RU129162U1 - HYDRO TURBINE SPEED CONTROLLER WITH Idle Issue - Google Patents

Abstract

1. Regulator of the speed of rotation of a hydraulic turbine with an idle exhaust, which includes a regulator of the speed of a hydraulic turbine, consisting of a mechanism for setting the speed of the hydraulic turbine, a sensor of the actual speed of the hydraulic turbine, a guide vane position sensor, a control mechanism for the guide vane servo drive, an adder for a hydraulic turbine speed regulator, an amplifier a hydraulic turbine speed regulator and a servo drive, the output of which is connected to a guide vane and an idle exhaust, consisting of an idle exhaust valve outlet pipe, an idle exhaust valve, a rod, a balancing piston, an oil servomotor, the piston of which, together with a balancing piston and an idle exhaust valve, is rigidly fixed to a stem, a spool, characterized in that an idle exhaust valve position sensor, a differentiating unit, a calculating unit for generating a specified speed and a specified position of an idle exhaust valve, a control mechanism idle exhaust pressure, an idle exhaust adder and an idle exhaust amplifier, and the differentiating unit is connected to the guide vane position sensor and to a computing unit for generating the set speed and set position of the idle exhaust valve connected to the adder of the hydraulic turbine speed regulator and the idle exhaust adder, which is connected to idle exhaust control mechanism, idle exhaust valve position sensor and idle exhaust amplifier, the idle exhaust valve position sensor is connected to the preset calculating unit

Description

The inventive utility model relates to speed controllers of a hydraulic turbine (hydraulic unit) with a single exhaust.

When regulating the operation of hydraulic turbines (hydraulic units), it is mandatory to ensure the specified regulatory guarantees, that is, to prevent exceeding the critical values of the angular rotational speeds of the turbine (generator) and excessive pressure increase in the water conduit when discharging full or partial power.

In low-pressure stations with short water conduits, guarantees for regulation of the speed of rotation of the turbine are provided due to the programmed closing of the guide vane. In high-pressure stations, with a pressure of more than one hundred meters, having pipelines with a length of more than five hundred meters, for a given value of the moment of inertia of the unit, the closing time of the guiding apparatus, which ensures guarantees of regulation of the speed of rotation of the turbine when the power is reset, leads to an unacceptable increase in pressure in the supply conduit.

To withstand the pressure in the conduit within the permissible limits and to prevent theft speed, an idle discharge is used, which is connected to a spiral chamber or a pressure conduit. With a quick movement of the guide apparatus to close, the idle outlet also quickly opens and then gradually closes.

The total flow rate through the turbine and idle outlet, which determines the speed of water flow in the pressure pipe, changes relatively slowly, as a result of which the pressure increase does not exceed the permissible value.

A known regulator of the frequency of rotation of a turbine turbine (GT) with an idle discharge, including: a regulator of the rotational speed of a turbine, consisting of a mechanism for setting the rotational speed of a turbine, a sensor of the actual rotational speed of a turbine, a control mechanism for a servo drive of a guide apparatus, a position sensor of a guide apparatus, an adder of a frequency regulator of rotation of a hydraulic turbine, an amplifier of a regulator of a frequency of rotation of a hydraulic turbine, a servo-drive providing opening (closing) of a guiding apparatus and given that water flow through the water turbine, as well as managing idle discharge. The idle discharge includes an idle exhaust valve outlet, an idle exhaust valve, a stem, a balancing piston, an oil servomotor, a spool, a linkage, a cataract and a cam that are rigidly connected to the position of the guide apparatus (see Turbine Equipment for Hydroelectric Power Plants. Design Guide. Edited by A.A. Morozov, Gosenergoizdat, Moscow, Leningrad, 1958) [1].

The oil pressure from the oil pressure unit (MNU) on the piston of the oil servomotor and the water pressure on the balancing piston keeps the idle valve in the closed position. When the spool is shifted down, the lower cavity of the oil servomotor is connected to the upper, constantly connected with the drain, and the idle valve, due to the larger area than the area of the balancing piston, opens with water pressure on the surface of the idle valve. The cataract is connected to a linkage linking the spool and piston of the oil servomotor to the stem, which also houses the balancing piston and the idle valve.

The cataract receives movement from the cam, driven by a servo drive of the turbine speed controller, which ensures the opening of the idle outlet when the guide apparatus is closed. The idle discharge closing time is determined by the time the oil does not flow from one cataract cavity to another, which can be regulated by a throttle.

A cataract and a cam with a lever transmission, with the help of which the required dependences of opening (closing) the idle valve when discharging full and partial power are realized are complex mechanical and pneumatic devices. Obviously, for each projected station, a different cam profiling, a different ratio of linkages, and a retuning of cataract and chokes will be required.

, где

- скорость перемещения клапана холостого выпуска, t - время с начала открытия (закрытия) клапана холостого выпуска, традиционным образом может быть реализовано следящим приводом с помощью масляного сервомотора, датчика обратной связи по перемещению клапана холостого выпуска и электрически управляемого золотника (гидрораспределителя), обеспечивающего заданную скорость перемещения поршня масляного сервомотора.On the contrary, the functions of mechanical and pneumatic devices that set the speed of movement of the idle-release valve to open (close) can be implemented in computing units. Tracking the setpoint value equal to S _KL =

where

is the idle exhaust valve movement speed, t is the time from the start of the idle exhaust valve opening (closing), in the traditional way it can be implemented by a follow-up drive using an oil servomotor, a feedback sensor for idle valve movement and an electrically controlled spool (hydrodistributor) providing speed of piston movement of the oil servomotor.

The task to which the claimed utility model is directed is to create a rotational speed controller for a turbine with an idle discharge that has the best technical characteristics: ease of implementation of the law of movement of the valve, the accuracy of maintaining the speed of movement of the valve, and also reducing the overall mass characteristics of the speed controller of a turbine with idle release.

The technical result is to improve the technical and regulatory characteristics, ease of maintenance and debugging.

The technical result is achieved by the fact that in the known regulator of the rotational speed of the turbine with an idle exhaust, which includes the actual regulator of the rotational speed of the turbine, consisting of a mechanism for setting the rotational speed of the turbine, the actual rotational speed of the turbine, the position sensor of the guide apparatus, the control mechanism of the servo drive of the guide apparatus , adder of the hydraulic turbine speed controller, amplifier of the hydraulic turbine speed controller and servo, output to It is connected with a guiding apparatus and an idle outlet, consisting of an outlet nozzle for an idle valve, an idle valve, a rod, a balancing piston, an oil servomotor, the piston of which, together with a balancing piston and an idle valve, is rigidly fixed to the rod, a spool valve position sensor is introduced release, differentiating unit, computing unit for forming a predetermined speed and a predetermined position of the idle-release valve, idle-out control mechanism, sum an idle exhaust mater and an idle exhaust amplifier, wherein the differentiating unit is connected to a position sensor of the guide apparatus and to a computing unit for generating a predetermined speed and a predetermined idle valve position connected to an adder of the hydraulic turbine speed controller and an idle adder which is connected to the idle control mechanism , the idle valve position sensor, the idle amplifier, the idle valve position sensor is connected to a sensing unit for forming a predetermined speed and a predetermined position of the idle exhaust valve and the idle exhaust stem, and the idle exhaust amplifier is connected to a spool, which is used as an electrically controlled valve.

The figure shows the speed controller of a turbine with an idle exhaust in accordance with the claimed technical solution, where:

1 - speed controller of a turbine including:

2 - mechanism for setting the frequency of rotation of the turbine;

3 - sensor actual speed of the turbine;

4 - a mechanism for controlling the servo drive of the guide apparatus;

5 - position sensor of the guide apparatus;

6 - adder speed controller of the turbine;

7 - amplifier speed controller of a turbine;

8 - servo drive;

9 - idle release, including:

10 - the outlet pipe of the valve idling;

11 - valve idle;

12 - stock;

13 - balancing piston;

14 - oil servomotor;

15 - spool;

16 - the gauge of position of the valve of single release;

17 - differentiating block;

18 is a computing unit for generating a predetermined speed and a predetermined position of an idle valve;

19 - idle release control mechanism;

20 - idler adder;

21 - amplifier idle release.

The proposed speed controller of a turbine with an idle exhaust works as follows.

The start of the hydraulic turbine in idle mode is carried out using the program or manually by changing the control signal at the input of the adder of the speed controller of the hydraulic turbine 6 by the servo drive control mechanism of the guide apparatus 4 to the minimum opening of the guide apparatus corresponding to the idle mode. The output of the hydraulic turbine to the power output mode is also carried out either by using the program or manually by gradually increasing the signal from the servo drive control mechanism of the guiding apparatus 4. The steady-state water flow through the guiding apparatus and the hydraulic turbine at this opening corresponds to a given available capacity of the hydraulic turbine at a given frequency of rotation, maintaining which is carried out by the speed controller of the turbine 1. The speed controller of the turbine 1 stabilizes the frequencies turbine rotation.

With the diameter of the seat D _x idle valve 11, its stroke is usually chosen from the ratio ([1] p. 157)

The actual flow rate through the idle valve is:

where H ₀ is the nominal pressure;

ζ is the relative increase in pressure in the pipeline (permissible ζ = 0.15 ÷ 0.2);

- приведенный расход через холостой выпуск, то есть расход при D_x=1 м и Н₀=1 м, в зависимости от хода S_x клапана.

- reduced flow rate through the idle discharge, i.e. flow rate at D _x = 1 m and Н ₀ = 1 m, depending on the stroke S _{x of the} valve.

The required maximum flow rate of water through the idle discharge when dumping full power is determined [1] p. 158 formula (5-11)

where Q ₀ is the maximum water flow through the turbine;

T _s - the closing time of the turbine guide apparatus from its full opening, which provides, in the presence of a single discharge, an allowable increase in pressure and speed;

T is the closing time of the turbine guide apparatus from its full opening, providing an allowable increase in pressure in the absence of idle discharge.

Similar to dependence (3) for the maximum required flow rate through the idle valve when partial power is reset

where Q is the flow rate of water through the turbine at the time of partial power discharge;

- время закрытия направляющего аппарата турбины от начального его открытия, обеспечивающее при наличии холостого выпуска допустимое повышение давления и частоты вращения;

- the closing time of the turbine guide apparatus from its initial opening, which, if there is a single discharge, permits an increase in pressure and speed;

Q _x is the maximum required flow rate through the idle valve when partial power is reset;

T ^* is the closing time of the turbine guide apparatus from its initial opening, providing an allowable increase in pressure in the absence of idle discharge.

Approximately time T can be determined using the formula of indirect hydraulic shock by the constant characteristic of the pipeline a and the permissible pressure increase ζ = 0.15 ÷ 0.2, for example, in the last phase of the hydraulic shock, i.e.

where from

;Where:

;

ΣL · V is the sum of the products of the lengths of the sections of the water main and the speed of water in them;

g is the acceleration of gravity;

, характеризующее начальный относительный расход воды через турбину, то есть

;τ _ON - initial relative opening of the guide vane

characterizing the initial relative flow of water through the turbine, i.e.

;

Y, Y _max - respectively, the initial and maximum opening of the guide vane.

Given the fact that Q = τ _HA · Q ₀ and Q _x = τ _КЛ · Q _xmax , expression (4) will have the form:

и

, получим:From (6) and (7), denoting

and

we get:

But between the actual water flow through the idle valve Q _x and valve movement, as follows from [1], Figure 5-27, there is a relationship due to the nonlinearity of the reduced flow Q _Ix , which can be approximated by a quadratic function of the valve valve S _CL .

Then the actual flow rate through the idle exhaust valve from the expression (2) can be represented as

where b ₁ ; b ₂ - coefficients, at constant values of H ₀ , D _x ; ζ.

Then the relative flow rate of water through the idle valve

and taking into account (8), the speed of movement of the idle-release valve to open should be in the ratio

Expression (11) establishes the relationship between the opening speed of the idle valve and the relative closing speed of the guide vane.

Determine the closing speed of the idle valve as follows.

The closing time of the idle valve from the condition that the permissible pressure in the water conduit is not exceeded can be determined using relation (6), where instead of the flow rate through the guiding apparatus τ _HA · Q _0, take the flow rate through the idle valve τ _КЛ · Q _xmax .

Then

Where:

, а с учетом (10)where from

, and taking into account (10)

Expression (13) establishes the dependence of the closing speed of the idle valve on the position of the valve 8cd, from the condition that the permissible pressure in the water conduit is not exceeded.

скорость перемещения клапана на открытие равна нулю независимо от начального открытия направляющего аппарата, то есть клапан должен быть закрыт.Кроме этого имеется начальное открытие направляющего аппарата τ_НА1, соответствующее части мощности, при сбросе которой не произойдет жесткого гидроудара при любой скорости закрытия направляющего аппарата.Analyzing expression (11), we can see that at the closing speed of the guide vane

the speed of movement of the valve to open is zero regardless of the initial opening of the guide vane, that is, the valve must be closed. In addition, there is an initial opening of the guide _vane τ _HA1 , corresponding to the part of the power that will not cause a hard water hammer at any speed of closing the vane.

Thus, the valve should open while fulfilling the conditions:

τ _AT ≥τ _AT1 and

существенно больше скорости перемещения направляющего аппарата в режиме стабилизации частоты, поэтому клапан холостого выпуска в этом режиме должен оставаться закрытым.If one of these conditions is not met, the idle valve must be closed or be in the closing stage. Value

significantly greater than the speed of movement of the guide vane in the frequency stabilization mode, so the idle valve in this mode should remain closed.

на его выходе формируется уставка по перемещению клапана холостого выпуска S_KЛуст=0. На выходе золотника 15 формируется сигнал, который с помощью масляного сервомотора 14 удерживает клапан холостого выпуска 11 в закрытом положении.Since the speed of movement of the guide apparatus when entering idle and the load is small, the idle valve 11 remains closed. In the computing unit for the formation of a given speed and a predetermined position of the idle valve 18 according to condition (14)

at its output, a setting is formed for moving the idle valve S _KLust = 0. At the output of the spool 15, a signal is generated which, with the help of an oil servomotor 14, holds the idle valve 11 in the closed position.

In critical situations of rapid shutdown of a hydraulic turbine during full or partial power discharges, the guiding apparatus Y quickly closes under the condition that the permissible acceleration of the hydraulic turbine does not exceed and at the same time the idle valve 11 is quickly opened so that the pressure increase in the water conduit does not exceed the permissible value.

, которые сравниваются, соответственно, с расчетными постоянными τ_НА1 и

.In the computing unit for the formation of a given speed and a predetermined position of the idle valve 18, the state of the guide apparatus is continuously evaluated, that is, the value of its relative opening τ _ON and the relative speed of movement

, which are compared, respectively, with the calculated constants τ _HA1 and

.

If conditions (14) are fulfilled simultaneously in the computing unit for the formation of the set speed and the set position of the idle valve 18 with S _KL = 0, according to dependence (11), the required speed of opening the idle valve 11 is calculated, and at its output, a set point for moving the idle valve is formed equal to opening

where t is the time since the opening of the idle valve. According to the signal of the idle exhaust control mechanism 19 in the idle exhaust adder 20, the setpoint according to formula (15) is compared with the readings of the idle valve position sensor 16. According to the difference in readings to the input of the spool 15, which is used as an electrically controlled directional control valve, a signal is supplied through the amplifier 21 which establishes the connection of the cavity under the piston of the oil servomotor 14 with the drain, the pressure in this cavity decreases, and the idle valve 11 due to the larger area compared to the area avnoveshivayuschego piston 13 opens the water pressure in the water line to the calculated valve opening speed.

If at least one of the conditions (14) is not fulfilled, the idle valve 11 closes at a speed equal to the set relation (13) at the moment the valve closes.

To ensure the given guarantees of regulation with greater reliability, the found opening speed of the idle valve should be slightly increased, and the found closing speed of the idle valve, on the contrary, should be reduced.

The proposed regulator of the rotational speed of a turbine with an idle discharge compares favorably with the known ones, namely: ease of debugging, reduction of overall mass characteristics, reduction of maintenance and debugging costs of the regulator.

For example, when changing any parameters of the water line or the initial data on the guarantees of regulation, leading to a change in the laws of opening (closing) the valve of idle release 11, the problem in the proposed device is solved by reprogramming the computing unit for the formation of a given speed and a given position of the valve of idle release 18, and not by reconfiguring and changing linkages, repurposing the cam, adjusting the cataract and other elements of a known mechanical idle release.

The exclusion of mechanical elements - lever transmission, cataract, cam, included in the idle exhaust, reduces its height by more than half a meter, which significantly reduces weight, provides ease of implementation of the valve's law of movement and accuracy of maintaining its speed of movement, increases its adjusting ability, and also guarantees simplicity maintenance and debugging.

Claims (2)

1. The idle speed turbine speed regulator including a turbine speed regulator, consisting of a mechanism for setting the rotational speed of the turbine, an actual rotational speed sensor of the turbine, a position sensor for the guide apparatus, a servo control mechanism for the guide apparatus, an adder for the governor of the rotational speed of the turbine, amplifier a regulator of the rotational speed of a hydraulic turbine and a servo drive, the output of which is connected with a guiding apparatus and a single exhaust consisting from the outlet pipe of the idle valve, idle valve, stem, balancing piston, oil servomotor, the piston of which, together with the balancing piston and the idle valve, is rigidly fixed to the piston rod, spool, characterized in that a position sensor for the idle valve, which differentiates unit, a computing unit for generating a predetermined speed and a predetermined position of an idle exhaust valve, an idle exhaust control mechanism, an idle adder and an amplifier an outlet, the differentiating unit connected to a position sensor of the guide apparatus and to a computing unit for generating a predetermined speed and a predetermined position of the idle valve connected to an adder of the hydraulic turbine speed controller and an idle adder that is connected to the idle control mechanism, the idle valve position sensor release and amplifier idle, the valve position sensor idle connected to the computing unit formation speed and a predetermined idle discharge position and idle discharge valve rod, and idle discharge amplifier is connected to the spool. 2. The idle speed turbine speed controller according to claim 1, characterized in that an electrically controlled hydraulic distributor is used as the spool.

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