JPH07238801A - Governor control device fir steam turbine - Google Patents

Abstract

PURPOSE:To provide the governor control device which can easily perform a full arc admission mode, and concurrently exhibit the full performance of a turbine. CONSTITUTION:In the steam governor control device which is equipped with a plurality of steam chambers 28a and 28b having a stop valve at its inlet in addition to a plurality of steam governors 2a through 2d, and is provided with a plurality of nozzle boxes 5 corresponding to a plurality of the steam governors located at the circumferential direction, steam inlet pipes 19 connecting the governors to each nozzle box, and with an electric governor 12 controlling the steam governors, each connecting pipe 22 is provided, which connects the steam inlet pipe at one steam chamber side to the steam inlet pipe at the other steam chamber side, and has a connecting valve 23 And moreover, a gain switching means 31 for the electric governor is provided, which can switch a gain in response to the opening/closing of the connecting valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control valve controller for a steam turbine applied to steam turbine power generation equipment.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIG.

The boiler is connected to two steam chambers 28a and 28b via stop valves 1a and 1b, respectively. Steam control valves 2a, 2c and 2 are provided in the steam chambers 28a, 28b, respectively.
b, 2d (may be 6 to 8). The steam turbine 6 has nozzle boxes 5 (A to D) arranged in the circumferential direction and having nozzles 20. Each steam control valve 2a-2d
Are connected to the corresponding nozzle boxes A to D by respective steam inlet pipes 19. Each steam control valve 2a, 2b and 2c, 2d
Is connected to the servomotor 3. Each servo motor 3
The hydraulic pressure is supplied to each of them via the electro-hydraulic converter 4.

An opening signal is sent from the electric governor 12 to each electro-hydraulic converter 4. Outputs from the rotation detector 8 of the turbine 6 and the load detector 9 of the generator 7 are input to the electric governor.

In the figure, 13 is a speed setting device, 14 is a load setting device, 15 and 16 are gain devices, and 30 is an adder.

In the above, the steam sent from the boiler is divided into two systems and sent to the steam chambers 28a and 28b through the main steam stop valves 1a and 1b, respectively. The valve opening degree of the steam control valves 2a to 2d in each steam chamber is controlled by a control signal (opening degree instruction signal) 17s from the electric governor 12 via the electro-oil converter 4 and the servo motor 3. Each steam control valve is opened in sequence according to the output demand in order to minimize throttling loss of the valve.

In the case of this figure (in the case of four valves), the valves 2a and 2b are first opened simultaneously, and then 2c and 2d.
Opens in response to the output demand and sends steam to the nozzle box 5 through the steam inlet pipe 19. The steam in the nozzle box 5 becomes a high-speed jet flow at the nozzle 20 to drive the rotor and the generator to generate electricity. The control of the steam control valves 2a to 2d is performed by the electric governor 12, and the deviation between the output of the speed setter 13 and the actual speed signal 10s from the speed detector 8 and the output of the load setter 14 and the generator load detector 9 are controlled. From the actual load signal 11s by the gains K ₁ and K ₂ in the proportional gain units 15 and 16, respectively, and the valve opening signal 17
s is created, and the opening degrees of the steam control valves 2a to 2d are controlled.

[0008]

The conventional control valve controller for a steam turbine has the following problems. (1) At the time of starting the steam turbine, in order to reduce the thermal stress generated in the rotor as much as possible, the operating method is changed according to the rotor temperature at the time of starting. When the temperature of the rotor is low, the partial injection mode in which the steam stop valve is fully opened and the steam control valve is sequentially opened is selected.

On the contrary, when the temperature of the rotor is warm, the all around injection mode is selected in which all the steam control valves are fully opened and controlled by the opening of the steam stop valve. In the full-circle injection mode, it is controlled by the steam stop valve, so in order to operate the turbine output in the full-circle injection mode up to a high value, the guide valve diameter in the main steam stop valve is increased in relation to the steam flow to be controlled, Also, the servo motor that drives the valve must be large. (Factor of cost increase) Further, since the load is adjusted by the main steam stop valve, the control function of the main steam stop valve needs a load control function, which causes a cost increase for the control device. (2) The main valve of the steam turbine is periodically opened and closed during operation so that the valve does not get out of control due to steam scale or the like, and a valve test is performed to prevent sticking.

The valve test method is performed by completely closing one series of steam control valves and then fully closing the main steam stop valve on the same side.

Therefore, at the time of the valve test, since the steam only flows through the main steam stop valve and the steam control valve of one series (the side not tested), the output of the turbine cannot be 100%, and the output of the turbine is close to 70% before the valve test. Output must be reduced to. (3) When the output of the turbine is rapidly increased or decreased according to demand, thermal stress occurs due to a rapid temperature change in the turbine. Therefore, it is better that the temperature change is smaller with respect to the output change from the viewpoint of relaxing the thermal stress, and the omnidirectional injection mode is selected as the operation mode. However, in the conventional system, the capacity of the main steam stop valve is at most 30.
There was only about% output, and in the high output area, operation in the full-circle injection mode was not possible, and rapid increase / decrease in output could not be performed.

[0012]

The present invention takes the following means in order to solve the above problems.

That is, a plurality of steam chambers having a plurality of steam control valves and a stop valve at the inlet, and a plurality of nozzle boxes arranged in the circumferential direction corresponding to the steam control valves.
In a control valve controller for a steam turbine having a steam inlet pipe connecting the steam control valve and a nozzle box, and an electric governor for controlling the steam control valve, one steam inlet pipe on the steam chamber side and the other steam A communication pipe that connects the steam inlet pipes on the chamber side and has a communication valve, and a gain switching device for the electric governor that switches the gain according to opening and closing of the communication valve are provided.

[0014]

In the above means, the full-circle injection mode is used, for example, in the case of rapid output increase operation. At this time, when each communication valve is first opened, steam is supplied to the nozzle box on the entire circumference through each communication pipe. Therefore, the full-circle mode operation is smoothly performed from the fully closed to fully opened state of the steam control valve, and the rapid output increase operation is possible.

At this time, the compensation gain of the electric governor is correspondingly switched and the optimum opening signal is output, so that the above operation is smoothly and stably performed.

Further, at the time of valve inspection, for example, even if one stop valve and the steam control valve of the steam chamber of the system are closed, when each communication valve is opened in the same manner as above, steam from other steam chambers will flow into each nozzle box. Since it is supplied to, the operation can be maintained without significantly reducing the output as in the conventional case.

Therefore, it is possible to inspect the valve while performing normal operation.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention described above will be described with reference to FIG. The parts explained in the conventional example are given the same numbers and their explanations are omitted, and the parts relating to the present invention will be mainly explained.

A communication pipe 22 having a communication valve 23 between the steam inlet pipe 19 emerging from the steam pressure reducing valve 2a of the one steam chamber 28a and the steam inlet pipe 19 emerging from the steam pressure reducing valve 2d of the other steam chamber 28b. Can be connected. Similarly, one steam chamber 28
A communication pipe 22 having a communication valve 23 connects the steam inlet pipe 19 from the steam pressure reducing valve 2c of a to the steam inlet pipe 19 from the steam pressure reducing valve 2b of the other steam chamber 28b. The electric governor 12 has a gain switching device 31 after the adder 30.
Can be connected. The gain switching device 31 includes a changeover switch 25.
There are a gain unit 26 and a gain unit 27 arranged in parallel.

In the above, during normal operation, the steam communication valve 23 is closed, and the steam from the steam control valves 2a to 2d is sent to the corresponding nozzle boxes to drive the turbine rotor and the generator. . In this case, α _{1 of the} gain unit 26 is selected as the correction gain of the electric governor 12.
This is a so-called partial injection mode, and is used during normal operation with little output fluctuation or when the rotor temperature is low at startup.

When the rotor temperature at startup is high, or when there is a rapid output increase / decrease request, the full-circle injection mode is used. In this case, each steam communication valve 22 provided in each steam communication pipe 22 is opened.

In this mode, two nozzle boxes are connected to one steam control valve. In other words, the steam control valves (2a and 2b) that start to open first are in a state of being connected to all the nozzle boxes (from 2a to the nozzle boxes 5A and 5D, and from 2b to 5B and 5C), so that 4 in all output ranges. This is the so-called full-circle injection mode in which steam is introduced into the turbine from individual nozzle boxes.

In this case, since steam is sent from one steam control valve to the two nozzle boxes, the flow rate of steam flowing from the steam control valve is in the state where the steam communication valve 23 is closed (partial introduction mode).
Compared with, the control of the steam turbine may become unstable. Therefore, in this mode, the gain β side of the correction gain unit 27 is selected, and the control gain is about 1/2.
The stable operation becomes possible.

During the valve test, the steam communication valve 23 is opened. Then, by performing the test, the nonconformity, which was conventionally required to reduce the turbine output due to the valve test, is eliminated.

For example, when the system side of the main steam stop valve 1a and the steam control valves 2a and 2c are closed by a valve test,
Conventionally, the steam from the steam control valves 2b and 2d is supplied only to the respective nozzle boxes 5B and 5D, so that the output of the turbine is limited.

However, the steam communication valve 23 is opened, two nozzle boxes 5 are connected to one steam control valve, and the steam from the steam control valves 2b and 2d is supplied to all the nozzle boxes 5A to 5D.
Supplied to 5D. Therefore, the turbine output can be selected at any value and the output reduction can be prevented.

As described above, in order to maximize the performance of the turbine, in the conventional configuration, the operation of the full-circle injection mode is performed, the capacity of the main steam stop valve and the servo motor is increased, and the load control of the main steam stop valve is performed. It is necessary to increase costs such as adding functions, but these are unnecessary.

Further, the all-around injection mode can be selected in any output range, and flexible operation becomes possible. Further, since the valve test can be performed at 100% output, it is not necessary to limit the turbine output for the valve test.

[0029]

As described above, the present invention has the following effects. (1) The full-circle injection mode can be selected in any output range, which enables flexible operation. (2) Since the valve test can be performed even at 100% output, it is not necessary to limit the turbine output for the valve test.

[Brief description of drawings]

FIG. 1 is a configuration system diagram of an embodiment of the present invention.

FIG. 2 is a configuration system diagram of a conventional example.

[Explanation of symbols]

 1 Main steam stop valve 2 Steam control valve 3 Steam control valve Servo motor 4 Steam control valve Electro-oil converter 5 Nozzle box 6 Steam turbine 7 Generator 8 Speed detector 9 Generator load detector 10s Actual speed signal 11s Actual load signal 12 Electric governor 13 Speed setting device 14 Load setting device 15 Speed gain device 16 Load gain device 17s Steam control valve opening command 18 High pressure oil 19 Steam inlet pipe 20 Nozzle 21 Main steam stop valve Servo motor 22 Steam communication pipe 23 Steam communication valve 24 Openness meter 25 Changeover switch 26 Correction gain device 27 Correction gain device 28 Steam chamber 29 Subtractor 30 Adder 31 Gain switching device

Claims (1)

[Claims] 1. A plurality of steam chambers having a plurality of steam control valves and a stop valve at an inlet, a plurality of nozzle boxes arranged in the circumferential direction corresponding to the steam control valves, the steam control valve and the nozzle box. In a control valve controller of a steam turbine having a steam inlet pipe connecting the steam control pipe and an electric governor for controlling the steam control valve, between the steam inlet pipe on the one steam chamber side and the steam inlet pipe on the other steam chamber side. A control valve control device for a steam turbine, comprising: a communication pipe that communicates with each other and a communication valve; and a gain switching device of the electric governor that switches a gain according to opening and closing of the communication valve.