A control method for opening degree analog quantity setting mode of a hydroelectric generator set monitoring system

Abstract

A control method for the analog input / output setting mode of a hydro-generator monitoring system includes a newly added program for identifying input / output pulses. The control logic is as follows: ① If an input pulse command of 1 is detected, the analog input / output setting value = analog input / output setting value + fixed step size; otherwise, the analog input / output setting value remains unchanged. ② If an input pulse command of 1 is detected, the analog input / output setting value = analog input / output setting value - fixed step size; otherwise, the analog input / output setting value remains unchanged. A new analog input / output setting value initialization program is also included, employing the following control logic: When other control modes are switched to analog input / output setting mode, the current input / output setting feedback value sent by the governor is assigned to the analog input / output setting value as the initial value. This invention can improve the guide vane opening and active power regulation speed, enhance equipment stability and reliability, reduce intermediate links and fault points, lower equipment failure rate, and ensure the safe, stable, and high-quality operation of the generator unit and the power grid.

Description

Technical Field

[0001] This invention relates to the field of hydro-generator monitoring technology, specifically to a method for controlling the opening degree of a hydro-generator monitoring system using an analog quantity given mode. Background Technology

[0002] In hydropower generation, the turbine regulation system needs to precisely perform crucial tasks such as speed regulation, turbine opening regulation, and power regulation. It controls the turbine guide vane opening by controlling the rotation of the relay ring, thereby regulating the water flow through the turbine casing and ultimately ensuring that the key power quality indicators of the controlled entity—frequency and active power output—meet the grid requirements. The performance of the unit's regulation is closely related to the safe, stable, and high-quality operation of the power grid. Especially for large-capacity single-unit units, poor regulation quality of the turbine regulation system will severely impact the power quality of the grid. How the monitoring system can coordinate with the turbine regulation system to improve regulation quality and ensure the safe, stable, and high-quality operation of giant units is a topic worthy of attention and research.

[0003] Traditional monitoring systems for hydro-generator units operating at their designated opening speeds often employ a power closed-loop conventional pulse regulation method to output opening increase / decrease pulses to the turbine regulating system, thereby controlling the turbine generator unit's opening speed. This control method suffers from slow regulation speeds of guide vane opening and active power.

[0004] In the prior art, the interpolation algorithm and correction ratio algorithm proposed in the Chinese patent "An Active Pulse Regulation System for LCU of Hydropower Station Unit" (application number: 201610327273.6) can improve the timeliness and reliability of the power regulation of the active pulse regulation system of hydropower station unit in the opening regulation mode.

[0005] Reference [1] "Retrofit and Experimental Analysis of Primary Frequency Regulation and AGC Coordination Control of Hydropower Units", Hydropower and Pumped Storage, Lu Zhouxin, Tu Yong, Ye Qing, 2020.02, p.123, introduces the control strategies of governor opening control mode and power closed-loop control mode.

[0006] However, most of the above studies adopt the closed-loop proportional pulse width modulation method, which still has problems such as slow adjustment speed of guide vane opening and active power. Moreover, the method uses intermediate relays to extend the transmission of opening increase and decrease pulse control commands, which increases intermediate links and fault points. Faults such as excitation coil failure or output node adhesion of intermediate relays may lead to loss of control of the turbine generator opening. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a control method for the analog quantity given mode of the turbine generator set monitoring system. This method optimizes the traditional pulse quantity mode control system for the turbine generator set monitoring system by adopting the analog quantity given mode control method. This improves the guide vane opening and active power regulation speed, enhances equipment stability and reliability, reduces intermediate links and fault points, lowers equipment failure rate, and ensures the safe, stable, and high-quality operation of the unit and the power grid.

[0008] The technical solution adopted in this invention is as follows:

[0009] A control method for the opening degree analog quantity given mode of a hydro-generator monitoring system.

[0010] The monitoring system controller adds an opening increase / decrease pulse recognition program, using the following control logic:

[0011] ①: If the monitoring system controller detects that the opening increment pulse command output by the controller in the intermediate control process is 1, the opening analog quantity setpoint = opening analog quantity setpoint + fixed step size; otherwise, the opening analog quantity setpoint remains unchanged.

[0012] ②: If the monitoring system controller detects that the opening increment pulse command output by the controller in the intermediate control process is 1, the opening analog quantity setpoint = opening analog quantity setpoint - fixed step size; otherwise, the opening analog quantity setpoint remains unchanged.

[0013] The opening increment pulse command output by the controller during the intermediate control process is existing technology, that is, the monitoring system of the traditional hydro-generator unit opening mode uses the power closed-loop conventional pulse regulation method to output the opening increment / decrease pulse.

[0014] The monitoring system controller adds an initialization program for the analog setpoint of the opening degree, using the following control logic:

[0015] When other control modes are switched to the opening degree analog quantity given control mode, the opening degree given feedback value sent by the current speed governor is assigned to the opening degree analog quantity given value as the initial value.

[0016] Other control modes include opening pulse quantity given control mode, power analog quantity given control mode, and power pulse quantity given control mode.

[0017] A control method for the analog input-output mode of a hydro-generator monitoring system includes the following steps:

[0018] Step 1: The controller checks whether the monitoring system is in analog input mode for opening degree. If yes, proceed to Step 2; otherwise, use the non-opening degree mode control method.

[0019] Step 2: The controller checks whether the monitoring system has switched to the opening analog input mode for the first time. If yes, the opening analog input value = the opening input feedback value sent by the speed controller, and proceeds to Step 3; if no, proceeds to Step 3.

[0020] Step 3: The controller checks whether the opening increment pulse command is 1. If yes, the opening analog quantity setpoint = opening analog quantity setpoint + fixed step size, and proceeds to step 4; if no, the opening analog quantity setpoint remains unchanged, and proceeds to step 4.

[0021] Step 4: The controller checks whether the opening reduction pulse command is 1. If yes, the opening analog quantity setpoint = opening analog quantity setpoint - fixed step size, and proceeds to step 5; if no, the opening analog quantity setpoint remains unchanged, and proceeds to step 5.

[0022] Step 5: The controller sends the analog opening value to the speed control system in real time through the AO module, and returns to Step 1.

[0023] This invention provides a control method for the analog input mode of the opening degree of a hydro-generator monitoring system, with the following technical advantages:

[0024] Improving guide vane opening and active power regulation speed enhances equipment stability and reliability, reduces intermediate links and failure points, lowers equipment failure rate, and ensures safe, stable, and high-quality operation of the unit and the power grid. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a traditional opening pulse mode control system for a water turbine monitoring system.

[0026] Figure 2 This is a schematic diagram of the turbine monitoring system opening analog quantity given mode control system of the present invention.

[0027] Figure 3 This is a flowchart of the control method of the present invention.

[0028] Figure 4 It is a waveform diagram of the load adjustment test of the analog quantity given mode of the monitoring system opening degree. Detailed Implementation

[0029] The diagram of the traditional opening pulse mode control system for the turbine monitoring system is shown below. Figure 1As shown. In the open-loop mode, the power closed loop is implemented on the monitoring system side. The speed controller controls the opening and closing of the guide vanes based on the pulse increment / decrement command signals issued by the monitoring system. After calculating the difference between the active power setpoint and the active power feedback value from the monitoring system, the difference is converted into an open-loop pulse increment / decrement command with varying widths through a proportional circuit. This command is then output through the controller's DO module to drive the power supply of the intermediate relay's excitation coil circuit, controlling the on / off state of the intermediate relay's output node, thereby controlling the on / off state of the speed controller's DI module's input circuit. This sends the open-loop pulse increment / decrement command to the speed controller, directly affecting the speed controller's open-loop setpoint signal. The pulse width depends on the magnitude of the power deviation; a larger power deviation results in a larger pulse width, and a smaller power deviation results in a smaller pulse width. A positive power deviation triggers an increment pulse, while a negative power deviation triggers a decrement pulse. Between the monitoring system's unit LCU and the speed controller's open-loop setpoint signal, there is essentially an integrator. As the active power approaches the setpoint value, its output decreases, ultimately eliminating the deviation and achieving a stable state for the open-loop setpoint and feedback.

[0030] This invention discloses a control method for the analog quantity given control mode of a hydro-generator monitoring system. It optimizes the traditional pulse quantity control mode of a hydro-generator monitoring system, retaining the pulse increase / decrease output structure and control method of the monitoring system. Instead of a hardware integral structure (where the pulse increase / decrease command (BOOL type variable) output by the monitoring system is sent to the governor via an intermediate relay), it optimizes this method into a software integral structure within the monitoring system controller. It also collects the opening setpoint feedback signal sent from the governor to the monitoring system and uses an analog quantity given control mode to convert the pulse increase / decrease command signal into an analog quantity signal, which is then output to the governor via the controller's AO module. The control system diagram for the analog quantity given control mode of the monitoring system is shown below. Figure 2 As shown.

[0031] A control method for the analog input-output mode of a hydro-generator monitoring system, employing the following control logic:

[0032] The monitoring system controller adds an opening increase / decrease pulse recognition program, using the following control logic:

[0033] ①: If the monitoring system controller detects that the opening increment pulse command output by the controller in the intermediate control process is 1, the opening analog quantity setpoint = opening analog quantity setpoint + fixed step size; otherwise, the opening analog quantity setpoint remains unchanged.

[0034] ②: If the monitoring system controller detects that the opening increment pulse command output by the controller in the intermediate control process is 1, the opening analog quantity setpoint = opening analog quantity setpoint - fixed step size; otherwise, the opening analog quantity setpoint remains unchanged.

[0035] The opening increment pulse command output by the controller during the intermediate control process is existing technology, that is, the monitoring system of the traditional hydro-generator unit opening mode uses the power closed-loop conventional pulse regulation method to output the opening increment / decrease pulse.

[0036] By adding the aforementioned control logic, the traditional output opening pulse command can be converted into an output opening analog setpoint command for the turbine regulating system, thereby achieving control of the turbine generator unit's opening. This avoids the need for intermediate relays to extend and transmit opening pulse control commands, reducing intermediate steps and potential failure points. It also prevents loss of control over the turbine generator unit's opening due to faults such as excitation coil failure or output node sticking in intermediate relays. Furthermore, reducing intermediate physical process steps improves control response speed and real-time performance. The fixed step size for adding or subtracting in the control logic can be flexibly adjusted and fixed according to on-site commissioning performance requirements to achieve optimal control and regulation performance.

[0037] The monitoring system controller adds an initialization program for the analog setpoint of the opening degree, using the following control logic:

[0038] When other control modes are switched to the opening degree analog quantity given control mode, the opening degree given feedback value sent by the current speed governor is assigned to the opening degree analog quantity given value as the initial value.

[0039] Other control modes include opening pulse quantity given control mode, power analog quantity given control mode, and power pulse quantity given control mode.

[0040] After adding the above control logic, the given value of the opening analog quantity can remain stable and unchanged instantaneously before and after the control mode switch, so as to ensure that the opening of the hydro-generator unit is not disturbed, that is, to realize the smooth switching function and improve the stability and reliability of the unit operation.

[0041] A control method for the analog input-output mode of a hydro-generator monitoring system includes the following steps:

[0042] Step 1: The controller checks whether the monitoring system is in analog input mode for opening degree. If yes, proceed to Step 2; otherwise, use the non-opening degree mode control method.

[0043] Step 2: The controller checks whether the monitoring system has switched to the opening analog input mode for the first time. If yes, the opening analog input value = the opening input feedback value sent by the speed controller, and proceeds to Step 3; if no, proceeds to Step 3.

[0044] Step 3: The controller checks whether the opening increment pulse command is 1. If yes, the opening analog quantity setpoint = opening analog quantity setpoint + fixed step size, and proceeds to step 4; if no, the opening analog quantity setpoint remains unchanged, and proceeds to step 4.

[0045] Step 4: The controller checks whether the opening reduction pulse command is 1. If yes, the opening analog quantity setpoint = opening analog quantity setpoint - fixed step size, and proceeds to step 5; if no, the opening analog quantity setpoint remains unchanged, and proceeds to step 5.

[0046] Step 5: The controller sends the analog opening value to the speed control system in real time through the AO module, and returns to Step 1.

[0047] The following describes a control structure and method for an analog input-output control system for monitoring system operation, applied to the automatic control of a hydroelectric generator unit in a hydropower plant. The analog input-output control system for this embodiment is as follows: Figure 2 As shown, the flowchart of the control method for analog quantity given mode of the monitoring system opening degree is as follows: Figure 3 As shown.

[0048] After application at the site, in order to verify the control effect of the monitoring system in the analog input mode, a load adjustment test of the monitoring system in the analog input mode was conducted. The test process is as follows:

[0049] In the open-loop mode, with the power closed loop engaged, the power plant's AGC initially sets an active power command of 550MW. After 29 seconds, the AGC sets a new active power command of 650MW. Ultimately, the unit's active power stabilizes at 650MW. The test waveform is shown below. Figure 4 .according to Figure 4 Based on the waveform analysis, the test results in this embodiment are normal, the control effect of the analog quantity given mode of the monitoring system is good, and the unit load regulation process is normal.

Claims

1. A control method for the opening degree analog quantity given mode of a hydro-generator monitoring system, characterized in that: Add a pulse recognition program for opening degree increment / decrement, using the following control logic: ①: If the opening increment pulse command is detected as 1, the opening analog quantity setpoint = opening analog quantity setpoint + fixed step size; otherwise, the opening analog quantity setpoint remains unchanged. ②: If the opening decrease pulse command is detected as 1, the opening analog quantity setpoint = opening analog quantity setpoint - fixed step size; otherwise, the opening analog quantity setpoint remains unchanged. Add an initialization program for the analog value setpoint of the opening degree, using the following control logic: When other control modes are switched to the opening degree analog quantity given control mode, the opening degree given feedback value sent by the current speed governor is assigned to the opening degree analog quantity given value as the initial value.

2. The control method for analog quantity given mode of opening degree of a hydro-generator monitoring system according to claim 1, characterized in that: Other control modes include: opening pulse quantity given control mode, power analog quantity given control mode, and power pulse quantity given control mode.

3. A control method for the opening degree analog quantity given mode of a hydro-generator monitoring system, characterized in that... Includes the following steps: Step 1: The controller checks whether the monitoring system is in analog input mode for opening degree. If yes, proceed to Step 2; otherwise, use the non-opening degree mode control method. Step 2: The controller checks whether the monitoring system has switched to the opening analog input mode for the first time. If yes, the opening analog input value = the opening input feedback value sent by the speed controller, and proceeds to Step 3; if no, proceeds to Step 3. Step 3: The controller checks whether the opening increment pulse command is 1. If yes, the opening analog quantity setpoint = opening analog quantity setpoint + fixed step size, and proceeds to step 4; if no, the opening analog quantity setpoint remains unchanged, and proceeds to step 4. Step 4: The controller checks whether the opening reduction pulse command is 1. If yes, the opening analog quantity setpoint = opening analog quantity setpoint - fixed step size, and proceeds to step 5; if no, the opening analog quantity setpoint remains unchanged, and proceeds to step 5. Step 5: The controller sends the analog opening value to the speed control system in real time through the AO module, and returns to Step 1.

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