RU2292483C1 - Speed checking device for hydraulic turbine speed governor - Google Patents

Abstract

FIELD: devices for check of speed.

SUBSTANCE: proposed device has rotational speed setter, current frequency sensor of hydraulic-turbine generator, proportional-integral-differential governor, sensor showing opening of hydraulic turbine guide apparatus and module for calculation of amount of limitation of opening of guide apparatus, electrohydraulic converter, pressure head sensor, manual pressure head setter, pressure head signal commutation module, module for limitation of rate of change of pressure head signal and module for calculation of amount of opening of guide apparatus at idling of hydraulic turbine, two sensors showing rotational speed of hydraulic-turbine generator shaft and hydraulic turbine starting and stopping module.

EFFECT: enhanced reliability.

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Description

The claimed invention relates to hydraulic engineering, specifically to speed control devices for speed controllers of a turbine.

A known speed control device for a speed controller in water turbine generators, which is the closest analogue of the claimed invention (JP 6317244 A1, (TOSHIBA ENGINEERING CO), 11/15/1994).

This device contains a speed controller, a generator frequency sensor, a proportional-integral-differential controller, hereinafter a PID controller, an opening sensor and a limiter for opening the guide apparatus, an electro-hydraulic converter and a compensation signal driver in the frequency setting circuit at the moment the generator exciter is turned on. In this device, the start-up process of the generator is improved by reducing the time the hydroturbine reaches its nominal rotation speed.

However, this device has several disadvantages that cause an increase in the start-up time of a hydraulic turbine, i.e. time from the moment the command was issued to start the hydraulic unit to complete the synchronization process with the power grid:

- the magnitude of the initial (starting) opening of the guiding apparatus of the turbine is constant and slightly larger than the magnitude of the open idle speed necessary to accelerate the turbine to the rated speed. This leads at the time of connecting the frequency controller to some closure of the guide apparatus and, accordingly, an increase in the regulation time at idle, and in some cases, for example, with an increase in the effective pressure, to overshoot;

- inclusion in the operation of the PID controller occurs from the moment the hydraulic unit is started, which leads to an increase in idling time due to disturbances coming in the frequency compensation compensation circuit at the time the generator exciter is connected.

The problem to which the invention is directed is the creation of a device that provides optimal control of the turbine at the start and stop stages and has increased reliability.

The technical result is expressed in improving the dynamic characteristics of the controller and increasing the reliability of the hardware.

The task is achieved by the fact that in the known device for controlling the speed of a turbine turbine speed controller containing a proportional-integral-differential controller (PID controller), a turbine speed controller connected via a main feedback combiner to a gain module of the proportional component of the PID controller, a module the limits of the current PID controller job, the first input of which is connected to the output of the module for calculating the opening restriction value of the guide apparatus, and the output from the input input of the local feedback adder module, the second input of which is connected to the sensor for opening the guiding apparatus of the hydraulic turbine, and the output is with an electro-hydraulic converter, the output of the latter is equipped with a hydraulic turbine, the generator’s current frequency sensor, and it additionally contains a pressure sensor, a manual pressure regulator connected to the module switching the signal by pressure, the output of which is connected to the module for limiting the rate of change of the signal by pressure, the module for calculating the opening value of the guiding apparatus in cold weather during the course of the turbine, the first and second sensors of the rotational speed of the hydrogenerator shaft, a module for starting and stopping the turbine, the outputs of the current generator of the hydrogenerator and the first and second sensors of the rotational speed of the hydrogenerator are connected respectively to the first, second and third inputs of the module for selecting the channels for measuring the frequency of rotation of the hydrogenerator the output of which is connected to the first input of the start and stop module of the hydraulic turbine, the differentiating module of the PID controller and the main feedback adder, the output of which о is connected to the first input of the first signal switching module, to the second input of which a signal is supplied from the output of the start and stop turbine turbine module, and the output is connected to the integrating module of the PID controller, and the outputs of the proportional amplification modules, integrating and differentiating components are connected respectively to the first , the second and third inputs of the adder PID controller, the output of which is connected to the first input of the second signal switching module, the second input of which receives a signal from the start module and of the turbine turbine, and the output is connected to the second input of the PID controller current value limiting module, the output of which is connected to the second input of the hydroturbine start and stop module, and the output of the signal change rate limiting module is connected to the input of the guide limitation opening limit calculation module and the module calculating the opening value of the guide vane during idle flow of the turbine, the output of which is connected to the third input of the start and stop module of the turbine, and the output of the latter oedinen to the third input of the adder local feedback.

Figure 1 presents the structural diagram of the speed control device for the speed controller of a turbine (GT) (double line circled the elements common to the prototype and the claimed device).

Figure 2 presents graphs of transient parameters of a turbine during start-up, operation under load and its stop.

Figure 1 shows:

1 - Speed dial turbine,

2 - Current generator frequency sensor (GT),

3 - hydrogenerator

4 - Adder main feedback,

5 - The first sensor of the rotational speed of the shaft of the hydrogenerator,

6 - Module limits the current job of the PID controller,

7 - the module for calculating the magnitude of the opening restriction of the guide apparatus (ON),

8 - Hydroturbine,

9 - Local feedback adder,

10 - Sensor opening guide vanes of a turbine,

11 - Electro-hydraulic Converter,

12 - The second sensor of the rotational speed of the shaft of the hydrogenerator,

13 - Module for selecting channels for measuring the frequency of rotation of the hydrogenerator,

14 - Pressure sensor,

15 - Manual pressure regulator,

16 - Module switching signal pressure,

17 - Module for restricting the rate of change of the signal by pressure,

18 - a module for calculating the magnitude of the opening of the guide vane when the turbine is idle,

19 - Module start and stop the turbine,

20 - The first signal switching module,

21 - The gain module of the proportional component of the PID controller,

22 - Module integrating link PID controller

23 - PID controller differentiator module,

24 - Adder PID controller

25 - The second module switching signal.

The speed controller of the turbine 1 generates the current frequency reference for the turbine controller through the channel for stabilizing the speed. Automatic and manual task changes are possible.

The frequency generator 2 of the current of the hydrogenerator measures the current frequency of the electric current of the hydrogenerator and has a narrow measurement range within the rated frequency and high accuracy. Data from the frequency sensor 2 is used in the regulation process during operation of the hydrogenerator in steady state.

The hydrogenerator 3 is rigidly connected to the turbine shaft and provides the generation of electrical energy.

The adder of the main feedback of the controller 4 provides a signal for the deviation of the current frequency of rotation of the hydrogenerator from a given frequency generated by the frequency setter 1.

The first sensor of the rotational speed of the hydrogenerator shaft 5 measures the current rotational speed of the hydrogenerator shaft in the entire range of its operation. Information from the sensor 5 is used when starting up, stopping the hydraulic turbine, in transient modes of operation, as well as when the frequency of the GH exceeds the measurement range of the frequency sensor 2 or in case of failure of the sensor 2.

The limiting module of the current task of the PID controller 6 provides a limitation of the opening of ON depending on the pressure head.

The module for calculating the opening restriction value of ON 7 calculates and generates, depending on the effective pressure, the values of the limiting signals determining the maximum opening of the ON.

Hydroturbine 8 converts the energy of water falling on the blades of the impeller into rotational motion and transmission of torque to the hydrogenerator.

The local feedback adder 9 generates a signal for deviation of the current position of the hydraulic turbine from the predetermined one.

The opening sensor ON the turbine 10 provides a measure of the current position of the guide apparatus of the turbine.

The electro-hydraulic converter 11 provides control of the hydraulic actuator (servo motor) of the turbine by redistributing the flow of working fluid supplied under pressure from an oil-pressure unit (not shown).

The second shaft generator rotational speed sensor 12 measures the current rotational shaft speed of the hydro generator in the entire range of its operation and is used by the channel selection module 13 as a backup sensor to evaluate the operability of two other frequency sensors 2 and 5.

The module for selecting channels for measuring the frequency of rotation of the GG 13 provides a check of the operability of the channels and the determination of a failed frequency sensor and switching channels in various modes of operation of the GG. Identification of a failed sensor occurs by pairwise comparison of the readings of all three frequency sensors. If the readings of any sensor deviate from the set values, it is considered inoperative. The frequency value from the selected channel enters adder 4 as the main feedback signal.

The pressure sensor 14 provides a measurement of the effective pressure by calculating the difference in levels of the upper and lower downstream of the hydroelectric power station.

A manual pressure head 15 provides manual input and generation of a current pressure signal. It is used in the absence of a pressure sensor or its failure. In this case, the current water pressure is determined by the operator visually from the marks in the reservoir.

The pressure switching signal module 16 provides the operator with the opportunity to choose the method of setting the current pressure: from the pressure sensor 14 in automatic mode or manually from the manual pressure control unit 15.

The module for restricting the rate of change of the signal by pressure 17 provides a smooth (shockless) change of the signal by the current pressure when switching from one pressure measurement mode to another (from automatic to manual and vice versa).

The module for calculating the opening value of the guide vane when the turbine 18 is idling provides the calculation of the opening value of the vane when the engine is idle at different pressures, which allows faster acceleration of the turbine to the idle frequency.

The GT 19 start-up and shutdown module provides control of the hydraulic turbine 8 in a stopped state, accelerated acceleration of the hydraulic turbine and minimum idling time, as well as control of the hydraulic turbine when it is stopped by an operator's command. Module 19 also provides the processing of external commands to start and stop the GT, and also generates commands to turn on the exciter of the generator at start-up and turn off the generator switch when the GT is stopped.

The first signal switching module 20 provides zeroing of the signal of the PID controller integrating module module, connecting the integrating module 22 after the turbine is accelerated to normalized speeds of 95-105% of the nominal speed, which allows to reduce the acceleration and synchronization time of the turbine with the power grid and reduce overshoot. The module 20 is controlled by the GT 19 start and stop module.

The PID controller block consists of:

- gain module of the proportional component 21,

- module integrating link 22,

- module differentiating element 23,

- adder 24.

The PID controller provides stabilization of the set speed setting generated by the speed controller GT 1.

At the input of modules 21 and 22, a frequency mismatch signal is received from the main feedback adder 4. The main frequency feedback signal is received at the input of module 23, which ensures the implementation of the differentiator function and does not allow disturbing effects when the operator changes the current job by frequency setpoint 1 and reduces time working out tasks.

The adder 24 of the component signals of the PID controller generates the resulting signal from the signals coming from the modules 21, 22, 23 (proportional, integral and differential).

The second PID controller 25 signal switching module provides the connection of the PID controller signal after the turbine has accelerated and reaches its normalized speed, as well as the PID controller signal shutdown when it stops. The module is controlled by a signal from the start-up and stop modules of the gas turbine 19. This reduces the time it takes to start the gas turbine and synchronize the gas turbine with the power grid, as well as provide the specified mode and stop the gas turbine.

The inventive device operates as follows. Before starting a GT in automatic mode, module 19 determines its readiness for start-up, the PID controller during this period is disconnected through the second signal switching module 25, the output signal from the integrating link module 22 is reset, and a zero signal from the first signal switching module 20 is also fed to its input .

Upon receipt of the “Start GT” command, the GT 19 start and stop module generates a linearly increasing signal to the value of the start-up of the ON (Fig. 2, the opening curve of the GT) and transfers it to the local feedback adder module 9. The maximum speed of the control signal is and limited only by regulatory guarantees. Then, after the HA is opened and the hydraulic turbine accelerates to a normalized value (80-90% of the nominal frequency (see Fig. 2, the GT rotation frequency curve), module 19 generates a command to turn on the GG exciter and generates a linearly decreasing signal to the HA opening value at Idling of the turbine engine. The speed of generating the control signal is determined from the condition that the actuator of the hydroturbine reaches the idle position and accelerates the turbine to a frequency of 100% of the nominal value. Then the PID controller is turned on by eniya first and second switching units 20 and 25 and provides stabilization of the rotational speed at idle. Then when the rotation frequency stabilization conditions hydrogenerator connected to a load.

Upon receipt of the “Stop GT” command, the GT 19 start and stop device memorizes the control signal of the PID controller coming from the restriction module 6, disables the PID controller using switching module 25, and compensates the control signal received at the input of the local feedback adder 9 ( see figure 2, the opening curves of the ON and the output of the PID controller), thereby ensuring an unshocked transition from the frequency control mode to the stop mode of the GT. Then, the module 19 generates a linearly decreasing signal with a speed limited by the guarantees of regulation to the idle open position and then after the generator switch is turned off, the hydropower turbines are further closed until it is completely closed.

The device circuit is reserved for speed measurement channels and includes two speed measurement channels with their own independent first and second frequency sensors 5 and 12, generating measuring pulses with a repetition rate proportional to the rotational speed of the GG shaft, as well as a channel with a sensor 2 measuring frequency of the electric current of the generator, which is also proportional to the frequency of rotation of the hydrogenerator. All signals are fed to the module for selecting frequency measurement channels 13, which provides the selection and connection of the desired sensor in accordance with the current GT operating mode, checking the operability of the frequency channels and determining the failed sensor. The operability of the frequency channels and the selection of the working channel are checked by pairwise comparison of their frequencies. The current value of the frequency from the sensor of the selected channel is used as the main feedback of the device.

To ensure optimal operation and shorten the start-up time of the turbine, information about the current head is used, which comes from the pressure gauge 14 or is manually set by the operator from the head gauge 15. To ensure an unshocked transition from the manual setting of the head to automatic and vice versa, the module for restricting the rate of change of the signal by pressure 17. The signal from the module 17 enters the module for calculating the opening restriction value of the ON 7, which limits the value of the opening signal of the hydraulic turbine ON coming from the PID controller, which allows you to limit the power of the GT in accordance with the operational characteristics. The pressure signal is also used when starting a hydraulic turbine to determine the amount of idle opening, which is calculated by the module for calculating the opening magnitude of the guiding apparatus when the turbine 18 is idling.

The control computing part of the controller is based on controllers, for example, Siemens controllers of the S7-300 series.

The speed sensors of the shaft of the hydrogenerator 5 and 12 can be made on the basis of well-known schemes of contactless inductive, capacitive or optical converters. As a frequency sensor 2 of the electric current of the GG, a well-known serial frequency converter of the E-858 type is used.

As an electro-hydraulic transducer 11, an inkjet or spool type transducer can be used.

Position sensors, for example, inductive, optical or potentiometric, can be used as a sensor for opening ON hydraulic turbines 10.

The pressure sensor 14 can be made on the basis of level sensors float, ultrasonic or capacitive type.

Claims (1)

A speed control device for a hydraulic turbine speed controller, comprising a proportional-integral-differential controller (PID controller), a hydraulic turbine speed controller connected via a main feedback combiner to a proportional component amplification module of the PID controller, a limiting module for the current PID controller job, first the input of which is connected to the output of the module for calculating the opening restriction of the guide vane, and the output with the first input of the local feedback adder module, the second input of which is connected to the opening sensor of the guiding apparatus of the hydraulic turbine, and the output is equipped with an electro-hydraulic converter, the output of the latter is equipped with a hydraulic turbine, and a current generator frequency sensor for the hydraulic generator, characterized in that it further comprises a pressure sensor, a manual pressure regulator connected to the pressure signal switching module, output which is connected to the module for limiting the rate of change of the signal by pressure, the module for calculating the opening value of the guiding apparatus at idle speed of the turbine, the first and second yes sensors of the rotational speed of the hydrogenerator shaft, a module for starting and stopping the turbine turbine, the outputs of the hydrogenerator current sensor and the first and second sensors of the rotational speed of the hydrogenerator shaft connected respectively to the first, second and third inputs of the module for selecting channels for measuring the rotational speed of the hydrogenerator, the output of which is connected to the first input start and stop hydroturbine module, differentiating module of the PID controller and the adder main feedback, the output of which is connected to the first input of the first module I switch the signal to the second input of which the signal from the output of the start and stop module of the hydraulic turbine is supplied, and the output is connected to the integrating module of the PID controller, and the outputs of the proportional amplification modules, integrating and differentiating components are connected respectively to the first, second and third inputs of the adder A PID controller, the output of which is connected to the first input of the second signal switching module, to the second input of which a signal is supplied from the start and stop unit of the hydraulic turbine, and the output is connected to the second input of the module for limiting the current value of the PID controller, the output of which is connected to the second input of the module for starting and stopping the hydraulic turbine, and the output of the module for limiting the rate of change of the signal by pressure is connected to the input of the module for calculating the magnitude of the limitation of opening the guide vane and the module for calculating the opening magnitude of the guide vane the course of the hydraulic turbine, the output of which is connected to the third input of the start and stop module of the hydraulic turbine, the output of the latter being connected to the third input of the adder No feedback.

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