RU1815336C - Load control method for multicylinder regenerative-extraction steam turbine - Google Patents

Abstract

Usage: heat power, operation of steam turbines of thermal and nuclear power plants. SUMMARY OF THE INVENTION: in order to increase the efficiency, maneuverability and reliability of a turbine, the regulation of its load is carried out by sequentially changing the position of the regulating bodies until the maximum permissible pressure condition for the corresponding cylinder is reached. 1 ill.

Description

The invention relates to a power system and can be used in the operation of steam turbines of thermal and nuclear power plants.

The purpose of the invention is to increase the efficiency, maneuverability and reliability of a turbine.

This goal is achieved by the fact that in the method of regulating the load of a multi-cylinder steam turbine with steam extraction by regulating the flow of steam passing through the flow part of the turbine cylinders by throttling the steam distribution bodies of these cylinders, the steam is controlled by sequentially changing the position of the regulating bodies (throttling) at the outlet from the turbine cylinders (at the entrance to the subsequent cylinder), starting from the last steam along the way, until reaching the maximum permissible, under the conditions of pressure, downstream of the last stage of these cylinders: with decreasing load, the pressure behind the cylinders is sequentially increased (the vacuum in the turbine condenser is reduced by the cooling water flow rate, the steam distribution valves or additionally installed dampers in the receivers for supplying steam to the turbine low pressure cylinders are covered, and the steam distribution valves are covered or additionally installed dampers in the steam pipelines at the inlet to the medium pressure cylinders, with a steam distribution cover x organs at the inlet of the high pressure cylinder, while increasing the load regulating cylinders bodies complete opening of the turbine (reducing the vapor pressure of the cylinders) and increase the vacuum in the turbine condenser is produced out in reverse order.

The drawing shows a schematic diagram of the load control of a single-cylinder steam turbine with steam extraction, which implements the described method.

A steam turbine contains cylinders of high (CVP) 1, medium (TsSD) 2 and low (TsND) 3 pressure with steam extraction 4, 5, b from these cylinders, respectively, an electric generator 7, a condenser 8, a steam

with

00

ate

00 (L) O

distribution (regulatory) bodies 9, 10, 11 at the entrance, respectively, to the CVP, TsSD, TsND, pressure sensors 12, 13 and 14 at the output of these cylinders, respectively, the circulation pump 15, the shut-off and regulating body 16 on water conduit, steam pressure regulators 17, 18, and 19 (as specified by the load regulator 20) at the outlet of the low, medium, and high pressure cylinders, respectively, and a turbine load regulator 20.

A method for controlling a turbine load is as follows.

With a decrease in the load of the turbine working with fully open steam distribution (control) bodies at the inlet of the turbine cylinders and with normal vacuum, a pressure regulator of steam 1.7 is sent to the turbine condenser (exhaust pipe) 1.7, which through the actuator (in the diagram) not shown) affects the closure of the regulator 16 on the water supply or on reducing the flow of the circulation pump 15 to a certain value of the pressure increase in the condenser, measured by the sensor ohm 14 and determined, for example, by the permissible temperature of the steam at the inlet to the turbine condenser. If it is necessary to further reduce the turbine load according to the task of the load regulator 20, a signal to the regulator 1.8 is sequentially sent to increase the pressure after the next (in the direction of increasing the vapor pressure) after the low-pressure cylinder of medium pressure. The regulator 18, through an actuator (actuator), acts to close the regulator 11 at the inlet of the low-pressure cylinder to the required, according to the conditions of reducing the turbine load, pressure increase at the outlet of the central cylinder. A pressure sensor 13 measures this pressure and provides a shutdown of the regulator 18 when the maximum permissible (predetermined), according to the conditions of strength, pressure at the outlet of the DDC is reached. With a further decrease in the turbine load, in the same way as for the central cylinder, the regulator 19 covers the regulating body 10 at the inlet of the central cylinder to the maximum permissible pressure value at the outlet of the central cylinder, recorded by the pressure sensor 12, and only after the exhaustion of the possibility of reducing the turbine load by a sequential increase in pressure behind the cylinders, the load regulator 20 through the drive (not shown in the drawing) acts on the cover of the regulatory body 9, which reduces the consumption of fresh steam in the turbine CVP.

If it is necessary to increase the turbine load, the full opening of the regulatory bodies is carried out in the reverse order (before the CVP, TsSD. TsND, pressure reduction in the turbine condenser (9.10, 11 and 16, respectively) or in case of an emergency increase in the turbine load by the simultaneous opening of all steam distribution bodies and accelerated dialing

vacuum. The control circuit provides for automatic blocking to open the regulatory body 11 at the entrance to the low-pressure cylinder 3. Until a normal vacuum in the capacitor 8 is set.

The load regulation according to the proposed method when the turbine is operating at loads below nominal leads to throttling of only part of the steam flow passing through the covered regulating body and does not throttling that part of the steam that enters the turbine take-offs located along the steam before this regulating body, which increases profitability. Since steam throttling in the lower pressure region leads to a more significant reduction in the available heat transfer, this allows an increase in the rate of change of the turbine power, which improves its maneuverability. In addition, since the vapor pressure in front of the turbine is kept constant, with the control valves fully open, the temperature of the high-temperature Turbine Parts remains

unchanged. Due to this, when the load changes, there is no unevenness of the temperature fields in the cross sections of the turbine casing, which causes thermal stresses, do not appear

relative thermal expansion (or shortening) of the rotor decreases bending stresses, especially dynamic ones, in the blades of the first stage. These circumstances significantly improve the reliability and maneuverability of the turbine.

The economic effect of the use of the invention is defined in relation to the basic object - a 100 MW steam turbine. When the turbine is operating

at partial loads in the range of 50-90% of the nominal increase in turbine power, compared with the prototype, reaches 0.5-1.5%.

Claims (1)

The claims 5 A method of regulating the load of a multi-cylinder steam turbine with regenerative steam extraction by measuring the pressure behind the cylinders and regulating the flow of steam by changing the position of the regulatory bodies, the fact that, in order to increase reliability, when the load is reduced, the regulatory bodies are closed sequentially, starting with the last steam conditions of pressure strength behind the corresponding cylinder, and with increasing load, the opening of the regulatory bodies is carried out in the reverse sequence until the maximum permissible level of 5 is reached.