Control method of unattended hydroelectric generating set maintenance drainage control system based on feedforward control

Abstract

The control method of the unattended hydroelectric generating set overhaul drainage control system based on feedforward control comprises the steps that when a set does not drain water, a disc valve is closed, an oil pump stops running, and the system works in a leakage drainage mode; at the moment, the collected water source in the water collecting well is mainly wall seepage water and unit leakage water; when the water level rises to the water level for starting the main pump, the main pump is started; when the water level rises to the stand-by pump starting water level, the stand-by pump is started; stopping the standby pump when the water level drops to the standby pump stopping water level; stopping the main pump when the water level drops to the water level of stopping the main pump; when the unit needs drainage, the system works in a maintenance drainage mode. Automatic adjustment of the opening degree of the disc valve is completed through feedforward compensation and double-closed-loop negative feedback, the water level of the water collecting well is controlled to maintain the main pump and the standby pump to start drainage, unattended operation on site is achieved, drainage efficiency is improved, manual operation is reduced, and working efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of unit maintenance and drainage control, and relates to a control method for an unattended hydropower unit maintenance drainage control system based on feedforward control. Background Art

[0002] Before entering the flow channel, volute, and tailwater pipe of the hydropower unit for maintenance work, it is necessary to open the type valve to drain the internal water to the maintenance water collection well. The maintenance drainage system controls the deep well pump to discharge the water to the downstream tailwater. The existing maintenance drainage control system and the disc valve hydraulic pump station operate independently of each other. When the unit needs to be drained, the maintenance personnel manually operate the hydraulic pump station to control the opening of the disc valve. If the opening is too large, the water level in the maintenance water collection well will rise too quickly, and there is a risk of flooding the plant. If the opening is too small, the deep well pump will start and stop frequently, which is easy to cause damage to the deep well pump and low drainage efficiency.

[0003] Maintenance personnel manually operate the hydraulic pump station to open the disc valve and observe the water level in the water collection well. If the water level still rises when both the main pump and the standby pump are in operation, the disc valve opening is reduced until the water level remains unchanged or slowly decreases. As the water pressure in the flow channel and volute decreases, someone needs to be on duty to operate the disc valve opening multiple times to maintain the drainage efficiency to keep the deep well pump running.

[0004] The existing maintenance drainage control system and the disc valve hydraulic pump station operate independently of each other. To maintain the drainage efficiency, someone needs to be on duty and operate the disc valve opening multiple times. The steps are cumbersome and inefficient, and unattended and automatic control cannot be achieved. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a control method for an unattended hydropower unit maintenance and drainage control system based on feedforward control, so as to solve the problem that the maintenance and drainage control system and the disc valve hydraulic pump station operate independently of each other and the disc valve opening control requires human supervision.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a control method for an unattended hydropower unit maintenance drainage control system based on feedforward control, the control system includes a deep well pump in a water collection well, a water level sensor electrically connected to a plurality of deep well pumps, an opening sensor electrically connected to a disc valve, and a proportional sensor electrically connected to a proportional valve; the proportional valve is connected to an oil pump and a disc valve; the deep well pump, the disc valve, the proportional valve, the water level sensor, the opening sensor and the proportional sensor are all electrically connected to a controller; the deep well pump includes a main activation pump and a standby pump; The control method includes the following steps: S1, when the unit does not drain water, the disc valve is closed, the oil pump stops running, and the system works in the leakage drainage mode; at this time, the water source collected in the water collection well is mainly wall seepage and unit leakage; S2: When the water level rises to the level to start the main pump, start the main pump; when the water level rises to the level to start the standby pump, start the standby pump; when the water level drops to the level to stop the standby pump, stop the standby pump; when the water level drops to the level to stop the main pump, stop the main pump; S3: When the unit needs to be drained, the system works in the maintenance drainage mode.

[0007] In S3, after the maintenance drainage mode is started, the water level control set value First, set the water level to start the main pump; after the main pump is started, the water level control set value Set to the water level for starting the standby pump to maintain the start-up drainage of all deep well pumps; as the pressure in the volute and the flow channel decreases, the opening of the disc valve gradually increases. When the upper limit of the opening is reached and the water level continues to drop to the water level for stopping the standby pump, the maintenance drainage mode is exited and the leakage drainage mode is restored until all deep well pumps stop running.

[0008] When the disc valve is opened to a certain degree and the main pump and the standby pump are all started to drain water, if the disc valve drains water into the well Q in The flow rate of deep well pump drainage Q out At the same time, the water level in the collection well remains stable.

[0009] Query the historical operation data and test data such as tailwater pipe pressure and disc valve opening when the water level in the water collection well is stable, and establish the corresponding relationship array of tailwater pipe pressure P and disc valve opening Y when the water level is dynamically balanced .

[0010] When the system is working in the maintenance drainage mode, the current tailwater pipe pressure is calculated by piecewise linear difference according to the corresponding relationship array. P The disc valve opening degree to maintain the dynamic balance of water level in the water collection well , as the feedforward control quantity; first determine the pressure P The segment interval where The corresponding ,but ,in For the corresponding relationship array The elements in .

[0011] The controller collects the water level of the water collection well in real time , and the water level control given value To make a difference, = ; In order to avoid frequent system adjustments, set a water level control dead zone ;when ≤ When PID control input value ,when > hour, ,when < hour, ; The difference is output through the parallel PID and the feedforward control quantity Superposition, as the given value of the disc valve opening ; Where: is the proportional coefficient of the PID module; is the integral coefficient of the PID module; It is the differential coefficient of the PID module.

[0012] A signal amplifier is set between the opening sensor and the proportional sensor. As the difference between the given value of the disc valve opening and the disc valve opening value, the difference is amplified and used as the proportional valve control given value, and is used together with the proportional valve feedback value as a small closed loop to control the flow direction of the pressure oil. When the pressure oil passes through the proportional valve and enters the lower oil chamber of the disc valve servo, the disc valve opening is increased, and when it enters the upper oil chamber, the disc valve opening is reduced. The oil circuit is closed, and the current opening is maintained unchanged.

[0013] The main beneficial effects of the present invention are: A feedforward control link is established based on historical data and test data. The disc valve opening compensation is calculated according to the measured value of the tailwater pipe pressure disturbance and directly added to the output of the PID controller, which reduces the intervention of the parallel PID controller and the difficulty of PID parameter identification and confirmation. The disc valve opening is then adjusted quickly, accurately and stably to achieve a dynamic balance between the inflow and outflow of the water collection well, achieving the purpose of unmanned on-site operation, greatly improving drainage efficiency, saving human resource costs, shortening the unit maintenance period, and having great economic benefits.

[0014] Through feedforward compensation + double closed-loop negative feedback, the disc valve opening is automatically adjusted, and the water level in the collection well is controlled to maintain the main pump and the standby pump to start drainage, achieving unmanned on-site operation, improving drainage efficiency, reducing manual operation, and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0016] Figure 1 It is a flow chart of the present invention.

[0017] Figure 2 It is a system diagram of the present invention.

[0018] In the figure: deep well pump 1; water level sensor 11; disc valve 2; opening sensor 21; proportional valve 3; proportional sensor 31; oil pump 4. DETAILED DESCRIPTION

[0019] like Figure 1~Figure 2 In the invention, a control method for an unattended hydropower unit maintenance drainage control system based on feedforward control is disclosed, wherein the control system includes a deep well pump 1 in a water collection well, a water level sensor 11 electrically connected to the deep well pump 1, an opening sensor 21 electrically connected to the disc valve 2, and a proportional sensor 31 electrically connected to the proportional valve 3; the proportional valve 3 is connected to the oil pump 4 and the disc valve 2; the deep well pump 1, the disc valve 2, the proportional valve 3, the water level sensor 11, the opening sensor 21 and the proportional sensor 31 are all electrically connected to the controller; the deep well pump 1 includes a main activation pump and a standby pump; The control method includes the following steps: S1, when the unit does not drain water, the disc valve 2 is closed, the oil pump 4 stops running, and the system works in the leakage drainage mode; at this time, the water source collected in the water collection well is mainly wall seepage and unit leakage; S2: When the water level rises to the level to start the main pump, start the main pump; when the water level rises to the level to start the standby pump, start the standby pump; when the water level drops to the level to stop the standby pump, stop the standby pump; when the water level drops to the level to stop the main pump, stop the main pump; S3: When the unit needs to be drained, the system works in the maintenance drainage mode.

[0020] Preferably, the controller is the core of the control system and is used for IO acquisition, numerical calculation, control output, fault alarm and status indication, etc.; Preferably, the controller is electrically connected to the starter, and the starter is electrically connected to the circuit breaker and the contactor and is connected to the deep well pump 1 to form a main circuit.

[0021] Preferably, the controller is a PID controller.

[0022] Preferably, the oil pump 4 includes a hydraulic valve group, hydraulic pipelines, meters, etc. connected to the oil pump motor, which are used to generate pressurized oil and switch the oil circuit according to the command of the control system.

[0023] In the preferred solution, in S3, after the maintenance drainage mode is started, the water level control given value First, set the water level to start the main pump; at this time, the drainage efficiency is the highest, and the disc valve opening can be adjusted quickly, accurately and stably to achieve a dynamic balance between the inflow and outflow of the collection well.

[0024] After the main pump is started, the water level control set value Set to the water level for starting the standby pump to maintain all deep well pumps 1 to start drainage; as the pressure in the volute and the flow channel decreases, the opening of the disc valve gradually increases. When the upper limit of the opening is reached and the water level continues to drop to the water level for stopping the standby pump, exit the maintenance drainage mode and resume the leakage drainage mode until all deep well pumps 1 stop running.

[0025] In the preferred solution, when the disc valve 2 is opened to a certain degree and the main pump and the standby pump are all started to drain water, if the disc valve 2 drains water into the well flow rate Q in The flow rate of deep well pump drainage Q out At the same time, the water level in the collection well remains stable.

[0026] In the preferred solution, the historical operation data and test data such as tailwater pipe pressure and disc valve 2 opening when the water level in the water collection well is stable are queried to establish the corresponding relationship array of tailwater pipe pressure P and disc valve opening Y when the water level is dynamically balanced. .

[0027] In the preferred solution, when the system is working in the maintenance drainage mode, the current tailwater pipe pressure is calculated by piecewise linear difference according to the corresponding relationship array. P The disc valve opening degree to maintain the dynamic balance of water level in the water collection well , as the feedforward control quantity; first determine the pressure P The segment interval where The corresponding ,but ,in For the corresponding relationship array The elements in .

[0028] In the preferred solution, the controller collects the water level of the water collection well in real time , and the water level control given value To make a difference, = ; In order to avoid frequent system adjustments, set a water level control dead zone ;when ≤ When PID control input value ,when > hour, ,when < hour, ; The difference is output through the parallel PID and the feedforward control quantity Superposition, as the given value of the disc valve opening ; Where: is the proportional coefficient of the PID module; is the integral coefficient of the PID module; It is the differential coefficient of the PID module.

[0029] In the preferred solution, a signal amplifier is provided between the opening sensor 21 and the proportional sensor 31. As the difference between the given value of the disc valve opening and the disc valve opening value, the difference is amplified and used as the proportional valve control given value, and is used together with the proportional valve feedback value as a small closed loop to control the flow direction of the pressure oil. When the pressure oil passes through the proportional valve and enters the lower oil chamber of the disc valve servo, the disc valve opening is increased, and when it enters the upper oil chamber, the disc valve opening is reduced. The oil circuit is closed, and the current opening is maintained unchanged.

[0030] The above method establishes a feedforward control link based on historical data and test data, calculates the disc valve opening compensation according to the measured value of the tailwater pipe pressure disturbance, and directly adds it to the output of the PID controller, reducing the intervention of the parallel PID controller and the difficulty of PID parameter identification and confirmation, thereby quickly, accurately and stably adjusting the disc valve opening to achieve a dynamic balance between the inflow and outflow of the water collection well, achieving the purpose of unmanned on-site operation, greatly improving the drainage efficiency, saving human resource costs, shortening the unit maintenance period, and having great economic benefits.

[0031] Through feedforward compensation + double closed-loop negative feedback, the disc valve opening is automatically adjusted, and the water level in the collection well is controlled to maintain the main pump and the standby pump to start drainage, achieving unmanned on-site operation, improving drainage efficiency, reducing manual operation, and improving work efficiency.

[0032] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A control method for an unattended hydropower unit maintenance drainage control system based on feedforward control, characterized in that: The control system comprises a deep well pump (1) in a water collection well, a plurality of water level sensors (11) electrically connected to the deep well pumps (1), an opening sensor (21) electrically connected to the disc valve (2), and a proportional sensor (31) electrically connected to the proportional valve (3); the proportional valve (3) is connected to the oil pump (4) and the disc valve (2); the deep well pump (1), the disc valve (2), the proportional valve (3), the water level sensor (11), the opening sensor (21), and the proportional sensor (31) are all electrically connected to the controller; the deep well pump (1) comprises a main activation pump and a standby pump; The control method includes the following steps: S1, when the unit does not drain water, the disc valve (2) is closed, the oil pump (4) stops running, and the system works in the leakage drainage mode; at this time, the water source collected in the water collection well is mainly water seepage from the wall and water leakage from the unit; S2: When the water level rises to the level to start the main pump, start the main pump; when the water level rises to the level to start the standby pump, start the standby pump; when the water level drops to the level to stop the standby pump, stop the standby pump; when the water level drops to the level to stop the main pump, stop the main pump; S3: When the unit needs to be drained, the system works in the maintenance drainage mode.

2. The control method of the unattended hydropower unit maintenance drainage control system based on feedforward control according to claim 1 is characterized by: In S3, after the maintenance drainage mode is started, the water level control set value First, set the water level to start the main pump; After the main pump is started, the water level control set value The water level for starting the standby pump is set to maintain all deep well pumps (1) started to drain water; as the pressure in the volute and the flow channel decreases, the opening of the disc valve gradually increases. When the upper limit of the opening is reached and the water level continues to drop to the water level for stopping the standby pump, the maintenance drainage mode is exited and the leakage drainage mode is restored until all deep well pumps (1) stop running.

3. The control method of the unattended hydropower unit maintenance drainage control system based on feedforward control according to claim 2 is characterized by: When the disc valve (2) is opened to a certain degree and the main pump and the standby pump are all started to drain water, if the disc valve (2) drains water into the well, the flow rate Q in The flow rate of deep well pump drainage Q out At the same time, the water level in the collection well remains stable.

4. The control method of the unattended hydropower unit maintenance drainage control system based on feedforward control according to claim 3 is characterized by: Query the historical operation data and test data such as tailwater pipe pressure and disc valve (2) opening when the water level in the water collection well is stable, and establish the corresponding relationship array between tailwater pipe pressure P and disc valve opening Y when the water level is dynamically balanced .

5. The control method of the unattended hydropower unit maintenance drainage control system based on feedforward control according to claim 4 is characterized by: When the system is working in the maintenance drainage mode, the current tailwater pipe pressure is calculated by piecewise linear difference according to the corresponding relationship array. P The disc valve opening degree to maintain the dynamic balance of water level in the water collection well , as the feedforward control quantity; first determine the pressure P The segment interval where The corresponding ,but ,in For the corresponding relationship array The elements in .

6. The control method of the unattended hydropower unit maintenance drainage control system based on feedforward control according to claim 1 is characterized by: The controller collects the water level of the water collection well in real time , and the water level control given value To make a difference, = ; In order to avoid frequent system adjustments, set a water level control dead zone ;when ≤ When PID control input value ,when > hour, ,when < hour, ; The difference is output through the parallel PID and the feedforward control quantity Superposition, as the given value of the disc valve opening ; Where: is the proportional coefficient of the PID module; is the integral coefficient of the PID module; It is the differential coefficient of the PID module.

7. The control method of the unattended hydropower unit maintenance drainage control system based on feedforward control according to claim 1 is characterized by: A signal amplifier is provided between the opening sensor (21) and the proportional sensor (31) to As the difference between the given value of the disc valve opening and the disc valve opening value, the difference is amplified and used as the proportional valve control given value, and is used together with the proportional valve feedback value as a small closed loop to control the flow direction of the pressure oil. When the pressure oil passes through the proportional valve and enters the lower oil chamber of the disc valve servo, the disc valve opening is increased, and when it enters the upper oil chamber, the disc valve opening is reduced. The oil circuit is closed, and the current opening is maintained unchanged.

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