Speed control mode switching method for large hydroelectric generating set

Abstract

The application provides a large hydroelectric generating set speed regulation control mode switching method, which is realized based on a speed regulator controller and comprises the following steps: step 1, state initialization; step 2, judging whether the control handle of the speed regulator control cabinet is in a first preset position, and if yes, entering step 3, otherwise, entering step 17; step 3, judging whether the general circuit breaker at the outlet of the large hydroelectric generating set is in a first preset state, and if yes, entering steps 5, 7, 9, 15 and 18 respectively, otherwise, entering step 4; step 4, determining that the control mode of the speed regulator is a frequency mode; step 5, judging whether a frequency mode switching command of the speed regulation local touch screen is received, and if yes, entering step 6; and step 6, determining that the control mode of the speed regulator is a frequency mode load state, and the large hydroelectric generating set adjusts the load through the frequency mode.

Description

Technical Field

[0001] This invention relates to the technical field of speed control mode switching methods for large hydropower units, and specifically to a method for switching speed control modes for large hydropower units. Background Technology

[0002] Currently, the automatic control system of large hydro-generator units is generally implemented by using digital devices such as programmable logic controllers to form local control units.

[0003] In terms of overall functional design, the governor should have functions such as frequency control, power control, opening degree control, guide vane opening degree limitation, maximum power limitation, frequency tracking control, online self-diagnosis and processing, and clock synchronization. When a fault occurs inside the governor or on the grid side, the switching of various control modes may cause instability and power output fluctuations in the turbine, or even low-frequency oscillations, which could seriously affect the safe and stable operation of the power system.

[0004] Existing research on turbine governor control systems mainly focuses on aspects such as speed regulation electro-hydraulic conversion, PID output, frequency, and power, while research on aspects such as the governor control mode switching process is very limited.

[0005] Therefore, there is a need for a method for switching speed control modes of large hydropower units that can ensure the safe and stable operation of power equipment and the long-term efficient operation of the units. Summary of the Invention

[0006] The purpose of this invention is to provide a method for switching speed control modes of large-scale hydropower units, in order to solve the technical problems existing in the background art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for switching speed control modes of a large hydropower unit, the method being implemented based on a speed governor controller, the method comprising:

[0009] Step 1: State initialization;

[0010] Step 2: Determine whether the control handle of the speed controller cabinet is in the first preset position. If so, proceed to step 3; otherwise, proceed to step 17.

[0011] Step 3: Determine whether the general circuit breaker at the outlet of the large hydropower unit is in the first preset state. If so, proceed to steps 5, 7, 9, 15 and 18 respectively; otherwise, proceed to step 4.

[0012] Step 4: Determine that the speed controller's control mode is frequency mode;

[0013] Step 5: Determine if a command to switch frequency mode has been received from the local touchscreen for speed adjustment. If so, proceed to step 6.

[0014] Step 6: Determine that the control mode of the speed governor is frequency mode load state, and the large hydropower unit adjusts the load through frequency mode;

[0015] Step 7: Control the speed controller's control mode to participate in the speed controller frequency difference detection; the detection includes: determining whether the frequency difference meets the first preset condition, and if it does, proceed to step 8; otherwise, continue the detection.

[0016] Step 8: Collect multiple unit frequency signals and perform unit frequency signal redundancy measurement; after judging the quality of the frequency channel based on the first preset method, participate in the logic judgment to ensure that the unit frequency signal is normal, and return to step 6.

[0017] Step 9: Determine whether a command to activate the active power closed-loop mode has been received. If so, proceed to step 10; otherwise, proceed to step 16.

[0018] Step 10: Determine if the monitoring analog power input channel is normal. If so, proceed to step 11; otherwise, proceed to step 14.

[0019] Step 11: In response to the detection of a monitoring power switching analog signal mode command, proceed to step 12;

[0020] Step 12: Collect multiple active power signals and perform redundant measurements. Based on the first preset method, determine whether the power sampling of the speed controller is normal. If the sampling is normal, proceed to step 13.

[0021] Step 13: Determine the control mode as power mode, change the power setpoint based on the second preset mode, and issue corresponding adjustment actions to achieve the purpose of adjusting the unit power;

[0022] Step 14: In response to the detection of the monitoring power pulse adjustment mode command, return to step 12;

[0023] Step 15: In response to the detection of a power mode switching command on the local touchscreen, return to step 12;

[0024] Step 16: In response to the detection of the monitoring cut angle mode command, proceed to step 17;

[0025] Step 17: Determine the control mode as the opening mode; change the guide vane opening through the third preset mode and issue a command to actuate the guide vanes to achieve the purpose of adjusting the unit power;

[0026] Step 18: In response to the detection of a local touchscreen cut-out mode command, return to step 17;

[0027] Step 19: In response to the speed regulation power sampling fault in step 13, determine that the control mode is switched to the opening mode, and return to step 17;

[0028] Step 20: In response to the control mode being power mode and the detection that the difference between the monitoring power sampling and the speed regulation power sampling meets the second preset condition, the monitoring power of the computer monitoring system is collected, and it is determined whether the monitoring power and the speed regulation power meet the third preset condition. In response to the monitoring power and the speed regulation power meeting the third preset condition, the process returns to step 17; in response to the monitoring power and the speed regulation power not meeting the third preset condition, the process continues.

[0029] In some embodiments, the first preset position is the automatic guide vane position, and the first preset state is the closed state, that is, the large hydropower unit is in the grid-connected state.

[0030] In some embodiments, in step 4, the large hydropower unit is in a non-grid-connected state, which includes at least one of the following: shutdown standby, startup process, idling state, no-load state, and shutdown process.

[0031] In some embodiments, the first preset condition includes the frequency difference being greater than a first threshold.

[0032] In some embodiments, the first threshold is 0.5Hz-0.6Hz.

[0033] In some embodiments, the second preset method includes monitoring and issuing analog power input or adjusting via power pulses.

[0034] In some embodiments, the third preset method includes changing the opening setpoint by monitoring remote increase / decrease signals, or issuing the opening setpoint via a local touchscreen.

[0035] In some embodiments, in step 17, the rate at which the guide vane opening is increased or decreased is related to the pulse width and frequency of the increase / decrease signal.

[0036] In some embodiments, the second preset condition includes the difference between the monitoring power sample and the speed regulation power sample exceeding a second threshold.

[0037] In some embodiments, the second threshold is 5% of the unit's rated power.

[0038] Beneficial effects

[0039] The significant advantages of this invention compared to existing technologies are:

[0040] The present invention fully utilizes existing procedural condition judgments and scientifically sound processes to execute the speed control mode switching process of large hydropower units. Under complex and uncertain power grid operation conditions, based on existing acquired signals, it innovatively proposes a switching mechanism for three speed governor control modes (frequency mode, power mode, and opening mode). During normal operation or fault switching, the control mode switching logic strategy is complete and fully functional, effectively preventing abnormal output or fluctuations during the switching process. At the same time, after switching, the load is adjusted in a timely manner according to monitoring or local instructions to ensure the safe and stable operation of the power grid. Moreover, it significantly improves the reliability and safety of speed control mode switching, effectively preventing load fluctuations and damage to major equipment and facilities. Attached Figure Description

[0041] Figure 1 This is a flowchart illustrating the method for switching speed control modes of large hydropower units in this embodiment; Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0043] Conversely, this application covers any substitutions, modifications, equivalent methods, and schemes made within the spirit and scope of this application as defined in the claims. Furthermore, to provide the public with a better understanding of this application, certain specific details are described in detail below. However, this application can be fully understood by those skilled in the art even without these detailed descriptions.

[0044] The following will combine Figure 1 This application provides a detailed description of a method for switching speed control modes of a large hydropower unit, as illustrated in the embodiments of this application. It is worth noting that the following embodiments are merely illustrative of this application and do not constitute a limitation thereof.

[0045] Example 1

[0046] like Figure 1 As shown, a method for switching speed control modes of a large hydropower unit is disclosed. The method is implemented based on a speed governor controller and includes:

[0047] Step 1: State initialization.

[0048] Step 2: Determine whether the control handle of the speed controller cabinet is in the first preset position. If so, proceed to step 3; otherwise, proceed to step 17.

[0049] For example, determine whether the control handle of the speed controller cabinet is in the "automatic guide vane" position. If so, proceed to step 3; otherwise, proceed to step 17.

[0050] Step 3: Determine whether the general circuit breaker at the outlet of the large hydropower unit is in the first preset state. If so, proceed to steps 5, 7, 9, 15 and 18 respectively; otherwise, proceed to step 4.

[0051] For example, to determine whether the general-purpose circuit breaker at the outlet of a large hydropower unit is in the closed state, i.e., the unit is in grid-connected state, the response proceeds to steps 5, 7, 9, 15, and 18 respectively; otherwise, it proceeds to step 4.

[0052] Step 4: Determine that the speed controller's control mode is frequency mode.

[0053] For example, if a large hydropower unit is in a non-grid-connected state, such as during standby, startup, idling, no-load operation, or shutdown, the governor control mode is frequency mode.

[0054] Step 5: Determine if a command to switch frequency mode on the local touchscreen has been received. If so, proceed to Step 6.

[0055] Step 6: Determine that the control mode of the speed governor is frequency mode load state, and the large hydropower unit adjusts the load through frequency mode;

[0056] Step 7: Control the speed controller to participate in the speed controller frequency difference detection; the detection includes: determining whether the frequency difference meets the first preset condition, and if it does, proceed to step 8; otherwise, continue the detection.

[0057] For example, when a large hydropower unit is in grid-connected mode, regardless of whether the governor control mode is power mode or open mode, it participates in the governor controller frequency difference detection. The governor controller detects whether the frequency difference is greater than the threshold F0, that is, whether the absolute value of the difference between the real-time unit frequency and the rated frequency of 50Hz is greater than the threshold F0. If so, proceed to step 8; otherwise, continue this step of detection. Preferably, considering the power grid safety and stability, the threshold F0 is generally 0.5Hz-0.6Hz.

[0058] Step 8: Collect multiple unit frequency signals and perform unit frequency signal redundancy measurement; after judging the frequency channel quality based on the first preset method, participate in the logic judgment to ensure that the unit frequency signal is normal, and return to step 6.

[0059] For example, the speed controller collects three or more unit frequency signals to achieve redundant measurement of unit frequency signals. It can use a three-to-two selection mechanism or select one channel as the frequency channel quality judgment and participate in the logic judgment to ensure that the unit frequency signal is normal, that is, there is no unit frequency fault. To prevent frequency difference jitter, a delay TON module is added. Preferably, T1 is generally 500ms-800ms. Return to step 6.

[0060] Step 9: Determine whether a command to activate the active power closed-loop mode has been received. If so, proceed to step 10; otherwise, proceed to step 16.

[0061] Step 10: Determine if the monitoring analog power input channel is normal. If so, proceed to step 11; otherwise, proceed to step 14.

[0062] Step 11: In response to the detection of a monitoring power switching analog signal mode command, proceed to step 12;

[0063] Step 12: Collect multiple active power signals and perform redundant measurements. Based on the first preset method, determine whether the power sampling of the speed controller is normal. If the sampling is normal, proceed to step 13.

[0064] For example, the speed controller can collect 3 active power signals to realize redundant measurement of active power signals. At the same time, it can use a 3-to-2 mechanism to determine whether the speed controller power sampling is normal. If the speed controller power sampling is normal, that is, the speed power sampling is fault-free, proceed to step 13.

[0065] Step 13: Determine the control mode as power mode, change the power setpoint based on the second preset mode, and issue corresponding adjustment actions to achieve the purpose of adjusting the unit power.

[0066] For example, if the speed governor controller is in power mode, that is, the speed governor is in "power mode", then the monitoring sends an analog power setpoint or changes the power setpoint value by increasing or decreasing it through the power pulse adjustment mode, or sends a power setpoint value through the local touch screen, so that the speed governor controller sends a corresponding adjustment action. The speed governor controller sends an instruction to the guide vane to achieve the purpose of adjusting the unit power.

[0067] Step 14: In response to the detection of the monitoring power pulse adjustment mode command, return to step 12;

[0068] Step 15: In response to the detection of a power mode switching command on the local touchscreen, return to step 12;

[0069] Step 16: In response to the detection of the monitoring cut angle mode command, proceed to step 17;

[0070] Step 17: Determine the control mode as the opening mode; change the guide vane opening through the third preset mode and issue a command to actuate the guide vanes to achieve the purpose of adjusting the unit power.

[0071] For example, if the speed governor controller is in the opening mode, that is, when the speed governor is in the "opening mode", the speed governor will increase or decrease the guide vane opening accordingly when the opening setpoint is changed by monitoring the remote increase or decrease signal or when the opening setpoint is sent by the local touch screen. The speed governor controller will issue the instruction to activate the guide vane, thereby achieving the purpose of adjusting the unit power. The speed of increasing or decreasing the guide vane opening is related to the pulse width and frequency of the increase or decrease signal.

[0072] Step 18: In response to the detection of a local touchscreen cut-out mode command, return to step 17;

[0073] Step 19: In response to the speed regulation power sampling fault in step 13, determine that the control mode is switched to the opening mode, and return to step 17.

[0074] For example, when the speed governor controller is operating in step 13, if there is a speed power sampling fault, that is, the power sampling collected by the speed governor controller shows faults such as jumps, exceeding limits, or comparison abnormalities, the speed governor control mode will switch to the opening mode without disturbance, that is, enter step 17, to ensure that important data such as the active power of the unit and the guide vane opening are kept at the time before the fault, and to ensure load stability.

[0075] Step 20: In response to the control mode being power mode and the detection that the difference between the monitoring power sampling and the speed regulation power sampling meets the second preset condition, the monitoring power of the computer monitoring system is collected, and it is determined whether the monitoring power and the speed regulation power meet the third preset condition. In response to the monitoring power and the speed regulation power meeting the third preset condition, the process returns to step 17; in response to the monitoring power and the speed regulation power not meeting the third preset condition, the process continues.

[0076] For example, when the governor controller is in power mode, if it detects that the difference between the monitored power sample and the speed-regulating power sample exceeds P0, a power transmitter is typically installed in the local control cabinet of the unit's LCU to collect the unit's active power. This power transmitter is used for LCU program power logic judgment, redundant signal processing, and fault tracing analysis. Specifically, the governor controller collects one channel of active power from the monitoring LCU and compares it with the active power collected by the governor itself. If the absolute value of the difference between the monitored power sample and the speed-regulating power sample is greater than the threshold P0, the process proceeds to step 17. Otherwise, the current detection step continues. Preferably, P0 is 5% of the unit's rated power.

[0077] In summary, the technical solution of this invention adopts the method of joint operation of three variable frequency water supply pumps, and combines the changes in water pump intake temperature and ambient temperature to establish and utilize a big data intelligent analysis platform, thereby significantly reducing the energy consumption of the technical water supply system while ensuring stable operation of the unit.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for switching the control mode of a large hydroelectric generating unit, said method being implemented based on a governor controller, characterized in that, The method comprises: Step 1, state initialization; Step 2, judging whether the control handle of the governor control cabinet is in the first preset position, and in response to yes, entering step 3; otherwise, entering step 17; Step 3, judging whether the general circuit breaker at the outlet of the large hydroelectric generating set is in the first preset state, and in response to yes, entering step 5, step 7, step 9, step 15 and step 18 respectively; otherwise, entering step 4; Step 4, determining that the control mode of the governor is the frequency mode; Step 5, judging whether a frequency mode switching command of the governor local touch screen is received, and in response to yes, entering step 6; Step 6, determining that the control mode of the governor is the frequency mode load state, and the large hydroelectric generating set adjusts the load through the frequency mode; Step 7, controlling the control mode of the governor to participate in the governor controller frequency difference detection; the detection comprises: judging whether the frequency difference satisfies the first preset condition, and in response to yes, entering step 8; otherwise, continuing the detection; Step 8, collecting multiple unit frequency signals, performing unit frequency signal redundancy measurement; after frequency channel quality judgment based on the first preset mode, participating in logical judgment to ensure that the unit frequency signal is normal, and returning to step 6; Step 9, judging whether a monitoring active closed loop mode input command is received, and in response to yes, entering step 10; otherwise, entering step 16; Step 10, judging whether the monitoring analog power given channel is normal, and in response to yes, entering step 11; otherwise, entering step 14; Step 11, in response to detecting a monitoring power analog mode command, entering step 12; Step 12, collecting multiple active power signals and performing redundancy measurement, judging whether the governor power sampling is normal based on the first preset mode, and in response to normal sampling, entering step 13; Step 13, determining that the control mode is the power mode, changing the power given value based on the second preset mode, and issuing corresponding adjustment actions to achieve the purpose of adjusting the unit power; Step 14, in response to detecting a monitoring power pulse regulation mode command, returning to step 12; Step 15, in response to detecting a governor local touch screen power mode command, returning to step 12; Step 16, in response to detecting a monitoring opening degree mode command, entering step 17; Step 17, determining that the control mode is the opening degree mode; changing the guide vane opening degree through the third preset mode, issuing the guide vane instruction to achieve the purpose of adjusting the unit power; Step 18, in response to detecting a local touch screen opening degree mode command, returning to step 17; Step 19, in response to governor power sampling failure in step 13, determining that the control mode is switched to the opening degree mode, and returning to step 17; Step 20, in response to the control mode being the power mode and detecting that the monitoring power sampling and the governor power sampling difference satisfy the second preset condition, collecting the monitoring power of the computer monitoring system, judging whether the monitoring power and the governor power satisfy the third preset condition, in response to the monitoring power and the governor power satisfying the third preset condition, returning to step 17; in response to the monitoring power and the governor power not satisfying the third preset condition, continuing this step; The first preset position is a guide vane automatic position, and the first preset state is a closed state, that is, the large hydroelectric generating set is in a grid-connected state. The first preset condition includes that the frequency difference is greater than a first threshold value; the second preset condition includes that a difference between the monitored power sample and the speed-regulating power sample exceeds a second threshold value; and the third preset condition is that an absolute value of a difference between the monitored power sample value and the speed-regulating power sample value is greater than a threshold value P0, and the threshold value P0 is 5% of a rated power of the generating set. The first preset mode is a three-out-of-two selection mechanism or a preferred one-way mode; the second preset mode includes a monitored power sample analog quantity power given mode or a power pulse regulation mode; and the third preset mode includes a mode of changing an opening degree given value through a monitored remote increasing or decreasing signal or a mode of issuing an opening degree given value through a local touch screen.

2. The method of claim 1, wherein In the step 4, the large hydroelectric generating set is in a non-grid-connected state, and the non-grid-connected state includes at least one of a shutdown standby state, a start-up process, an idling state, an unloaded state, and a shutdown process.

3. The method of claim 1, wherein The first threshold value is 0.5 Hz-0.6 Hz.

4. The method of claim 1, wherein In the step 17, a speed of increasing or decreasing the guide vane opening degree is related to a pulse width and a frequency of the increasing or decreasing signal.

5. The method of claim 1, wherein The second threshold value is 5% of the rated power of the generating set.

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