JPS59213906A - How to start a 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] [Technical field to which the invention pertains] Two steam supply systems each having a main steam stop valve and a steam control valve as a pair are arranged, and the steam supplied from the steam source is divided into two series. The present invention relates to a method for starting a steam turbine, which is operated by controlling the control valve.

[Prior art and its problems]

Generally, when starting a steam turbine, a main steam stop valve is opened first, and then a steam control valve is opened and the opening degree of the steam control valve is controlled to increase the speed of the turbine. However, for inlet valves that lower the inlet pressure, such as in geothermal turbines, the diameter of the valve is between 300 and 700 mm, so butterfly valves are often used as steam control valves, and butterfly valves have a rotating valve body. In this case, a gap is created between the valve body and the valve body, and when the main steam stop valve opens, steam flows into the turpin due to leakage from the back 72 valve as a steam control valve, reducing the rotational speed of the turbine. Therefore, there is a need for a startup method that allows for more stable turbine speed control.

Figures 1 to S show conventional embodiments, Figure 1 is a control system diagram of the main parts of the steam turbine, Figure 2 is a sectional view of the main part of the inlet valve in Figure 1, and Figure 3 is the control system diagram of the main parts of the steam turbine. FIG. 2 is a diagram showing the starting characteristics of the turbine shown in FIG. 1; In the figure, l is a steam turbine. Steam turbine l is equipped with two steam supply systems in which a main steam stop valve and a steam control valve are paired, lO indicates the first series of the steam supply system, and The second series is shown. 11 is the first
The main steam stop valve provided in the series 10, 12 is a steam control valve that pairs with the main steam stop valve 11, and 13 is a pipe line thereof.

2] is the main steam stop valve provided in the second train 20, 22
1 is a steam control valve that is paired with the main steam stop valve 21, and 1 is its pipe line. 2 is a governor impeller of a rotation speed detector directly connected to the rotor shaft of the steam turbine l; 3 is a rotation speed setting device; 4 is a secondary oil pressure setting device for the steam control valve 12; 5 is a secondary oil pressure of the steam control valve 22. It is a setting device. In addition, 6 indicates a generator, and M indicates a condenser.

Next, a method of starting the steam turbine 1 using this device will be explained. Steam supplied from a steam source (not shown) is
The steam flows through the conduit 13 of the series and the conduit of the second series, and is guided to the steam control valves 12 and 22 from the main steam stop valves n and 21, which are fully opened by the opening operation at the same time. The rotation speed setting device 3 is manually operated so that the steam control valves 12 and 22 can be slightly opened. As a result, the pipes 14 and 15 of the secondary oil pressure setting devices 4 and 5
A secondary oil pressure is set to the pressure oil, and the steam control valve 12
, 22 open slightly, and the turbine l starts rotating. When the rotational speed of the turbine 1 increases to approximately 1.00 rpm, the operation of the rotational speed setting device 3 is temporarily stopped, and the turbine 1 is warmed up. After the warm-up operation is completed, the rotational speed of the turbine I is further increased. This is done by operating the rotation speed setting device 3 again as described above, and setting the rotation speed of the turbine l to the rated value (approx. 3.00 Orpm for 5012, 60H).
In the case of No. 2, the speed is increased to 90y (approximately 3,600 rpm), and then the control operation of the steam control valve is started. As a result, a primary oil pressure is established in the conduit 16 via the rotation speed detector 2 using a governor impeller directly connected to the rotor shaft, and the primary oil pressure is transmitted to the rotation speed setting device f3.

When the load of the turbine 1 increases and the rotational speed decreases, the primary oil pressure decreases, and the secondary oil pressure setting device 4 is changed via the lever 3a.
．． 5 is operated, and the hydraulic pressure in the secondary hydraulic pressure lines 14 and 15 is raised to increase the opening angle of the steam control valves 12 and 22. Also, when the load on the turbine decreases and the rotational speed increases, the movement is opposite to that described above.1. The secondary oil pressure decreases and the opening angles of the steam control valves 12 and 22 become smaller.

In the above startup method, the steam control valve λ, 22 is the second
As shown in the figure, since it is a butterfly valve with a diameter of about 700 +ra+, the valve body rotates in the direction of arrow 25.
The main steam stop valves 11 and 22 move in the direction of the arrow 4, and the steam 2
6 is passed through the body 2γ, even if the valve body of the butterfly valve is closed, steam leaks from the gap between the valve body and the valve body, and the steam flows into the turbine 1, causing the rotational speed of the turbine 1 to decrease. to rise. This rising speed is approximately 3.00 Orpm as shown by the dotted line 31 in Figure 3, which is the 3.00 Orpm required for warm-up operation.
The drawback was that the heat soak rotation speed exceeded the heat soak rotation speed LOOOrpm shown in 2, and the heat soak rotation speed could not be controlled.

[Purpose of the invention]

An object of the present invention is to provide a method for starting a steam turbine, which eliminates the above-mentioned drawbacks and enables stable speed control of the turbine so that a heat-on rotation speed can be obtained and warm-up operation can be reliably performed. With the goal.

[Key points of the invention]

According to the present invention, the above-mentioned object is a method for starting a steam turbine having two series of steam supply systems each having a main steam stop valve and a steam control valve as a pair, wherein the main steam stop valve of the first series is At the same time, the steam control valve of the series is slightly opened to warm up the turbine, and after the operation is completed, the steam control valve is opened again to increase the rotational speed of the turbine, and the turbine is warmed up. When the rotational speed of
This is achieved by opening both the steam control valves of the second series to increase the rotational speed of the turbine and shifting to a controlled operation using the steam control valves.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings. Fourth
5 and 5 show an embodiment of the present invention, FIG. 4 is a control system diagram of the main parts of the steam turbine, and FIG. 5 is a diagram showing the starting characteristics of the steam turbine shown in FIG. 4. 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 steam turbine 1 is provided with two steam supply systems, 1O is the first system, 30 is the second system, and 31 is the main steam stop valve of the second system. Reference numeral 32 denotes a main steam stop valve switching device of the second series. It is set so that the main steam stop valve 31 can be opened when the rotational speed is slightly higher than OOOrpm. Reference numerals 34 and 35 denote secondary oil pressure setting devices, and the secondary oil pressure setting devices 34 and 35 have different built-in springs (not shown), respectively, and the secondary oil pressure setting device 35 of the steam control valve 22 is adjusted so that the secondary oil pressure is set when the main steam stop valve switching device 32 opens the main steam stop valve 31 of the second series.

With the above configuration, the main steam stop valve n of the first series is opened. Steam from a steam source (not shown) is guided to a steam control valve 12 by opening a main steam stop valve 11. The rotation speed setting device 3 is manually operated so that the steam control valve 12 can be slightly opened. As a result, the secondary oil pressure is set in the conduit 14 of the secondary oil pressure setting device of the first series, the steam control valve 12 is slightly opened by the pressure oil, and the turbine l starts rotating. turbine 1
The rotation speed of approximately 1. When the heat soak speed increases to QOOrpm, the operation of the rotation speed setting device 3 is temporarily stopped, and the turbine 1 is warmed up. After the warm-up operation is completed, the rotation speed setting device 3 is further operated to increase the rotation speed of the turbine 1. At this time, the secondary oil pressure is set in the conduit 14 of the secondary oil pressure setting device in the first $ column, the rotation speed of the tarpier 1 increases, and the heat soak rotation speed is 1+ooor.
When the rotation speed reaches a point slightly higher than pm, the rotation speed detector 2 detects the preset rotation speed, the primary oil pressure is established in the line 37, and the line of the main steam stop valve switching device 32 of the second series is established. A secondary oil pressure is set at 36, and the main steam stop valve 31 of the second series is fully opened by this pressure oil. After the main steam stop valve 31 is fully opened, the rotation speed setting device 3 is further operated to control the turbine 1.
increase the rotation speed. At this time, the secondary oil pressure is also set in the pipe line 15 of the secondary oil pressure setting device 35 for the steam control valve, and both the steam control valves 22 are opened and the turbine 1
The rotation speed will increase. When the rotational speed of the turbine 1 exceeds the rated percentage, the control operation of the steam control valve is started.

In the above startup method, when the main steam stop valve (1) opens and steam is guided to the steam control valve 12, steam leaking from the gap between the valve body of the steam control valve and the valve body flows into the turbine 1. However, since only the main steam stop valve 11 of the first series was opened, the amount of steam flowing into the turbine 1 was small, and the rising speed of the turbine 1 was approximately 80 rpm, as indicated by the dotted line 51 in FIG. Therefore, 1. of the heat soak rotation speed indicated by reference numeral 32. OOO rpm can be lowered. Furthermore, when the main steam stop valve 31 of the second series is opened, leaking steam from the gap between the valve body and the valve body of the steam control valve 22 of the series similarly flows into the turbine l, but the steam has already been removed from the turbine l. Since the rotational speed of turbine 1 is relatively high and a relatively large amount of steam is flowing into turbine 1, leakage steam from steam control valve 22 of the second series has little effect on increasing the rotational speed of turbine 1. do not. Therefore, after the main steam stop valve 31 is fully opened, the rotation speed setting device 3 is operated to open the steam control valves 12 and 22, and the turbine 1 is raised until the rotation speed of the turbine l reaches 90% of the rated speed. It is possible to quickly shift to steam control valve control operation.

〔Effect of the invention〕

As described above, the present invention warms up the turbine by opening the main steam stop valve of the first series and slightly opening the steam control valve of the series, and after the end of the operation, closes the steam control valve. When the rotational speed of the turbine is increased by the opening operation again and the rotational speed of the turbine exceeds a predetermined value, the main steam stop valve of the second series is opened, and after the opening operation of the throttle valve, the first and the first steam stop valves are opened. By opening both steam control valves in the two series to increase the rotational speed of the turbine and shifting to control operation using the steam control valves, more stable turbine speed control can be achieved compared to conventional startup methods. Thus, it is possible to provide a method for starting a steam turbine that can obtain a heat soak rotational speed and reliably perform warm-up operation.

[Brief explanation of drawings]

Figures 1 to 3 show conventional embodiments, where Figure 1 is a control system diagram of the main parts of the steam turbine, Figure 2 is a sectional view of the main parts of the inlet valve in Figure 1, and Figure 3 is the Fig. 1 is a diagram showing the startup characteristics of the turbine, Figs. 4 and 5 show embodiments of the present invention, Fig. 4 is a control system diagram of the main parts of the steam turbine, and Fig. 5 is the diagram shown in Fig. FIG. 3 is a diagram showing the starting characteristics of the steam turbine shown in FIG. 1... Steam turbine, 10... 1st series, 11,
31... Main steam stop valve, 12, 22... Steam control valve, 30... Second series. Figure 1 Figure 3-''1 Figure 4

Claims (1)

[Scope of Claims] 1) Two series of steam supply systems each having a main steam stop valve and a steam control valve as a pair are arranged, and steam supplied from a steam source is multi-controlled by the steam control valve of each series. A method for starting a steam turbine which is operated by opening the main steam stop valve of the first train, and slightly opening the steam control valve of the train to warm up the turbine, and then terminating the operation. After that, the steam control valve is opened again to increase the rotational speed of the turbine, and when the rotational speed of the turbine exceeds a predetermined value, the second
The main steam stop valve of the series is operated to open, and after the opening operation of the valve, the steam control valves of the first and second series are both opened to increase the rotational speed of the turbine, and the control operation by the steam control valve is performed. A method for starting a steam turbine characterized by a transition. 2. A method for starting a steam turbine according to claim 1, wherein the steam control valve is a butterfly valve with a rotating valve body.