JPH03267507A - Test circuit for turbine valve - Google Patents

Abstract

PURPOSE:To make it possible to stabilize the opening degree characteristics of a throttle valve at the time of the execution of a usual main check valve and throttle valve test by adding a function computing element for correction, deflection computing element, and proportional plus integral computing element to the side of a throttle valve test circuit. CONSTITUTION:In a test circuit for a turbine valve in a steam turbine having one or more main check valves and throttle valves on the right and left sides respectively, a function computing element 13 for correction for computing throttle opening degree corresponding to present load setting value and a deflection computing element 14 for outputting the deflection between the opening degree of the throttle valve and the present opening degree of the throttle valve which is not tested, and proportional plus integral computing element 15 for adding the proportional plus integral output resulting from inputting the deflection to the demand of the throttle valve which is not tested are added to the side of a throttle valve circuit. By this constitution, besides the output deflection of a loaded controller, the opening degree of the throttle valve which is not tested is raised, and the reduction of output due to the change from opening to closing demand of the throttle valve which is in test is canceled by the increase in the output of the proportional plus integral computing element 15 resulting in the reduction of fluctuation of loads.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a turbine valve test circuit for a steam turbine having one or more main blocking valves and one or more throttle valves (turbine valves) on the left and right sides. The present invention relates to a turbine valve test circuit used when testing the main stop valve/throttle valve of an electric governor control device.

BACKGROUND OF THE INVENTION FIGS. 2(a) and 2(b) show a main shutoff/throttle valve test circuit in a conventional electric vaner control system. In these figures, symbols 1 and 7 are deviation calculators, 2, 3, 8.9
is an adder, 4. 5.10.11 is a correction function calculator for each main stop valve/throttle valve control signal, 6,1
2 is a change rate limiter for adjusting the valve closing speed during each test of the main stop valve/throttle valve. Further, T and -T are signal switching relays, among which signal switching relays Ts and T2.
T4. Normally (except during the main stop valve/throttle valve test) Ts is b-c, and only the left or right side is a-c during the main stop valve/throttle valve test.

The operating procedure during the main stop valve/throttle valve test is as follows.

(a) Select the left or right side (b) Start the main blocking valve/throttle valve test using a push button switch, etc. (c) Close the selected throttle valve (d) Completely close the selected throttle valve and then close it Close the valve (e)
Open the main blocking valve (f) Open the throttle valve (g) End (h) Test the opposite side in the same way.

Problem to be Solved by the Invention As described above, the main shutoff valve/throttle valve test circuit in the conventional electric governor control device closes the main shutoff valve/throttle valve on one side (left or right) at a certain rate of change. Load fluctuations that occur at that time are controlled by load feedback or load simulation signal (first stage pressure) feedback control.

However, feedback control in the prior art causes a delay, leading to load fluctuations.

The present invention aims to reduce load fluctuations by stabilizing the opening characteristics of a throttle valve, which is an element that actually controls the load, during a normal main blocking valve/throttle valve test.

Means for Solving the Problems The present invention provides a turbine valve test circuit for a steam turbine having one or more main stop valves and one or more throttle valves each on the left and right sides in order to prevent load fluctuations during main stop valve/throttle valve tests. , a correction function calculator that calculates a throttle valve opening corresponding to the current load setting value; a deviation calculator that outputs a deviation between the throttle valve opening and the current opening on the side that is not tested; The turbine valve test circuit includes a proportional integral calculator which inputs the proportional integral output and adds the proportional integral output to the throttle valve demand on the side that is not tested, and is added to the throttle valve test circuit side.

Effect According to the above means, when testing the left or right main blocking valve/throttle valve, the throttle valve demand corresponding to the load setting value set by the correction function calculator and the throttle valve demand selected by the rM switching relay are set. The proportional-integral calculator works to bring the deviation from the throttle valve demand to O, and increases the opening degree of the throttle valve on the side that is not being tested, independent of the change in the output of the load controller.

Therefore, as the throttle valve under test changes from open to closed, the throttle valve demand is offset by the increase in the preceding signal (output of the proportional-integral calculator), and the load fluctuation becomes smaller.

EXAMPLE A preferred embodiment of the present invention illustrated in FIG. 1 will be described in detail below. In FIG. 1, the same parts as those shown in FIG. 2 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

Note that FIG. 1 shows only the throttle valve test circuit that is directly related to load fluctuations.

In FIG. 1, numeral 13 is a function calculator for correcting the load setting value and throttle valve demand (load controller output), 14 is a deviation calculator, 15 is a proportional-integral calculator,
16.17 is an adder. T6 to T are signal switching relays, and among these, signal switching relay T is normally b-
c through, and when testing the left or right main blocking valve/throttle valve, it becomes a through c.

The signal switching relays Tv and Ts are for left/right selection, and are b-c when testing the left side, and a-c when testing the right side.

The proportional integral calculator 15 is in tracking mode except during the main blocking valve/throttle valve test, and its output is 0%.

Normally, during turbine operation, both left and right throttle valves control the load (generator output) by a load controller.

At that time, the signal switching relays T1 and T2 are connected b-c, and the 0% multiplied signal is added to the load controller output, so the throttle valve demand matches the load controller output.

Here, when testing the left main blocking valve/throttle valve, only the signal switching relay T is connected to a-C, and the left throttle is stopped at the rate of change set by the rate of change limiter 6 for adjusting the valve closing speed. The valve is closed.

At this time, the signal switching relay T6 is connected to a-c, T7°T
, becomes b-c, and correction function calculator 1
Throttle valve demand equivalent to the load setting value set in step 3,
The proportional-integral calculator 15 acts so that the deviation from the right throttle valve demand that is not tested becomes O, and increases the demand of the right throttle valve that is not tested separately from the output of the load controller. prevent a decrease in

For the right-hand main block/throttle valve test, the reverse operation is performed.

As described above, in the present invention, the throttle valve opening prediction corresponding to the current load setting value created by the correction function calculator 13 is added to the untested side of the signal input to the adder 2 or 3. The integral output of the proportional integral calculator 15 is set to the test side valve opening of the rate of change limiter 6 for adjusting the valve closing speed so that the deviation between the current opening on the non-tested side (twice the normal opening) and the current opening on the non-tested side is O. input to adder 16 or 17 to coordinate with speed;
Assists in load control on the side not being tested.

Therefore, the throttle valve to be tested moves at a constant speed from opening to closing, but the throttle valve demand on the side that is not being tested increases in advance by the output of the proportional-integral calculator 15, so the load changes. This allows for load control similar to that during normal operation.

By applying the turbine valve test circuit of the present invention, which has more than the effects of the invention, to an electric turbine control device, load fluctuations are minimized and stability is maintained even during turbine valve (main stop valve/throttle valve) tests. load control becomes possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a turbine valve test circuit according to the present invention, and FIG. 2 is a block diagram of a conventional main stop valve/throttle valve test circuit. 1... Deviation calculator, 2.3... Adder, 4.5... Correction function calculator, 6... Change rate limiter for adjusting valve closing speed, 13... Function calculator for correction, 14...
Deviation calculator, 15... Proportional integral calculator, 16.17...
Adder, T1. T*, Ts~T,...Signal switching relay

Claims (1)

[Claims] In a turbine valve test circuit for a steam turbine having one or more main stop valves and one or more throttle valves on each of the left and right sides, a correction function calculator for calculating a throttle valve opening corresponding to a current load setting value, and a correction function calculator for calculating a throttle valve opening corresponding to a current load setting value are used. a deviation calculator that outputs the deviation between the current opening degree of the throttle valve on the side that is not tested, and a proportional integral calculator that inputs the deviation and adds the proportional integral output to the throttle valve demand on the side that is not tested. Turbine valve test circuit added to the test circuit side.