JPS6172804A - Turbine controlling equipment - Google Patents

Abstract

PURPOSE:To enable more suitable control by calculating the oil pressure of a hydraulic mechanism in accordance with the steam pressure at the time of start of valve opening and correcting the amount of lift of the main steam check valve when the hydraulic switch is turned on the calculated pressure is higher than the set pressure of the hydraulic switch. CONSTITUTION:In the captioned equipment a main steam check valve 3 and an adjusting valve 4 are installed within a steam pipe 1, which introduces the steam generated by a boiler to a turbine. Opening of a bypass valve 7, which forms the main steam check valve 3 together with a main valve 6, is controlled by a hydraulic mechanism, which is controlled by a motor M1 via a driving mechanism 10. The start of opening of the bypass valve 7 is detected by a hydraulic switch PS. In this case a steam pressure transmitter A, which detects the pressure of the steam flowing into the main steam check valve 3, is provided. The oil cylinder pressure Kp is calculated by the controlling equipment in accordance with the detected steam pressure P. If this oil cylinder pressure Kp is higher than the set pressure of the hydraulic switch PS, the amount of the lift of the valve 3 when the valve begins to open is corrected.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a turbine control device.

[Technical Background of the Invention] In order to control the speed, load, etc. of a turbine, steam flow is performed by adjusting the openings of a main steam stop valve, a bypass valve, and a control valve.

FIG. 6 shows a conventional example of a steam flow rate control valve mechanism for a turbine. In the figure, steam discharged from a boiler is supplied from an inlet 2 of a steam pipe 1 to a turbine through an outlet 5 via a main stop valve (main steam stop valve) 3 and a control valve 4.

As shown in the figure, the main stop valve 3 consists of a combination of a main stop valve main valve 6 and a main stop valve bypass valve 7, and a drive mechanism 9 driven by a drive motor M1 supplies and discharges pressure oil to a hydraulic mechanism 10. By applying oil, the valve rod 8 is pushed up and pulled down via the rod 12 of the piston 11 to control the opening and closing of the bypass valve 7, and the position of the bypass valve 7 is detected by a position detector 13 such as a drive transformer or a potentiometer. .

Further, the regulating valve 4 rotates the cam 15 via the regulating valve drive mechanism 14 by the regulating valve drive motor M2, and the valve rod 16
The opening and closing of the regulating valve 4 is controlled by the position detector 1 to detect its position.
7 is detected.

In such a steam flow rate control valve mechanism, for example, when controlling the speed of a turbine, the regulator valve 4 is fully opened, the drive mechanism 9 of the bypass valve 7 is operated by the drive motor M1, and the main stop valve bypass valve 7 is opened while the steam is controlled. Increase the flow.

When the bypass valve 7 begins to push up the main valve 6, both the main valves 6 are fully open, but at this time, the regulator valve 4 is throttled in advance and operated to control the steam flow rate. Further, the hydraulic mechanism 10 in the turbine steam flow rate control valve mechanism is provided with a hydraulic switch PS that detects when the bypass valve 7 starts to open.

Since this oil pressure switch PS opens against the steam pressure when the bypass valve 7 starts to open, it responds to the rise in pressure at the lower part of the piston 11 of the hydraulic mechanism 10.

The above control valve mechanism is controlled by a turbine control device (not shown).

In the turbine control device, as shown in the flowchart of FIG. 7, before the oil pressure switch P5 operates, the raising operation is performed by a simple raising pulse, but the oil pressure switch PS
8 or when the actual rotation of the turbine generator is detected, control by the automatic control system shown in FIG. 8 is started.

The automatic control system calculates the command value R and the actual rotation speed N of the turbine generator T/G by 1 in an adder, and calculates the deviation Q and the valve mechanism M.
The difference between the value r detected at the position of a by the detector Calculate the valve opening degree with 2 in the adder, and calculate the deviation ■ as the control element M.
This is a control system that applies the manipulated variable Q to the turbine generator T/G from b.

However, in such a control system, the valve opening degree of the valve mechanism Ma is fed back, but the hydraulic pressure switch PS
Since the setting is a constant value, if the steam pressure fluctuates, the oil pressure switch PS will respond at a point different from the actual valve opening point.
The position of ' is shifted, and as a result, the absolute value of the detected quantity is shifted, and the offset of the control characteristic changes each time the turbine is started, which also affects the final rotational speed N relative to the command value R.

[Purpose of the Invention] The present invention has been made in view of the above points, and it is possible to correct the lift amount at the beginning of opening in order to obtain an accurate lift amount in a turbine control device that has the lift amount as a feedback amount. The purpose of the present invention is to provide a turbine control device.

[Summary of the invention] The present invention calculates the oil pressure of the hydraulic mechanism when the valve starts to open from the steam pressure, and if the calculation result is higher than the set pressure of the oil pressure switch, the valve lift amount when the oil pressure switch is turned on is calculated. is being corrected.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 illustrates a control valve mechanism according to an embodiment of the present invention. In this figure, the same or corresponding parts as those in FIG. 6 are given the same reference numerals, and the explanation thereof will be omitted.

In the figure, the pressure of steam flowing into a steam pipe 1 is detected by a steam pressure transmitter A, and the detected steam pressure P is transmitted to a turbine control unit W (as shown).

Here, since the steam pressure P and the oil cylinder pressure KP of the hydraulic mechanism 10 at the time of opening start have a functional relationship as shown in FIG. 2, the turbine control device adjusts the received steam pressure P based on this relationship. The oil cylinder pressure KP at the time of opening can be calculated from .

Normally, the set pressure Kp of the oil pressure switch PS is set to the lowest KP value based on the steam pressure P that can start the turbine, so when the steam pressure P is high, that is, the oil cylinder pressure Kp when the set pressure KF starts to open. There are cases where it is lower.

At this time, the oil pressure switch PS operates before the valve actually opens, so the memory output r' stored by the oil pressure switch PS is not an accurate lift amount when the valve starts to open, and therefore needs to be corrected.

Therefore, in the present invention, when the oil cylinder pressure Kp at the time of opening is greater than KF, and the corrected value of the memory output r' is r#, the automatic control system is activated until the output r of the detector A function is added to prevent movement and to move to the automatic control system after the memory output r' becomes equal to r#.The automatic control system has the same configuration as shown in FIG.

The portions surrounded by broken lines in the flowchart of FIG. 3 are functions added according to the present invention.

Here, the correction coefficient F of the lift amount memory r' stored when the oil pressure switch PS is operated is determined as shown in the following equation so that it becomes 1 when KP and KF are equal.

However, α is a constant.

As described above, according to the present invention, it is possible to accurately detect and correct the valve opening at the beginning of opening, and therefore, it is possible to provide a turbine control device that can feed back an accurate lift amount and has good control characteristics.

By the way, as can be seen from Fig. 2, if the oil cylinder pressure KF can be input directly to the turbine control device, the opening point determined from the steam pressure P shown in Fig. 2 can be used instead of the oil pressure switch PS in the turbine control device. By detecting with a comparator that the oil cylinder pressure KP and the oil cylinder pressure KF match, it is possible to accurately detect the beginning of opening of the valve.

Therefore, by setting the detected conditions as the conditions to be stored in the memory instead of the oil pressure switch PS shown in FIG. 7, it is possible to obtain an accurate lift amount memory output r' at the beginning of opening.

FIG. 4 shows a device according to another embodiment of the present invention in which an oil cylinder pressure transmitter B is attached in place of the oil pressure switch PS in the control valve mechanism shown in FIG.

A part of the automatic control system in this embodiment is shown in FIG.

In the figure, FNG is a function generator and CP is a comparator. The steam pressure P output from the steam pressure transmitter A is added to the function generator FNG, and the corresponding oil cylinder pressure Kp is output from the function generator FNG. It is applied to one input terminal of comparator CP. Note that the other parts of this automatic control system are the same as those shown in FIG. 8, so illustration thereof is omitted.

The oil cylinder pressure KF is applied from the oil cylinder pressure transmitter B to the other input terminal of the comparator CP, and when the two human power signals become equal, the comparator CP activates the memory and gives the output r' to the automatic control system. That's what I do.

Thereby, the valve begins to open when the oil cylinder pressure KF reaches a pressure corresponding to the steam pressure P, so that control can be performed appropriately.

[Effects of the Invention] As described above, according to the present invention, since the lift amount at the beginning of opening of the valve is corrected and controlled in accordance with the steam pressure, more appropriate control is realized.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing a control valve mechanism according to an embodiment of the present invention, Fig. 2 is a graph showing the relationship between steam pressure and oil cylinder pressure at the beginning of opening, and Fig. 3 is an example of control. FIG. 4 is a block diagram illustrating a control valve mechanism according to another embodiment of the present invention, FIG. 5 is a block diagram illustrating an automatic control system according to another embodiment of the present invention, and FIG. FIG. 7 is a block diagram showing a conventional example of a control valve mechanism, FIG. 7 is a flowchart showing a conventional example of control, and FIG. 8 is a block diagram showing a conventional example of an automatic control system. A... Steam pressure transmitter, B... Oil cylinder pressure transmitter, F
NG...Function generator, CP...Comparator. (7317) Agent: Patent Attorney Noriyuki Chika (
(and 1 other person) Figure 1 Figure 2 Figure 3 Figure 41!1 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] In a turbine control device that detects the start of opening of the main steam stop valve by a hydraulic switch provided on an oil cylinder that drives the main steam stop valve to open and close, a steam pressure detection means that detects the pressure of steam flowing into the main steam stop valve; A calculation means for calculating the oil cylinder pressure corresponding to when the main steam stop valve starts to open based on the output of the steam pressure detection means, and a calculation means for calculating the lift amount when the main steam stop valve starts to open based on the output of this calculation means. A turbine control device comprising a correction means for correcting, and correcting the lift amount of the main steam stop valve by the output of the correction means when the output of the calculation means is higher than the set pressure of the oil pressure switch.