JPH065250B2 - Accident location method for cable tracks - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a fault location method for a cable line, and in particular,
The present invention relates to an accident point locating method for cable lines that can quickly and accurately locate an accident point.

[Technical Background of the Invention] Conventionally, as shown in FIG. 2 as a fault location method of a cable line, a discharge pulse generated at a fault point A of the cable line in the fault phase is connected to a capacitor C at a measurement end of the cable line. And the impedance Z to detect as the first propagation signal S1, and the discharge pulse is transmitted through the cable line of the sound phase connected at the far end of the cable line, and the capacitor C and the impedance Z at the measurement end 2 as the propagation signal S2, and the amplifier 1
A method of locating with an oscillogram on the synchroscope 12 through 0 is known. A typical example of the oscillogram at this time is shown in FIG. 3, where the first propagation signal S1 is the accident point A.
Pulse propagating directly to the measurement end from the second propagation signal S2
Indicates a pulse transmitted from the accident point A to the measurement end by transmitting the sound phase connected at the far end. Therefore, the time difference Δt between the first propagation signal S1 and the second propagation signal S2 at the measuring end is the time when the pulse travels back and forth between the accident point A and the far end, and the distance X from the measuring end to the accident point A is the pulse. Is calculated from the propagation velocity V of

X = L−VΔt / 2 where L is the cable length.

[Problems of background art] In such an accident location method, when the line is grounded by the cross bond method, there is an induction that the propagation wave of the discharge pulse is demultiplexed from the accident phase to the sound phase in the insulation junction box. The time difference Δ occurs because it cannot be distinguished from the propagating wave that returns from the far end.
There is a problem that t becomes unclear and the location of the accident point cannot be located.

Further, in this case, the above-mentioned measurement is carried out after changing the insulated junction box of the line to the ordinary junction box, and a great deal of labor and time is spent on the work for changing the insulated junction box. Despite the need to find this kind of accident point as soon as possible, the above-mentioned change work is the biggest difficulty.

[Object of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a method for locating an accident point of a cable line capable of locating an accident point with high accuracy and speed.

[Summary of the Invention] In order to achieve such an object, according to the fault location method of the cable line of the present invention, the discharge pulse generated at the fault point of the cable line is first measured at the measurement end of the cable line.
Of the discharge pulse, the discharge pulse is detected as a second propagation signal at the far end of the cable line, and is transmitted to a radio receiver provided at the measurement end by a radio transmitter, and the discharge pulse is detected at the first end at the measurement end. The time difference between the propagation signal and the second propagation signal is detected to locate the fault point of the cable line.

Embodiments of the Invention Preferred embodiments of the present invention will be described below with reference to the drawings.

The fault location method of the cable line of the present invention is realized by the system configuration shown in FIG. That is, in the figure, the measurement end of the cable line 2 is connected to the terminal 3 for applying a high voltage, and is grounded via the capacitor C and the impedance Z. The midpoint between the capacitor C and the impedance Z is connected to the amplifier 8. On the other hand, the far end of the cable line 2 is grounded via the capacitor C and the impedance Z, and the midpoint between the capacitor C and the impedance Z is connected to the radio transmitter 4. A wireless receiver 6 capable of receiving a signal from the wireless transmitter 4 is provided at the measuring end. The output terminal of the wireless receiver 6 is connected to the amplifier 8. The output terminal of the amplifier 8 is connected to the synchroscope 9.

In such a system configuration, the fault location of the cable line according to the present invention is performed by the following procedure.

A pulse for calibration is applied to the far end of the accident cable line 2, and the pulse propagated through the accident cable line and detected at the measuring end is wirelessly transmitted by the wireless transmitter 4 and the wireless receiver 6 and detected at the measuring end. Time difference from the pulse
Is measured with an oscillogram on the synchroscope 9. This time difference δt is used to calibrate the time delay of the pulse signal in the wireless transmission system by the wireless transmitter 4 and the wireless receiver 6 with respect to the transmission system by the accidental cable line 2 in advance.

A high voltage is applied to the accident cable line 2 from the terminal 3. It is assumed that the discharge pulse occurs at accident point A, for example. This discharge pulse is measured by an oscillogram on the synchroscope 9 at the measurement end of the cable line to generate the first propagation signal S.
Detect as 1. Further, this discharge pulse is detected as a second propagation signal S2 at the far end of the cable line and transmitted by the radio transmitter 4 to the radio receiver 6 provided at the measurement end, and the oscillogram on the synchroscope 9 is measured at the measurement end. The time difference Δt between the first propagation signal S1 and the second propagation signal S2 is calculated.

If the cable line length is L and the pulse propagation velocity in the cable line is V, the distance X from the measurement end to the fault point A is X = LV (Δt−δt) / 2, and the fault point of the cable line is Oriented.

The propagation velocity V can be calculated as V = 2L / (ΔT−Δt) by applying a pulse to the measurement end and measuring the same time difference ΔT.

[Effects of the Invention] As is apparent from the above embodiments, according to the fault location method of the cable line of the present invention, the discharge pulse traveling from the fault point to the far end is measured even when grounded by the cross bond method. Since the wireless transmission path is used when transmitting to the end, it is possible to locate the accident point with high accuracy without being affected by the guidance by the cross bond.

In addition, since there is no need to change the insulation junction box of the cable line to a normal junction box, it is possible to greatly reduce the time and quickly locate the accident point.

[Brief description of drawings]

FIG. 1 is a system configuration diagram for realizing a fault location method for a cable line according to the present invention, FIG. 2 is a system configuration diagram used in a conventional fault location method, and FIG. 3 is obtained by the location method. It is a wave form diagram of a discharge pulse propagation signal. 2 ... Cable line A ... Accident point S1 ... First propagation signal S2 ... Second propagation signal 4 ... Radio transmitter 6 ... Radio receiver Δt ... Time difference

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasutaka Fujiwara 2-1-1 1-1 Oda Sakae, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Showa Electric Wire & Cable Co., Ltd. 2-1-1 No. 1 Showa Cable Denki Co., Ltd. (72) Inventor Akira Nagaoka 2-1-1 1-1 Oda Sakae, Kawasaki-ku, Kawasaki-shi, Kanagawa Kanagawa Prefecture (56) Reference Japanese Patent Laid-Open No. 56-16878 (JP, A) JP-A-60-100061 (JP, A) JP-B-46-35465 (JP, B1)

Claims (1)

[Claims] 1. A discharge pulse generated at an accident point of a cable line is detected as a first propagation signal at a measurement end of the cable line, and the discharge pulse is used as a second propagation signal at a far end of the cable line. Characterized by detecting and transmitting to the wireless receiver provided at the measuring end by the wireless transmitter, calculating the time difference between the first propagation signal and the second propagation signal at the measuring end, and locating the fault point of the cable line A method for locating accident points on cable tracks.