overcomes the drawbacks of the prior art, and by judging the vibration mode characteristic detection and the unstable precursor characteristic signal in combination, and selecting a proper adjustment method in combination with the current working condition of the gas turbine, the present invention can achieve the purpose of improving the operation stability of the gas turbine by performing the adjustment of the operation parameters in advance through communication with the control system of the gas turbine.

The technical scheme adopted by the invention is that in order to achieve the above purpose and other related purposes, the following technical scheme is provided:

the automatic combustion stability adjusting method of the gas turbine extracts unstable precursor features sensitive to the stability of the combustion chamber through a combustion feature acquisition module, and compares and judges whether the unstable precursor features sensitive to the stability of the combustion chamber are the unstable precursor features in a PLC module or a control system; or, the signals of probes arranged at different positions of the combustion chamber are used for real-time judgment, the vibration mode and the characteristics of Zhou Xiangbo in the combustion chamber are calculated, and when Zhou Xiangbo vibration meets a set value, the signals are judged to be the sign of unstable gas turbine;

the method comprises the steps that through joint judgment of vibration mode characteristic detection and unstable precursor characteristic signals, on-duty air flow and TETC values are corrected and sent to corresponding on-duty air setting and TETC setting logics in a gas turbine control system, and under different working conditions, an automatic combustion adjusting system can adopt different gas turbine combustion parameter adjusting methods to correct on-duty air flow or TETC set values;

TETC refers to turbine exhaust temperature corrected by compressor inlet temperature, turbine exhaust temperature refers to final temperature of gas after turbine expansion process is finished, and is usually very high, because the turbine needs to extract as much energy as possible from the gas to drive a generator, high turbine exhaust temperature helps to improve thermal efficiency of the gas turbine;

the PLC is called as a programmable logic controller, and comprises a Central Processing Unit (CPU), a power module, an I/O networking module, an output module O/C module, a memory module, a bottom plate and a rack module;

the PLC module also comprises or combines the following modules according to the need: the system comprises a communication module, a positioning module, a pulse output module, a high-speed counting module, a PID control module and the like, wherein the communication module, the positioning module, the pulse output module, the high-speed counting module, the PID control module and the like are used for realizing the communication, data counting and control functions of the PLC and external equipment;

further, the combustion characteristic acquisition module acquires combustion chamber buzzing signals, acceleration signals, emission data and gas turbine operation state parameters for auxiliary analysis in real time in a hard-wired and Profibus bus mode, and performs Fourier transformation;

profibus is Process Field Bus, which belongs to an industrial communication protocol and is used for communication among various devices in an automation system; open standards for Profibus for connecting sensors, actuators, controllers, and other devices in an automation system; profibus is one of the widely used Fieldbus systems.

Further, through extracting the unstable precursor characteristic sensitive to the stability of the combustion chamber, and through collecting the signals of buzzing sensors arranged at different positions of the combustion chamber, the vibration mode and the characteristic of Zhou Xiangbo in the combustion chamber are obtained, and the characteristic index signal comprising the combustion chamber thermoacoustic intensity amplitude signal, the combustion chamber thermoacoustic dynamic attenuation rate signal and the composite signal thereof is obtained.

Further, the collected buzzing and acceleration original signals are processed into the following five types of characteristic index signals, including: the method comprises the steps of adopting different automatic combustion adjustment methods according to acquired characteristic index signals by a combustion chamber dynamic pressure intensity amplitude signal, a relative dynamic pressure intensity signal, a dynamic pressure oscillation attenuation rate signal, a relative dynamic pressure oscillation attenuation rate signal and an acceleration root mean square signal;

the characteristics of the dynamic pressure intensity amplitude signal, the relative dynamic pressure intensity signal, the dynamic pressure oscillation attenuation rate signal, the relative dynamic pressure oscillation attenuation rate signal and the acceleration root mean square signal of the combustion chamber are introduced as follows:

the dynamic pressure intensity amplitude signal of the combustion chamber is used for measuring the amplitude of the dynamic pressure in the combustion chamber, namely the peak value of the dynamic pressure; the calculation method comprises the steps of acquiring dynamic pressure signals in a combustion chamber, and then carrying out Fourier transform or other frequency domain analysis to acquire amplitude values;

the relative dynamic pressure intensity signal is used for measuring the relative change of dynamic pressure amplitude values of different frequency bands in the combustion chamber, namely the change of the amplitude value of the dynamic pressure signal relative to a certain reference frequency band; the calculation method comprises the following steps: acquiring a dynamic pressure signal in a combustion chamber, comparing the dynamic pressure signal with a certain reference frequency band amplitude value, and calculating a relative amplitude value;

the dynamic pressure oscillation attenuation rate signal is used for measuring the attenuation rate of dynamic pressure oscillation in the combustion chamber, namely the attenuation rate of the dynamic pressure oscillation; the calculation method comprises the following steps: the method comprises the steps of generally collecting dynamic pressure signals of at least three or more positions in a combustion chamber, performing frequency domain analysis, and then fitting or calculating attenuation rate; the calculation Zhou Xiangbo of the oscillation attenuation rate index not only uses the value of the dynamic pressure itself, but also comprises the circumferential installation position information of the dynamic pressure sensor relative to the rotor.

The relative dynamic pressure oscillation attenuation rate signal is used for measuring the relative change of dynamic pressure oscillation attenuation rates of different frequency bands; the calculation method comprises the following steps: the oscillation decay rate at a particular frequency band is obtained and then multiplied by the dynamic pressure intensity amplitude signal at the particular frequency band.

The acceleration root mean square signal is used for measuring the intensity of the vibration acceleration signal of the combustion chamber cylinder body; the calculation method comprises the following steps: acquiring a combustion chamber acceleration signal, and then calculating a root mean square value;

the acquisition of these signals generally requires the use of corresponding sensors; mounting a suitable sensor, such as a dynamic pressure sensor, to measure the dynamic pressure within the combustion chamber; recording dynamic pressure signals through a data acquisition system, and preprocessing the acquired dynamic pressure signals, such as trending, filtering and the like; the required signal characteristics are calculated by using corresponding mathematical tools, such as fourier transform, spectrum analysis, etc., and the calculations referred to in this application, including those referred to herein and others, can be performed manually or by cooperating with existing calculators, or by prior art program calculations, such as MATLAB calculation, or by means of existing program modules, or by means of existing function programs, without involving new programs or codes, and can be performed by existing programs.

Further, the automatic combustion adjusting method comprises a multistage judging method based on a dynamic pressure intensity amplitude signal, an acceleration root mean square signal, a dynamic pressure oscillation attenuation rate signal and a relative dynamic attenuation pressure oscillation attenuation rate signal, and is divided into three action channels according to different combination modes of characteristic index signal parameters and corresponding parameter adjusting methods, wherein the three action channels comprise:

and judging the combustion stability according to the dynamic pressure intensity signal, the acceleration root mean square signal and the dynamic pressure oscillation attenuation rate signal and generating an on-duty air flow correction value.

And the second channel is used for judging the combustion stability according to the relative dynamic pressure oscillation attenuation rate signal and generating a turbine exhaust temperature correction value.

And thirdly, judging the stability according to the dynamic pressure oscillation attenuation rate signal and the relative dynamic pressure oscillation attenuation rate signal, and generating a turbine exhaust temperature correction value.

Further, the automatic combustion adjusting method comprises an on-duty air flow dynamic adjusting method based on a dynamic pressure oscillation attenuation rate signal; the on-duty air flow dynamic adjustment method takes the increment of the on-duty air flow as a function of a dynamic pressure oscillation attenuation rate and the IGV opening of the gas turbine, dynamically calculates an on-duty air flow correction parameter value according to a current dynamic pressure oscillation attenuation rate signal value in the operation process of the gas turbine, and the lower the oscillation attenuation rate is, the more the on-duty air correction quantity is, and the upper limit of the correction quantity is used as a function of the IGV opening;

the IGV refers to an adjustable guide vane at the inlet of the compressor, and the air flow entering the compressor can be adjusted by controlling the opening degree of a blade of the IGV; the IGV opening, namely the relative opening angle of the inlet guide vanes of the compressor, is usually automatically adjusted by a control system according to the running state so as to ensure that the gas turbine can stably run and obtain the best performance under different loads and working conditions;

the attenuation rate is the percentage of the reduction of the fluctuation amplitude of the regulated quantity after each fluctuation period, namely the ratio of the difference between the previous amplitude and the previous amplitude of two adjacent waves in the same direction subtracted from the previous amplitude;

the dynamic pressure oscillation damping rate of the combustion chamber is a parameter describing the propagation and damping of pressure waves in the combustion chamber and is an important indicator of the stability of combustion dynamics, in particular with respect to avoiding instabilities caused by pressure wave oscillations and vibrations damaging the equipment; dynamic pressure oscillation refers to pressure change caused by thermo-acoustic coupling inside a combustion chamber; if these oscillations are increased uncontrolled, they may lead to unstable operation of the gas turbine and even to vibrations or damage;

further, the automatic combustion adjustment method includes an automatic combustion adjustment control method based on the relative dynamic pressure intensity; the automatic combustion adjustment control method uses a relative dynamic pressure intensity signal to control the change rate and a set value of the turbine exhaust temperature, wherein the change rate of the turbine exhaust temperature is a function of the relative dynamic pressure intensity, when the relative dynamic pressure intensity is lower than a preset threshold value, the turbine exhaust temperature can be automatically reduced at a certain rate according to the magnitude of the current relative dynamic pressure intensity, the lower the relative dynamic pressure intensity is, the faster the turbine exhaust temperature is reduced until the turbine exhaust temperature is reduced to a lower limit value, and similarly, when the relative dynamic pressure intensity is restored to a certain threshold value, the turbine exhaust temperature can be automatically restored at a certain rate according to the magnitude of the current relative dynamic pressure intensity until the turbine exhaust temperature is restored to the original value.

The invention has the beneficial effects that:

the automatic combustion adjusting method can enable the gas turbine to adapt to different combustion boundary changes without manual combustion adjustment in the self stable operation application range, so that the gas turbine can adapt to flexible operation modes such as rapid peak shaving, wide fuel application range and the like. The combustion stability margin of the gas turbine can be obviously improved, the non-stop times of the unit caused by unstable combustion are reduced, and a series of losses caused by non-stop are reduced; the fuel adaptability range is improved, the combustion stability of the gas turbine in the combustion of natural gas with different heat values is improved, and the undisturbed switching of multiple fuels is realized. Meanwhile, the planned combustion adjustment times in winter and summer can be reduced; further, due to the improvement of combustion stability, the operation flexibility of the gas turbine is improved, and the gas turbine is suitable for faster peak shaving requirements.

The invention can monitor the combustion state on line in real time, automatically adjust the combustion parameters before the unstable combustion phenomenon occurs, so that the combustion is restored to the stable state, the safe, stable and reliable operation of the unit is ensured, and the times of manual debugging are reduced.

The economic benefit of the automatic combustion adjustment method is mainly evaluated from two aspects.

1. The number of manual combustion adjustments is reduced, thereby achieving a reduction in overall cost expenditures due to gas turbine combustion adjustments and impact on conventional operating plans. According to the calculation of the combustion adjustment cost which can be reduced twice per year for the user due to the large change of the operation boundary and the fuel composition, the combustion adjustment cost is reduced by about 40 ten thousand yuan per year.

2. The trip and non-stop fines are reduced, such as 1-2 times, and the non-stop caused by unstable combustion is reduced, so that the economic benefit is about 100 ten thousand yuan people's bank notes. If the machine is prevented from jumping outside for 1-2 times, the equivalent operation hours are saved by 200-400EOH, the service life and maintenance period of the equipment are prolonged, the cost per EOH is estimated according to 2000-3000, and the cost is reduced and increased by 40-80 ten thousand yuan/year. If the combustion chamber tile breakage caused by the trip is considered, and even further equipment damage is considered, the economic loss is greater.

EOH in the gas turbine art, "EOH" is commonly referred to as "Equivalent Operating Hours", chinese translated into "equivalent operating hours"; concepts are used to represent the useful life of a device, system, or component based on its actual run time under a certain load or operating condition;

each year	Before application	After application	Cost saving
				The number of manual adjustments	2-3 times	0-1 times	40 ten thousand (40)
Jumping and non-stop	1-2 times	0 times	100 ten thousand
				Saving EOH	0	200-400EOH	40-80 ten thousand

EOH refers herein to the number of equivalent operating hours.

Drawings

FIG. 1 is a signal flow diagram schematic diagram of an automatic combustion adjustment system of the present application;

FIG. 2 is a schematic diagram of an auto-combustion tuning step of the present application;

FIG. 3 is a schematic diagram of a multi-level judgment strategy based on a plurality of feature index combinations according to the present application;

FIG. 4 is a schematic diagram of an example of an automatic combustion adjustment method for a power plant according to the present application;

Detailed Description

The following describes the embodiments of the present invention in further detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and are not intended to be limiting.

In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

Furthermore, in the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

Example 1

In the case of annular combustion chambers or annular combustion chamber structures with crossfire tubes, there are thermo-acoustic oscillations propagating in the axial and circumferential directions inside the combustion chamber, and when the phase angle difference of the thermo-acoustic oscillations is too small, both produce coupled oscillation excitation and cause unstable phenomena to occur. Thermoacoustic oscillations in the combustion chamber of a gas turbine are a major cause of excessive combustor acceleration, which can lead to load shedding protection or trip protection of the gas turbine and even damage to combustor tiles, resulting in further losses. In a gas turbine, a buzzing probe is used to measure the intensity of thermoacoustic oscillations in a combustion chamber, and an acceleration probe is used to measure the vibration of the combustion chamber.

1-4, extracting unstable precursor characteristics sensitive to the stability of a combustion chamber through a combustion characteristic acquisition module, and comparing and judging whether the unstable precursor characteristics sensitive to the stability of the combustion chamber are the unstable precursor characteristics or not in a PLC module or a control system; alternatively, the vibration mode and characteristics of Zhou Xiangbo in the combustion chamber are obtained by real-time judgment of signals of probes installed at different positions in the combustion chamber, and when Zhou Xiangbo vibration satisfies a set value, the judgment is that the gas turbine is unstable. By means of combined judgment of vibration mode characteristic detection and unstable precursor characteristic signals, the on-duty gas flow and the TETC value are corrected and sent to corresponding on-duty gas setting and TETC setting logics in a gas turbine control system, and under different working conditions, an automatic combustion adjusting system can adopt different gas turbine combustion parameter adjusting methods to correct the on-duty gas flow or the TETC set value.

The combustion characteristic acquisition module acquires combustion chamber buzzing signals, acceleration signals, emission data and gas turbine operation state parameters for auxiliary analysis in real time through hard wiring and Profibus buses, and performs Fourier transformation.

The characteristic index signal of combustion stability, which comprises a combustion chamber thermal sound intensity amplitude signal, a combustion chamber thermal sound dynamic attenuation rate signal and a composite signal thereof, is obtained by extracting unstable precursor characteristics sensitive to the combustion chamber stability and acquiring signals of buzzing sensors at different positions of the combustion chamber to obtain the vibration mode and characteristics of Zhou Xiangbo in the combustion chamber.

The shift flow and the corrected Turbine Exhaust Temperature (TETC) are the main adjustable parameters affecting combustion stability during gas turbine operation. Therefore, when the characteristic signal index calculated by the automatic combustion adjustment system exceeds a predefined limit value, the combustion adjustment strategy is automatically selected according to the characteristic index parameter range and the current running state signal of the gas turbine, and the on-duty air flow and the TETC correction value are generated and sent to corresponding on-duty air setting and TETC setting logic in the gas turbine control system. Under different working conditions, the automatic combustion adjusting system can adopt different adjusting strategies, and strict priority division and switching schemes are arranged among the strategies to prevent mutual interference.

The collected buzzing and acceleration original signals are processed into the following five types of characteristic index signals, including: the dynamic pressure intensity amplitude signal, the relative dynamic pressure intensity signal, the dynamic pressure oscillation attenuation rate signal, the relative dynamic pressure oscillation attenuation rate signal and the acceleration root mean square signal of the combustion chamber are adopted by different automatic combustion adjustment methods according to the acquired characteristic index signals.

The automatic combustion adjustment method comprises a multistage judgment method based on a dynamic pressure intensity amplitude signal, an acceleration root mean square signal, a dynamic pressure oscillation attenuation rate signal and a relative dynamic attenuation pressure oscillation attenuation rate signal, and can be divided into three action channels according to different combination modes of characteristic index signal parameters and corresponding parameter adjustment methods, wherein the three action channels comprise:

and judging the combustion stability according to the dynamic pressure intensity signal, the acceleration root mean square signal and the dynamic pressure oscillation attenuation rate signal and generating an on-duty air flow correction value.

And the second channel is used for judging the combustion stability according to the relative dynamic pressure oscillation attenuation rate signal and generating a turbine exhaust temperature correction value.

And thirdly, judging the stability according to the dynamic pressure oscillation attenuation rate signal and the relative dynamic pressure oscillation attenuation rate signal, and generating a turbine exhaust temperature correction value.

In each channel, the difference between the adjustment direction, the upper limit and the speed according to the threshold range of the characteristic index and the correction parameter can be divided into A, B, C states.

The state A represents the situation that the combustion is seriously unstable, the judgment criterion is that the dynamic pressure intensity amplitude is larger than a threshold A1 or the dynamic pressure oscillation attenuation rate is lower than a threshold A2 in the channel 1, when the state A condition is met, the on-duty air flow is subjected to forward correction, the increase rate of the on-duty air correction value is A3, the correction upper limit is a function of the opening degree (IGV) of the current compressor inlet guide vane of the gas turbine, and the channels 2 and 3 do not judge the state A.

The state B represents the condition of unstable combustion, the judgment criterion is that the dynamic pressure intensity amplitude is larger than a threshold value B1 or the acceleration root mean square is larger than a threshold value B2 in the channel 1, the on-duty air flow is positively corrected when the condition of the state B is met, the on-duty air correction value is increased at a rate of B3, the upper limit of the correction is a function of the current gas turbine inlet guide vane opening (IGV), and the rate and the upper limit are lower than those of the state A. In the channel 2, the judgment criterion is that the attenuation rate of the relative dynamic pressure oscillation is higher than a threshold value B4, and when the condition B is satisfied, the turbine exhaust temperature is negatively corrected by adopting a gradient reduction method. In the channel 3, the judgment criterion is that the dynamic pressure oscillation attenuation rate is lower than B5 or the relative dynamic pressure oscillation attenuation rate is higher than B6, and when the condition of the state B is satisfied, the correction method is the same as that of the channel 2.

The state C represents the condition of stable combustion, the judgment criterion is that the dynamic pressure intensity amplitude is smaller than the threshold value C1 and the NOX emission is larger than the threshold value C2 in the channel 1, the combustion state is stable but the emission exceeds the standard, so that when the condition of the state C is met, negative correction is generated on duty, the descending rate of the duty correction is C3, and the lower limit of the correction is a function of the current gas turbine inlet guide vane opening (IGV). The judgment criteria in the channel 2 and the channel 3 are that the dynamic pressure oscillation attenuation rate is larger than a threshold value C4, the relative dynamic attenuation pressure oscillation attenuation rates of two different frequency bands are smaller than the threshold values C4 and C5, and when the condition of the state C is met, the turbine exhaust temperature is increased according to a gradient C6 until the correction value is restored to 0;

the automatic combustion adjusting method comprises a duty air flow dynamic adjusting method based on a dynamic pressure oscillation attenuation rate signal, the duty air flow dynamic adjusting method takes the increment of the duty air flow as a function of the dynamic pressure oscillation attenuation rate and the gas turbine IGV opening, the duty air flow correction parameter value is dynamically calculated according to the current dynamic pressure oscillation attenuation rate signal value in the operation process of the gas turbine, the duty air correction quantity is more when the oscillation attenuation rate is lower, and the IGV opening function is taken as the upper limit of the correction quantity. The dynamic control function and the dynamic pressure oscillation attenuation rate judgment criterion of the state A of the channel 1 in FIG. 3 can be selected by a manual setting mode.

The automatic combustion adjustment method comprises an automatic combustion adjustment control method based on relative dynamic pressure intensity, wherein the automatic combustion adjustment control method uses a relative dynamic pressure intensity signal to control the change rate and the set value of the turbine exhaust temperature, the change rate of the turbine exhaust temperature is a function of the relative dynamic pressure intensity, when the relative dynamic pressure intensity is lower than a preset threshold value, the turbine exhaust temperature automatically decreases at a certain rate according to the magnitude of the current relative dynamic pressure intensity value, and the lower the relative dynamic pressure intensity, the faster the turbine exhaust temperature decreases until the turbine exhaust temperature decreases to a lower limit value; similarly, when the relative dynamic pressure intensity is restored to a certain threshold value, the turbine exhaust temperature is automatically restored at a certain rate according to the current relative dynamic pressure intensity value until the turbine exhaust temperature is restored to the original value.

The conflict processing method triggered by the automatic combustion adjustment event comprises the following steps:

the above control methods may be triggered simultaneously (state a/B/C, functional exit, functional failure), and since multiple different trigger logics may adjust the same variable, the control of on-duty airflow and the control of turbine exhaust temperature define the priority and signal screening criteria of different trigger signals, respectively, in order to avoid collision.

For on-duty airflow control, the trigger priority is from high to low:

failure of automatic combustion system

State A trigger

State B trigger

State a exit

State B exit

State C exit

State C trigger

Correction value zeroing in no-trigger condition

For turbine exhaust temperature control, when a plurality of conditions are triggered simultaneously, the value with the minimum turbine exhaust temperature correction is selected, and because the turbine exhaust temperature correction value output by the automatic combustion system is negative under most conditions, the function actually selects the value with the maximum reduction amplitude when the turbine exhaust temperature is reduced, and selects the value with the minimum amplitude when the turbine exhaust temperature is increased.

Example two

FIG. 4 is a schematic diagram of an example of an automatic combustion adjustment method in a power plant, where during normal operation, a larger stability margin is reserved, such as a lower turbine exhaust temperature, to ensure that the unit can stably burn under most working conditions due to unstable combustion areas, so that the performance potential of the unit is not fully released. When the automatic combustion adjusting method is adopted, the higher turbine exhaust temperature can be set at partial load, when the gas turbine runs close to an unstable area, the stability characteristic index calculated by the automatic combustion adjusting system can exceed a predefined threshold value, the automatic combustion adjusting system automatically selects proper adjusting logic according to a plurality of index judging strategies in the automatic combustion adjusting system and sends on-duty gas and turbine exhaust temperature adjusting signals to the gas turbine control system, the control system can automatically reduce the turbine exhaust temperature and adjust on-duty gas flow at the same time, so that the gas turbine "bypasses" the unstable area, and the combustion instability phenomenon is avoided, and the unit fully releases performance potential on the premise of ensuring safety based on the automatic combustion adjusting system. In addition, the automatic combustion adjustment method can effectively reduce the risk of unstable combustion in the rapid load change and fuel switching process of the gas turbine, and greatly improve the operation stability and safety of the gas turbine power plant.

1. According to the automatic combustion adjusting method of the gas turbine, through original signals measured by a buzzing and acceleration probe installed in a combustion chamber, combustion stability is comprehensively judged by calculating a dynamic pressure intensity amplitude signal, a relative dynamic pressure intensity signal, a dynamic pressure oscillation attenuation rate signal, a relative dynamic pressure oscillation attenuation rate signal and an acceleration root mean square signal of the combustion chamber.

2. According to different combination modes of the dynamic pressure intensity signal, the acceleration root mean square signal and the dynamic pressure oscillation attenuation rate signal, the method for automatically adjusting the combustion stability by adjusting the duty gas flow of the burner and the turbine exhaust temperature through a multi-stage judging method is adopted.

3. According to the method for dynamically adjusting the on-duty air flow based on the combustion chamber dynamic pressure oscillation attenuation rate signal, the on-duty air increase is used as a function of the dynamic pressure oscillation attenuation rate and the opening of the gas turbine IGV (gas compressor inlet adjustable guide vane), and the on-duty air flow adjustment parameter value is dynamically calculated in the operation process of the gas turbine.

4. The invention relates to a method for adjusting the rate of change of the turbine exhaust temperature and a set value of a gas turbine based on the relative dynamic pressure intensity, wherein the rate of change of the turbine exhaust temperature and/or the set value are functions of the relative dynamic pressure intensity.

The conflict processing method triggered by the automatic combustion adjustment event is disclosed, the priority and the signal screening criterion of different trigger signals are respectively defined for the control of the on-duty air flow and the control of the turbine exhaust temperature, and the signal conflict is effectively avoided;

according to the method, unstable precursor characteristics sensitive to the stability of the combustion chamber are extracted through the combustion characteristic acquisition module, the stable precursor characteristics sensitive to the stability of the combustion chamber are compared and judged in the PLC module or the control system, the vibration mode and characteristics of Zhou Xiangbo in the combustion chamber are obtained through real-time judgment of signals of probes installed at different positions of the combustion chamber, the vibration mode characteristic detection and the unstable precursor characteristic signals are judged in a combined mode, on-duty air flow and TETC values are corrected, and under different working conditions, an automatic combustion adjustment system can adopt different gas turbine combustion parameter adjustment methods to correct on-duty air flow or TETC set values.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and substitutions can be made by those skilled in the art without departing from the technical principles of the present invention, and these modifications and substitutions should also be considered as being within the scope of the present invention.

Claims (8)

1. The automatic combustion stability adjusting method for the gas turbine is characterized by acquiring characteristics sensitive to the stability of a combustion chamber, and comparing and judging whether the characteristics are unstable characteristics or not in a PLC module or a control system; alternatively, the vibration mode and the characteristics of Zhou Xiangbo in the combustion chamber are obtained, and when Zhou Xiangbo vibration meets a set value, the vibration mode and the characteristics are judged to be the sign of unstable occurrence of the gas turbine;

by means of combined judgment of vibration mode characteristic detection and unstable precursor characteristic signals, the on-duty gas flow and turbine exhaust temperature values are corrected and sent to corresponding on-duty gas setting and TETC setting logics in a gas turbine control system, and under different working conditions, an automatic combustion adjusting system can adopt different gas turbine combustion parameter adjusting methods to correct the on-duty gas flow or turbine exhaust temperature set values.

2. The automatic combustion stability adjusting method of a gas turbine according to claim 1, wherein the vibration mode and the characteristics of Zhou Xiangbo in the combustion chamber are obtained by extracting unstable precursor characteristics sensitive to the stability of the combustion chamber and collecting signals of buzzing sensors arranged at different positions of the combustion chamber, and the characteristic index signals comprising a combustion chamber thermoacoustic intensity amplitude signal, a combustion chamber thermoacoustic dynamic attenuation rate signal and a composite signal thereof are obtained.

3. The method for automatically adjusting combustion stability of a gas turbine according to claim 1, wherein the collected buzzing and acceleration raw signals are processed into five characteristic index signals, comprising: the method comprises the steps of applying different automatic combustion adjustment methods according to acquired characteristic index signals, wherein the characteristic index signals comprise a combustion chamber dynamic pressure intensity amplitude signal, a relative dynamic pressure intensity signal, a dynamic pressure oscillation attenuation rate signal, a relative dynamic pressure oscillation attenuation rate signal and an acceleration root mean square signal; unstable predictive features in the five types of feature index signals are identified.

4. The method for automatically adjusting combustion stability of a gas turbine according to claim 3, wherein the method for automatically adjusting combustion comprises a multi-stage judgment method based on a dynamic pressure intensity amplitude signal, an acceleration root mean square signal, a dynamic pressure oscillation attenuation rate signal and a relative dynamic attenuation pressure oscillation attenuation rate signal, and is divided into three action channels according to different combination modes of characteristic index signal parameters and corresponding parameter adjustment methods:

the first channel judges combustion stability according to the dynamic pressure intensity signal, the acceleration root mean square signal and the dynamic pressure oscillation attenuation rate signal and generates an on-duty air flow correction value;

judging combustion stability according to the relative dynamic pressure oscillation attenuation rate signal and generating a turbine exhaust temperature correction value;

and thirdly, judging the stability according to the dynamic pressure oscillation attenuation rate signal and the relative dynamic pressure oscillation attenuation rate signal, and generating a turbine exhaust temperature correction value.

5. The method for automatically adjusting combustion stability of a gas turbine according to claim 4, wherein the method for automatically adjusting combustion comprises a method for dynamically adjusting on-duty air flow based on a dynamic pressure oscillation decay rate signal; the on-duty air flow dynamic adjustment method takes the increment of the on-duty air flow as a function of the dynamic pressure oscillation attenuation rate and the gas turbine IGV opening; in the running process of the gas turbine, the value of the on-duty gas flow correction parameter is dynamically calculated according to the current dynamic pressure oscillation attenuation rate signal value, the lower the oscillation attenuation rate is, the more the on-duty gas correction quantity is, and the IGV opening function is used as the upper limit of the correction quantity.

6. The method for automatically adjusting combustion stability of a gas turbine according to claim 4, wherein the method for automatically adjusting combustion comprises an automatic combustion adjustment control method based on a relative dynamic pressure intensity, the automatic combustion adjustment control method controlling a rate of change of a turbine exhaust gas temperature and a set value using the relative dynamic pressure intensity signal; the change rate of the turbine exhaust temperature is a function of the relative dynamic pressure intensity, when the relative dynamic pressure intensity is lower than a preset threshold value, the turbine exhaust temperature automatically decreases at a certain rate according to the magnitude of the current relative dynamic pressure intensity, and the lower the relative dynamic pressure intensity, the faster the turbine exhaust temperature decreases until the turbine exhaust temperature decreases to a lower limit value; when the relative dynamic pressure intensity is restored to a certain threshold value, the turbine exhaust temperature is automatically restored at a certain rate according to the magnitude of the current relative dynamic pressure intensity value until the turbine exhaust temperature is restored to the original value.

7. The automatic combustion stability adjusting method of a gas turbine according to claim 1, wherein the judgment is made by signals of probes installed at different positions of the combustion chamber, and the combustion characteristic acquisition module acquires combustion chamber buzzing signals, acceleration signals and emission data and gas turbine operation state parameters for auxiliary analysis in real time by means of hard wires and Profibus buses and performs Fourier transformation.

8. The automatic combustion stability adjusting method of a gas turbine according to claim 1, wherein the calculation Zhou Xiangbo of the oscillation attenuation rate index input parameters comprises a numerical value of dynamic pressure itself and circumferential installation position information of a dynamic pressure sensor relative to a rotor; an unstable predictive feature sensitive to combustor stability is acquired by a combustion feature acquisition module.