Low-sensitivity gas turbine fuel regulating valve control system and control method

Abstract

The invention discloses a low-sensitivity gas turbine fuel regulating valve control system and method, and relates to the technical field of gas turbines. The invention aims to solve the problems that the working condition switching process and the load change easily cause sudden change of rotating speed, overlarge acceleration and deceleration of a rotor and frequent switching of a gas turbine control reference, so that the rotating speed and load control of the gas turbine rotor is unstable, and the long-term stable operation of the gas turbine is influenced. The device comprises an instruction unit, a feedback unit, a comparator, a controller and an executing mechanism, the instruction unit is used for providing a target rotating speed signal and outputting different rotating speed instructions according to different working conditions, the controller is provided with an adjusting dead zone, and when the deviation between a rotating speed set value and a rotating speed actual value is within the adjusting dead zone, the executing mechanism is started. The controller does not send out a control instruction any more, the controller can be prevented from being frequently adjusted within the dead zone range by setting the adjusting dead zone, the more stable rotating speed control effect is achieved, frequent actions of the fuel adjusting valve can be reduced, mechanical abrasion is reduced, and the service life of the valve is prolonged.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, and more specifically to a low-sensitivity gas turbine fuel regulating valve control system and control method. Background Technology

[0002] Closed-loop control of gas turbine speed is the core control system that ensures the safe, stable and efficient operation of gas turbines. It can adjust the rotor speed in real time according to changes in load.

[0003] For low-sensitivity gas turbine fuel regulating valves, the switching of operating conditions and changes in load can easily cause sudden changes in speed, excessive rotor acceleration and deceleration, and frequent switching of gas turbine control references, resulting in unstable control of gas turbine rotor speed and load, which affects the long-term stable operation of the gas turbine. Summary of the Invention

[0004] The purpose of this invention is to address the problem that sudden changes in rotational speed, excessive rotor acceleration and deceleration, and frequent switching of gas turbine control references during operating condition transitions and load changes can easily lead to unstable rotor speed and load control, affecting the long-term stable operation of the gas turbine. Therefore, this invention provides a low-sensitivity gas turbine fuel regulating valve control system and method.

[0005] The technical solution of the present invention is: a low-sensitivity gas turbine fuel regulating valve control system, comprising: a command unit for providing a target speed signal and outputting different speed commands according to different operating conditions;

[0006] The feedback unit is used to collect the actual rotational speed of the gas turbine rotor in real time;

[0007] A comparator is used to compare the target speed with the actual speed and calculate the speed deviation;

[0008] The controller is used to calculate the fuel quantity adjustment value based on the magnitude, direction, and trend of the speed deviation.

[0009] The actuator is used to receive instructions from the controller, physically adjust the valve opening, and ultimately change the speed of the gas turbine.

[0010] The controller is equipped with an adjustment dead zone. When the deviation between the set speed value and the actual speed value is within the adjustment dead zone, the controller will no longer issue a control command to adjust the speed. When the deviation between the set speed value and the actual speed value is outside the adjustment dead zone, the controller will normally issue a control command to adjust the speed.

[0011] Furthermore, the setting range of the adjustment dead zone is ±2 rpm / min.

[0012] Furthermore, the controller is set with a deviation limit value, and the deviation between the set speed value and the actual speed value is not higher than the deviation limit value.

[0013] Furthermore, the deviation limit is set to 700 rpm / min.

[0014] Furthermore, the integral time for speed control of the controller is greater than 3 seconds.

[0015] Furthermore, the rotational speed control integral time of the controller is set to 12 seconds.

[0016] Furthermore, the controller adopts a variable parameter proportional coefficient adjustment method.

[0017] A method for controlling a low-sensitivity gas turbine fuel regulating valve includes the following steps:

[0018] Step 1: The instruction unit and feedback unit transmit their respective signals to the comparator;

[0019] Step 2: The comparator transmits the speed deviation signal to the controller;

[0020] Step 3: The controller determines whether the speed deviation value is within the adjustment dead zone. If it is within the adjustment dead zone, proceed to Step 4; otherwise, proceed to Step 5.

[0021] Step 4: The controller sends a control command to the actuator to adjust the rotational speed;

[0022] Step 5: The controller does not send control commands to the actuator to adjust the speed.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The low-sensitivity gas turbine fuel regulating valve control system provided by the present invention can prevent the controller from frequently adjusting within the dead zone by setting an adjustment dead zone, thereby achieving a more stable speed control effect, reducing the frequent operation of the fuel regulating valve, reducing mechanical wear, and extending the service life of the valve.

[0025] 2. The low-sensitivity gas turbine fuel regulating valve control system provided by the present invention reduces the controller response time, making the gas turbine more stable under closed-loop speed control and ensuring stable operation of the gas turbine at the set speed value.

[0026] 3. The low-sensitivity gas turbine fuel regulating valve control system provided by the present invention uses a variable proportional coefficient to enable the controller to adapt to the speed control of the gas turbine under different operating conditions. Whether the gas turbine is accelerating or decelerating, the actual speed value can always follow the change of the speed set value, so that the controller is always in the speed closed-loop control mode, preventing the acceleration control mode from intervening in the gas turbine speed control and preventing large speed fluctuations. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the workflow of the present invention;

[0028] Figure 2 This is a schematic diagram illustrating the working principle of the present invention. Detailed Implementation

[0029] Specific implementation method one: Combining Figure 1 , Figure 2 This embodiment describes an implementation that includes an instruction unit, a feedback unit, a comparator, a controller, and an actuator. The instruction unit (setpoint module) provides a target speed signal and outputs different speed commands based on different operating conditions. Specifically, during the startup phase, it outputs a preset speed curve, such as increasing from the turning gear speed to the ignition speed and then to the rated speed. After grid connection, it dynamically adjusts the target speed according to grid frequency requirements or load commands. The feedback unit is used to collect the actual speed of the gas turbine rotor in real time. This can be achieved by mounting a gear disk on the rotor shaft end, with sensors detecting the gear tooth tips. The change in tooth valley is used to calculate the rotational speed, thereby acquiring the actual rotational speed. The sensor can be a magnetoelectric sensor or a photoelectric sensor. The comparator is used to compare the target rotational speed with the actual rotational speed and calculate the rotational speed deviation. This is implemented by the control system hardware (such as the analog comparison module of PLC or DCS) or software (the deviation calculation link in the control algorithm). The controller is used to calculate the control command for adjusting the fuel quantity based on the magnitude, direction, and trend of the rotational speed deviation. Specifically, it can be a PID controller. The actuator is used to receive the controller's command, physically adjust the valve opening, and ultimately change the rotational speed of the gas turbine. The controller is equipped with an adjustment dead zone. When the deviation between the rotational speed setpoint and the actual rotational speed is within the adjustment dead zone, the controller will no longer issue a control command to adjust the rotational speed, keeping the fuel stroke reference unchanged and maintaining the current fuel valve opening. When the deviation between the rotational speed setpoint and the actual rotational speed is outside the adjustment dead zone, the controller will normally issue a control command to adjust the rotational speed and enter the subsequent proportional-integral regulation.

[0030] The low-sensitivity gas turbine fuel regulating valve control system of this embodiment can prevent the controller from frequently adjusting within the dead zone by setting an adjustment dead zone, thereby achieving a more stable speed control effect, reducing the frequent operation of the fuel regulating valve, reducing mechanical wear, and extending the valve's service life.

[0031] It should be noted that the appendix Figure 2 In the diagram, the first area represents the dead zone of the speed control setting in the control system; the second area represents the upper limit of the deviation between the speed setpoint and the actual speed value in the speed control setting; the third area represents the extension of the integral time of the speed control in the control system; and the fourth area represents the part of the speed control in the control system that uses a variable parameter proportional coefficient adjustment method. Here, SET represents the speed setpoint, ASR represents the controller, LS represents the limit switch, and LAG represents the delay response time.

[0032] Specific Implementation Method Two: Combining Figure 1 , Figure 2 This embodiment differs from Specific Embodiment 1 in that the adjustment dead zone is set within ±2 rpm / min. This smaller dead zone range filters out meaningless minor fluctuations while ensuring the controlled speed remains within a very small range around the set value. This avoids overly sensitive speed response, resulting in a better balance between stability and response speed. It also reduces frequent operation of the fuel regulating valve, lowers mechanical wear, and extends valve lifespan. Other components and connections are the same as in Specific Embodiment 1.

[0033] Specific implementation method three: Combining Figure 1 , Figure 2 This embodiment differs from Specific Embodiment 1 in that the controller has a deviation limit value. The deviation between the setpoint speed and the actual speed value is not higher than this deviation limit value. Specifically, the smaller of the deviation between the setpoint speed and the actual speed value and the deviation limit value is taken. For example, during startup and idle conditions, the setpoint speed is always set to 5500 rpm / min. The deviation limit value allows the speed to switch from startup to idle conditions earlier, around 5300 rpm / min, preventing overshoot when the speed reaches 5500 rpm / min. Other components and connections are the same as in Specific Embodiment 1.

[0034] Specific implementation method four: Combination Figure 1 , Figure 2This embodiment differs from Specific Embodiment Three in that the deviation limit value is set to 700 rpm / min. 700 rpm / min is a suitable value that effectively avoids speed overshoot. After optimization, there is no overshoot in the actual speed value after transitioning from the start-up condition to the idle warm-up condition. Other components and connections are the same as in Specific Embodiment Three.

[0035] Specific Implementation Method Five: Combining Figure 1 , Figure 2 This embodiment differs from Specific Embodiment 1 in that the speed control integral time of the controller is higher than 3 seconds. By reducing the response time of the control system, the gas turbine becomes more stable under closed-loop speed control, ensuring stable operation of the gas turbine at the set speed value. Other components and connections are the same as in Specific Embodiment 1.

[0036] Specific Implementation Method Six: Combination Figure 1 , Figure 2 This embodiment differs from Specific Embodiment Five in that the speed control integral time of the controller is set to 12 seconds. This time allows for synchronized operation with the actuator, avoiding situations where the speed control integral time is too short, requiring waiting for the actuator to operate after issuing a command. This reduces the response speed of the control system, resulting in smoother fuel regulation and preventing speed oscillations caused by excessively fast integral time. Other components and connections are the same as in Specific Embodiment Five.

[0037] Specific implementation method seven: Combination Figure 1 , Figure 2 This embodiment differs from Specific Embodiment 1 in that the controller uses a variable parameter proportional coefficient adjustment method. During the process of the gas turbine going from startup to full load, it needs to switch between multiple operating conditions, including startup, idle warm-up, acceleration, and load conditions. After switching operating conditions, the gas turbine's fuel demand changes significantly. Using a variable proportional coefficient allows the control system to adapt to the gas turbine's speed control under different operating conditions. Whether accelerating or decelerating, the actual speed value of the gas turbine can constantly follow the changes in the speed setpoint, ensuring the control system is always in a closed-loop speed control mode, preventing acceleration control from intervening in the gas turbine speed control and preventing large speed fluctuations.

[0038] Table 1-1 shows the proportional values ​​corresponding to different working conditions;

[0039]

[0040] Other components and connections are the same as any one of the specific embodiments one to six.

[0041] Specific implementation method eight, combined with Figure 1 , Figure 2 This embodiment also provides a low-sensitivity gas turbine fuel regulating valve control method, including the following steps:

[0042] Step 1: The instruction unit and feedback unit transmit their respective signals to the comparator;

[0043] Step 2: The comparator transmits the speed deviation signal to the controller;

[0044] Step 3: The controller determines whether the speed deviation value is within the adjustment dead zone. If it is within the adjustment dead zone, proceed to Step 4; otherwise, proceed to Step 5.

[0045] Step 4: The controller sends a control command to the actuator to adjust the rotational speed;

[0046] Step 5: The controller does not send control commands to the actuator to adjust the speed.

[0047] The content of this invention is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the invention.

Claims

1. A low-sensitivity gas turbine fuel regulating valve control system, characterized in that, include: The instruction unit is used to provide the target speed signal and output different speed commands according to different operating conditions; The feedback unit is used to collect the actual rotational speed of the gas turbine rotor in real time; A comparator is used to compare the target speed with the actual speed and calculate the speed deviation; The controller is used to calculate the fuel quantity adjustment value based on the magnitude, direction, and trend of the speed deviation. The actuator is used to receive instructions from the controller, physically adjust the valve opening, and ultimately change the speed of the gas turbine. The controller is equipped with an adjustment dead zone. When the deviation between the set speed value and the actual speed value is within the adjustment dead zone, the controller will no longer issue a control command to adjust the speed. When the deviation between the set speed value and the actual speed value is outside the adjustment dead zone, the controller will normally issue a control command to adjust the speed.

2. The low-sensitivity gas turbine fuel regulating valve control system according to claim 1, characterized in that, The adjustment dead zone is set within a range of ±2 rpm / min.

3. The low-sensitivity gas turbine fuel regulating valve control system according to claim 1, characterized in that, The controller is set with a deviation limit value, and the deviation between the set speed value and the actual speed value shall not exceed the deviation limit value.

4. The low-sensitivity gas turbine fuel regulating valve control system according to claim 3, characterized in that, The deviation limit is set at 700 rpm / min.

5. A low-sensitivity gas turbine fuel regulating valve control system according to claim 1, characterized in that, The speed control integral time of the controller is greater than 3 seconds.

6. A low-sensitivity gas turbine fuel regulating valve control system according to claim 5, characterized in that, The speed control integral time of the controller is set to 12s.

7. A low-sensitivity gas turbine fuel regulating valve control system according to any one of claims 1-6, characterized in that, The controller uses a variable parameter proportional coefficient adjustment method.

8. A method for controlling a low-sensitivity gas turbine fuel regulating valve, characterized in that, Includes the following steps: Step 1: The instruction unit and feedback unit transmit their respective signals to the comparator; Step 2: The comparator transmits the speed deviation signal to the controller; Step 3: The controller determines whether the speed deviation value is within the adjustment dead zone. If it is within the adjustment dead zone, proceed to Step 4; otherwise, proceed to Step 5. Step 4: The controller sends a control command to the actuator to adjust the rotational speed; Step 5: The controller does not send control commands to the actuator to adjust the speed.

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