JPS60128824A - Display wire monitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a display line monitoring device, and more particularly to a display line monitoring device that does not display a widespread failure in response to an instantaneous failure.

[Technical background of the invention]

In a display line relay device, if a failure such as a disconnection, short circuit, or ground fault occurs in the display line, the relay installed in this device to protect the power transmission line may adjust or the line may be damaged. It may become inoperable when there is a fault on the line. Therefore, it becomes necessary to monitor the display lines in order to prevent these problems.

A conventional display line monitoring device will be explained below. In Fig. 1, l is an indicator line relay connected to a current transformer connected to a power transmission line (not shown), and this indicator line relay 1 is connected to the secondary side of 2.
It is connected to the primary side of an isolation transformer 2 having several windings. To illustrate the secondary winding of this isolation transformer 2, display lines 3,
4 respectively. 5 is a capacitor for forming an AC circulation circuit. A pressure regulator 6 is placed on both ends of the capacitor 5.
Connect the output side terminals 6m and 6b of the
, 6d branches into two lines LH and L, and each line L
H and L are connected to terminals t1 and t1 via relays 7 and 8, which will be described later.
Connect to t3. Each line Ll.

In L, one line L1 is provided with a short-circuit relay 7 that detects and operates when the display line is short-circuited or disconnected, and the other line is equipped with a short-circuit relay 7 that detects and operates when the display line is short-circuited or disconnected. A working earth relay 8 is provided. The terminals tl, t are connected to a monitoring power source, such as a DC power source, via a normally closed contact 20b of an auxiliary relay 20 whose purpose is to stop the supply of monitoring current in response to the activation of each of the relays 7.8. Connect to the output terminal of An electric station configured in this manner will be called an observation electric station (indicated by a dotted line in the figure).

On the other hand, the display lines 3 and 4 are connected to two of the insulation transformers 9 (similar to those at the observation station) installed at the other party's electric station.
Connected to the next side. The primary side of this transformer 90 is connected via an indicator line relay 10 to a current transformer provided on a power transmission line (not shown).

A capacitor 11 similar to the capacitor 5 described above for forming an AC circulation circuit is connected to the secondary side of the isolation transformer 90, and both ends of this capacitor 11 are connected to the output side terminals 12m and 12b of the transformer 12. Input side terminal 12c
, 12d, one end of a resistor 13 is connected to the terminal 12a of the resistor 12d, and a relay 14 that operates with a sufficiently small sensitivity current is provided between the other end and the terminal 12d. The electrical station configured in this manner will be referred to as a secondary electrical station (shown surrounded by a dashed line in the figure).

The normally closed contact 20b provided at the observation electric station is an auxiliary relay 20.0 auxiliary liquid point, and this relay 20 is connected in series with the auxiliary contact 7a of the short-circuit relay 7 mentioned above and connected to the power supply buses P and N. There is. As shown in the figure, the auxiliary contact 7a of the relay 7 is normally open, but if there is an abnormality such as a short circuit or disconnection in the display line and the current value of the monitoring current increases, it will operate and close. It is something. On the other hand, the auxiliary contact 81 of the ground fault relay 8 is a normally open contact as shown in the figure, and is operated and closed when there is an abnormality such as a ground fault in the display line and the monitored current value decreases. It is.

The observation and child side electric stations are separated by a predetermined distance. Therefore, the current flowing through the power transmission lines at these electrical stations is detected, and this current is circulated between the electrical stations via indicator wires 3 and 4, and the protective relay (not shown) operates while this circulating current is flowing. It is designed not to. When a failure occurs in a power transmission line, this circulation and current change, causing 1
If the protective relay operates, the interrupter will be tripped to protect the equipment. Direct current is applied to this display line 3.4 from a monitoring power source (not shown) through normally closed contacts 20b - relays 7, 8 - transformer 6.
- supplied via the isolation transformer 2;

When the monitoring current is flowing through the display wires 3 and 4 from the monitoring power source, if the display wire is disconnected at the 21 points shown in the figure, the monitoring current flowing through the secondary electrical station will become zero, and the electrical appliance 14 will be restored. do. At the same time, the monitoring DC current at the observation electric station also drops to zero, and the short-circuit relay 7 is activated. The operation of this relay 7 closes the normally closed contact 7a, and the auxiliary relay 20 closes the bus bars P, N.
is energized by a voltage of , opening its normally closed contact 20b. Therefore, the monitoring current is completely interrupted by opening this normally closed contact 20b, ensuring that the relay 14 installed at the secondary electric station is restored, and a fault occurs in the display lines 3 and 4. Display what has been done.

Since the relay 7 of the observation electric station is already activated, the message "Disconnection" is displayed.

Next, when the display lines 3 and 4 are short-circuited at the point F■ in the diagram, the short-circuit point F! The resistance of the display line 3.4 when looking at the electric station on the child side is large because the distance of the display line is relatively long, and can be almost ignored when compared with the resistance at the short circuit point of F2. Therefore, the monitoring current of the observation electric station creates a short circuit relay 7,
This relay 7 will operate if it is large enough to operate. Therefore, the normally open contact 7a of the relay 7 is closed, the auxiliary relay 20 is energized and its normally closed contact 20b is opened, and the supply of monitoring current is cut off, so the relay 14 of the secondary electric station is restored. detects and displays failures.

Meanwhile, at the same time, a short circuit display was also observed on relay 7 at the electrical station.
It will be displayed on the screen.

In addition, if a ground fault occurs in the display line 3.4, this can be detected by the operation of the grounding relay 8 at the monitoring electrical station, and the normally open contact 8a of this relay 8 is closed, so the auxiliary relay 2
0 is energized and its normally closed contact 20b is opened, so that the monitoring current no longer flows to the display line 3.4, and the relay 14 of the secondary electric station is restored, indicating a failure and the monitoring electric station It is also displayed that there is a ground fault due to the operation of the ground relay 8.

[Problems with background technology]

As mentioned above, when a failure occurs in the display lines 3 and 4, the monitoring current supply is cut off in order to ensure that the relay 14 of the secondary electric station is restored. This also occurs in response to the operation of the relay 7 due to the inrush current that occurs when the fault occurs, and even if the fault is recovered, the fault display continues because the monitoring current has been cut off.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a display line monitoring device that takes measures against instantaneous failures.

[Summary of the invention]

In the present invention, the relay 7 of the observation electric station operates, and after a certain period of time when the supply of the monitoring current is once cut off, the monitoring current is forcibly supplied to the display line 3.4, and even at that point, the relay 7 When the operation of the line is confirmed, it is determined that there is a failure in the display line and is displayed.There is no failure indication for instantaneous failures, which further improves reliability.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to FIG. The auxiliary relay 21 has a normally open contact point 20m of the auxiliary relay 20.
The normally closed contact 21b of the auxiliary relay is connected in series with the auxiliary relay 20 and the auxiliary contact 7a of the relay 7 is inserted in series with the auxiliary relay 7a of the relay 7.

The auxiliary relay 22 is connected in series with the normally open contact 21a of the time-limited auxiliary relay 21 and the auxiliary contact 7a of the relay 7, respectively, and is used for display purposes.

Next, the operation of the above-described embodiment will be explained. When a short circuit or disconnection failure occurs in the display line, the normally open contact 7a is closed and the auxiliary relay 20 is energized as explained in FIG. At the same time, the supply of the monitoring current is cut off by opening the normally closed contact 20b! The normally open contact 20m energizes the auxiliary relay 21. After a certain period of time has elapsed, the normally closed contact 21b is opened and the auxiliary relay 20 is deenergized, and the normally closed contact 20b is closed and the monitoring current is supplied again, and at the same time, the time-limited auxiliary relay 21 is deenergized. The closing of the normally open contact 211L energizes the auxiliary relay 22, and then the opening of the normally closed contact 22b deenergizes the time-limited auxiliary relay 21, and the auxiliary relay 21 is deenergized by its normally open contact 22a. It is connected in series to the normally open contact 7a side of the relay 7. If the failure of the indicator line continues at this point, since the normally open contact 7a is closed, a holding circuit with the auxiliary relay 22 is formed. Therefore, the display is displayed for the first time. However, if the failure of the display line is instantaneous and has already recovered, the holding circuit will not be formed and the auxiliary relay 22 will operate to instantly unenergize itself and no display will occur. Become.

〔Effect of the invention〕

As explained above, according to the present invention, when a failure occurs, the monitoring current is cut off, the monitoring current is supplied again after a predetermined period of time, and the failure is displayed only when the failure is confirmed. In the case where a line failure can be recovered instantly, a highly reliable display line monitoring device can be provided by not displaying a failure indication.

[Brief explanation of drawings]

FIG. 1 is a schematic wiring diagram of a conventional display line monitoring device, and FIG. 2 is a schematic wiring diagram showing an embodiment of the present invention. 1.10... Indication line relay 2.9... Insulation transformer 3, 4-... Indication line 5.1
1... Capacitor 6, 12... Transformer 7- Short circuit relay 8... Earth fault relay 13... Resistor 14-...
Relay 20.22... Auxiliary relay 21 - Time-limited auxiliary relay (7317) Agent, patent attorney Noriyuki Chika (Haka 1)
given name)

Claims (1)

[Claims] In a display line monitoring device that circulates a constant value of monitoring current to the display line and indicates a failure of the display line by cutting off the supply of the monitoring current to the display line when the magnitude of the monitoring current changes. , a display line characterized in that the monitoring current is forcibly supplied again after a predetermined period of time after the supply of the monitoring current is cut off, and if the failure continues, it is determined that there is a failure and a display is made. monitoring equipment.