JPS62132181A - Memory reading system - Google Patents

Abstract

PURPOSE:To enable the determination of a location distance, regardless of a fault point caused in a transmission line when a transmission circuit is suspended, by reading out counts written into a memory of a master unit to be shown on a display circuit. CONSTITUTION:A distance counter 2 of a master unit is reset by a time reference pulse and the counting operation thereof is stopped by an output of a surge detection circuit 1. A memory 3 is for writing counts M of the counter 2 and reading them therefrom. A signal receiving circuit 4 receives counts S of a distance counter of a slave unit transmitted and an arithmetic circuit determines a location distance from the counts M and S. A reading control circuit 12 reads out the counts M written in the memory 3 to be displayed 6. Then, when a switch 13 is depressed once, the output of a selector 14 moves to an L state and an H state inverted with an inverter 151 is applied to a memory 3 and hence, a No.1 memory is read out. With the further depression of the switching 13, an output 142 of the selector 14 goes to L and a No.2 memory is read out. In such a manner, the counts of the master and slave units can be obtained even when a transmission circuit is interrupted.

Description

[Detailed Description of the Invention] [Summary] In the memory read method, the count value M written in the memory of the parent device can be read out and displayed, so that the count value S of the child device may be changed to the parent device due to a failure in the transmission line. Even if it is not sent to the device, the orientation distance can be determined by manual calculation using the count values displayed on the parent device and child device.

[INDUSTRIAL APPLICATION FIELD 1] The present invention relates to a memory reading method, particularly to an improvement of a memory reading method used in a power transmission line fault locating device.

In general, a power transmission line failure point locating device is a device that locates a failure point occurring on a power transmission line at the terminal of the power transmission line, and there are various locating principles, one example of which is as follows.

As shown in the illustration of the orientation principle in Fig. 2, the parent device sends time reference pulses (hereinafter referred to as scanning pulses) at fixed time intervals of, for example, 2 ms, in both directions or in one direction of the power transmission line, and the slave devices receive.

Now, if a failure occurs at point A of the power transmission line, the surge will proceed from here towards the parent device and the child device, but the parent device will be able to detect the time from sending out the scanning pulse to receiving the surge (hereinafter referred to as the count value M). ) is tl, and the time from when the child device receives the scanning pulse until it receives the surge (hereinafter referred to as the count value S) is t2, then the distance from the parent device to the failure point A (referred to as the target distance) d is expressed by the following formula.

d''%(tl-t2)Vp (1) Here, Vp is the speed of light, 3XIO' m/s.

Therefore, the parent device automatically calculates the orientation distance using the above formula and displays it on the display circuit, but it is necessary to make it possible to calculate the orientation distance even if t2 is not sent from the child device due to a failure in the transmission line. .

[Conventional technology]

FIG. 3 is a block diagram of a conventional example, with FIG. 3(a) showing a block diagram of a parent device, and FIG. 3(b) showing a block diagram of a child device.

First, the parent device shown in FIG. 3 (al) sends scanning pulses from a scanning pulse generation circuit (not shown) to the slave device via a power transmission line at intervals of, for example, 2 ms. Note that the distance counter 2 is reset by the scanning pulse. and starts counting operation.

After that, when a fault occurs in the power transmission line and a surge is input to the main device, the distance counter 2 stops counting operation by the output of the surge detection circuit 1 that detects this, and the count value M at that time
is written to memory.

On the other hand, the child device shown in Fig. 3 (bl) starts counting operation after the distance counter 2 is reset by the received scanning pulse, but when a surge is input, the output of the surge detection circuit 1 that detects this is used to calculate the distance. The counter 2 stops its counting operation, and the counted value S at this time is written into the memory 9 and displayed on the display circuit 10, and this value is also transmitted to the signal transmitting circuit 11. For example, l is 20 m5. O is 40 m5. After being converted into pulses, the FS signal fo±35Hz is sent to the parent device via a transmission line (for example a micro line).

Therefore, the signal receiving circuit 4 of the parent device shown in FIG. The display circuit 6 reads the data and calculates the above equation (1).
The orientation distance is displayed, but all of this is done automatically.

Note that the memory 3 is, for example, an IC memory, and the 2
I have two on one side so that I can write the counted values even if a failure occurs for the second time.

[Problem that the invention seeks to solve]

However, if the transmission circuit is disconnected, the count value S from the child device cannot be manually calculated, so the arithmetic circuit cannot calculate the orientation distance and does not display it. That is, there is a problem in that when a transmission line is disconnected and a fault point occurs in the power transmission line, the orientation distance cannot be determined.

[Means for solving problems]

The above problem can be solved by the present invention, which is equipped with a readout control circuit 12 that reads out the count value M written in the memory 3 of the parent device, and displays the successively read count value M on the display circuit 6. This problem is solved by a memory read method.

[Effect]

In the present invention, the count value M written in the memory 3 of the parent device can be read out and displayed on the display circuit 6.

Therefore, when the transmission line is disconnected and a failure point occurs in the power transmission line, a person displays the count value M of the parent device on the display circuit 6, and the target value S of the slave device is and look at the value on the display circuit 1o.

Therefore, the orientation distance can be determined using these two counts.

〔Example〕

FIG. 1 shows a block diagram of an embodiment of the present invention. Throughout the figures, the same reference numerals indicate open objects, and the dotted line portions are the parts added in the embodiment of the present invention.

As shown in the figure, when switch 13 is pressed once, selector 14
The output 141 of is in the L state, and the H state inverted by the inverter 151 is added to the memory 3, so No. 1
memory is read.

Furthermore, when the switch 13 is pressed, the output 142 of the selector 14 becomes L, and the inverter 152 applies the H state to the memory 3, and the memory No. 12 is read out one after another.By repeating this, it is possible to read out the four memories. Become.

Therefore, even if the transmission circuit is disconnected, the count values of the parent device and child device can be obtained, so the orientation distance can be determined.

- Note that 12 indicates a continuous output control circuit.

〔Effect of the invention〕

As described in detail above, even if a fault point occurs in the power transmission line when the transmission line is disconnected, there is an advantage that the orientation distance can be determined.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a diagram explaining the principle of orientation, and FIG. 3 is a block diagram of a conventional example. In the figure, 1 is a surge detection circuit, 2 is a distance counter, 5 is an arithmetic circuit, 6 is a display circuit,

Claims (1)

[Claims] A distance counter (
2), a memory (3) for writing and reading the count value M of the distance counter, a signal receiving circuit (4) for receiving the transmitted count value S of the distance counter of the slave device, and a memory (3) for writing and reading the count value M of the distance counter; S
In the parent device of the power transmission line failure point locating device, which includes an arithmetic circuit (5) that calculates the orientation distance from the arithmetic circuit (5) and a display circuit (6) that displays the output of the arithmetic circuit, A memory read method characterized in that a read control circuit (12) for reading a numerical value M is provided, and the read count value M is displayed on the display circuit (6).