JP3098317B2 - Abnormal current and voltage waveform storage device in power line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage device for abnormal current and voltage waveforms in electric lines.

[0002]

2. Description of the Related Art In general, when a lightning surge current enters a power line in a power transmission and distribution line, it is discharged from a wire supporting insulator device to a steel tower, and a subsequent continuation current is generated, resulting in a temporary ground fault. In the event of such an accident, there is almost no hindrance to the power supply due to the re-closing of the substation circuit breaker or the switching of the transmission line, but subsequent inspections will investigate the cause of the accident, inspect it, and recover from equipment damage. The work may require a lot of time and effort because the course is mountainous or extensive, and the accident is restored by reclosing.

In order to cope with this problem, as a conventional device for detecting an abnormal current at the time of occurrence of an accident, a commercial frequency in a transmission / distribution line, that is, a current of 60 Hz (or 50 Hz) is detected and measured. When the current was observed, it was regarded as abnormal.

[0004]

However, the above-mentioned conventional abnormality detecting device can determine that an accident has occurred. However, whether the abnormal current is due to a ground accident or simply a lightning surge current There was a problem that it was not possible to judge whether the accident was just flowing or the nature of the accident.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art, and when an abnormal current flows through a transmission / distribution line and an accident occurs, the contents of the abnormal current in the line can be determined. It is to provide a voltage waveform storage device.

[0006]

According to the present invention, an optical sensor for optically detecting a current and / or a voltage of an electric wire is connected to the optical sensor via an optical fiber. , Which converts optical signals into electrical signals
An electrical converter, an A / D converter that converts an analog signal output from the optical / electrical converter into a digital signal,
A storage circuit that stores a digital signal output from the A / D converter, a non-contact abnormality detection sensor that detects a change in an electric field or a magnetic field when an abnormal current or an abnormal voltage is generated in an electric wire, When the output signal of the abnormality detection sensor exceeds a set value, the waveforms before and after the signal are subjected to the A / D conversion.
The sampling rate of the sample
And a trigger signal generating circuit for outputting a trigger signal for storing the waveform data in the storage circuit at a low speed .

[0007]

According to the present invention, when an abnormal current flows through an electric wire, the current and / or voltage is optically detected by an optical sensor, and an optical signal is input from the optical sensor to an optical / electrical converter via an optical fiber. The electric signal converted by the converter is converted from an analog signal to a digital signal by an A / D converter. Then, the digital signal output from the A / D converter is stored in a storage circuit, and the old storage data and the new storage data of the storage circuit are constantly updated at a predetermined cycle. When an abnormal current is generated in the electric wire, an abnormality due to a change in the magnetic field is detected by the abnormality detection sensor. When an output signal from the abnormality detection sensor exceeds a set value, a trigger signal is generated from the trigger signal generation circuit. Output and abnormal data is recorded. Therefore, the contents of the abnormal current and / or voltage can be determined based on the abnormal data stored in the storage circuit.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 2, an insulator 3 with built-in optical fiber is fixed to the tower 1 via a mounting plate 2, and a cap fitting 4 fitted and fixed to the lower end of the built-in insulator 3 is connected to an electric wire via a clamp fitting 5. 6 are gripped. A bracket 7 is provided on one side of the cap fitting 4.
Through a ring-shaped optical current sensor 8 (hereinafter referred to as an optical CT).
Is supported so as to surround the electric wire 6.
In the light CT8, a gap is provided in a part of an annular iron core (not shown), and a Faraday element (not shown) is interposed in the gap.
Both members are enclosed by an insulating jacket. The optical fiber built-in insulator 3 and the optical CT 8 configured as described above are provided at three places corresponding to the three-phase electric wires 6 respectively. Further, the light CTs 8A to 8C can detect a frequency range of 30 Hz to 50 kHz. The reason for this is that the relationship between the frequency of the load current and the fault current (landing current, lightning current) and the current value is clear from IEEJ Technical Report (2) No. 278 “Recent trends and problems of lightning research” According to this data, if the frequency of the detection current is set in the range of 30 Hz to 50 kHz, both the load current and the fault current can be detected.

The three light CTs 8A to 8C are transmitted via an optical fiber cable 9 to a waveform storage unit 1 described in detail later.
A signal is output to 0. In addition, an abnormality detection sensor 11 that detects the occurrence of an abnormal current or voltage is attached to the three-phase electric wire 6. The abnormality detection sensor 11 outputs a signal to the waveform storage unit 10 via an optical fiber cable 13.

Next, the configuration of the control device in the waveform storage unit 10 will be described with reference to FIGS. The high-speed response type photodetectors 14 to 16 convert the optical signal data detected by the light CTs 8A to 8C into electric signals and output the detected currents of the three phases to the waveform recording device 17, respectively. The waveform recording device 17 includes a data storage circuit 18 that stores the detected current for each phase.

On the other hand, the abnormality detecting sensor 11 is connected to a level detecting circuit 19, and the level detecting circuit 19 has a built-in trigger signal generating circuit 20. This generating circuit 20 is connected to the data storage circuit 18. The detection signal from the abnormality detection sensor 11 is
9 is used to determine whether the value is a set value, and a trigger signal is output from the trigger signal generation circuit 20 to the data storage circuit 18.

Further, as shown in FIG. 1, a solar cell 24 is connected to the waveform storage unit 10, and the solar cell 24 is connected to a storage battery 25 provided in the storage unit 10. The storage battery 25 includes a switchboard unit 26.
And the high-speed response type photodetectors 14 to 16 and the waveform recording device 17 are connected via a DC / DC converter 27,
The required direct current can be supplied.

Next, the operation of the abnormal current / voltage waveform storage device in the electric line configured as described above will be described.
Now, when a normal current is flowing through the three-phase electric wire 6, the output signal from the abnormality detection sensor 11 is normal,
The electric and magnetic fields due to the zero-sequence voltage and zero-sequence current do not exceed the set values. Therefore, the trigger signal generation circuit 20
Does not operate, the optical signal data detected by each of the optical CTs 8A to 8C is input to the high-speed response type photodetectors 14 to 16 via the optical fiber cable 9, where they are converted into electric signals. The update is repeated at a predetermined cycle by the storage circuit 18, and only the latest data is stored and held in the storage circuit 18. The sampling speed of the A / D converter of the waveform storage device is set to a sufficiently high speed before and after the occurrence of a failure, and thereafter the sampling speed is reduced. Since high-frequency components are generated before and after the occurrence of a failure, sampling accuracy in this range (here ± 8 ms) was increased, and thereafter the sampling speed was reduced to reduce the total memory capacity.

Here, when a ground current or a lightning surge current enters the electric wire 6, an abnormality detection signal is output from the abnormality detection sensor 11 to the level detection circuit 19, and the circuit 1
An abnormal signal is output to the trigger signal generating circuit 20 incorporated in the memory 9. As a result, the trigger signal is output from the trigger signal generating circuit 20 to the data storage circuit 18, and the storage circuit 18 stores the abnormal data. At this time, as shown in FIG. 3, a point at which the lightning surge enters and reaches the trigger level is set as a boundary point, and the waveform data of the abnormal current before and after the point is stored. Therefore, after an accident occurs and is restored,
The recorded abnormal waveform data can be read out and displayed on, for example, an oscilloscope or the like, and the contents of the fault current can be confirmed. The sampling of the waveform for recording the waveform needs to be changed at the flashing point and at the point where the fault current continues thereafter, and the sampling cycle needs to be set in accordance with the change in the waveform.

The present invention is not limited to the above embodiment. For example, means (not shown) for adjusting the period for storing the waveform of abnormal data may be provided, or a memory card or data storage circuit 18 may be provided for storage. The configuration of each unit may be arbitrarily changed and embodied without departing from the gist of the present invention, for example, by connecting a display circuit (not shown) capable of displaying data stored in the storage unit.

[0016]

As described above in detail, according to the present invention, when an abnormal current flows in an electric line , the sampler before and after the occurrence of the abnormality is sampled.
Accuracy, and the waveform data can be stored. As a result, the content of the abnormal current can be easily determined, which greatly contributes to the investigation of the cause of the accident, inspection, and restoration work in case of equipment damage. Can also, the whole memory
There is an effect that can be achieved savings of over capacity.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing an embodiment embodying an abnormal current / voltage waveform storage device of the present invention.

FIG. 2 is a front view showing a support structure for optical CT.

FIG. 3 is a graph illustrating abnormal waveform data.

[Explanation of symbols]

3 Insulator with built-in optical fiber, 6 electric wire, 8A-8C optical CT, 9 optical fiber cable, 10 waveform storage unit, 11 abnormality detection sensor, 13 optical fiber cable, 14-16 high-speed response type photodetector, 17 waveform recording device, 18 data storage Circuit, 19 level detection circuit,
20 Trigger signal generation circuit.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroyuki Katsukawa 62, Inaba, Takagi, Fuso-cho, Niwa-gun, Aichi Prefecture (72) Inventor, etc.Ishikawa, etc. Koji 259, Matsui-cho, Meito-ku, Nagoya-shi, Aichi (72) Inventor Nobutaka Fukui 857-51, Fukudome-cho, Matsuto-shi, Ishikawa (56) References JP-A-2-35369 (JP, A) JP, U) JP-A-5-14933 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01R 13/00-13/42 G01R 19/00 G01R 19/165

Claims (1)

(57) [Claims] 1. An optical sensor for optically detecting current and / or voltage of an electric wire, and an optical / electrical converter connected to the optical sensor via an optical fiber and converting an optical signal into an electric signal. An A / D converter for converting an analog signal output from the optical / electrical converter into a digital signal; a storage circuit for storing the digital signal output from the A / D converter; Or a non-contact abnormality detection sensor that detects a change in an electric field or a change in a magnetic field when an abnormal voltage is generated; and when an output signal of the abnormality detection sensor exceeds a set value, the waveforms before and after the A / A D converter sampling
Increase the speed and then reduce the sampling speed
A trigger signal generating circuit for outputting a trigger signal for storing waveform data in a storage circuit .