JPS5937209A - Control device of reheating steam turbine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a reheat steam turbine that performs all-round injection startup.

Generally, when starting up this German reheat turbine, steam supplied from the steam source is controlled by a bypass valve built into the main steam stop valve to perform full-circle injection startup, and then from the bypass valve to the steam control valve. Normal operation is performed by switching the control, and when switching from full-circle injection start to normal operation, it is desirable that the reheat steam pressure be kept constant and that there will be no output fluctuations or excess or deficiency in the steam temperature.

FIG. 1 shows a conventional embodiment and is a control system diagram of a reheat steam turbine. First, normal control of the reheat steam turbine will be explained based on the drawings. Steam from the boiler 9, which is a steam source, is guided through a pipe 9a, passes through the main steam stop valve 1 (incorporating a bypass valve 11) and the steam control valve 2, and reaches the high pressure section of the high pressure casing 21 of the turbine. rt, which performs work in the upland pressure section and low pressure section. Further, the steam discharged from the high pressure casing 21 is reheated by the reheater 8, and is supplied to the high pressure section of the intermediate pressure casing 22 of the turbine through the reheat steam stop valve 7 and the intercept valve 3, and is then supplied to the high pressure section of the intermediate pressure casing 22 of the turbine. Work in low pressure areas.

Further, the steam coming out of the intermediate pressure casing 22 is supplied to the high pressure section of the low pressure casing 23, does work in the high pressure section and the low pressure section, and reaches the condenser 24. The total work of the reheat turbine is
1. This is the sum of the work done by the steam in the medium pressure casing 22 and the low pressure casing 23. The turbine is connected to a generator 25, and a governor impeller 26 is directly connected to the rotor shaft on the high pressure casing 21 side. The governor impeller 26 establishes a primary hydraulic pressure in the conduit 27 having a pressure depending on the rotation speed of the rotor. The primary hydraulic pressure established in the conduit 27 acts on the bellows 31 of the rotational speed setting device 30. When the load on the turbine increases and the rotational speed of the rotor decreases, the primary oil pressure decreases, and the spring 3
Reno rotating around pin join 33 with the force of 2 (3
4 is pushed down, and the sleeves 35, 36 and 37 attached to the other end of the lever 34 are pushed down. On the other hand, pressure setting cylinders 45, 46 and 47 are provided with these sleeves facing each other,
A steam valve reduction switching device 10 that sets the secondary oil pressure of each
1. A bypass valve switching device 102 and an intercept valve switching device 103 are configured. Since the pressure setting elements of these three devices are the same, only the steam control valve switching device 101 will be described. This switching device 101 receives pressure oil from a high-pressure oil supply source (not shown) through a high-pressure oil pipe line 201, and connects the pressure setting cylinder 45 to the pipe line 201.
01, and has a piston 49 inside which is biased upward by a spring 48. The piston 49 is hollow and allows the pressure oil from the pipe line 201 to enter therein, and has an outflow boat 50 in its lower part, and the outflow port 50 is opened and closed by sliding fitting into the piston 49. This is done by changing the relative position of the mating sleeve 35 and the boat 35a. As mentioned above, when the load on the turbine increases and the rotational speed decreases, the primary oil pressure decreases, and when the sleeve 35 attached to the lever 34 is lowered, the outflow from the outflow port formed between the sleeve 35f and the piston 49 decreases. If the area is reduced, the hydraulic pressure of the secondary hydraulic pipe 5 will increase. The secondary oil pressure increased in this way increases the opening angle of the steam control valve 2. On the other hand, in the intercept valve switching device 103, due to a change in the relative position between the built-in piston and the sleeve 37, the secondary oil pressure in the pipe line 6 where the intercept valve switching device 103 and the intercept valve 3 are connected increases. The opening angle of the intercept valve 3 increases, increasing the rotation of the coupin rotor. Furthermore, when the load on the turbine decreases and the rotational speed increases, the effect is opposite to that described above, the secondary oil pressure decreases, and the steam reduces the opening degrees of both the reducing valve 2 and the intercept valve 3.

Next, a conventional example of a turbine starting operation will be described with reference to FIGS. 1, 2, 3, and 4. Figure 1 is a control system diagram of the turbine described above, Figure 2 is a diagram showing the mutual relationship between the valve openings of the steam control valve, intercept valve, and bypass valve at the time of starting full-circle injection, and Figure 3 is a diagram showing the mutual relationship between the valve openings of the steam control valve, intercept valve, and bypass valve at the time of starting all-round injection. A diagram showing the mutual relationship between the valve opening degrees of the steam regulating valve and the intercept valve during the regulating valve control operation, and the fourth part is a diagram showing the characteristics of the reheat steam pressure. In order to warm up the turbine, this turbine first performs a full-circumference injection start-up using a bypass valve (1), which is built in the main steam stop valve (1 is added because it is built in the main steam stop valve). First, set the 1-rotation speed setting device 30 to the minimum setting and
intercept valve switching device B102 and intercept valve switching device 1
03 to the minimum setting. As a result, the relative positional relationship among the steam control valve 2, intercept valve 3, and binox valve 1' becomes as shown in FIG. 2. The reheat steam stop valve 7 is fully opened 7, and then the rotation speed setting device 30 is operated to compress the spring 32 in the direction of the arrow 32a. The pressure receiving surface 31aK of the bellows 3J is in contact with a control member from a load control device (not shown), and the lever 34 is pushed down together with the control member (not shown), and the steam control valve is opened as shown in FIG. 2 is opening. Furthermore, when the rotational speed setting device 30 is operated, the steam control valve 2 is fully opened as shown in FIG. 2, and the intercept valve 3 and bypass valve P begin to open. Steam flows into the jitter pin through this 2'L, and the rotational speed of the turbine increases. When the turbine rotational speed reaches 94% of the rated value, a hydraulic banner (not shown) is activated to maintain the rotational speed constant. After that, the pressure receiving surface 31 of the bellows is controlled by operating the load control device (not shown).
The rotation speed is further increased by operating the rotation speed setting device 30 that releases the contact of the control member from a, and synchronization is applied to the system, and the bypass valve 1' lowers the load up to the rated load of approximately 20 meters. Take.

After completion of all-round injection start, switch to nozzle speed control control,
Control is switched from the bypass valve 11 to the steam control valve 2. This operation raises the bypass valve switching device 102 and the intercept valve switching device 103e to their maximum setting positions.

As a result, as shown in FIG. 3, the intercept valve 3 forms a relative position with the steam control valve 2 side, the bypass valve 11 is still set at its upper limit, and the main steam stop valve 1 is fully opened. The switching to the steam control valve 2 is completed in the above manner, and thereafter, the steam control valve 2 is opened by operating the rotation speed setting device 30, and normal control operation accompanying the load increase operation is performed.

In the above-mentioned turbine startup operation, when switching control from all-round injection startup to a normal steam control valve, it is important to raise the relative positions of bypass valve II and intercept valve 3 to the upper limit without changing them to prevent reheating. 6. Maintain the pressure just below the steam pressure. This keeps the reheat steam temperature constant and prevents fluctuations in turbine output.

In this device, the bypass valve switching device 102 and the intercept valve switching device 103 are both equipped with electric motors (not shown), which are used when switching the control from the conventional all-round injection start to the steam control valve.

The same pulse signal was applied to the electric motor of the bypass valve switching device 102 and the electric motor of the intercept valve switching device, and the relative positions of the bypass valve 11 and the intercept valve 3 were raised to the upper limit so as not to change their positions.

However, in this method, the relative positional relationship between the bypass valve 11 and the intercept valve 3 is disrupted due to motor slippage and errors in the set values, and as a result, as shown by the dotted line in FIG. Disturbances occur in the pressure of hot steam, resulting in unfavorable operational phenomena such as output fluctuations and excess or deficiency in steam temperature. An object of the present invention is to provide a control device for a reheat steam turbine that can easily and accurately obtain reheat steam pressure characteristics.

According to the present invention, the above object is to set a rotation speed setting device, a bypass valve switching device including an electric motor, and an intercept valve switching device to the minimum setting, and then operate the rotation speed setting device to fully open the steam control valve. In a reheat steam turbine that operates by switching from the bypass valve to the steam control valve, the intercept valve and the bypass valve are opened to allow steam to pass through, and the bypass valve starts full-circle injection. A pressure regulator that generates an electric signal according to the reheat steam pressure is provided between the pipe line that guides the reheat steam to the intercept valve and the intercept valve switching device,
This is achieved by configuring the intercept valve switching device to be operated to the maximum setting position by a signal from the pressure regulator when switching from full-circle injection activation using the bypass valve to operation using steam control valve control.

5 and 6 show the implementation of the present invention, FIG. 5 is a control system diagram of a reheat steam turbine, and FIG. 6 is a diagram showing characteristics of reheat steam pressure. In the figure, the same components as those shown in FIG. 1 are given the same reference numerals and their explanations will be omitted. The present invention is.

When switching the control from the above-mentioned all-round injection start to steam control valve operation, the reheat steam pressure near the outlet of the reheater 8 is detected and sent to the intercept valve switching device 103 via the pressure regulator 10. A feedback signal is given to the branch pipe 1 between the reheater 8 and the intercept valve 3.
0a, and a pressure regulator 10 is attached to the branch pipe line 10a.

The pressure regulator 10 generates an electric signal according to the reheat steam pressure, and is connected to an intercept valve switching device 1030 (not shown). In this turbine, after performing the all-around injection start vtb in the same way as explained in the conventional embodiment shown in FIG. :Open and perform load increase operation.

When switching from full-circle injection activation to normal steam control valve 2 control operation, first manually operate the electric motor of the bypass valve switching device 102 to set it to the maximum setting. At that time, one intercept valve switching device 103 is connected to the pressure regulator 10.
It is now possible to operate it to the maximum setting position using an electric signal from. That is, the pressure regulator 10 detects the reheat steam pressure between the heater 8 and the intercept valve 3, and gives a feedback signal to the intercept valve switching device 103 via the pressure regulator 10, so that the reheat steam pressure As shown by the dashed line in FIG. 6, the intercept valve switching device 103 is controlled so as to always maintain a constant value.

According to this method, when shifting to operation using steam control valve control, the bypass valve can be raised to the upper limit without changing the relative position of the intercept valve, and the reheat steam pressure can be maintained constant. It becomes possible to

As described above, the present invention provides a pressure regulator that generates an electric signal according to the reheat steam pressure between the pipe line that guides reheat steam from the reheater to the intercept valve and the intercept valve switching device, and By operating the intercept valve switching device via the regulator, the reheat steam pressure can be held constant at the time of turbine startup, reducing the turbine warm-up time, and preventing output fluctuations and steam temperature from being too much or too little. Therefore, it is possible to provide a controlled installation of a reheat steam turbine that provides good operating conditions.

[Brief explanation of the drawing]

Figures 1, 2, 3, and 4 show conventional examples, Figure 1 is a system diagram of a reheat steam turbine, and Figure 2 shows the steam control valve and interceptor when starting all-round injection. A line diagram showing the mutual relationship between the valve opening degrees of the valve and the bypass valve, Fig. 3 is a diagram showing the mutual relationship between the valve opening degrees of the steam control valve and the intercept valve during steam control valve control operation, and Fig. 4 54 and 6 show the embodiment of the present invention, and FIG. 5 is a control system diagram of a reheat steam turbine. The sixth factor is a characteristic of reheat steam pressure. FIG. 11... Bypass valve, 2... Steam control valve, 3...
Intercept valve, 8... Reheater, 1o... Pressure regulator. 30... Rotation speed setting device, 1o2... Bypass valve switching device, 103... Intercept valve switching device. 71 figure tz figure f3 old f4 Ki-o, 5-ki

Claims (1)

[Claims] J) Set the rotational speed setting device, the bypass valve switching device and the intercept valve switching device equipped with an electric motor to the minimum setting,
After that, the rotation speed setting device is operated to fully open the steam control valve, and the intercept valve and the bypass valve are opened to pass the steam and the full-circle injection is started by the I-pass valve, and then the steam control valve is controlled. In a reheat steam turbine operated by switching, a pressure regulator generates an fc electric signal in accordance with reheat steam pressure between a pipe line that guides reheat steam from a reheater to an intercept valve and the intercept valve switching device. (a) a control device for operating the intercept valve switching device to a maximum setting position using a signal from the pressure regulator when switching from full-circle injection activation using the Kuinokusu valve to operation using steam control valve control;