A wide load energy-saving control method for gas turbine

Abstract

The present invention relates to a wide load energy-saving control method for a gas turbine, the method comprising: 1) reading the real-time values ​​of the gas turbine power setting value, the gas turbine power rating and the boundary condition parameters of the gas turbine; 2) calculating the temperature setting value of the air heated by the gas turbine intake heating system according to the gas turbine power setting value, the gas turbine power rating and the real-time values ​​of the boundary condition parameters of the gas turbine; 3) measuring the temperature measurement value of the heated air, using the heated air temperature measurement value as the controlled variable for closed-loop control, and obtaining an actuator instruction for regulating the thermal fluid energy flow. Compared with the prior art, the present invention realizes wide load energy-saving operation for a gas turbine equipped with an intake heating system, realizes real-time control of the heated air temperature setting value, and can realize accurate and rapid regulation of the heated air temperature, thereby achieving the purpose of wide load economic operation, flexible peak-shaving capability, and good response characteristics.

Description

Technical Field

[0001] The invention relates to the field of gas turbine control, and in particular to a wide load energy-saving control method for a gas turbine. Background Art

[0002] Building a new power system with new energy as the main body is an important support for achieving the dual carbon goals, but it also poses a higher challenge to the safe operation of the power grid. As a flexible peak-shaving power source that can be quickly started and stopped, gas turbines will play an important role in promoting the large-scale consumption of renewable energy such as wind and solar power, improving the peak-shaving and frequency-regulating performance of the power grid, and ensuring the safe and stable operation of the power grid. However, in gas turbines and their combined cycle units operating at partial load, there are problems such as increased throttling losses of the compressor inlet guide vanes (IGV), decreased compressor operating efficiency, decreased gas turbine load rate, and increased gas turbine heat rate, which affect the economic efficiency of the peak-shaving operation of gas turbines and their combined cycle units. Taking a PG9351FA gas turbine as an example, when the gas turbine load rate drops from 100% to 77.4%, the gas turbine heat rate increases by about 5.93%. It can be seen that the load rate has a crucial impact on the economic efficiency of gas turbine operation.

[0003] The operation of gas turbines is easily affected by external environmental conditions. At the same time, due to the precision of the gas turbine system and the equipment characteristics of the axial flow impeller machinery, the operating efficiency of the gas turbine is very sensitive to the operating load. The decline in partial load efficiency of the gas turbine unit is related to its equipment characteristics. The gas turbine consists of a compressor, a burner, and a turbine, and its internal flow channels are designed according to ISO operating conditions. Therefore, when the unit is at partial load, the internal components of the gas turbine deviate from their optimal operating points, resulting in a decrease in overall operating efficiency.

[0004] A gas turbine is a rotary power machine that uses a continuously flowing gas as a working fluid and converts heat energy into mechanical work. In addition to consuming natural gas, gas turbines also require a large amount of air for power generation. Changes in the inlet ambient temperature have a significant impact on the efficiency and output of the gas turbine. When the ambient temperature rises, the air density decreases, resulting in a decrease in the mass flow of air entering the compressor. Usually, an IGV is installed at the compressor inlet. The air flow rate is changed by adjusting the IGV angle to maintain a higher turbine exhaust temperature under partial load and improve the thermal efficiency of the combined cycle under partial load. When the gas turbine operating at partial load maintains the same power generation capacity, as the ambient temperature rises, the IGV angle will gradually increase, the compressor inlet throttling loss will decrease, the gas turbine operating load rate will gradually increase, and the gas turbine heat rate will decrease accordingly.

[0005] Therefore, for gas turbines and their combined cycle units operating at partial load or peak load, the use of a gas turbine intake air heating system (IAHS) can effectively improve the economy of gas turbines and their combined cycle units operating at partial load, but this also requires a matching control system to achieve wide load energy-saving control operation.

[0006] After searching, Chinese patent CN104912669A discloses "the air intake air conditioning system of a gas-steam combined cycle power plant and its use method". The air intake air conditioning system includes: a surface cooler group, the air outlet end of the surface cooler group is connected to the air intake end of the gas turbine, and a heat exchange water pipe is provided in the surface cooler group, and the heat exchange water pipe is connected to the waste heat boiler; a lithium bromide absorption refrigerator is connected to the heat exchange water pipe. This technology can increase the unit output under summer conditions, and at the same time improve the unit efficiency under winter conditions and the unit efficiency under partial load conditions, thereby alleviating the problem of mismatch between the supply and demand of the power plant and the power grid at different operating stages of the unit. However, there is no mention of specific energy-saving control methods.

[0007] After searching, Chinese patent publication number CN209469494U discloses a "gas turbine inlet air temperature control system", which includes an inlet air cooling subsystem and an inlet air heating subsystem. The inlet air heating subsystem includes a heating heat exchange device, an inlet air heat exchange device, a heating circulation pump, a heating branch pipeline, and a hot water flow regulating valve located on the heating branch pipeline, and the inlet air temperature is controlled by the hot water flow regulating valve.

[0008] However, the existing patented technology does not solve the problem of how to set the target air temperature for intake heating when the gas turbine is operating at partial load or peak load to ensure the economy of wide load operation; and it only uses a single-loop control system. Faced with an air temperature control system with large capacity lag and time constant, it is unable to achieve accurate and fast energy-saving control of the gas turbine with good response characteristics within a wide load range.

[0009] Therefore, how to design a control method that has wide-load economic operation, flexible peak-shaving capability, and good response characteristics to achieve wide-load energy-saving operation of a gas turbine equipped with an intake heating system has become a technical problem that needs to be solved. Summary of the invention

[0010] The purpose of the present invention is to provide a wide load energy-saving control method for a gas turbine in order to overcome the defects of the above-mentioned prior art, to realize wide load energy-saving operation of a gas turbine equipped with an air intake heating system, and to achieve the purpose of wide load economical operation, flexible peak-shaving capability, and good response characteristics.

[0011] The purpose of the present invention can be achieved by the following technical solutions:

[0012] According to one aspect of the present invention, a wide load energy-saving control method for a gas turbine is provided, the method comprising the following steps:

[0013] 1) Read the real-time values ​​of the gas turbine power setting value, the gas turbine power rating and the gas turbine boundary condition parameters;

[0014] 2) calculating the temperature setting value of the air heated by the gas turbine inlet heating system according to the gas turbine power setting value, the gas turbine power rating and the real-time value of the boundary condition parameter of the gas turbine;

[0015] 3) Measuring the measured value of the heated air temperature, and using the measured value of the heated air temperature as the controlled variable to perform closed-loop control, thereby obtaining an actuator instruction for regulating the thermal fluid energy flow.

[0016] As a preferred technical solution, the boundary condition parameters of the gas turbine include the external ambient temperature of the gas turbine, atmospheric pressure, relative humidity, speed ratio, lower calorific value and the molar ratio of hydrogen atoms and carbon atoms in the fuel components, compressor inlet pressure loss, turbine exhaust pressure loss, fuel temperature and unit operating hours.

[0017] As a preferred technical solution, the method for calculating the temperature setting value of the heated air includes the following steps:

[0018] 21) Use the current ambient temperature as the reference value for setting the air temperature after heating;

[0019] 22) Calculating the gas turbine power correction factor based on the reference value of the heated air temperature and the boundary conditions of the gas turbine;

[0020] 23) Calculate the ratio of the gas turbine power setting value in the AGC instruction currently received by the gas turbine and the gas turbine power correction coefficient to obtain the corrected gas turbine power;

[0021] 24) If the deviation between the corrected gas turbine power and the rated power of the gas turbine is within the allowable range, proceed to step 25); otherwise, return to step 21);

[0022] 25) Output the reference value of the heated air temperature and use it as the set value of the temperature of the heated air in the gas turbine intake heating system.

[0023] As a preferred technical solution, the gas turbine power correction coefficient calculation method is as follows:

[0024] a) Based on the ambient temperature power correction curve, a polynomial fitting method is used to obtain the ambient temperature to power correction coefficient calculation model FX1, and the ambient temperature correction coefficient k1 is calculated using the heated air temperature reference value as input;

[0025] b) Based on the atmospheric pressure power correction curve, a polynomial fitting method is used to obtain the atmospheric pressure to power correction coefficient calculation model FX2 at different air temperatures, and the real-time atmospheric pressure value and the reference value of the heated air temperature are used as input to calculate the atmospheric pressure correction coefficient k2 using an interpolation calculation method;

[0026] c) Based on the relative humidity power correction curve, a polynomial fitting method is used to obtain a relative humidity to power correction coefficient calculation model FX3 at different air temperatures, and the real-time relative humidity value and the reference value of the heated air temperature are used as input to calculate the relative humidity correction coefficient k3 using an interpolation calculation method;

[0027] d) Based on the speed ratio power correction curve, a polynomial fitting method is used to obtain a speed ratio to power correction coefficient calculation model FX4 at different air temperatures, and the real-time speed ratio and the reference value of the heated air temperature are used as inputs to calculate the speed ratio correction coefficient k4 using an interpolation calculation method;

[0028] e) Based on the power correction curve of the molar ratio of hydrogen atoms and carbon atoms in the lower calorific value and the fuel components, a polynomial fitting method is used to obtain the correction coefficient calculation model FX5 of the lower calorific value to power under the molar ratio of hydrogen atoms and carbon atoms in different fuel components, and the real-time lower calorific value and the molar ratio of hydrogen atoms and carbon atoms in the fuel components are used as inputs, and the correction coefficient k5 of the molar ratio of hydrogen atoms and carbon atoms in the lower calorific value and the fuel components is calculated by an interpolation calculation method;

[0029] f) Based on the compressor inlet pressure loss power correction curve, a polynomial fitting method is used to obtain the compressor inlet pressure loss to power correction coefficient calculation model FX6 at different air temperatures, and the real-time compressor inlet pressure loss and the heated air temperature reference value are used as input, and the compressor inlet pressure loss correction coefficient k6 is calculated by the interpolation calculation method;

[0030] g) Based on the turbine exhaust pressure loss power correction curve, a polynomial fitting method is used to obtain a correction coefficient calculation model FX7 of turbine exhaust pressure loss to power at different air temperatures, and the real-time turbine exhaust pressure loss and the reference value of the heated air temperature are used as inputs, and the turbine exhaust pressure loss correction coefficient k7 is calculated by an interpolation calculation method;

[0031] h) Based on the fuel temperature power correction curve, a polynomial fitting method is used to obtain a fuel temperature to power correction coefficient calculation model FX8, and the real-time fuel temperature is used as input to calculate the fuel temperature correction coefficient k8;

[0032] i) Based on the power correction curve of the unit operating hours, a polynomial fitting method is used to obtain the correction coefficient calculation model FX9 of the unit operating hours to power, and the real-time unit operating hours are used as input to calculate the unit operating hours correction coefficient k9;

[0033] j) Calculate the gas turbine power correction factor k using the following formula:

[0034]

[0035] As a preferred technical solution, the closed-loop control method for the heated air temperature adopts a cascade control method, and the control loop involved in the cascade control method includes a main control loop and a sub-control loop;

[0036] The main control loop adopts a proportional-integral controller or a proportional-integral-differential controller, and the controller calculates the set value of the thermal fluid energy flow required for heating the air according to the deviation between the calculated set value of the heated air temperature and the measured value of the heated air temperature;

[0037] The secondary control loop adopts a proportional controller or a proportional integral controller or a proportional differential controller or a proportional integral differential controller, and the controller calculates and outputs a control instruction of the actuator according to the deviation between the set value of the thermal fluid energy flow and the calculated value of the thermal fluid energy flow.

[0038] As a preferred technical solution, the thermal fluid energy flow is calculated by multiplying the thermal fluid flow rate and the thermal fluid enthalpy value.

[0039] As a preferred technical solution, a feedforward amount is superimposed on the output of the main control loop, and the feedforward amount includes an IGV angle feedforward correction coefficient and an ambient air enthalpy feedforward correction coefficient.

[0040] As a preferred technical solution, the IGV angle feedforward correction coefficient is obtained by model calculation, the ambient air enthalpy feedforward correction coefficient is obtained by model calculation, and the feedforward amount is obtained by multiplying the IGV angle feedforward correction coefficient by the ambient air enthalpy feedforward correction coefficient.

[0041] As a preferred technical solution, the actuator can be a frequency converter supporting a regulating valve or a circulating pump; when the actuator is a regulating valve, its output is the opening of the regulating valve; when the actuator is a frequency converter supporting a circulating pump, its output is the frequency of the frequency converter.

[0042] As a preferred technical solution, the gas turbine power rating is the power design value of 100% load of the gas turbine under ISO operating conditions.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The present invention calculates in real time the maximum value of the heated air temperature allowed for the gas turbine inlet air based on the power setting value of the gas turbine unit receiving the AGC instruction, the gas turbine ISO operating condition 100% load power rating, and the correction curve of the boundary condition to the gas turbine power, and obtains the heated air temperature setting value after considering a certain safety margin, thereby achieving real-time control of the heated air temperature setting value and ensuring economy and safety within a wide load operating range.

[0045] (2) A cascade control system in which a main control loop and a sub-control loop are connected in series is used to control the temperature of the heated air. The sub-control loop can effectively eliminate the disturbances of the hot fluid enthalpy and the hot fluid flow rate from the hot fluid side, and the main control loop can effectively eliminate the disturbances of the IGV angle and the enthalpy value changes of the ambient air. Therefore, the influence of these disturbance factors on the heated air temperature can be greatly reduced, and the control effect is significantly improved, realizing accurate and rapid adjustment of the heated air temperature, achieving the purpose of flexible peak regulation and good response characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Diagram of the steps for calculating the temperature setpoint of the heated air for the gas turbine inlet air heating system.

[0047] Figure 2 A schematic diagram of a wide load energy-saving control method for a gas turbine.

[0048] Figure 3 It is the ambient temperature power correction curve.

[0049] Figure 4 It is the atmospheric pressure power correction curve.

[0050] Figure 5 This is the relative humidity power correction curve.

[0051] Figure 6 It is the speed ratio power correction curve.

[0052] Figure 7 It is the lower heating value & H / C molar ratio power correction curve.

[0053] Figure 8 It is the compressor inlet pressure loss power correction curve.

[0054] Fig. 9 It is the power correction curve of turbine exhaust pressure loss.

[0055] Fig.10 It is the fuel temperature power correction curve.

[0056] Fig.11 This is the power correction curve for the unit’s operating hours.

[0057] Fig.12 It is the IGV angle feedforward correction coefficient curve.

[0058] Fig.13 It is the feedforward correction coefficient curve of ambient air enthalpy.

[0059] Marked in the figure:

[0060] 1. Heat exchanger, 2. Compressor, 3. Combustion chamber, 4. Turbine, 5. Generator, 6. Control valve, 7. Circulation pump, 101. Gas turbine, 102. Main control loop, 103. Sub-control loop, 104. Feedforward quantity, 23. Main controller, 26. Sub-controller, 27. Frequency converter. DETAILED DESCRIPTION

[0061] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0062] like Figure 2 The invention shows a wide load energy-saving control method for a gas turbine to control a gas turbine device equipped with an intake heating system. In this embodiment, the heat fluid is pressurized by a circulating pump 7, passes through a regulating valve 6, and reaches the inlet of a heat exchanger 1 before the compressor 2. The heat of the heat fluid is transferred to the ambient air through the heat exchanger 1. After the air is heated, it will enter the compressor 2 for temperature and pressure increase, and then enter the combustion chamber 3 for mixed combustion with natural gas. The high-temperature flue gas after combustion enters the turbine 4 to do work, and part of the work drives the compressor 2 to rotate, and the remaining net output work is output from the generator 5 in the form of electrical energy. The energy flow of the heat fluid can be adjusted by the regulating valve 6 or the frequency converter matched with the circulating pump 7. When the regulating valve 6 is used for adjustment, the opening of the regulating valve 6 can be changed to control the energy flow of the heat fluid; when the frequency converter is used for adjustment, the frequency of the frequency converter can be changed, and then the speed of the circulating pump 7 can be changed, so as to adjust the energy flow of the heat fluid, so as to achieve the purpose of controlling the temperature of the heated air.

[0063] In one embodiment, the gas turbine 101 is a PG9351FA gas turbine of GE Company, and the power rating of the gas turbine 101 is P ISO The power design value of the gas turbine at 100% load under ISO conditions is: 252.6MW.

[0064] The current boundary conditions of the gas turbine 101 can be determined based on the on-site DCS sensor ( Figure 2 In one embodiment, the current boundary conditions of the gas turbine 101 are: the ambient temperature: 0°C, the atmospheric pressure P amb: 1015.71mbar, relative humidity RH: 23.3%, speed ratio n: 0.99996, lower heating value and the molar ratio of hydrogen atoms and carbon atoms in the fuel components LHV: lower heating value is 49381kJ / kg, the molar ratio of hydrogen atoms and carbon atoms in the fuel components is 3.78, compressor inlet pressure loss ΔP inlet : 58.14mmH2O, turbine exhaust pressure loss ΔP outlet : 263.78mmH2O, fuel temperature T fuel : 184.6℃, Unit operating hours: 20000 hours.

[0065] Combination Figure 1 In one embodiment, the method for determining the set value of the heated air temperature comprises the following steps:

[0066] Step 1101: Assume that the heated air temperature is set to a reference value T calc The current ambient temperature is 0℃;

[0067] Step 1102: According to Figure 3 The correction curve of ambient temperature to gas turbine power is obtained by polynomial fitting method to obtain the correction coefficient calculation model FX1 of ambient temperature to power. According to the reference value T of heated air temperature assumed in step 1101 calc : 0℃, the calculated ambient temperature correction coefficient k1 is 1.07137;

[0068] according to Figure 4 The correction curve of atmospheric pressure on gas turbine power is obtained by polynomial fitting method, and the correction coefficient calculation model FX2 of atmospheric pressure on power at different air temperatures is obtained. amb :1015.71mbar and the reference value of the heated air temperature T calc : 0℃ is input, and the atmospheric pressure correction coefficient k2 is calculated by interpolation method: 1.00277;

[0069] according to Figure 5 The correction curve of relative humidity to gas turbine power is obtained by polynomial fitting method, and the correction coefficient calculation model FX3 of relative humidity to power at different air temperatures is obtained. And the real-time relative humidity RH: 23.3% and the reference value of heated air temperature T calc : 0℃ is input, and the relative humidity correction coefficient k3 is calculated by interpolation method: 0.99827;

[0070] according to Figure 6The correction curve of the speed ratio to the gas turbine power is obtained by using the polynomial fitting method to obtain the correction coefficient calculation model FX4 of the speed ratio to the power at different air temperatures. And the real-time speed ratio n: 0.99996 and the reference value of the heated air temperature T calc : 0℃ is input, and the speed ratio correction coefficient k4 is calculated by interpolation method: 0.99866;

[0071] according to Figure 7 The correction curve of low and medium calorific value and the molar ratio of hydrogen atoms and carbon atoms in the fuel components to the gas turbine power, the polynomial fitting method is used to obtain the correction coefficient calculation model FX5 of low calorific value to power under the molar ratio of hydrogen atoms and carbon atoms in different fuel components. And the real-time low calorific value of 49381kJ / kg and the molar ratio of hydrogen atoms and carbon atoms in the fuel components of 3.78 are used as input, and the interpolation calculation method is used to calculate the correction coefficient k5 of low calorific value and the molar ratio of hydrogen atoms and carbon atoms in the fuel components: 1.00002;

[0072] according to Figure 8 The correction curve of the compressor inlet pressure loss to the gas turbine power is obtained by using the polynomial fitting method to obtain the correction coefficient calculation model FX6 of the compressor inlet pressure loss to the power at different air temperatures. inlet : 58.14mmH2O and the reference value of the air temperature after heating T calc : 0℃ is input, and the compressor inlet pressure loss correction coefficient k6 is calculated by interpolation method: 1.00529;

[0073] according to Fig. 9 The correction curve of turbine exhaust pressure loss to gas turbine power is obtained by polynomial fitting method, and the correction coefficient calculation model FX7 of turbine exhaust pressure loss to power at different air temperatures is obtained. And the real-time turbine exhaust pressure loss ΔP outlet : 263.78mmH2O and the reference value of the air temperature after heating T calc : 0℃ is input, and the turbine exhaust pressure loss correction coefficient k7 is calculated by interpolation method: 1.00111;

[0074] according to Fig.10 The correction curve of fuel temperature to gas turbine power is obtained by polynomial fitting method to obtain the correction coefficient calculation model FX8 of fuel temperature to power. And the real-time fuel temperature T fuel : 184.6℃ is input, and the fuel temperature correction coefficient k8 is calculated to be 1.00000;

[0075] according to Fig.11The correction curve of the unit's operating hours to the gas turbine power is obtained by using the polynomial fitting method to obtain the correction coefficient calculation model FX9 of the unit's operating hours to power. And using the real-time unit operating hours Hour: 20000 hours as input, the unit operating hours correction coefficient k9: 1.03846 is calculated;

[0076] Calculate the gas turbine power correction factor k:

[0077]

[0078] Step 1103: In one embodiment, the gas turbine 101 currently receives the gas turbine power setting value P of the dispatching AGC instruction. AGC is 205MW, according to the gas turbine power setting value P AGC The ratio of the gas turbine power correction coefficient k obtained in step 1102 is used to obtain the corrected gas turbine power P corr :197.50MW.

[0079] Step 1104: In one embodiment, the corrected gas turbine power P of the gas turbine 101 corr With gas turbine power rating P ISO The allowable error δ of the difference is 0.3MW, and |P corr -P ISO |>δ, then go to step 1101 to perform loop iteration until the deviation between the corrected gas turbine power and the rated value of the gas turbine power is within the allowable range δ.

[0080] Step 1105: Output the heated air temperature reference value T according to the calculation calc : 39.0℃.

[0081] Step 1106: In one embodiment, the heated air temperature calculated value T obtained in step 1105 is calc : 39.0℃, and considering a bias term Bias of 2.0℃, the set value of the air temperature after heating is obtained T set : 37.0℃.

[0082] The measured value of the heated air temperature is obtained according to the measurement, and is used as the controlled variable for closed-loop control to obtain an actuator instruction for regulating the thermal fluid energy flow.

[0083] In one embodiment, the closed-loop control method of the heated air temperature adopts a cascade control method, including a main control loop 102 and a sub-control loop 103 .

[0084] The main control loop 102 includes a main controller 23, a feedforward amount 104, an adding unit 25, a sub-control loop 103, and a measured value T of the heated air temperature.

[0085] The sub-control loop 103 includes a sub-controller 26, a frequency converter 27, and a thermal fluid energy flow calculation value M.

[0086] In the embodiment, the main controller 23 is a proportional integral controller. The main controller 23 of the main control loop 102 sets the temperature of the heated air according to the set value T set The deviation ΔT (=T set -T) is calculated through proportional integration to obtain the thermal fluid energy flow control instruction MA.

[0087] The thermal fluid energy flow control command MA and the output ΔMA of the feedforward quantity 104 are added to obtain the thermal fluid energy flow setting value M set .

[0088] The feedforward 104 takes into account the effect of the IGV angle and the ambient air enthalpy on the thermal fluid energy flow setpoint M set The feedforward quantity 104 includes an IGV angle feedforward correction coefficient calculation model FX10 and an ambient air enthalpy value feedforward correction coefficient calculation model FX11.

[0089] Furthermore, the IGV angle feedforward correction coefficient calculation model FX10 has a characteristic that when the IGV angle of the gas turbine 101 increases, the IGV angle feedforward correction coefficient calculation model output p increases. Fig.12 For example, when the IGV angle is a reference angle (e.g. 64°), the output value p is 88; when the IGV angle is greater than the reference angle, the output value is a constant p greater than 88; when the IGV angle is less than the reference angle, the output value is a constant p less than 88.

[0090] The ambient air enthalpy value feedforward correction coefficient calculation model FX11 has a characteristic that when the ambient air enthalpy value outside the gas turbine 101 increases, the ambient air enthalpy value feedforward correction coefficient calculation model output q decreases. Fig.13 For example, when the ambient air enthalpy value is a reference enthalpy value (for example, 30 kJ / kg), the output value q is 395; when the ambient air enthalpy value is greater than the reference enthalpy value, the output value is a constant q less than 395; when the ambient air enthalpy value is less than the reference enthalpy value, the output value is a constant q greater than 395.

[0091] The feedforward amount 104 is multiplied by the IGV angle feedforward correction coefficient p and the ambient air enthalpy value feedforward correction coefficient q by the multiplication unit 24 to obtain a feedforward amount output ΔMA.

[0092] The feedforward output ΔMA and the thermal fluid energy flow control command MA are added by the adding unit 25 to output the thermal fluid energy flow setting value M. setThe main control loop 102 sets the value M according to the thermal fluid energy flow. set Control of thermal fluid energy flow.

[0093] In the embodiment, the sub-controller 26 is a proportional-integral controller. The sub-controller 26 of the sub-control loop 103 sets the value M according to the energy flow of the thermal fluid. set The deviation ΔM (=M set -M) After proportional integral calculation, the control instruction PA of the inverter 27 is obtained. set .

[0094] The auxiliary control loop 103 uses the calculated value M of the thermal fluid energy flow as the controlled variable, which is calculated by multiplying the thermal fluid enthalpy value and the mass flow rate.

[0095] The cascade control system with the main control loop and the auxiliary control loop connected in series is used to control the temperature of the heated air. The interference factors from the hot fluid side are included in the auxiliary control loop, so the influence of these disturbance factors on the temperature of the heated air can be greatly reduced. The cascade control can also improve the interference of the IGV angle and the enthalpy value of the external ambient air, and the control effect is significantly improved. Thus, the wide load energy-saving control operation of the gas turbine can be realized.

[0096] The present invention realizes wide-load energy-saving operation for a gas turbine equipped with an air intake heating system, realizes real-time control of the set value of the heated air temperature, ensures economy and safety within a wide load operation range, and can simultaneously realize accurate and rapid adjustment of the heated air temperature, thereby achieving the purposes of wide-load economic operation, flexible peak-shaving capability, and good response characteristics.

[0097] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A wide load energy-saving control method for a gas turbine, characterized in that: The method comprises the following steps: 1) Read the real-time values ​​of the gas turbine power setting value, the gas turbine power rating and the gas turbine boundary condition parameters; 2) calculating the temperature setting value of the air heated by the gas turbine inlet heating system according to the gas turbine power setting value, the gas turbine power rating and the real-time value of the boundary condition parameter of the gas turbine; 3) measuring the temperature value of the heated air, using the temperature value of the heated air as the controlled variable for closed-loop control, and obtaining an actuator instruction for regulating the energy flow of the thermal fluid; The method for calculating the temperature setting value of the heated air comprises the following steps: 21) Use the current ambient temperature as the reference value for setting the air temperature after heating; 22) Calculating the gas turbine power correction factor based on the reference value of the heated air temperature and the boundary conditions of the gas turbine; 23) Calculate the ratio of the gas turbine power setting value in the AGC instruction currently received by the gas turbine and the gas turbine power correction coefficient to obtain the corrected gas turbine power; 24) If the deviation between the corrected gas turbine power and the rated power of the gas turbine is within the allowable range, proceed to step 25); otherwise, return to step 21); 25) Outputting a reference value of the heated air temperature and using it as a set value of the heated air temperature of the gas turbine intake air heating system; The gas turbine power correction factor calculation method is as follows: a) Based on the ambient temperature power correction curve, a polynomial fitting method is used to obtain the ambient temperature to power correction coefficient calculation model FX1, and the ambient temperature correction coefficient k1 is calculated using the heated air temperature reference value as input; b) Based on the atmospheric pressure power correction curve, a polynomial fitting method is used to obtain the atmospheric pressure to power correction coefficient calculation model FX2 at different air temperatures, and the real-time atmospheric pressure value and the reference value of the heated air temperature are used as input to calculate the atmospheric pressure correction coefficient k2 using an interpolation calculation method; c) Based on the relative humidity power correction curve, a polynomial fitting method is used to obtain a relative humidity to power correction coefficient calculation model FX3 at different air temperatures, and the real-time relative humidity value and the reference value of the heated air temperature are used as input to calculate the relative humidity correction coefficient k3 using an interpolation calculation method; d) Based on the speed ratio power correction curve, a polynomial fitting method is used to obtain a speed ratio to power correction coefficient calculation model FX4 at different air temperatures, and the real-time speed ratio and the reference value of the heated air temperature are used as inputs to calculate the speed ratio correction coefficient k4 using an interpolation calculation method; e) Based on the power correction curve of the molar ratio of hydrogen atoms and carbon atoms in the lower calorific value and the fuel components, a polynomial fitting method is used to obtain the correction coefficient calculation model FX5 of the lower calorific value to power under the molar ratio of hydrogen atoms and carbon atoms in different fuel components, and the real-time lower calorific value and the molar ratio of hydrogen atoms and carbon atoms in the fuel components are used as inputs, and the correction coefficient k5 of the molar ratio of hydrogen atoms and carbon atoms in the lower calorific value and the fuel components is calculated by an interpolation calculation method; f) Based on the compressor inlet pressure loss power correction curve, a polynomial fitting method is used to obtain the compressor inlet pressure loss to power correction coefficient calculation model FX6 at different air temperatures, and the real-time compressor inlet pressure loss and the heated air temperature reference value are used as input, and the compressor inlet pressure loss correction coefficient k6 is calculated by the interpolation calculation method; g) Based on the turbine exhaust pressure loss power correction curve, a polynomial fitting method is used to obtain a correction coefficient calculation model FX7 of turbine exhaust pressure loss to power at different air temperatures, and the real-time turbine exhaust pressure loss and the reference value of the heated air temperature are used as inputs, and the turbine exhaust pressure loss correction coefficient k7 is calculated by an interpolation calculation method; h) Based on the fuel temperature power correction curve, a polynomial fitting method is used to obtain a fuel temperature to power correction coefficient calculation model FX8, and the real-time fuel temperature is used as input to calculate the fuel temperature correction coefficient k8; i) Based on the power correction curve of the unit operating hours, a polynomial fitting method is used to obtain the correction coefficient calculation model FX9 of the unit operating hours to power, and the real-time unit operating hours are used as input to calculate the unit operating hours correction coefficient k9; j) Calculate the gas turbine power correction factor k using the following formula:

2. A gas turbine wide load energy-saving control method according to claim 1, characterized in that: The boundary condition parameters of the gas turbine include the external ambient temperature, atmospheric pressure, relative humidity, speed ratio, lower calorific value and molar ratio of hydrogen atoms and carbon atoms in the fuel components, compressor inlet pressure loss, turbine exhaust pressure loss, fuel temperature and unit operating hours of the gas turbine.

3. A gas turbine wide load energy-saving control method according to claim 1, characterized in that: The closed-loop control method for the heated air temperature adopts a cascade control method, and the control loop involved in the cascade control method includes a main control loop and a sub-control loop; The main control loop adopts a proportional-integral controller or a proportional-integral-differential controller, and the controller calculates the set value of the thermal fluid energy flow required for heating the air according to the deviation between the calculated set value of the heated air temperature and the measured value of the heated air temperature; The secondary control loop adopts a proportional controller or a proportional integral controller or a proportional differential controller or a proportional integral differential controller, and the controller calculates and outputs a control instruction of the actuator according to the deviation between the set value of the thermal fluid energy flow and the calculated value of the thermal fluid energy flow.

4. A gas turbine wide load energy-saving control method according to claim 3, characterized in that: The thermal fluid energy flow is calculated by multiplying the thermal fluid flow rate and the thermal fluid enthalpy value.

5. A wide load energy-saving control method for a gas turbine according to claim 3, characterized in that: A feedforward amount is superimposed on the output of the main control loop, and the feedforward amount includes an IGV angle feedforward correction coefficient and an ambient air enthalpy feedforward correction coefficient.

6. A wide load energy-saving control method for a gas turbine according to claim 5, characterized in that: The IGV angle feedforward correction coefficient is obtained by model calculation, the ambient air enthalpy feedforward correction coefficient is obtained by model calculation, and the feedforward amount is obtained by multiplying the IGV angle feedforward correction coefficient by the ambient air enthalpy feedforward correction coefficient.

7. A gas turbine wide load energy-saving control method according to claim 1, characterized in that: The actuator may be a frequency converter supporting a regulating valve or a circulating pump; when the actuator is a regulating valve, its output is the opening of the regulating valve; when the actuator is a frequency converter supporting a circulating pump, its output is the frequency of the frequency converter.

8. A gas turbine wide load energy-saving control method according to claim 1, characterized in that: The gas turbine power rating is the power design value of the gas turbine at 100% load under ISO conditions.

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