JPH0537613Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to an oscillator with a sense meter used for work such as determining whether the cable is alive or dead and matching when cutting and connecting cables on underground power lines. .

(Prior art) When replacing the cable of an underground power line with a new line or changing the route, when cutting the cable and connecting a new cable, as shown in Figure 3A, the cable An oscillator P is installed between any two phases of the power transmission end, for example, between the S phase and the T phase,
At the power receiving end C, the phases corresponding to the two phases at the power transmitting end B are connected by a line D. Then, the oscillator P is activated, a sensor is used to determine whether the cable is alive or dead at the cutting and connection site, the target cable is confirmed, and the cable is cut. Then, as shown in Figure 3B, remove the oscillator P at the power transmission end, and connect the sense meter _S1 to S.
Attach it to the S phase and T phase, remove the line D at the receiving end C, and attach the sense meter _S2 to the S phase and T phase. The phase is then determined at the cutting site. In this case, the resistance of each phase is ∞ for R phase, R for S phase, and 0 for T phase.
becomes. Then, after checking each of the three phases, connect the new cable to the relevant location.

(Problem that the invention aims to solve) However, the transmitting end and the receiving end are usually far apart, so when installing an oscillator or a sense meter, a worker must go to the transmitting end or receiving end, which are far away, respectively, making the work of connecting a new cable extremely time-consuming.

(Means for solving the problem) Therefore, this invention provides a single device that can perform life and death determination and phase determination of cables, and has a structure in which the transition from life and death determination to phase determination is automatically switched by cutting the cable. It is an object of the present invention to solve the above-mentioned problems by providing a device that does this.

The specific configuration of this invention consists of a device for the sending end and a device for the receiving end. A resistor is connected in parallel via a changeover switch, and from this line,
The grounding wire is branched through a second changeover switch whose one end is an open end, and these changeover switches are configured to be interlocked by a relay of a current detection circuit having a CT connected in series with the above-mentioned oscillator. A line is provided to connect the two phase terminals at the other end of the cable, a resistor is connected in parallel to this line via a third changeover switch, and a fourth line with one end open is connected to this line. The grounding line is branched through a changeover switch, and these changeover switches are configured to be interlocked by a relay of a current detection circuit having a CT provided on the line.

(Function) When cutting one part of the cable of an underground power line and connecting a new cable to that part, use the power transmission end equipment of this invention on any two phases of the power transmission end of the cable, for example, R phase and S phase. Connect the line, and also connect the line of the power receiving end equipment to the corresponding 2-phase, R-phase, and S-phase of the power receiving end of the cable. Then, the oscillator of the transmitting end device is activated to cause a signal current to flow through the two phases of the cable. In this case, the signal current flows through each line of the power transmitting end equipment and the power receiving end equipment, so the CT detects this.
A current flows through each current detection circuit, and the changeover switch maintains its state by each relay. Then, in the middle of this underground power line, at the point where the cable is scheduled to be cut, a sensor is used to determine whether the cable is dead or alive, detecting a signal current, confirming the target cable, and cutting it. As a result, the lines ringing from the line of the power transmitting end equipment, the two-phase cable, and the line of the power receiving end equipment are immediately disconnected, no signal current flows, and each relay is turned off in the current detection circuit installed in each line. Each changeover switch will change automatically. Therefore, each line of the power transmitting end device and the power receiving end device is grounded to become a sense meter with resistance, and each phase is determined at the cut end of the cable, and a new cable is connected to each of these phases.

(Example) An example of this invention will be described below with reference to the drawings.

1 is the device for the sending end, 2 is the device for the receiving end, 3 is the three-phase cable to be disconnected and connected, and both ends 3
A power transmitting end device 1 and a power receiving end device 2 are connected to a and 3b, respectively. 4 is a line of the above-mentioned power transmission end equipment 1, and both ends of this line 4 are connected to one end 3 of the above-mentioned cable 3.
It is connected to any two phases of R phase, S phase, and T phase of a. 5 is an oscillator provided in this line 4, 6 is a 1MQ resistor connected in parallel with this oscillator 5 via the first changeover switch 7, 8 is a grounding line branched from this line 4, and 9 is this grounding line 8. A second changeover switch, 1, with one end 9a being an open end, provided in
0 is a CT connected to the line 4 in series with the oscillator 7.
This CT 10 forms a current detection circuit 11,
This current detection circuit 11 is provided with a relay 12 . This relay 12 is connected to the first changeover switch 7.
and the second changeover switch 9 are operated in conjunction with each other, and when the relay 12 is in the ON state, the first changeover switch 7 is brought into contact with the oscillator 5 side, and the second changeover switch 9 is brought into contact with the open end 9a side, and when the relay 12 is in the ON state, the first changeover switch 7 is brought into contact with the open end 9a side. In this case, the first changeover switch 7 is brought into contact with the resistor 6 side, and the second changeover switch 9 is brought into contact with the grounding wire 8 side. Reference numeral 13 denotes a line of the power receiving end device 2, and both ends of this line 13 are connected to the R of the other end 3b of the cable 3.
It connects to any two phases: phase, S phase, and T phase. 14 is a 1 MΩ resistor connected in parallel to the line 13 via a third changeover switch 15; 16 is a grounding line branched from the line 13; the end of the resistor 14 is connected to this grounding line 16; 17 is a fourth changeover switch provided on the grounding wire 16, with one end 17a being an open end; 18 is a CT provided in the line 13 in parallel with the resistor 14; this CT 18 forms a current detection circuit 19; , this current detection circuit 19 is provided with a relay 20 . This relay 20 is connected to the third changeover switch 15 and the fourth changeover switch 1.
7 are operated in conjunction with each other, and is similar to the relay 12 described above.

In this embodiment, the power transmitting end device 1 is held at one end 3a of the cable 3, both ends of the line 4 are connected to arbitrary two phases, the R phase and the S phase, and one end of the grounding wire 8 is grounded. Also, hold the power receiving end device 2 at the other end 3b of the cable 3, connect both ends of the line 13 to the same two-phase, R phase, and S phase as the power transmitting end device 1, and connect one end of the grounding wire 16. Ground. When the oscillator 5 of the power transmitting end device 1 is activated, current flows through the line 4, the cable 3, and the line 13 of the power receiving end device 2, and the current detecting circuit 11,
Current flows through relays 12 and 20, respectively, and the first changeover switch 7 contacts the oscillator 5 side,
The ground wire 8 is opened by a second changeover switch 9, the third changeover switch 15 contacts the line 13 side, and the ground wire 16 is opened by a fourth changeover switch 17 and maintained. Therefore lines 4 and 1
3 is closed via cable 3.

In this way, a sensor is used in the middle of the cable 3 to be cut, and the target cable is confirmed and cut. Due to this disconnection, no current flows through the lines 4 and 13, and each relay 12 and 20 is turned off as shown in FIG. The third switch 15 is automatically switched to the resistor 14 side, and the fourth switch 17 is automatically switched to the ground line 16 side, thereby functioning as a sense meter. At this time, when the resistance of each phase of the cables 3, 3 is measured at the cut end X, the R phase is 0, the S phase is the value R of the resistor 6 or 14, and the T phase is ∞, and each phase is determined from these.

(Effects of the invention) This invention has the above-mentioned configuration, and includes a device for the sending end and a device for the receiving end, which have both a conventional oscillator and a sense meter, and further operates the oscillator to determine whether the cable is alive or dead before cutting the cable. By doing this and cutting the cable, it automatically becomes a sense meter.

Therefore, when cutting and connecting cables such as underground power lines, workers can transport the sending and receiving end equipment to the sending and receiving ends of the cable, respectively, and connect them. Can perform discrimination and phase discrimination work. Therefore, it is possible to save labor by having the operator go to the power transmitting end and the power receiving end of the distant cable again after determining whether the cable is dead or alive and reconnecting the cable to the sense meter as in the past.

[Brief explanation of the drawing]

The figure shows an embodiment of this invention. Figure 1 is a circuit diagram showing a state in which this invention is used to determine whether a cable is alive or dead, and Figure 2 is a circuit diagram showing a state in which a cable phase is determined using this invention. Figures 3A and 3B show conventional examples, respectively; Figure A is a configuration diagram for determining whether the cable is dead or alive, and Figure B is a configuration diagram for determining the phase of the cable. In the figure, 1 is the power transmitting end device, 2 is the power receiving end device, 3 is the cable, 4 is the line, 5 is the oscillator, 6 is the resistor, 7 is the first changeover switch, 8 is the grounding wire, 9
is the second changeover switch, 12 is the relay, 13 is the line, 14 is the resistor, 15 is the third changeover switch, 1
6 is a grounding wire, 17 is a fourth changeover switch, and 20 is a relay.

Claims (1)

[Scope of utility model registration request] It consists of equipment for the sending end and equipment for the receiving end.The equipment for the sending end is provided with an oscillator in the line connecting two phase terminals at one end of the cable, and is connected in parallel with this oscillator via a first changeover switch. A grounding line is branched from this line via a second changeover switch, and these changeover switches are configured to be interlocked by a relay of a current detection circuit having a CT connected in series with the above oscillator. The equipment includes a line connecting two phase terminals at the other end of the cable, a resistor connected in parallel to this line via a third changeover switch, and a grounding line connected to this line via a fourth changeover switch. An oscillator with a sense meter, characterized in that lines are branched and these changeover switches are interlocked by relays of a current detection circuit having a CT provided on the line.