Gas-steam combined cycle unit steam drum water level control method, device and equipment

Abstract

The invention provides a method, device and equipment for controlling the steam drum water level of a gas-steam combined cycle unit. The method comprises the steps that the opening degree of an inlet guide vane of a gas compressor, the turbine exhaust temperature, the feed water flow, the steam flow, a steam drum water level set value and the steam drum water level are obtained in real time; according to the opening degree of an inlet guide vane of a gas compressor and the exhaust temperature of a turbine, the gas turbine side feed-forward control quantity is determined; according to the steam drum water level set value and the steam drum water level, a first PID controller is adopted to determine an original feed water flow set value; according to the feed water flow, the steam flow, the original feed water flow set value and the gas turbine side feed-forward control quantity, a second PID controller is adopted to determine a first feed water adjusting valve opening instruction; and adjusting the opening degree of the feed water adjusting valve according to the first feed water adjusting valve opening degree instruction, and controlling the steam drum water level of the gas-steam combined cycle unit. According to the invention, reliable guarantee is provided for safe and efficient operation of the unit through a cooperative regulation mechanism of the gas turbine side feed-forward control quantity and three-impulse control.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of gas turbine control, and particularly relates to a gas-steam combined cycle unit steam drum water level control method, device and equipment. BACKGROUND

[0002] In a gas-steam combined cycle unit, a steam drum is often used to complete steam-water separation by means of a waste heat boiler, and controlling the steam drum water level in a reasonable range is a key to ensuring safe operation of the waste heat boiler. However, the current steam drum water level control method of the gas-steam combined cycle unit is mostly borrowed from a coal-fired unit, and there is no significant difference from the control method of the coal-fired unit. However, compared with the coal-fired unit, the load change rate of the gas-steam combined cycle unit is faster. Moreover, due to the characteristics of the gas-steam combined cycle unit, when the load changes, the load of the gas turbine will change first, at this time, the exhaust gas temperature and the exhaust gas flow of the gas turbine change, which will change the heat absorption of the waste heat boiler, and then affect the steam drum evaporation, and finally affect the steam drum water level. In the traditional way, the steam drum water level three-impulse control is used, only when the steam drum evaporation changes and causes the steam flow to change or the steam drum water level to change, the opening degree of the feedwater regulating valve is calculated by using the steam drum water level, the feedwater flow and the steam flow, and the steam drum water level is controlled and adjusted by adjusting the feedwater flow. This adjustment has obvious hysteresis, which makes the steam drum water level fluctuate back and forth during operation, and the control effect is poor, which easily causes safety hazards. SUMMARY

[0003] The present disclosure provides a gas-steam combined cycle unit steam drum water level control method, device and equipment to solve the problem that the current steam drum water level three-impulse control of the gas-steam combined cycle unit is too hysteresis, and the steam drum water level fluctuates back and forth during operation of the unit, which easily causes safety hazards.

[0004] Based on the above problems, in a first aspect, the present disclosure provides a gas-steam combined cycle unit steam drum water level control method, which comprises:

[0005] real-time acquisition of the compressor inlet guide vane opening, the turbine exhaust temperature, the feedwater flow, the steam flow, the steam drum water level set value and the steam drum water level;

[0006] determining a gas turbine side feedforward control amount according to the compressor inlet guide vane opening and the turbine exhaust temperature;

[0007] determining an original feedwater flow set value by using a first PID controller according to the steam drum water level set value and the steam drum water level;

[0008] Based on the feedwater flow rate, the steam flow rate, the original feedwater flow rate setpoint, and the gas turbine-side feedforward control quantity, a second PID controller is used to determine the opening command of the first feedwater regulating valve.

[0009] Adjust the opening of the feedwater regulating valve according to the first feedwater regulating valve opening command to control the steam drum water level of the gas-steam combined cycle unit.

[0010] In conjunction with the first aspect, in one possible implementation, determining the gas turbine-side feedforward control quantity based on the compressor inlet guide vane opening and the turbine exhaust temperature includes:

[0011] Based on the compressor inlet guide vane opening, the feedforward control quantity of the compressor inlet guide vane opening is determined using a first-order inertial element.

[0012] Based on the turbine exhaust temperature, a second first-order inertial element is used to determine the feedforward control quantity for the turbine exhaust temperature.

[0013] The feedforward control quantity on the gas turbine side is determined based on the feedforward control quantity of the compressor inlet guide vane opening and the feedforward control quantity of the turbine exhaust temperature.

[0014] In conjunction with the first aspect, in one possible implementation, determining the gas turbine-side feedforward control quantity based on the feedforward control quantity of the compressor inlet guide vane opening and the feedforward control quantity of the turbine exhaust temperature includes:

[0015] Based on the feedforward control quantity of the compressor inlet guide vane opening and the feedforward control quantity of the turbine exhaust temperature, an adder / subtractor is used to perform addition operations to determine the first feedforward control quantity.

[0016] Based on the first feedforward control quantity, the speed limiting module is used to determine the gas turbine-side feedforward control quantity.

[0017] In conjunction with the first aspect, in one possible implementation, determining the gas turbine-side feedforward control quantity using a speed limiting module based on the first feedforward control quantity includes:

[0018] Acquire the status of the three-impulse control switch and the feedforward control switch status of the compressor inlet guide vane opening and turbine exhaust temperature;

[0019] Based on the state of the three-impulse control switch and the state of the feedforward control switch for the compressor inlet guide vane opening and turbine exhaust temperature, an AND operation is performed to determine the state of the first control switch.

[0020] Based on the state of the first control switch, the feedforward coefficient is determined using an analog selection module.

[0021] Based on the first feedforward control quantity and the feedforward coefficient, a multiplier is used to determine the second feedforward control quantity;

[0022] Based on the second feedforward control quantity, the speed limiting module is used to determine the gas turbine-side feedforward control quantity.

[0023] In conjunction with the first aspect, in one possible implementation, determining the original feedwater flow rate setpoint using a first PID controller based on the steam drum water level setpoint and the steam drum water level includes:

[0024] Based on the set steam drum water level and the steam drum water level, an adder / subtractor is used to perform a subtraction operation to determine the steam drum water level deviation value.

[0025] Based on the steam drum water level deviation value, the first PID controller is used to determine the original feedwater flow rate setpoint.

[0026] In conjunction with the first aspect, in one possible implementation, the step of determining the opening command of the first feedwater regulating valve using a second PID controller based on the feedwater flow rate, the steam flow rate, the original feedwater flow rate setpoint, and the gas turbine-side feedforward control quantity includes:

[0027] Based on the steam flow rate, a third first-order inertial element is used to determine the feedforward control quantity of the steam flow rate.

[0028] Based on the feedforward control quantity of the steam flow rate, the original feedwater flow rate setpoint, and the feedforward control quantity of the gas turbine side, an adder / subtractor is used to perform addition operations to determine the corrected feedwater flow rate setpoint.

[0029] Based on the corrected water supply flow rate setpoint and the water supply flow rate, an adder / subtractor is used to perform a subtraction operation to determine the water supply flow rate deviation value.

[0030] Based on the water supply flow deviation value, a second PID controller is used to determine the opening command of the first water supply regulating valve.

[0031] In conjunction with the first aspect, in one possible implementation, the step of adjusting the opening of the feedwater regulating valve according to the first feedwater regulating valve opening command to control the steam drum water level of the gas-steam combined cycle unit includes:

[0032] Based on the set steam drum water level and the steam drum water level, an adder / subtractor is used to perform a subtraction operation to determine the steam drum water level deviation value.

[0033] Based on the steam drum water level deviation value, a third PID controller is used to determine the opening command of the second feedwater regulating valve;

[0034] The opening degree of the feedwater regulating valve is adjusted according to the opening degree command of the first feedwater regulating valve or the opening degree command of the second feedwater regulating valve to control the water level in the steam drum of the gas-steam combined cycle unit.

[0035] In conjunction with the first aspect, in one possible implementation, the step of adjusting the opening of the feedwater regulating valve according to the first feedwater regulating valve opening command or the second feedwater regulating valve opening command to control the steam drum water level of the gas-steam combined cycle unit includes:

[0036] Obtain the status of the three-impulse control switch;

[0037] The opening commands of the first water supply regulating valve, the second water supply regulating valve, and the status of the three-impulse control switch are input to the analog quantity selection module.

[0038] When the three-impulse control switch is in the ON state, the opening of the feedwater regulating valve is adjusted according to the opening command of the first feedwater regulating valve to control the steam drum water level of the gas-steam combined cycle unit.

[0039] When the three-impulse control switch is closed, the opening of the feedwater regulating valve is adjusted according to the second feedwater regulating valve opening command to control the steam drum water level of the gas-steam combined cycle unit.

[0040] Secondly, a steam drum water level control device for a gas-steam combined cycle unit is provided, comprising:

[0041] The acquisition module is used to acquire in real time the compressor inlet guide vane opening, turbine exhaust temperature, feedwater flow rate, steam flow rate, steam drum water level setpoint, and steam drum water level.

[0042] The gas turbine-side feedforward control quantity determination module is used to determine the gas turbine-side feedforward control quantity based on the compressor inlet guide vane opening and the turbine exhaust temperature.

[0043] The original feedwater flow rate setpoint determination module is used to determine the original feedwater flow rate setpoint based on the steam drum water level setpoint and the steam drum water level, using a first PID controller.

[0044] The feedwater regulating valve opening command determination module is used to determine the first feedwater regulating valve opening command based on the feedwater flow rate, the steam flow rate, the original feedwater flow rate setpoint and the gas turbine side feedforward control quantity, using a second PID controller.

[0045] The steam drum water level regulating module is used to adjust the opening of the feedwater regulating valve according to the opening command of the first feedwater regulating valve, and control the steam drum water level of the gas-steam combined cycle unit.

[0046] Thirdly, an electronic device is provided, characterized in that the electronic device stores a computer program, which, when executed by a processor, performs the steps of the gas-steam combined cycle unit drum water level control method as described in the first aspect or any possible embodiment in conjunction with the first aspect.

[0047] The beneficial effects of the embodiments disclosed herein include:

[0048] The gas-steam combined cycle unit steam drum water level control method, apparatus, and equipment provided in this disclosure include: real-time acquisition of compressor inlet guide vane opening, turbine exhaust temperature, feedwater flow rate, steam flow rate, steam drum water level setpoint, and steam drum water level; determining the gas turbine-side feedforward control quantity based on the compressor inlet guide vane opening and turbine exhaust temperature; determining the original feedwater flow rate setpoint using a first PID controller based on the steam drum water level setpoint and steam drum water level; determining the first feedwater regulating valve opening command using a second PID controller based on the feedwater flow rate, steam flow rate, original feedwater flow rate setpoint, and gas turbine-side feedforward control quantity; and adjusting the feedwater regulating valve opening according to the first feedwater regulating valve opening command to control the steam drum water level of the gas-steam combined cycle unit. The steam drum water level control method for gas-steam combined cycle units provided in this disclosure addresses the significant characteristics of gas-steam combined cycle units, namely, rapid load changes and gas turbine-side changes preceding waste heat boiler-side changes. It achieves proactive steam drum water level control through a coordinated adjustment mechanism of gas turbine-side parameter feedforward control and three-impulse control, thereby more accurately adapting to the unit's operating patterns. By introducing feedforward control parameters such as compressor inlet guide vane opening and turbine exhaust temperature, changes in waste heat boiler heat absorption caused by gas turbine load variations can be detected and responded to in advance. This effectively overcomes the limitation of traditional three-impulse control, which only initiates adjustment after changes in steam drum water level or steam flow, fundamentally solving the problem of adjustment lag. Furthermore, by combining real-time collected operating parameters, such as feedwater flow, steam flow, and steam drum water level, the feedwater flow is dynamically adjusted, significantly reducing the fluctuation range of steam drum water level and significantly improving the stability of the control process. This ensures that the steam drum water level is always maintained within a reasonable range, providing a reliable guarantee for the safe and efficient operation of the gas-steam combined cycle unit. Attached Figure Description

[0049] Figure 1 A flowchart of a method for controlling the water level in a gas-steam combined cycle unit provided in this disclosure embodiment;

[0050] Figure 2 This is a control logic diagram of the steam drum water level control method for a gas-steam combined cycle unit provided in the embodiments of this disclosure;

[0051] Figure 3 This is a structural diagram of the steam drum water level control device for a gas-steam combined cycle unit provided in an embodiment of this disclosure. Detailed Implementation

[0052] This disclosure provides a method, apparatus, and equipment for controlling the water level in the steam drum of a gas-steam combined cycle unit. The preferred embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of this disclosure. Furthermore, the embodiments and features described herein can be combined with each other unless otherwise specified.

[0053] This disclosure provides a method for controlling the water level in the steam drum of a gas-steam combined cycle unit, such as... Figure 1 As shown, it includes:

[0054] S101. Real-time acquisition of compressor inlet guide vane opening, turbine exhaust temperature, feedwater flow rate, steam flow rate, steam drum water level setpoint, and steam drum water level;

[0055] S102. Determine the gas turbine-side feedforward control quantity based on the compressor inlet guide vane opening and turbine exhaust temperature.

[0056] S103. Based on the steam drum water level setpoint and the steam drum water level, the first PID controller is used to determine the original feedwater flow rate setpoint.

[0057] S104. Based on the feedwater flow rate, steam flow rate, original feedwater flow rate setpoint and gas turbine side feedforward control quantity, a second PID controller is used to determine the opening command of the first feedwater regulating valve.

[0058] S105. Adjust the opening of the feedwater regulating valve according to the opening command of the first feedwater regulating valve to control the water level in the steam drum of the gas-steam combined cycle unit.

[0059] In this embodiment of the disclosure, the waste heat boiler of a gas-steam combined cycle unit typically uses a steam drum to achieve steam-water separation. The steam drum water level is a key parameter reflecting the balance of the boiler's steam-water system. An excessively high steam drum water level may cause water carryover in the steam, affecting steam quality and even causing superheater scaling; an excessively low steam drum water level may cause overheating of the boiler's heating surfaces, leading to tube rupture accidents. Therefore, maintaining the steam drum water level within a reasonable range is a necessary condition for ensuring the safe operation of the waste heat boiler. The steam drum water level of the waste heat boiler is affected by various factors, such as feedwater flow rate, steam flow rate, gas turbine exhaust temperature, and exhaust flow rate. These factors are coupled and time-delayed, posing a challenge to the precise control of the steam drum water level. Currently, the drum water level of gas-fired combined cycle (GWC) units is typically controlled using single-impulse control at low loads, where the feedwater regulating valve opening is determined based on the drum water level. At higher loads, three-impulse control is usually employed to improve control accuracy, where the feedwater regulating valve opening is determined based on three parameters: drum water level, feedwater flow rate, and steam flow rate. This adjustment of the feedwater flow rate controls the drum water level. However, traditional methods for controlling the drum water level in GWC units are largely borrowed from coal-fired units and are not significantly different. Compared to coal-fired units, GWC units experience faster load changes. Due to the characteristics of GWC units, the gas turbine load changes first during load changes. Changes in the gas turbine exhaust temperature and flow rate alter the heat absorption of the waste heat boiler, affecting the drum evaporation rate and ultimately the drum water level. The current three-impulse control of the steam drum water level only starts adjusting when the steam drum evaporation rate changes, resulting in changes in steam flow or steam drum water level. This adjustment is too delayed, causing the steam drum water level to fluctuate during operation, resulting in poor control performance.

[0060] In this embodiment of the disclosure, such as Figure 2 As shown, the compressor inlet guide vane (IGV) refers to the adjustable blades at the inlet of the gas turbine compressor, used to control the direction and flow rate of the airflow entering the compressor, thereby affecting the performance and efficiency of the gas turbine. IGV This indicates the compressor inlet guide vane opening, that is, the opening angle or position of the compressor inlet guide vanes. U IGV It is a control variable, typically used to adjust the intake airflow of a gas turbine to adapt to different operating conditions, and can reflect the changing trend of the turbine exhaust airflow. Turbine exhaust temperature (T EX Turbine Exhaust Temperature refers to the flue gas temperature at the exhaust port of a gas turbine, which is directly related to the heat absorption of the waste heat boiler. Feedwater flow rate F W This can refer to the actual amount of feedwater entering the steam drum, and is a control parameter for steam drum water level control. Steam flow rate F SThis can refer to the amount of steam produced by the steam drum, reflecting the steam drum evaporation intensity, and is directly related to changes in the steam drum water level. Steam drum water level setpoint L S This can refer to the ideal or target steam drum water level. The steam drum water level L can refer to the actual water level in the boiler drum during operation. Real-time acquisition of the compressor inlet guide vane opening U... IGV Turbine exhaust temperature T EX Water supply flow rate F W Steam flow rate F S Steam drum water level setpoint L S And the steam drum water level L. In a gas-steam combined cycle unit, the gas turbine load change precedes the change in the heat absorption of the waste heat boiler. The process can be expressed as: gas turbine load change accompanied by flue gas temperature / flow rate change → boiler heat absorption change → steam drum evaporation rate change → steam drum water level change. Therefore, based on the compressor inlet guide vane opening U... IGV Turbine exhaust temperature T EX Determine the feedforward control quantity FF on the gas turbine side. GT This allows for advance compensation for adjustments to the feedwater flow rate, offsetting the impact of changes in gas turbine-side parameters on the steam drum water level. For example, adjusting the compressor inlet guide vane opening U... IGV Feedforward control quantity FF IGV Turbine exhaust temperature T EX Feedforward control quantity FF EX The gas turbine-side feedforward control quantity FF is obtained by performing addition operations using an adder / subtractor. GT The adder / subtractor is represented as The first PID controller PID1 uses the steam drum water level setpoint L. S The deviation from the steam drum water level L is used as input, and the original feedwater flow setpoint F is calculated using a PID algorithm (proportional-integral-derivative control). WS0 .

[0061] Furthermore, the gas turbine-side feedforward control quantity FF GT Original water supply flow rate setpoint F WS0 Steam flow feedforward control quantity FF S With real-time water supply flow rate F W The difference is calculated, and the final regulating valve opening command is output by the PID2 controller, realizing the coordinated regulation of gas turbine-side parameter feedforward control and three-impulse control. The input parameters of the second PID controller, PID2, may include: feedwater flow rate F. W Steam flow feedforward control quantity FF S Original water supply flow rate setpoint F WS0 And gas turbine side feedforward control quantity FF GT The second PID controller, PID2, calculates the comprehensive deviation of the above parameters and outputs the opening command U of the first water supply regulating valve through the PID algorithm. CV3According to the opening command U of the first water supply regulating valve CV3 Adjusting the opening of the feedwater regulating valve ultimately achieves stable control of the steam drum water level.

[0062] This application's embodiments, addressing the characteristics of gas-steam combined cycle units where "load changes rapidly and gas turbine-side changes precede waste heat boiler-side changes," achieve proactive control of the steam drum water level through coordinated adjustment of gas turbine-side parameter feedforward control and three-impulse control, thus better adapting to the unit's operating patterns. By introducing feedforward control parameters such as compressor inlet guide vane opening and turbine exhaust temperature, the system responds in advance to changes in waste heat boiler heat absorption caused by gas turbine load variations, solving the lag problem of traditional three-impulse control that "adjusts only after changes in steam drum water level or steam flow." Furthermore, by dynamically adjusting feedwater flow based on real-time parameters, it reduces steam drum water level fluctuations and improves control stability.

[0063] In another embodiment of this disclosure, step S102 above, determining the gas turbine-side feedforward control quantity based on the compressor inlet guide vane opening and turbine exhaust temperature, includes:

[0064] Step 1: Based on the compressor inlet guide vane opening, use the first-order inertial element to determine the feedforward control quantity of the compressor inlet guide vane opening;

[0065] Step 2: Based on the turbine exhaust temperature, use a second first-order inertial element to determine the feedforward control quantity for the turbine exhaust temperature.

[0066] Step 3: Determine the feedforward control quantity on the gas turbine side based on the feedforward control quantity of the compressor inlet guide vane opening and the feedforward control quantity of the turbine exhaust temperature.

[0067] In this embodiment of the disclosure, such as Figure 2 As shown, the compressor inlet guide vane opening U is affected by a first-order inertial element. IGV Turbine exhaust temperature T EX The process yields the feedforward control quantity FF for the compressor inlet guide vane opening. IGV Feedforward control quantity FF of turbine exhaust temperature EX Combining the results from both, the feedforward control quantity FF on the gas turbine side was finally determined. GT This provides gas turbine-side parameter feedforward for the advanced regulation of the steam drum water level. Regarding step 1 above, the compressor inlet guide vane opening U... IGV After being input into the first-order inertial element, the feedforward control quantity FF of the compressor inlet guide vane opening is obtained. IGV The formula for the first-order inertial element is expressed as: Where s is the Laplace operator, and K2 and T2 can be determined based on the characteristics of the gas-steam combined cycle unit. For example, K2 = 0.15 and T2 = 30. Regarding step 2 above, the turbine exhaust temperature T... EXAfter being input into the second-order inertial element, the feedforward control quantity FF for the turbine exhaust temperature is obtained. EX The formula for the second-order inertial element is expressed as: K3 and T3 can also be determined based on the characteristics of the gas-steam combined cycle unit. For example, K3 = 0.2 and T3 = 20. Regarding step 3 above, the feedforward control quantity FF for the compressor inlet guide vane opening... IGV The feedforward control quantity FF, which focuses on reflecting changes in turbine exhaust flow rate and turbine exhaust temperature, is... EX The focus is on reflecting changes in turbine exhaust temperature. The feedforward control variable FF for the compressor inlet guide vane opening is used. IGV Feedforward control quantity FF of turbine exhaust temperature EX By combining the two, for example by using an adder / subtractor to perform addition operations, the feedforward control quantity FF on the gas turbine side can be obtained. GT This can comprehensively cover the dynamic changes on the gas turbine side. Using a first-order inertial element can simulate the compressor inlet guide vane opening U. IGV Turbine exhaust temperature T EX The lag effect on the heat absorption of the waste heat boiler ensures that the timing of the feedforward control variable matches the actual physical process, avoiding either "over-leading" or "slow response." Compressor inlet guide vane opening U IGV The turbine exhaust temperature T reflects the change in gas turbine exhaust flow rate. EX It reflects changes in turbine exhaust temperature and comprehensively considers turbine exhaust flow rate and temperature, which can fully cover the potential impact of gas turbine side parameters on steam drum water level.

[0068] In another embodiment of this disclosure, step 3 above, determining the gas turbine-side feedforward control quantity based on the feedforward control quantity of the compressor inlet guide vane opening and the feedforward control quantity of the turbine exhaust temperature, includes:

[0069] Step 1: Based on the feedforward control quantity of the compressor inlet guide vane opening and the feedforward control quantity of the turbine exhaust temperature, use an adder / subtractor to perform addition operations to determine the first feedforward control quantity;

[0070] Step 2: Based on the first feedforward control quantity, use the speed limiting module to determine the gas turbine-side feedforward control quantity.

[0071] In this embodiment of the disclosure, such as Figure 2 As shown, the feedforward control quantity FF of the compressor inlet guide vane opening is first calculated by addition. IGV Feedforward control quantity FF of turbine exhaust temperature EX The summation yields the first feedforward control quantity; then, the rate of change of the first feedforward control quantity is limited by the speed limiting module, ultimately determining the gas turbine-side feedforward control quantity FF. GT To ensure the feedforward control quantity FF on the gas turbine side GTThis approach comprehensively reflects the impact on the gas turbine side without causing excessively rapid changes that could disrupt the steam drum water level. Regarding step one above, the feedforward control variable FF for the compressor inlet guide vane opening is... IGV Feedforward control quantity FF of turbine exhaust temperature EX Summing yields the first feedforward control quantity. Regarding step two above, to limit the rate of change of the first feedforward control quantity, avoid over-adjustment due to sudden changes in the first feedforward control quantity, and ensure stable steam drum water level, the first feedforward control quantity is input to the speed limiting module to obtain the gas turbine-side feedforward control quantity FF. GT The speed limit module is represented as... The speed limit value of the speed limiting module should be determined based on the characteristics of the unit during commissioning. For example, a speed limit value of 0.25 is used. This can prevent issues caused by the compressor inlet guide vane opening U... IGV Or turbine exhaust temperature T EX The sudden change caused a sharp fluctuation in the first feedforward control quantity, thereby preventing excessive subsequent feedwater regulation from impacting the steam drum water level.

[0072] In another embodiment of this disclosure, in step two above, determining the gas turbine-side feedforward control quantity using a speed limiting module based on the first feedforward control quantity includes:

[0073] Step (1): Obtain the status of the three-impulse control switch and the status of the feedforward control switch for the compressor inlet guide vane opening and turbine exhaust temperature;

[0074] Step (2): Based on the state of the three-impulse control switch and the state of the feedforward control switch for the compressor inlet guide vane opening and turbine exhaust temperature, use AND operation to determine the state of the first control switch.

[0075] Step (3): Based on the state of the first control switch, determine the feedforward coefficient using the analog selection module;

[0076] Step (4): Based on the first feedforward control quantity and the feedforward coefficient, use a multiplier to determine the second feedforward control quantity;

[0077] Step (5): Based on the second feedforward control quantity, the speed limiting module is used to determine the gas turbine-side feedforward control quantity.

[0078] In this embodiment, by acquiring and processing the state of the three-impulse control switch, the compressor inlet guide vane opening, and the turbine exhaust temperature feedforward control switch, the activation conditions of the gas turbine-side feedforward control quantity are determined through logical judgment. Then, the activation conditions of the gas turbine-side feedforward control quantity are realized through analog quantity selection and a multiplier. Finally, the final gas turbine-side feedforward control quantity is obtained through speed limiting processing, ensuring that the gas turbine-side feedforward control quantity takes effect smoothly under effective operating conditions. Regarding step (1) above, as follows... Figure 2As shown, the three-impulse control switch status is represented by SW, and the feedforward control switch status for compressor inlet guide vane opening and turbine exhaust temperature is represented by MAN. SW=1 indicates that the three-impulse control switch is enabled; SW=0 indicates that the three-impulse control switch is disabled. MAN=1 indicates that the feedforward control switch for compressor inlet guide vane opening and turbine exhaust temperature is enabled; MAN=0 indicates that the feedforward control switch for compressor inlet guide vane opening and turbine exhaust temperature is disabled. The three-impulse control switch status is generally determined by the control logic of other parts of the gas-steam combined cycle unit, while the feedforward control switch status for compressor inlet guide vane opening and turbine exhaust temperature can be controlled by the operator. For step (2) above, the three-impulse control switch status SW and the feedforward control switch status MAN for compressor inlet guide vane opening and turbine exhaust temperature are ANDed to obtain the first control switch status. The first control switch status of 1 indicates that it is enabled, and the first control switch status of 0 indicates that it is disabled. Regarding step (3) above, the logic signal of the first control switch state is used as the analog quantity selection signal. The function of the analog quantity selection module T is to select the output value from the preset analog quantity according to the input logic signal (first control switch state). Usually, two values ​​are preset: when the first control switch state is 1, the analog quantity "1" is selected as the output; when the first control switch state is 0, the analog quantity "0" is selected as the output. This process realizes the conversion of logic signal to analog quantity signal, obtains feedforward coefficient, and makes it possible to perform operations with the first feedforward control quantity. Regarding step (4) above, the conditional activation of the first feedforward control quantity is realized through multiplication operation, that is, the first feedforward control quantity is effective only when the feedforward coefficient is "1"; when the feedforward coefficient is "0", the first feedforward control quantity is masked. The first feedforward control quantity and the feedforward coefficient are input into the multiplier and multiplied to obtain the second feedforward control quantity. The multiplier is represented as Regarding step (5) above, the rate of change of the second feedforward control quantity is limited to ensure that the second feedforward control quantity changes smoothly when it takes effect, adapting to the dynamic response capability of the feedwater regulating valve and avoiding impact on the steam drum water level. The second feedforward control quantity is input to the speed limiting module to determine the gas turbine-side feedforward control quantity FF. GT The speed limit value of the speed limiting module should be determined based on the characteristics of the unit during commissioning. For example, the speed limit value is 0.25. If the current unit load is low and three-impulse control is not suitable, then SW=0, the analog selection module T selects "0" as the output, and FF... GT Set MAN to 0. In cases of abnormal feedforward control of compressor inlet guide vane opening and turbine exhaust temperature, the operator can set MAN to 0. At this time, FF... GT It also becomes 0, canceling the feedforward control of the compressor inlet guide vane opening and turbine exhaust temperature. By using an AND operation to correlate the three-impulse control switch state SW and the feedforward control switch state MAN for the compressor inlet guide vane opening and turbine exhaust temperature, the feedforward control quantity FF on the gas turbine side is ensured.GT This only takes effect when both are enabled, improving the reliability of the control logic. Ultimately, the rate of change of the second feedforward is limited by the speed limiting module, combined with conditional control, to ensure the stability of the gas turbine-side feedforward control quantity FF. GT It plays a proactive regulatory role under effective operating conditions, while avoiding excessive U-shaped opening of the compressor inlet guide vanes. IGV Or turbine exhaust temperature T EX The sudden changes in feedwater regulation further enhance the stability of steam drum water level control.

[0079] In another embodiment of this disclosure, in step S103 above, determining the original feedwater flow rate setpoint based on the steam drum water level setpoint and the steam drum water level using a first PID controller includes:

[0080] Step 1: Based on the set value of the steam drum water level and the steam drum water level, use an adder / subtractor to perform subtraction to determine the deviation value of the steam drum water level;

[0081] Step 2: Based on the deviation value of the steam drum water level, use the first PID controller to determine the original feedwater flow rate setpoint.

[0082] In this embodiment of the disclosure, such as Figure 2 As shown, the steam drum water level setpoint L is first calculated. S The deviation from the actual water level L is then calculated using the first PID controller PID1 to finally obtain the original water supply flow setpoint F. WS0 This provides a basic target value for subsequent feedwater regulation. Regarding step 1 above, the steam drum water level setpoint L... S This can refer to the ideal boiler drum water level. The boiler drum water level L can refer to the actual water level in the boiler drum during operation. By performing a subtraction operation using an adder / subtractor, the difference between the two can be obtained, which is the boiler drum water level deviation. Regarding step 2 above, the water level deviation is processed using a PID control algorithm, converting the deviation into a specific feedwater flow demand, i.e., the original feedwater flow setpoint F. WS0 The first PID controller, PID1, can update the original feedwater flow setpoint F in real time according to the change in the steam drum water level L. WS0 This ensures timely control.

[0083] In another embodiment of this disclosure, in step S104 above, the first feedwater regulating valve opening command is determined using a second PID controller based on the feedwater flow rate, steam flow rate, original feedwater flow rate setpoint, and gas turbine-side feedforward control quantity, including:

[0084] Step 1: Based on the steam flow rate, use the third first-order inertial element to determine the feedforward control quantity of the steam flow rate;

[0085] Step 2: Based on the feedforward control quantity of steam flow, the original feedwater flow setpoint and the feedforward control quantity of the gas turbine side, use an adder / subtractor to perform addition operations to determine the corrected feedwater flow setpoint.

[0086] Step 3: Based on the corrected water supply flow rate setpoint and water supply flow rate, use an adder / subtractor to perform subtraction to determine the water supply flow rate deviation value;

[0087] Step 4: Based on the water supply flow deviation value, use the second PID controller to determine the opening command of the first water supply regulating valve.

[0088] In this embodiment of the disclosure, such as Figure 2 As shown, the steam flow rate F is first processed through a third-order inertial element. S The feedforward control quantity FF of the steam flow rate is obtained. S Then, the feedforward control quantity FF of the steam flow rate is... S Compared with the original water supply flow rate setpoint F WS0 Gas turbine side feedforward control quantity FF GT The corrected water supply flow rate setpoint F is obtained by adding the results together. WS Then, the corrected water supply flow rate setpoint F was calculated. WS With actual water supply flow rate F W The deviation is finally calculated by the second PID controller PID2 to determine the opening command U of the first water supply regulating valve. CV3 This allows for precise regulation of the water supply flow rate. Regarding step 1 above, the steam flow rate F... S The input is fed into the third-order inertial element to obtain the steam flow feedforward control quantity FF, which conforms to its actual influence on the steam drum water level. S To avoid steam flow rate F S The interference of instantaneous fluctuations on water supply regulation. The formula for the third-order inertial element is expressed as follows: Among them, the gain coefficient K1 of the third-order inertial element determines the steam flow rate F. S The magnitude of the feedforward effect on the feedwater flow rate is determined by the inertial time constant T1, which in turn determines the steam flow rate F. S The timing of the feedforward action on the feedwater flow rate can be determined by adjusting K1 and T1 based on the characteristics of the gas-steam combined cycle unit. For example, K1 = 0.12 and T1 = 6.4. Regarding step 2 above, the feedforward control quantity FF of the steam flow rate... S Original water supply flow rate setpoint F WS0 With gas turbine-side feedforward control quantity FF GT Summing these values ​​yields the corrected water supply flow setpoint F, which comprehensively reflects multi-dimensional demands. WS This improves the comprehensiveness and accuracy of the setpoints. The steam drum water level deviation value characterizes the basic regulation target; the feedforward control quantity FF of the steam flow rate... SReflecting the real-time demand of "steam flow rate changes synchronized with feedwater flow rate"; gas turbine-side feedforward control quantity FF GT To reflect the proactive need for feedwater compensation due to changes in evaporation caused by variations on the gas turbine side, the three parameters are added together using an adder-subtractor to obtain the corrected feedwater flow rate setpoint. Regarding step 3 above, the corrected feedwater flow rate setpoint F... WS With actual water supply flow rate F W By using an adder / subtractor to perform subtraction, the difference between the two values ​​can be directly obtained, which is the feedwater flow deviation value. Regarding step 4 above, the PID control algorithm uses the feedwater flow deviation value to calculate the regulating valve opening command, enabling the actual feedwater flow to quickly and stably track the corrected feedwater flow setpoint F. WS Ultimately, precise control of the steam drum water level is achieved. The feedwater flow deviation value is input to the second PID controller PID2, which generates the first feedwater regulating valve opening command U, including three-impulse control calculations. CV3 The feedforward control quantity FF of the steam flow rate is calculated through addition. S Original water supply flow rate setpoint F WS0 And gas turbine side feedforward control quantity FF GT Summing yields the corrected water supply flow rate setpoint F. WS This improves the comprehensiveness and accuracy of the setpoint. By calculating the water flow deviation and adjusting it via the second PID controller PID2, it can quickly respond to the corrected water flow setpoint F. WS Changes in water flow rate are monitored to ensure real-time tracking of the target value and reduce fluctuations in the steam drum water level.

[0089] In another embodiment of this disclosure, step S105 above, adjusting the opening of the feedwater regulating valve according to the first feedwater regulating valve opening command to control the steam drum water level of the gas-steam combined cycle unit, includes:

[0090] Step 1: Based on the set value of the steam drum water level and the steam drum water level, use an adder / subtractor to perform subtraction to determine the deviation value of the steam drum water level;

[0091] Step 2: Based on the steam drum water level deviation value, use the third PID controller to determine the opening command of the second feedwater regulating valve;

[0092] Step 3: Adjust the opening of the feedwater regulating valve according to the opening command of the first feedwater regulating valve or the opening command of the second feedwater regulating valve to control the water level in the steam drum of the gas-steam combined cycle unit.

[0093] In this embodiment of the disclosure, such as Figure 2As shown, firstly, the deviation between the setpoint and the actual steam drum water level is calculated. The second feedwater regulating valve opening command is then obtained through the third PID controller. Combined with the previously obtained first feedwater regulating valve opening command, one command is selected to control the steam drum water level, ensuring it remains stable within a reasonable range. For step 1, the deviation between the steam drum water level and the setpoint is calculated and used as the input signal for the third PID controller. For step 2, the steam drum water level deviation is processed using a PID control algorithm, and the third PID controller (PID3) converts this deviation into the second feedwater regulating valve opening command U. CV1 This allows for the regulation of feedwater flow. In actual operation, one of the commands can be selected based on the operating conditions to change the feedwater flow by adjusting the opening of the feedwater regulating valve, thereby affecting the steam drum water level. The first feedwater regulating valve opening command U... CV3 Second water supply regulating valve opening command U CV1 The settings allow for flexible selection of appropriate commands to adjust the opening degree of the water supply regulating valve under different operating conditions. The first water supply regulating valve opening command is U. CV3 Suitable for adjusting the opening of the feedwater regulating valve to control the steam drum water level under high load, the second feedwater regulating valve opening command U CV1 It is suitable for adjusting the opening of the feedwater regulating valve to control the water level in the steam drum when the load is low and the steam output is small.

[0094] In another embodiment of this disclosure, step 3 above, adjusting the opening of the feedwater regulating valve according to the first feedwater regulating valve opening command or the second feedwater regulating valve opening command to control the steam drum water level of the gas-steam combined cycle unit, includes:

[0095] Step 1: Obtain the status of the three-impulse control switch;

[0096] Step 2: Input the opening commands of the first and second water supply regulating valves and the status of the three-impulse control switch into the analog selection module.

[0097] Step 3: With the three-impulse control switch in the open position, adjust the opening of the feedwater regulating valve according to the opening command of the first feedwater regulating valve to control the steam drum water level of the gas-steam combined cycle unit.

[0098] Step 4: With the three-impulse control switch in the off state, adjust the opening of the feedwater regulating valve according to the opening command of the second feedwater regulating valve to control the steam drum water level of the gas-steam combined cycle unit.

[0099] In this embodiment of the disclosure, such as Figure 2As shown, by acquiring the three-impulse control switch status SW, the analog selection module T selects either the first feedwater regulating valve opening command or the second feedwater regulating valve opening command to adjust the feedwater regulating valve opening, thereby achieving control of the steam drum water level of the gas-steam combined cycle unit and ensuring accurate adjustment of the steam drum water level under different control modes. For step one above, the three-impulse control switch status SW is acquired. For example, operators can control the opening and closing of the three-impulse control switch. SW=1 indicates that the three-impulse control switch is enabled; SW=0 indicates that the three-impulse control switch is disabled. For step two above, the first feedwater regulating valve opening command U... CV3 Second water supply regulating valve opening command U CV1 The three-impulse control switch status SW is input to the analog selection module T. The analog selection module T can select the opening command U of the first water supply regulating valve based on the input three-impulse control switch status SW. CV3 Second water supply regulating valve opening command U CV1 Choose one as the output. Regarding step three above, with the three-impulse control switch state SW=1, the analog quantity selection module T selects the first water supply regulating valve opening command U. CV3 As the final water supply regulating valve opening command U CV Adjust the opening of the feedwater regulating valve to control the water level in the steam drum of the gas-steam combined cycle unit. Regarding step four above, with the three-impulse control switch SW=0, the analog selection module T selects the second feedwater regulating valve opening command U. CV1 As the final water supply regulating valve opening command U CV Adjust the opening of the feedwater regulating valve to control the water level in the steam drum of the gas-steam combined cycle unit.

[0100] Based on the same disclosed concept, this disclosure also provides a steam drum water level control device for a gas-steam combined cycle unit. Since the principle of solving the problem by these devices is similar to the aforementioned steam drum water level control method for gas-steam combined cycle units, the implementation of this device can refer to the implementation of the aforementioned method, and the repeated parts will not be described again.

[0101] The gas-steam combined cycle unit steam drum water level control device provided in this disclosure embodiment, such as Figure 3 As shown, it includes:

[0102] The acquisition module 301 is used to acquire in real time the compressor inlet guide vane opening, turbine exhaust temperature, feedwater flow rate, steam flow rate, steam drum water level setpoint, and steam drum water level.

[0103] The gas turbine-side feedforward control quantity determination module 302 is used to determine the gas turbine-side feedforward control quantity based on the compressor inlet guide vane opening and the turbine exhaust temperature.

[0104] The original feedwater flow rate setting value determination module 303 is used to determine the original feedwater flow rate setting value based on the steam drum water level setting value and the steam drum water level, using a first PID controller.

[0105] The feedwater regulating valve opening command determination module 304 is used to determine the first feedwater regulating valve opening command based on the feedwater flow rate, the steam flow rate, the original feedwater flow rate set value and the gas turbine side feedforward control quantity, using a second PID controller.

[0106] The steam drum water level regulating module 305 is used to adjust the opening of the feedwater regulating valve according to the first feedwater regulating valve opening command, and control the steam drum water level of the gas-steam combined cycle unit.

[0107] In another embodiment of this disclosure, the gas turbine-side feedforward control quantity determination module 302 is used to determine the feedforward control quantity of the compressor inlet guide vane opening based on the compressor inlet guide vane opening degree and using a first-order inertial element.

[0108] Based on the turbine exhaust temperature, a second first-order inertial element is used to determine the feedforward control quantity for the turbine exhaust temperature.

[0109] The feedforward control quantity on the gas turbine side is determined based on the feedforward control quantity of the compressor inlet guide vane opening and the feedforward control quantity of the turbine exhaust temperature.

[0110] In another embodiment of this disclosure, the gas turbine-side feedforward control quantity determination module 302 is used to determine the first feedforward control quantity by performing addition operations using an adder and subtractor based on the feedforward control quantity of the compressor inlet guide vane opening and the feedforward control quantity of the turbine exhaust temperature.

[0111] Based on the first feedforward control quantity, the speed limiting module is used to determine the gas turbine-side feedforward control quantity.

[0112] In another embodiment of this disclosure, the gas turbine-side feedforward control quantity determination module 302 is used to acquire the three-impulse control switch status and the feedforward control switch status of the compressor inlet guide vane opening and the turbine exhaust temperature.

[0113] Based on the state of the three-impulse control switch and the state of the feedforward control switch for the compressor inlet guide vane opening and turbine exhaust temperature, an AND operation is performed to determine the state of the first control switch.

[0114] Based on the state of the first control switch, the feedforward coefficient is determined using an analog selection module.

[0115] Based on the first feedforward control quantity and the feedforward coefficient, a multiplier is used to determine the second feedforward control quantity;

[0116] Based on the second feedforward control quantity, the speed limiting module is used to determine the gas turbine-side feedforward control quantity.

[0117] In another embodiment of this disclosure, the original water supply flow rate setting value determination module 303 is used to determine the steam drum water level deviation value by performing a subtraction operation using an adder and subtractor based on the steam drum water level setting value and the steam drum water level.

[0118] Based on the steam drum water level deviation value, the first PID controller is used to determine the original feedwater flow rate setpoint.

[0119] In another embodiment of this disclosure, the water supply regulating valve opening command determination module 304 is used to determine the feedforward control quantity of steam flow rate based on the steam flow rate using a third first-order inertial element.

[0120] Based on the feedforward control quantity of the steam flow rate, the original feedwater flow rate setpoint, and the feedforward control quantity of the gas turbine side, an adder / subtractor is used to perform addition operations to determine the corrected feedwater flow rate setpoint.

[0121] Based on the corrected water supply flow rate setpoint and the water supply flow rate, an adder / subtractor is used to perform a subtraction operation to determine the water supply flow rate deviation value.

[0122] Based on the water supply flow deviation value, a second PID controller is used to determine the opening command of the first water supply regulating valve.

[0123] In another embodiment of this disclosure, the steam drum water level adjustment module 305 is used to determine the steam drum water level deviation value by performing a subtraction operation using an adder and subtractor based on the steam drum water level set value and the steam drum water level.

[0124] Based on the steam drum water level deviation value, a third PID controller is used to determine the opening command of the second feedwater regulating valve;

[0125] The opening degree of the feedwater regulating valve is adjusted according to the opening degree command of the first feedwater regulating valve or the opening degree command of the second feedwater regulating valve to control the water level in the steam drum of the gas-steam combined cycle unit.

[0126] In another embodiment of this disclosure, the steam drum water level regulating module 305 is used to acquire the state of the three-impulse control switch.

[0127] The opening commands of the first water supply regulating valve, the second water supply regulating valve, and the status of the three-impulse control switch are input to the analog quantity selection module.

[0128] When the three-impulse control switch is in the ON state, the opening of the feedwater regulating valve is adjusted according to the opening command of the first feedwater regulating valve to control the steam drum water level of the gas-steam combined cycle unit.

[0129] When the three-impulse control switch is closed, the opening of the feedwater regulating valve is adjusted according to the second feedwater regulating valve opening command to control the steam drum water level of the gas-steam combined cycle unit.

[0130] Based on the same disclosed concept, embodiments of this disclosure provide an electronic device that stores a computer program, which, when executed by a processor, performs the steps of the steam drum water level control method for a gas-steam combined cycle unit as described in any of the above embodiments.

[0131] Through the above description of the embodiments, those skilled in the art can clearly understand that the embodiments of this disclosure can be implemented in hardware or by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solutions of the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) and includes several instructions to cause a computer device (such as a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments of this disclosure.

[0132] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the modules or processes in the drawings are not necessarily essential for implementing this disclosure.

[0133] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0134] The sequence numbers of the embodiments disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0135] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A method of controlling the water level in a drum of a gas-steam combined cycle unit, the method comprising: The method comprises the following steps: real-time acquisition of the compressor inlet guide vane opening, turbine exhaust temperature, feed water flow, steam flow, set value of the drum water level and the drum water level; determination of the gas turbine side feedforward control amount according to the compressor inlet guide vane opening and the turbine exhaust temperature; determination of the original feed water flow set value by using a first PID controller according to the set value of the drum water level and the drum water level; determination of the first feed water regulating valve opening instruction by using a second PID controller according to the feed water flow, the steam flow, the original feed water flow set value and the gas turbine side feedforward control amount; adjustment of the feed water regulating valve opening according to the first feed water regulating valve opening instruction to control the drum water level of the gas-steam combined cycle unit.

2. The method of claim 1, wherein, The determination of the gas turbine side feedforward control amount according to the compressor inlet guide vane opening and the turbine exhaust temperature comprises the following steps: determination of the feedforward control amount of the compressor inlet guide vane opening by using a first first-order inertial link according to the compressor inlet guide vane opening; determination of the feedforward control amount of the turbine exhaust temperature by using a second first-order inertial link according to the turbine exhaust temperature; determination of the gas turbine side feedforward control amount according to the feedforward control amount of the compressor inlet guide vane opening and the feedforward control amount of the turbine exhaust temperature.

3. The method of claim 2, wherein, The determination of the gas turbine side feedforward control amount according to the feedforward control amount of the compressor inlet guide vane opening and the feedforward control amount of the turbine exhaust temperature comprises the following steps: determination of the first feedforward control amount by using an adder to perform addition operation according to the feedforward control amount of the compressor inlet guide vane opening and the feedforward control amount of the turbine exhaust temperature; determination of the gas turbine side feedforward control amount by using a speed limiting module according to the first feedforward control amount.

4. The method of claim 3, wherein, The determination of the gas turbine side feedforward control amount according to the first feedforward control amount by using a speed limiting module comprises the following steps: acquisition of the three-injection control switch state and the feedforward control switch state of the compressor inlet guide vane opening and the turbine exhaust temperature; determination of the first control switch state by using an AND operation according to the three-injection control switch state and the feedforward control switch state of the compressor inlet guide vane opening and the turbine exhaust temperature; determination of the feedforward coefficient by using an analog quantity selection module according to the first control switch state; determination of the second feedforward control amount by using a multiplier according to the first feedforward control amount and the feedforward coefficient; determination of the gas turbine side feedforward control amount by using a speed limiting module according to the second feedforward control amount.

5. The method of claim 1, wherein, The determination of the original feed water flow set value by using a first PID controller according to the set value of the drum water level and the drum water level comprises the following steps: determination of the drum water level deviation value by using an adder to perform subtraction operation according to the set value of the drum water level and the drum water level; determination of the original feed water flow set value by using a first PID controller according to the drum water level deviation value.

6. The method of claim 1, wherein, The determination of the first feed water regulating valve opening instruction by using a second PID controller according to the feed water flow, the steam flow, the original feed water flow set value and the gas turbine side feedforward control amount comprises the following steps: determination of the feedforward control amount of the steam flow by using a third first-order inertial link according to the steam flow; According to the feedforward control amount of the steam flow, the original feedwater flow set value and the gas turbine side feedforward control amount, an adder is used for addition operation to determine a corrected feedwater flow set value; According to the corrected feedwater flow set value and the feedwater flow, a subtracter is used for subtraction operation to determine a feedwater flow deviation value; According to the feedwater flow deviation value, a second PID controller is used to determine a first feedwater regulating valve opening degree instruction.

7. The method of claim 1, wherein, The adjusting the feedwater regulating valve opening degree according to the first feedwater regulating valve opening degree instruction or the second feedwater regulating valve opening degree instruction to control the steam drum water level of the gas-steam combined cycle unit comprises: According to the steam drum water level set value and the steam drum water level, a subtracter is used for subtraction operation to determine a steam drum water level deviation value; According to the steam drum water level deviation value, a third PID controller is used to determine a second feedwater regulating valve opening degree instruction; The adjusting the feedwater regulating valve opening degree according to the first feedwater regulating valve opening degree instruction or the second feedwater regulating valve opening degree instruction to control the steam drum water level of the gas-steam combined cycle unit comprises:

8. The method of claim 7, wherein, An acquisition module is configured to acquire a three-input control switch state; The first feedwater regulating valve opening degree instruction, the second feedwater regulating valve opening degree instruction and the three-input control switch state are input to an analog quantity selection module, In a case where the three-input control switch state is turned on, the adjusting the feedwater regulating valve opening degree according to the first feedwater regulating valve opening degree instruction to control the steam drum water level of the gas-steam combined cycle unit; In a case where the three-input control switch state is turned off, the adjusting the feedwater regulating valve opening degree according to the second feedwater regulating valve opening degree instruction to control the steam drum water level of the gas-steam combined cycle unit. The method comprises:

9. A gas-steam combined cycle unit drum level control apparatus, characterized by, An acquisition module is configured to acquire a compressor inlet guide vane opening degree, a turbine exhaust temperature, a feedwater flow, a steam flow, a steam drum water level set value and a steam drum water level; A gas turbine side feedforward control amount determination module is configured to determine a gas turbine side feedforward control amount according to the compressor inlet guide vane opening degree and the turbine exhaust temperature; An original feedwater flow set value determination module is configured to determine an original feedwater flow set value according to the steam drum water level set value and the steam drum water level by using a first PID controller; A feedwater regulating valve opening degree instruction determination module is configured to determine a first feedwater regulating valve opening degree instruction by using a second PID controller according to the feedwater flow, the steam flow, the original feedwater flow set value and the gas turbine side feedforward control amount; A steam drum water level adjusting module is configured to adjust the feedwater regulating valve opening degree according to the first feedwater regulating valve opening degree instruction to control the steam drum water level of the gas-steam combined cycle unit. The electronic device stores a computer program, which is run by a processor to execute the steps of the steam drum water level control method of the gas-steam combined cycle unit according to any one of claims 1 to 8.

10. An electronic device, comprising: ​

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