JPS62210204A - High speed valve controller for turbine - Google Patents

Abstract

PURPOSE:To prevent the step out of a generator and to suppress the fluctuation of the generator output by constructing such that a plurality of intercept valves are classified into plural groups so as to perform the open/close control of the intercept valves independently for every group. CONSTITUTION:Upon occurrence of a fault on a transmission line connected with a generator 4, said fault is detected and the high speed valve control circuits 8A, 8B for the first and second turbines function to provide the open/ close commands to the intercept valves 7A, 7B. Here, the starting times for closing and opening the intercept valves 7A, 7B and the opening speeds of said valves 7A, 7B are differentiated and the outputs from the low pressure first and second stage turbines 3A, 3B are regulated by utilizing the steam energy in the reheater 2. Consequently, the pressure rise of steam in the reheater 2 is suppressed to prevent the function of a safety valve, thereby the fluctuation of the output from the generator 4 is suppressed and the step out of generator in the way of recovery of the turbine output can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a turbine high-speed valve control device that controls the output of a steam turbine at high speed.

[Conventional technology]

A conventional device of this type is shown in FIG. 4.

In the figure, 1 is a high-pressure turbine, 2 is the high-pressure turbine 1
3A is a low-pressure first-stage turbine, 3B is a low-pressure second-stage turbine, 4 is a t-th generator that converts the rotational energy of the turbine into electrical energy, Reference numeral 5 denotes a rotary shaft to which the above-mentioned turbine/generator 4 is integrally connected, and 6 is a control valve for adjusting the flow rate of steam supplied to the high-pressure turbine 1. 7A is a low-pressure straw one-stage turbine/
17B adjusts the flow rate of reheated steam from the reheater 2 supplied to the low-pressure second stage turbine 3B. The intercept valve 8 is a ninth turbine high-speed pulp control circuit that detects an accident occurring in the power transmission system to which the output of the generator 4 is connected and promptly controls the opening of the intercept valves 7A and 7B.

Next, the operation of the conventional device shown in FIG. 4 will be explained.

When an accident occurs in a connected transmission line (not shown) that connects the generated output of the generator 4 to other systems, the accident is detected and the turbine high-speed pulp control circuit 8 is activated, commanding the intercept valves 7A and 7B to open and close. Output. As a result,
The opening degrees of intercept valves 7A and 7B change as shown in FIG.

In the figure, tl is the opening/immobility time including accident detection delay, t2 is the fully closing time, t is the opening/immobility time required until the valve starts to open, and tll is the full opening time. Here, the respective times 11, 12, 1. is set to the shortest possible time in consideration of the response characteristics of the turbine high-speed pulp control device. The intercept valve 7, which is once fully closed in this manner, is opened at a predetermined time t4 and returns to the fully open position.

Figure 6 shows the temporal change in turbine output (curve T) during turbine high-speed pulp control, the temporal change in the output of the generator 4 (curve, WG), and the temporal change in the steam pressure inside the reheater 2 (curve T).
It is a figure showing curve V).

That is, by rapidly closing the intercept valves 7A and 7B, the flow rate of steam from the reheater 2 supplied to the low-pressure turbines 3A and 3B decreases rapidly, so that the turbine output and f
The output of high pressure turbine 1 and low pressure turbines γA and 7B
As shown by curve T, the sum of the outputs of 1 and 2 rapidly decreases, and at the same time, as shown by curve V, the steam pressure inside the reheater 2 rapidly increases. At the same time, the output of the generator 4 is also greatly captured as shown by curve G, centering on the turbine output shown by curve ilT, in a manner that follows the change in turbine output.

[Problem that the invention seeks to solve]

Since the conventional turbine high-speed pulp control device is configured as described above, when the turbine high-speed pulp control circuit 8 is activated due to a power transmission line accident, etc., and the intercept valves 7A and 7B are suddenly closed, the inside of the reheater 2 is The rise in steam pressure becomes so great that the safety valve operates and the reheater 2 itself needs to be reinforced with pressure resistance. In addition, in an attempt to suppress the rise in steam pressure inside the reheater 2, the intercept valve 7
If the full opening time of A and 7B is made too early, there is a problem that the synchronization of the generator 4 cannot be maintained in the middle of the opening control, resulting in a loss of synchronization.Furthermore, the change in the output of the first generator 4 is large, resulting in a very There were problems such as large disturbances being caused to the power system.

This invention was made with the aim of solving the above-mentioned problems, and it is possible to suppress the rise in steam pressure in the reheater, prevent tax adjustment of the generator during the process of opening the intercept valve, and reduce the burden on one generator. The object of the present invention is to obtain a turbine high-speed pulp control device that can reduce fluctuations in a power system by reducing changes in output.

[A precautionary measure to resolve the problem]

The turbine high-speed pulp control device according to the present invention divides a plurality of intercept valves into a plurality of groups, and includes a turbine high-speed pulp control circuit for controlling opening and closing of the intercept valves for each group.

[Effect]

The turbine high-speed pulp control device according to the present invention utilizes the energy of reheated steam by setting differences in the time at which intercept valves begin to close, the time at which they begin to open, and the opening speed for each group of intercept valves by each turbine high-speed pulp control circuit. to adjust the output of the rotating low-pressure turbine.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same parts as in FIG. 4 have the same symbols. In FIG. 1, 8A detects an accident that has occurred in the power transmission system to which the generator 4 is connected and supplies reheated steam to the low-pressure turbine 3A. t-th first turbine high-speed pulp control circuit 8B that promptly controls the opening degree of the intercept valve 7A;
is a second turbine high-speed pulp control that detects a failure that occurs in the power transmission system to which the generator 4 is connected and promptly controls the opening degree of the intercept valve 7B that supplies reheated steam to the low-pressure turbine Y3B. It is a circuit.

Next, the operation will be explained. When an accident occurs in the power transmission system (not shown) to which the generator 4 is connected, the accident is detected and the first and second turbine/high-speed pulp control circuits 8
A and 8B operate and output opening/closing commands to intercept valves 7A and 7B, respectively.

As a result, the opening degree of the intercept valve 7A is as shown in Fig. 2(a).
It changes like this. In the figure, tIA is the closing immobility time including the delay in detecting an accident, and t2A is the fully closing time.

t, A is the opening immobility time required until the valve starts to open, t
4A is the full opening time. Here the respective times tIA.

t2A+tLA is set to the shortest possible time in consideration of the response characteristics of the turbine high speed pulp control device.

In this way, the intercept valve 7A is once fully closed.
is opened at a predetermined time t, A, and returns to the fully open position.

At the same time as cn, the opening degree of intercept valve 7B is changed as shown in Fig. 2 (
It changes as shown by the solid line in b). In the figure, tlB is the closing immobility time including accident detection delay, t2B is the fully closing time, t and B are the opening immobility time required until the valve starts to open, and t and B are the full opening time. Here, each of the above-mentioned times t2B, t, and B are set to the shortest possible time in consideration of the response characteristics of the turbine high-speed pulp control device.7 In this way, once the intercept valve is fully closed, 7B is released at a predetermined time tuB and returns to the fully open position.

In addition, in Figure 1, time txB, which is the closing start time, is a certain period of time later than time t1A, and full-open time t1
1B is set to be longer than the full open time tlIA. The one-dot chain line in FIG. 2(a) is a comparative illustration of the opening degree curve of the intercept valve 7A in FIG. 2(a).

Figures 3(a) and 3(a) and 3(a) and 3(a) and 4(a) and 3(a) and 3(a) and 4(a) and 3(a) and 4(b), respectively) show the temporal change in turbine output (curve T) during turbine high-speed pulp control according to the present invention.
) is a diagram showing a temporal change in the output of the generator 4 (curve G) and a temporal change in the steam pressure inside the reheater 2 (curve V). That is, by quickly closing the intercept valve 7A, the low pressure g, the steam flow rate supplied to the first stage turbine 3A is rapidly reduced, and the turbine output, that is, the output of the high pressure turbine 1, the output of the low pressure first stage turbine 3A, and the low pressure The total output of the second stage turbine 3B is shown by curve T and decreases somewhat rapidly as shown in FIG. After starting to open intercept valve 7A, which was once fully closed.

Subsequently, the intercept valve 7B is quickly closed, and then returned to the fully open position relatively slowly at 9 hours t4B. As is clear from the comparison of both curves in Fig. 2 (Fig. 2), since the times at which the intercept valves 7A and 7B are fully closed are shifted, the amount of decrease in turbine output in this invention shown by curve T is less than that in the prior art. It's quite small in comparison. As shown by curve V, the steam pressure inside the reheater 2 is:

Since the closing time of the outlet pipe is shifted, the rise does not occur too rapidly, and the amount of rise is also small. At this time, the output of the first generator 4 also follows the change in the turbine output shown by the curve T, and vibrates with a relatively smaller amplitude than the conventional device as shown by the curve G around the turbine output. .

In addition, in the above embodiment, there are two or more intercept valves.
In this example, three or more intercept valves are divided into three or more groups and controlled by output signals from two turbine high-speed pulp control circuits. The closing times of the outlet pipes of the reheater may be controlled to be staggered from each other by output signals from the reheater.

〔Effect of the invention〕

As described above, according to the present invention, a plurality of intercept valves are divided into a plurality of groups, and the opening and closing times of each are staggered to control the opening and closing, thereby suppressing the rise in steam pressure inside the reheater. This prevents the safety valve from operating, and eliminates the need to unnecessarily increase the pressure-resistant design of reheaters, etc.1.It reduces the output fluctuations of the generator and prevents excessive oscillations from being applied to the power system, reducing the turbine output. This has the effect of preventing the generator from losing synchronization and synchronizing during recovery.

[Brief explanation of drawings]

Figure 1 is a block configuration diagram showing a turbine high-speed pulp control device according to an embodiment of the present invention, and Figures 2 (a) and 2 (b) are characteristics showing the opening/closing operation of an intercept valve in an embodiment of the present invention. 3(a) and 3(a) are characteristic diagrams showing the temporal changes in turbine output, generator output, and reheater steam pressure when controlled by an embodiment of the present invention, respectively. Fig. 4 is a block configuration diagram showing a conventional turbine high-speed pulp control device, Fig. 5 is a characteristic diagram showing the operation of the intercept valve in the conventional device IK, and Fig. 6
Figures (a) and 3(a) are characteristic diagrams showing temporal changes in turbine output, electrical output, and reheater steam pressure, respectively, when controlled by a conventional device. In the figure, 1 is a high-pressure turbine, 2 is a reheater, 3A, 3
B is a low pressure turbine, 4 is a generator, 7A. 7B is an intercept valve, and 8A and 8B are turbine high-speed valve control circuits. In addition, in FIG. 1, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a turbine high-speed valve control device that detects the occurrence of an accident in a power transmission line connected to the power generation output of a steam turbine generator, fully closes an intercept valve, and then controls the intercept valve to fully open, the plurality of intercept valves are connected to a plurality of groups. A turbine high-speed valve control device comprising: a turbine high-speed valve control circuit which outputs respective opening/closing control signals for giving mutually different closing start times and full-open times to the respective groups.