RU2674375C2 - Method of controlling blades of impeller of adjustable blade turbine - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention relates to the field of energy, and in particular to a method of controlling the servomotor of the blades of an impeller of adjustable blade turbine, using when determining the position of actuator servomotor 7 blades of the impeller in accordance with the combinatorial dependence as input signals, the output signal of proportional-integrating regulator 4 of turbine power, specifies the position of servomotor to drive 6 of blades of guide vanes 8, and the power developed by the turbine in the combinatorial mode. Method consists in the fact that as the signal of combinatorial power use the signal of the expected combinatorial power of the turbine, determined by the values of the active and measured reactive powers of the generator, as well as the known dependences of its efficiency factor from them.

EFFECT: invention is aimed at ensuring the accuracy of the angle of rotation of the blades.

1 cl, 2 dwg, 1 tbl

Description

The invention relates to the field of energy, in particular, to the field of active electric power control of generators driven by jet hydraulic turbines with two regulatory bodies, the coordinated control of which allows to achieve high efficiency energy conversion over a wide range of loads.

Rotary lobed, capsular and diagonal turbines have two regulating bodies: a guiding apparatus (hereinafter “ON”), and impeller blades (hereinafter “RK blades”). Each of the positions of the NL blades corresponds to the angle of rotation of the blades of the RK depending on the acting pressure, at where the circulation of the flow at the outlet of the turbine will ensure the achievement of the maximum value of its efficiency The hydraulic mode of the turbine in this case is called combinatorial [G.I. Krivchenko. Hydraulic machines. Turbines and pumps. M. "Energy", 1978, pp. 29-30, 119-123.], And about the mutual position of regulatory bodies they say that they are connected by combinatorial dependence. The magnitude of the opening of the air conditioner and the angle of rotation of the blades of the Republic of Kazakhstan are uniquely determined by the positions of the servomotors of their hydraulic drives, therefore the position of the regulatory bodies and the assignment of this position to the servomotors of their drives are identified by the control systems.

Further, by combinatorial dependence is meant ensuring the achievement of maximum efficiency the dependence of the position, the servomotor of the drive of the blades of the Republic of Kazakhstan on the position of the servomotor of the drive of the blades of the NA and some operating parameter that is uniquely associated with the net pressure at this position of the regulatory bodies. If we indicate the position of the servomotor of the drive blades ON - Y1, the position of the servomotor of the drive of the blades of the impeller - Y2 and the pressure head net - N, then the record of the combinatorial dependence will look like:

Where:

Y1 is counted from the position corresponding to the fully enclosed guide apparatus, in fractions of the full stroke of the ON servomotor;

Y2 is counted from the position corresponding to the rotation of the blades by the minimum angle, in shares from the movement of the servomotor when the angle of rotation of the blades to the maximum angle changes;

i = 1, ..., k is the number of selected constant values of the net head N.

A well-known drawback of using combinatorial dependencies (1) parameterized by the net pressure is the difficulty in determining the net pressure. At low pressures, errors in determining the position of the RK servomotor at the same position of the ON servomotor can reach 5-6%, which leads not only to a reduction in efficiency, but also causes increased vibration and premature wear of the unit, [cm . RD 153-43.2-21.564-00. Guidelines for accounting for water flow at hydroelectric stations. 2.3.7. The total error of pressure measurement at hydroelectric power plants. RAO UES of Russia. Shall be enforced from 04/02/2001]

An alternative to the combinatorial mechanism, in which the dependence of the position of the RK servomotor on the position of the ON is parameterized by the net head, is a method that uses the parameterization of the turbine power developed by it in the combinatorial mode (see USSR AS No. 291583: V. I. Grigoryev. USSR Author's Certificate No. 291583 in class F03B 15/06. A method for controlling the impeller blades of a hydraulic turbine. Bull. No. 41, 11/05/77.). Using the dependence of the position 72 of the blade rotation servomotor on the position Y1 of the servomotor ON and the turbine power P _T gives, in comparison with the dependencies in which the net head N is used as a parameter, the following advantages:

- simplicity and accuracy of determining the mechanical power of the turbine by the values of the active P _G and reactive Q _G generator power;

- correspondence of the parameter of the natural object and the model, on the basis of the experimental characteristics of which the used combinatorial dependencies were obtained;

- the integral nature of the “power” and “local” values of the measured net head.

Next, along with the expression combinatorial mechanism, the term “combinatorial dependence shaper” or PCF will be used, having in mind its function: determining the position Y2 of the rotor blade drive servomotor required for the implementation of the combinatorial mode from the input signals proportional to the position of the drive servo motor Y1 of the HA actuator and the turbine power P _T . Mode parameters, for example, turbine power, flow through it, etc., in combinatorial mode will be called “combinatorial power” or “combinatorial flow”.

When using combinatorial dependencies parameterized by the net head, setting two parameters “position of the servo motor ON” and “net head” unambiguously determines the “position of the servo motor RK”. Setting two parameters “position of the servomotor ON” and “combinatorial power” in the case of using combinatorial dependencies parameterized by the value of combinatorial power ensures the achievement of the combinatorial mode only if the turbine power is equal to the set value of combinatorial power.

In view of the foregoing, the FKZ operation algorithm with parameterization of dependences by combinatorial power is as follows:

1. To obtain data on the magnitude of the required turbine power and apply a signal proportional to its value to the input “combinatorial power” of the shaper of combinatorial dependence, while the input “position of the servomotor ON” continuously sends a signal to set the position Y1 of the position of the servomotor ON.

2. If the measured current power of the turbine is less than the required, then generate a command for the actuator drive ON to “open more”, if the measured current power of the turbine is more than required, then generate a command to the servomotor of the drive ON “less”.

3. If the required and current powers are equal, stop the movement of the servo motor ON.

The use of FKZ with the parameterization of combinatorial dependences by the value of the combinatorial power of the turbine necessarily requires the use of power feedback in order to achieve the main goal: to ensure the operation of the turbine in combinatorial mode.

When operating as part of a powerful receiving system, the electric active power of the generator P _G is equal to the product of the power of the turbine P _T and the efficiency of the generator depending on the active P _G and reactive Q _G "Η _G " and mechanical efficiency η _meh ", taking into account the friction loss in the turbine bearing:

All active generator power P _G is transmitted to the network.

Hydro generator control systems incorporate a proportionally-integrating power regulator with main feedback on the generator active power. The positioner of the servomotor of the guide vane, formed by the regulator, is transformed: in accordance with the current pressure by the combinatorial dependency shaper, the position of the impeller servomotor, required for efficient operation of the turbine, is converted. Thus, the power controller with one signal for setting the position of the guide apparatus simultaneously controls two regulatory bodies. An example of the implementation of power control of a hydraulic turbine can be a block diagram [see VOITH "HyCon ™. Digital turbine governor", Heidenheim. https://voith.com/de/12_06_Digital_Turbine_Governor.pdf].

The previously considered technical solution [A.S. SU 291583 A] for the implementation of the combinatorial mode has feedback on the active power of the generator, the sensor signal of which is fed to the input FKZ intended for the signal proportional to combinatorial power. This technical solution completely eliminates the use of frequency and power regulators of hydraulic turbines, due to the unpredictable behavior of the drive of the servo motor of the Republic of Kazakhstan, caused by the inclusion of positive feedback on power parallel to the main feedback on its position.

A technical solution is also known [see “A method and apparatus for improving the accuracy of controlling the angle of installation of the blades of a rotary-vane turbine”, RF patent RU 2608793 C2], which consists in maintaining an indicator of the deviation of the turbine operation mode from the combinatorial one in the control system of the blades of the Republic of Kazakhstan by means of PCF, parameterized by the net pressure: the difference between the turbine power and the power that it should generate if its regime under the current mutual position of regulatory bodies is combinatorial. The additive correction of the net head is proportional to the integral of the signal generated by the indicator to compensate for errors in the determination of the net head by tools.

In its technical essence, the proposed method for controlling the blades is closest to the PI-power controller of a turbine with a PCF parameterized by a net head, since it does not require a special additional circuit with power feedback to realize the PCB function parameterized by a combinatorial signal.

The objective of the invention is to develop a method for controlling the impeller blades of a rotary vane turbine, based on determining the angle of rotation of its blades according to combinatorial dependencies parameterized by the value of the combinatorial power of the turbine, to predict the value of which the signal of setting the active power of the generator is used, which is the input to the guiding servo motor proportionally -integrating turbine power regulator. This will ensure high accuracy in determining the angle of rotation of the blades, achieved by using a shaper of combinatorial dependencies parameterized by the value of the combinatorial power of the turbine, and at the same time, preserve the structural simplicity of the drive control system for servo motors of regulating organs characteristic for controlling the impeller blades by a shaper of combinatorial dependencies parameterized by the net head. when performing tasks of the power regulator.

The problem is solved in a method of controlling the impeller blades of a hydraulic turbine, including the use of signals for setting the active power of the generator, sensors for its active and reactive powers, the output signal of the proportional-integrating power regulator of the turbine, the input signal of which is the difference between the reference signals and the output signal of the active power sensor, and output - setting the position of the servomotor of the drive vanes of the guide apparatus, based on the use of ensuring the achievement of m ksimalnogo efficiency experimental dependence of the position of the rotor blades drive servomotor on setting the position of the servomotor of the guiding apparatus and the turbine power in combinatorial mode, which consists in determining the signal of the expected combinatorial power of the turbine from the signal values of the active, measured reactive power of the generator and its efficiency as a function of them and using the signal of the expected combinatorial power as an input in the mentioned experimental dependence for determining the position of the servomotor for the drive of the impeller blades.

In FIG. Figure 1 shows the standard inclusion of a shaper 5.1 of combinatorial dependencies parameterized by the net pressure into the power control system of the rotary-blade unit, where the signals of the generator 2 active power of the generator and sensor 1 of its active power are fed to the input of the PI controller 4, which generates an output signal for setting the position of the servomotor drive 6 blades ON, also received at the input of the shaper combinatorial dependence 5.1, the other input of which is fed a pressure signal net from the transmitter 3 station system changes in hydraulic values, and its output signal is the setting of the position of the servomotor of the drive 7 of the blades of the Republic of Kazakhstan, changes in the position of the servomotors of the drives 6 and 7 provide changes in the power of the turbine 8 and generator 9;

In FIG. Figure 2 shows a diagram of the inclusion of a shaper 5.2 of combinatorial dependencies parameterized by the value of the combinatorial power of a turbine in its power control system. The signals of the generator 2 active power of the generator and the sensor 1 of the active power of the generator are fed to the input of the proportional-integrating controller 4, the output signal of which is the position of the servomotor of the drive 6 of the blades of the guiding apparatus of the turbine 8, as well as the input for the shaper 5.2 of combinatorial dependencies, to the other input of which the signal of the calculator 11 of the expected combinatorial power of the turbine, determined by the output signals of the master unit 2 of the active power and the sensor 10 of the reactive power of the generator 9, determined by the dependence of the generator efficiency on its active and reactive powers, the output signal of the shaper 5.2 is the position of the actuator of the drive of the 7 blades of the Republic of Kazakhstan.

Presented in FIG. 2, the diagram illustrates methods for processing sensor signals and functional elements that are the subject of patenting of the proposed method for controlling the impeller blades of a rotary vane turbine.

The possibility of implementing the proposed method confirms the consideration of the characteristics of some of the elements that make up the device that implements the proposed method for controlling the impeller blades of a rotary vane turbine. The generator 11 of the signal proportional to the mechanical power of the turbine according to the values of the active power and the current value of the reactive power of the generator is a converter that calculates the expected mechanical power of the turbine according to formula (6) and the technical parameters of the generator. For example, for the generator SV-1343 / 140-96UHL4 (Novosibirsk hydroelectric station), the parameters are given in table No. 1.

The mechanical efficiency of the turbine according to the LMZ varies in the range η _meh = 0.995 ÷ 0.998.

From table No. 1 it follows that the reactive power of the generator when changing it from zero (cosϕ = 1) to the nominal value at a given level of load (active power) weakly affects the value of the efficiency generator. This means that the output signal of the shaper 11 weakly depends on the nature of the change in the reactive power of the generator, and, therefore, the value of the combinatorial power P _K selected on the basis of the set value of the active power P _ZAD , determining which line, parameterized by its value, changes the position setting Y2 of the RK servomotor when changing the job Y1, the position of the ON servomotor will remain almost unchanged until the end of the control process, until the active power of the generator becomes equal to the set (P _ZAD = P _G ) and reactive power value. The role of the shaper signal 11 is to a certain extent similar to a constant value (more precisely, slightly changing due to a change in pressure loss in the hydroelectric power lines) of the net pressure signal (Fig. 2) when using combinatorial dependences parameterized by the net pressure. In both cases, the position of the blades of the RK is determined by the ordinates almost unchanged in the process of controlling the curve. The abscissa for finding the value of this ordinate on it is a signal for setting the position of the servomotor ON.

Proportional-integrating controller 4, which are input to P _ZAD setpoint signal 2 and the active power signal P _G sensor signal will change the reference position of the servomotor 71 ON, as long as the difference (P _ZAD -P _G) becomes zero.

Thus, at the final equilibrium point, two basic equalities will be satisfied: (P _ZAD -P _G ) = 0 and P _T = P _K , which indicates the achievement of the objective of the proposed method for controlling the blades of a hydraulic turbine.

The proposed method for controlling the impeller blades of a rotary-vane hydraulic turbine, due to the connected movement of both regulatory bodies and the need to bring the unit to the generation mode of a certain power level, cannot be applied in two cases: when the speed is stabilized in an isolated area when the power is determined by the consumer, and depends on the rotation frequency, and in the case of direct control of the magnitude of the opening of the guide vane, when the regulation of the watercourse.

Claims (1)

A method for controlling the impeller blades of a hydraulic turbine, including the use of signals for setting the active power of the generator, sensors for its active and reactive powers, the output signal of the proportionally-integrating power regulator of the turbine, the input signal of which is the difference between the set signal and the output signal of the active power sensor, and the output is setting the position servomotor drive vanes guide vanes, based on the use of achieving maximum efficiency experimental dependence of the position of the rotor blades drive servomotor of the impeller on setting the position of the servomotor of the guiding apparatus and the turbine power in combinatorial mode, which consists in determining the signal of the expected combinatorial power of the turbine from the signal values of the active, measured reactive power of the generator and its efficiency as a function of them and using the signal of the expected combinatorial power as an input in the mentioned experimental dependence for determining the position of the servomotor for the drive of the impeller blades.

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