JPH0758654B2 - Tap position detection device for tap change transformer under load - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention uses an arithmetic unit such as an electronic computer to detect the tap position of a load tap change transformer (hereinafter referred to as LRT). The present invention relates to an LRT tap position detecting device.

(Prior Art) FIG. 4 shows an example of an electric power system diagram to which LRT is applied. The electric power supplied from the power supply facility 1 via the circuit breaker 2 is subjected to voltage adjustment by the LRT 3 after the voltage adjustment. Supplied to the load.

The tap switching operation in the LRT3 is performed by driving a tap switching device (hereinafter referred to as LCT) 4 equipped with a motor M.

FIG. 5 is a block diagram showing a configuration of a conventional tap position detecting device. This device detects the tap position of the transformer 3 by sequentially reading the output from a multi-directional switching dial switch (hereinafter referred to as an LRT dial switch) 3a that works in conjunction with the tap switching operation of the LRT3. Has been done.

FIG. 6 is a flowchart showing the configuration of the control program of the arithmetic unit 5. As shown in the figure, the arithmetic unit 5 reads the output data of the LRT dial switch 3a at a constant cycle or at an arbitrary timing (step 601),
The data read this time is compared with the data read previously (602).

As a result, if there is a change between the previous time and this time (step
603YES), while the detected tap position is updated to the changed tap position (step 604), if there is no change (step 603 NO), the detected tap position is not updated (step 605).

(Problems to be Solved by the Invention) However, in such a conventional tap position detecting device, it is difficult to manufacture a switch with high accuracy so that the tap position signal is instantly switched from TAP1 to TAP2, for example. For the above reasons, as shown in FIGS. 7 (a) and 7 (b), the tap position signals TAP1 and TAP2, which are output data of the LRT dial switch 3a, are in the ON state for the period TL in the transition period of tap switching. Therefore, if sampling is performed during this transition period as shown by S2 in the same figure (d), TAP1 data A and TAP2 will be shown as shown in the same figure (c).
There is a problem that the data B is detected redundantly and the tap position is mistaken.

An object of the present invention is to provide a tap position detecting device for a load tap change transformer which can always accurately detect the tap position without mistaking the tap position even in the transition period of the tap change. .

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above-mentioned object, the present invention successively outputs the output from a multi-directional changeover dial switch that is interlocked with a tap changeover operation of a load tap changeover transformer. By reading,
In a tap position detection device for a tap switching transformer under load, which detects the tap position of the transformer, the operating state of the tap switching drive tap switching transformer of the tap switching transformer under load is monitored and it is operating. During the period, the update of the detection tap position based on the read output of the dial switch is prohibited.

(Operation) According to such a configuration, in the transitional period of tap switching, updating of the detected tap position based on the output of the dial switch is prohibited, so that it is considered that the adjacent tap position signals are detected in duplicate. Also, there is no mistake in the tap position.

(Embodiment) FIG. 1 is a block diagram showing a configuration of an embodiment of a tap position detecting device according to the present invention.

The LRT dial switch 3a interlocks with a tap switching operation of an LRT (not shown), and outputs dup position signals TAP1 to TAPn according to each tap position.

The LTC operation detection switch 4a is a switch that turns on only when the LTC (not shown) is in operation, and the output of this switch serves as the LTC operation detection signal.

The arithmetic unit 5 is composed of a microcomputer,
While monitoring the LTC operation signal, the tap position of the LRT is detected based on the tap position signals TAP1 to TAPn.

FIG. 2 is a flow chart showing the configuration of the control program executed in the arithmetic unit 5. Below, with reference to this flow chart and the time chart of FIG.
The operation of this device will be systematically described.

In FIG. 2, input signal reading processing (step 20
1), LRT dial switch 3a, LTC operation detection switch
Read tap position signals TAP1 to TAPn and LTC operation signal from 4a.

Then, based on the read LTC motion detect signal, LTC
Is checked (step 202).

Next, if it is determined that the LTC is not in operation by this confirmation (NO in step 203), the conventional process is performed.

That is, the state of the dial switch 3a read this time is compared with the state of the dial switch 3a read last time (step 204), and if there is a change between the previous time and this time (step 205 YES), the current time is read. The tap position determined by the state of the LRT dial switch 3a is updated as a new detected tap position (step 206).

If there is no change between the previous time and this time (Step 205N
O), the detection tap position is not updated, and the state of the detection tap position is maintained at the previous state (step 207).

On the other hand, when LTC is determined to be in operation based on the LTC operation detection signal (step 207), the state comparison between the previous time and this time is not performed, update of the detection tap position is also prohibited, and the detection tap The position state is maintained at the previous state (step 207).

As a result, as shown in FIG. 3, in the transition period of tap switching, the tap position signals TAP1 and TAP2 are changed to those in FIG.
Even if the ON state is duplicated as shown in (b), the LTC operation detection signal is also in the ON state as shown in (c) of the figure in the transition period of such tap switching. Therefore, by prohibiting the update of the detection tap position based on this, it is possible to prevent the detection tap position from becoming uncertain in the transition period of tap switching, as shown in FIGS. it can.

As described above, according to the device of the present embodiment, in the tap position detecting device of this kind, it is possible to improve the reliability of the device by preventing the generation of an incorrect tap position detection output during the transition period of tap switching. .

In the above embodiment, the dial switch 3a has been described as a system in which the tap position signals are overlapped and turned on during the transition period of the dup switching, but the tap position signals do not overlap during the transition period and both are off. Of course, even in the case of the method, the false tap position signal is not issued.

[Effects of the Invention] As described above, according to the present invention, in this type of tap position detecting device, it is possible to reliably prevent an erroneous tap position detection output from being issued during the transition period of the tap switching of the LRT. The reliability of can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a hardware configuration of a tap position detecting device according to the present invention, FIG. 2 is a flowchart showing the software configuration, FIG. 3 is a time chart for explaining the operation of the device, FIG. FIG. 4 is a diagram showing an example of a power supply system to which LRT is applied, FIG. 5 is a block diagram showing a hardware configuration of a conventional device, FIG. 6 is a flowchart showing a software configuration of a conventional device, and FIG. 6 is a time chart for explaining the operation of the device. 3 …… LRT 3a …… LRT dial switch 4 …… LTC 4a …… LTC operation detection switch 5 …… Calculator

Claims (1)

[Claims] 1. A load tap change transformer adapted to detect the tap position of the transformer by successively reading the output from a multi-type change dial switch that is interlocked with the tap change operation of the load tap change transformer. In the tap position detection device of the device, the operating state of the tap changer for tap change driving of the load tap change transformer is monitored, and the detected tap position based on the output of the read dial switch for the period during which this is in operation. A tap position detection device for a tap switching transformer of a tap switching transformer under load, characterized in that the updating of the tap is prohibited.