JPH08110801A - Turbine controller - Google Patents

Abstract

PURPOSE: To enable the conversion and readjustment of the opening extent detecting circuit of a faulty system to be performed without stopping a turbine by adjusting the characteristics of the level converting means on an abnormal side on the basis of the signal outputted from the other normal A/D converting means. CONSTITUTION: The opening extent of a steam governor valve 1 is converted by an A-system differential transformer 2A into an AC electric signal, which is converted by an A-system demodulating circuit 3A into an opening extent signal of DC level. Further, the signal is converted by an A-system A/D converter 5A into a digital signal value, which is inputted to the controller C, adjusted to a range predetermined by an A-system level converting circuit 7A, and inputted to a control circuit 6. B-system input is the same. An input range arithmetic circuit 8 instructs the control circuit 6 to disconnect an abnormal system side if one of the A-system and B-system opening extent detecting circuit A and B becomes abnormal, and readjusts the level converting circuit on the faulty side on the basis of the signal of the normal system once informed that the abnormal side is put back in the normal state, informing the control circuit 6 of the usable state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine control device for controlling the speed of a turbine.

[0002]

2. Description of the Related Art A detected opening value of a steam control valve used for steam turbine control is obtained by demodulating an output signal of a differential transformer by hardware, adjusting the level after demodulation, and then converting it into a digital value. It is used by being incorporated in the control device. FIG. 3 shows an example of a conventional duplex configuration circuit.

In this figure, A system opening detection circuits (A) and B are shown.
The system opening detection circuit (B) is an electronic circuit, and the control device (C)
Is realized by a computer (microcomputer). The opening degree of the steam control valve (1) is first converted into an AC electric signal by the A system differential transformer (2A), input to the A system demodulation circuit (3A), and converted into a DC level opening signal. This opening signal has a variation in signal level due to the working accuracy of the A system differential transformer 2A, mounting error, demodulation circuit error, etc.
It is necessary to adjust the voltage to a predetermined voltage range (for example, 0 to 100%: 0 to 10 V) by the system level conversion circuit (4A). The level-adjusted signal is converted into a digital signal value by the A-system A / D conversion circuit (5A) at the next stage, taken into the control device (C) and input to the control circuit (6).

Even in the B system input, the output of the B system differential transformer (2B) is the same as the A system, and the B system demodulation circuit (3B), the B system level conversion circuit (4B), and the B system A / D conversion. The control circuit (6) is taken into the control device (C) through the circuit (5B).
Is input to. In the case of duplication, the A and B system opening inputs are generally selected by the control circuit (6) to have a high value, and the larger value is generally used as the actual opening input for control.

[0005]

However, in the conventional configuration, after the failure circuit is converted in order to restore the failure circuit because automatic adjustment is impossible when the one-side opening detection circuit is abnormal. , The level conversion circuit had to be readjusted, and in order to make that adjustment, it was necessary to stop the turbine once and adjust the opening of the steam control valve to the fully open and fully closed positions. It was not possible to replace and recover the abnormal system opening detection circuit while continuing control without stopping.

Therefore, an object of the present invention is to provide a turbine control device having a function capable of exchanging a circuit of a failure system and performing readjustment without stopping the turbine in the above case.

[0007]

The invention according to claim 1 is as follows.
Detecting the opening of the steam control valve, a plurality of opening detection means for converting into an electric signal, and provided according to the opening detection means,
A / D conversion means for converting the electric signal into a digital signal, and the A / D conversion means provided in accordance with the A / D conversion means.
A level converting means for adjusting the signal output from the converting means to a predetermined level and outputting the signal, and a signal output from the plurality of A / D converting means is taken in to calculate presence / absence of abnormality, and level conversion on the abnormal side is performed. Input range calculating means for adjusting the characteristics of the means based on signals output from other normal A / D converting means, and the steam control valve based on signals output from the plurality of level converting means And a control means for outputting a signal for controlling the opening degree.

The invention according to claim 2 is the first and second opening degree detecting means for detecting the opening degree of the steam control valve and converting it into an electric signal, and the first and second opening degree detecting means. First and second converters provided according to the above and converting the electric signals into digital signals.
Of the A / D conversion means and the first and second A / D conversion means, after adjusting the signals output from the first and second A / D conversion means to a predetermined level. First and second level converting means for outputting, and the first and second A / D
Taking in the signal output from the conversion means, calculating the presence or absence of abnormality, and adjusting the characteristics of the level conversion means on the abnormal side,
Input range calculation means for performing the operation based on the signal output from the normal A / D conversion means, and control of the opening degree of the steam control valve based on the signals output from the first and second level conversion means. And a control means for outputting a signal for

According to the invention of claim 3, in the invention of claim 2, XA1 and XA2 are signals output from the A / D conversion means on the abnormal side, and XB1 and XB2 are A / D on the normal side.
When the signals output from the conversion means, YB1 and YB2, are signals output from the level conversion means on the normal side, the gain / offset, which is the characteristic of the level conversion means on the abnormal side, is calculated and adjusted based on the following equation. It has an input calculation means. Gain = YB2-YB1) / (XA2-XA1) Offset = (XA2 * YB1-XA1 * YB2) /
(YB1-YB2)

[0010]

With the above structure, since the adjustment and restoration of the faulty circuit can be performed without stopping the turbine, the average repair time can be greatly shortened and the average fault interval can be extended, and highly reliable turbine control can be performed.

[0011]

1 is a block diagram of an embodiment of a turbine control device of the present invention. The circuit of the conventional turbine control device of FIG. 3 described above, the A system demodulation circuit (3A), the B system demodulation circuit (3B), the A system A / D conversion circuit (5A), and the B system A / D.
The conversion circuit (5B) and the control circuit (6) are the same, but A
The system A level conversion circuit (A) and the B system level conversion circuit (4A) and the B system level conversion circuit (4B) in the B system opening detection circuit (B) are incorporated into the control device (C) and realized by software. The A-system level conversion circuit (7A) and the B-system level conversion circuit (7B) are different from each other in that an input range arithmetic circuit (8) is added. The input range arithmetic circuit (8) controls the control circuit (to cut off the signal on the abnormal system side when an abnormality occurs in either the A system opening detection circuit (A) or the B system opening detection circuit (B). 6)
When receiving a notification (from humans etc.) that the abnormal system circuit has returned to the normal state, the level conversion circuit on the faulty side is readjusted based on the signal of the normal system, and when the adjustment is completed, it is sent to the control circuit (6). It is a circuit that informs that the signal of the restored system is available.

In the configuration of FIG. 1, the opening of the steam control valve (1) is converted into an AC electric signal by the A system differential transformer (2A) as in FIG. 3, and the DC level is converted by the A system demodulation circuit (3A). It is converted to an opening signal. This opening signal contains a variation in the signal level due to the working accuracy of the A system differential transformer 2A, the mounting error, the error of the demodulation circuit, etc., and the A system A / D converter (5
Converted to a digital signal value in A), and the control device (C)
It is taken into the inside of the control circuit (6) where it is adjusted to a predetermined range by the A system level conversion circuit (7A).
Is input to.

Even in the B system input, the output of the B system differential transformer (2B) is the same as the A system, and the B system demodulation circuit (3B) and the B system A are used.
It is taken into the control device (C) through the / D conversion circuit (5B), and after being level-adjusted by the B system level conversion circuit (7B), it is input to the control circuit (6).

In the case of duplexing, the A and B system opening inputs are generally selected by the control circuit (6) to have a high value, and the larger value is generally used as the actual opening input for control. is there. In the present circuit configuration, a case where a one-system opening detection circuit, for example, the A-system opening detection circuit (A) has failed will be described with reference to the flowchart of FIG.

Since the B system opening detection circuit (B) is normal, the control is continued by the B system input signal. Where A
After replacing the system opening detection circuit (A) with a new opening detection circuit (step 1), the completion of replacement is notified to the input range circuit (8) (step 2). At this time, the A system opening degree input signal cannot be used for control because the signal error described above is not adjusted because the A system level conversion circuit (7A) is set at the time of failure, so the control circuit In (6), the input from the A system is ignored, and the control is continued with the B system input.

A system level conversion circuit (7
The input of A) is XA, the output is YA, the input of the B system level conversion circuit (7B) which is a normal system circuit is XB, and the output is YB. The signals XA1, YA1, XB1, YB1 and XA2, YA2, X, which are the signals at arbitrary two different opening positions.
The data of B2 and YB2 are read (step 3).

Then, it is determined whether the data difference between the signal YB1 and the signal YB2 has a predetermined deviation (step 4).
If the deviation is equal to or more than the predetermined deviation in (step 4), the signal XA
It is determined whether the data difference between 1 and the signal XA2 has a predetermined deviation (step 5).

If the predetermined deviation is not satisfied in (step 5), the process returns to (step 4). On the other hand, if the predetermined deviation is exceeded, the level conversion circuit is realized by the following equation (1). If so, the gain and offset of the A system level conversion circuit (7A) are calculated by the following equations (2) and (3) (step 6).

[0019]

## EQU1 ## Output = (Input-Offset) * Gain (1) Gain = (YB2-YB1) / (XA2-XA1) (2) Offset = (XA2 * YB1-XA1 * TB2) / (YB1-YB2) ) (3) Set the correct gain / offset calculated in (step 6) in the A system level conversion circuit (7A) (step 7)
In addition, the control circuit (6) is connected to the A system level conversion circuit (7
Notify that A) has returned to normal (step 8).

In the input range arithmetic circuit (8), when the failure system input is restored, the signal input to the level conversion circuit of the recovery system circuit and its output signal, and the input signal of the level conversion circuit of the normal system circuit and its output The gain and offset, which are the set values of the level conversion circuit of the restoration system circuit, are calculated from the signal relationship.

Since the output of the B system level conversion circuit (7B) is normal and both A and B systems are trying to detect the same opening, the output of the A system level conversion circuit (7A) is always the B system level conversion circuit. The A system level conversion circuit (7A) may be adjusted so as to match the output of (7B).

In practice, since the input range calculation circuit (8) is realized by software, if the difference between YB1 and YB2 and between XA1 and XA2 is too small, the error in the calculation result will be large, so that the system is allowed. The width is set in consideration of possible error, the positions of two points exceeding the width are held in the control process, and the value is used to calculate the set value to the A system level converter (7A), and then the value is set. After the setting, the permission for use of the A system input signal is issued to the control circuit, thereby returning to the duplex operation using the A and B system inputs.

Even if the B system side becomes abnormal and the A system side is normal, the B system opening degree detection circuit (B) can be restored without stopping the turbine control. By using the turbine control device of the present embodiment, the turbine control is restored without stopping when one system of the opening detection circuit that is duplicated for detecting the opening of the steam control valve becomes abnormal, It is possible to continue the redundant operation.

The above embodiment is an example at the time of duplexing, but even in the case of multiplex system input of triple or more, the relationship between the signal of the normal system and the signal of the recovery system is utilized in the same manner to continue the control of the adjustment of the recovery system. You can do it while.

[0025]

As described above, according to the turbine control device of the present invention, it is possible to restore the opening detection circuit in which an abnormality has occurred while continuing the control of the turbine, and to improve the operating rate of the system. Can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a turbine control device according to the present embodiment.

FIG. 2 is a flowchart of a turbine control device showing the present embodiment.

FIG. 3 is a configuration diagram of a conventional turbine control device.

[Explanation of symbols]

 A ... A system opening detection circuit 4A ... A system level conversion circuit B ... B system opening detection circuit 4B ... B system level conversion circuit C ... Control device 5A ... A system A / D conversion circuit 1 ... Steam control valve 5B ... B system A / D conversion circuit 2A ... A system differential transformer 6 ... Control circuit 2B ... B system differential transformer 7A ... A system level conversion circuit 3A ... A system demodulation circuit 7B ... B system level conversion circuit 3B ... B System demodulation circuit 8 ... Input range calculation circuit

Claims (3)

[Claims] 1. A plurality of opening detecting means for detecting the opening of the steam control valve and converting it into an electric signal, and an A / A provided for the opening detecting means for converting the electric signal into a digital signal. D conversion means, level conversion means provided corresponding to the A / D conversion means, for adjusting the signal output from the A / D conversion means to a predetermined level and then outputting the signal,
The signal output from the A / D conversion means is taken in, the presence or absence of abnormality is calculated, and the characteristic of the level conversion means on the abnormal side is adjusted based on the signal output from another normal A / D conversion means. A turbine control device comprising: an input range calculating means for performing the above; and a control means for outputting a signal for controlling an opening of the steam control valve based on signals output from the plurality of level converting means. 2. The first and second opening degree detecting means for detecting the opening degree of the steam control valve and converting it into an electric signal, and the first and second opening degree detecting means.
Provided in accordance with the opening degree detection means, and provided in accordance with the first and second A / D conversion means for converting the electric signal into a digital signal and the first and second A / D conversion means. , First and second level conversion means for adjusting the signals output from the first and second A / D conversion means to a predetermined level and then outputting the signals, and the first and second A / D conversion means Input range calculating means for fetching a signal output from the CPU, calculating presence / absence of abnormality, and adjusting the characteristic of the level converting means on the abnormal side based on the signal output from the normal A / D converting means. And a control means for outputting a signal for controlling the opening degree of the steam control valve based on the signals output from the first and second level conversion means. 3. XA1 and XA2 are signals output from the A / D conversion means on the abnormal side, and XB1 and XB2 are A / D signals on the normal side.
When the signals output from the D conversion means and YB1 and YB2 are signals output from the level conversion means on the normal side, the gain / offset, which is the characteristic of the level conversion means on the abnormal side, is calculated and adjusted based on the following equation. 3. The turbine control device according to claim 2, further comprising input calculation means for performing the operation. Gain = YB2-YB1) / (XA2-XA1) Offset = (XA2 * YB1-XA1 * YB2) /
(YB1-YB2)