JPS60259709A - Control unit for steam turbine - Google Patents

Abstract

PURPOSE:To improve the reliability of steam turbine by providing a low value selector corresponding to each of plurality of steam valves in a steam turbine control unit. CONSTITUTION:A plurality of steam valve opening controllers 26-28 corresponding to a plurality of steam valves 9-11 of a steam turbine are provided, and the respective controllers 26-28 contain low value selectors 16-18 and steam valve opening controlling sections 6-8. The respective low selectors 16-18 receive the signal of the output of a load limitter 1 and the outputs of a governer setter 2 and a rotational frequency deviation detector 3 added together by an adder 4 to select and send the signal having lower value to control sections 6-8. Thus, the reliability can be improved by preventing all steam valves 9-11 from being affected with any failure in any one of the low value selectors.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an electric control device for a steam turbine used in thermal power generation equipment, nuclear power generation equipment, and the like.

<Prior art> Figure 1 shows a conventional example of this type of control device. In the figure, 1 is a load limit setting device as a functional element for limiting the upper limit opening of a steam valve, and 2 is a load limit setting device that controls the steam valve by changing the rotation speed. 3 and 4 are rotation speed deviation detectors and adders which are also speed governing function elements, 5 is a low value selector, and 6 to 8 are steam turbines, which will be described later. 9 steam valve opening degree control units distributed corresponding to each steam valve to be operated;
- 11 are steam valves whose opening degree is controlled by a control device, 9
A to IIA are drive mechanisms for the steam valves 9 to 11.

Next, the operation will be explained.

The low value selector 5 manually inputs the output of the load limit setting device 1 and the signal obtained by adding the outputs of the governor setting device 2 and rotational speed deviation detector 3 using an adder 4, and selects the signal with the lowest value. is selected and supplied to steam valve opening degree control units 6 to 8 distributed corresponding to each steam valve 9 to 11.

Since the conventional steam turbine control device is configured as described above, if the low value selector 5 fails, the load limit setting device 1 and the speed governor control elements 2.3 and 4 are both healthy or
Even if one side is healthy and the other side is malfunctioning such that the output increases, an appropriate control signal will not be supplied to the steam valve opening degree control parts 6, 7.8, and the steam valve control will be interrupted. There was a drawback that it was impossible to do so.

<Summary of the Invention> The present invention has been made in order to eliminate the drawbacks of conventional ones such as steam, and the low 4Fi selector is distributed to each steam valve opening control section. It is an object of the present invention to overcome the drawbacks of the prior art described in - by providing a low value selector and a steam valve opening controller corresponding to each valve cylinder.

<Embodiments of the invention> Hereinafter, one embodiment of the present invention will be described based on FIG. 2.

In this figure, the same elements as those in FIG. 1 are given the same reference numerals to simplify the explanation.

In FIG. 2, reference numerals 16 to 1B indicate a plurality of low 4fi units that supply independent low signal values to each of the steam valve opening control units 6 to 8, which are provided in correspondence with the plurality of steam valves 9 to 11. It is a selector. 26 to 28 are the low value selectors 16 to 28.
18 and steam valve opening controllers 6 to 8 are integrated.

Next, the operation of the control device having the above configuration will be explained.

In this configuration, the low value selector in FIG. Similar to the one in the figure, the output of the load limit setting device 1, the output of the governor setting device 2, and the rotation speed deviation detector 3 are added by the adder 4, and the signal with the lowest value is selected. . However, in the case of FIG.
11, it is possible to limit the situation to a single steam valve, and other steam valves can be smoothly controlled.

In the above embodiment, the number of steam valves is three in the figure, but it goes without saying that the same effect can be obtained if there are two or more steam valves.

<Effects of the Invention> As described above, according to the present invention, a plurality of low value selectors are provided for each steam valve, so that if the low value selector malfunctions, all steam valves cannot be controlled. This has the effect of providing a control device with a high availability rate for steam turbine operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a conventional steam turbine control device, and FIG. 2 is a block diagram showing the configuration of a steam turbine control device according to an embodiment of the present invention. 1...Load limit setting device 2...Governor setting device 3...
・Rotational speed deviation detector 4...Adder 6-8...Steam valve opening control section 16-18...Low value selector

Claims (1)

[Claims] The steam valve's opening limit function element, the speed regulating function element that adjusts the opening degree of the steam valve according to changes in rotation speed, and the output signals from both elements are input, and the signal with the lowest value is input. A low value selector for selecting, the plurality of low value selectors supplying independent low value signals for each of the plurality of steam valve opening degree control units provided corresponding to the plurality of steam valves. A steam turbine control device characterized by: