JPH095360A - Non-contact current sensor - Google Patents

Abstract

(57) [Summary] [Structure] It is composed of a transmitter A and a receiver B. The transmitter A includes a current transformer 1 attached to a power line 10 such as an overhead power transmission line, and the current transformer 1. It is composed of the connected primary coil 2. On the other hand, the receiving unit B includes a secondary coil 5 electromagnetically coupled to the primary coil 2 of the transmitting unit A, and an amplifying device 6 that amplifies a current induced in the secondary coil 5.
And a display device 7 for displaying the current amplified by the amplification device 6.
It is composed of [Effect] The current transformer 1 detects an output current proportional to the current flowing through the power line 10, causes this current to flow through the primary coil 2, and causes the primary coil to generate an electromagnetic wave according to the current. The secondary coil 5 of the receiver electromagnetically coupled to the primary coil 2 receives the electromagnetic wave, the secondary coil 5 converts the electromagnetic wave into a current, and the current in the secondary coil 5 is amplified by the amplifying device 6 to be displayed on the display device 7. By displaying with, the current can be detected with a simple structure and without requiring a special power source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact current sensor used for detecting or monitoring a current flowing through a power line such as an overhead power transmission line.

[0002]

2. Description of the Related Art For maintenance and inspection of overhead power transmission lines,
It may be necessary to detect or monitor the current flowing in overhead power lines. Generally, as the current detecting means, there are a method using an ammeter, a method using a current transformer (CT), a method using an optical magnetic field sensor, and the like. When attempting to measure a current flowing through a power line such as an overhead power transmission line using these methods, a detected signal is detected because a voltage of tens of thousands of V to several hundreds of KV is applied to the power line such as the overhead power transmission line. ,
There is a problem that the lead wire or the optical fiber cannot be directly drawn out.

Therefore, a method of detecting the current of the power line by using a telemeter device that transmits a signal by radio waves has been considered. That is, the current detected by the current transformer (CT) or the optical magnetic field sensor is transmitted by the telemeter device, and the current is received by the receiver to detect the current of the power line.

[0004]

When such a telemeter device is used, it is possible to measure the current of a power line to which a voltage of tens of thousands of V to several hundreds of KV is applied. However, current detection using the telemeter device is possible. With the means, there is a problem that the structure of the device is complicated and expensive. In addition, in the current detection means using the telemeter device, it is necessary to stop the power supply to the overhead power transmission line and bring the overhead power transmission line to the ground potential at the time of inspection or removal in the case of a failure, which is extremely difficult. There was a problem that it was troublesome. Further, the current detection means using the telemeter device requires a power source, so that a battery or a solar cell must be used, and power is supplied to the overhead power transmission line in order to replace the battery or the solar cell. There was a problem that it had to be stopped regularly.

[0005]

The present invention has been made in view of the above problems, and provides a non-contact current sensor which has a simple structure and is inexpensive, and which does not require a power source. The configuration includes a transmitter and a receiver. The transmitter includes a current transformer and a primary coil connected to the current transformer, and the receiver is a primary coil of the transmitter. It is characterized by comprising a secondary coil that is electromagnetically coupled, an amplifying device that amplifies the current induced in the secondary coil, and a display unit that displays the current amplified by the amplifying device.

[0006]

When a current transformer is attached to a power line such as an overhead transmission line, an output current proportional to the current flowing through the power line can be detected. When this current is passed through the primary coil, the primary coil generates an electromagnetic wave according to the current. This electromagnetic wave is received by the secondary coil of the receiver electromagnetically coupled to the primary coil, and the secondary coil converts the electromagnetic wave into a current. The current of the secondary coil is amplified by the amplification device, and the current amplified by the amplification device is displayed on the display device to detect the current.

[0007]

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a basic configuration diagram of the present invention, and a non-contact current sensor according to the present invention includes a transmitter A and a receiver B. The transmission unit A includes a current transformer 1 attached to a power line 10 such as an overhead power transmission line, and a primary coil 2 connected to the current transformer 1. On the other hand, the receiver B
Displays a secondary coil 5 electromagnetically coupled to the primary coil 2 of the transmitter A, an amplification device 6 for amplifying the current induced in the secondary coil 5, and the current amplified by the amplification device 6. It is composed of a display device 7. The secondary coil 5 is preferably oriented so that the magnetic field generated by the current flowing through the power line 10 does not interlink with the secondary coil 5.

The non-contact current sensor having the above structure detects an output current proportional to the current flowing through the power line 10 in the current transformer 1, sends this current to the primary coil 2 and responds to the current in the primary coil. An electromagnetic wave is generated, the electromagnetic wave is received by the secondary coil 5 of the receiver electromagnetically coupled to the primary coil 2, the secondary coil 5 converts the electromagnetic wave into a current, and the current of the secondary coil 5 is amplified. The current is detected by amplifying it by the device 6 and displaying it on the display device 7.

FIG. 2 shows another embodiment of the non-contact current sensor according to the present invention, in which a diode bridge 3 is interposed between the current transformer 1 and the primary coil 2 of the transmitting section A. Further, the receiver B is provided with a filter device (8). In this way, by interposing the diode bridge 3 between the current transformer 1 and the primary coil 2 and providing the filter device (8) in the receiving section B, noise due to the magnetic field generated from the power line itself is effectively made. Can be removed. That is, 50Hz or 60H from the power line itself
Although an alternating magnetic field of z is generated, this alternating magnetic field is 100 due to the diode bridge 3 in the case of 50 Hz, for example.
The frequency is converted into Hz and 120 Hz in the case of 60 Hz. The detection accuracy can be improved by removing the frequency-converted signal component through the filter device (8) provided in the amplifying device 6 of the receiving unit B or the like.

FIG. 3 shows an embodiment in which the non-contact current sensor according to the present invention is attached to an overhead power transmission line. As for the overhead power transmission line, the overhead power transmission line 10 is connected to the steel tower 1 via the insulator 11.
The overhead power transmission lines 10 which are retained at 2 and retained at the steel tower 12 through the insulator 11 are electrically connected to each other by jumper lines 13. In the non-contact current sensor according to the present invention, the transmitter A is attached to the overhead power transmission line 10 side, and the receiver B is placed on the steel tower 12. The primary coil 2 of the transmitter A and the secondary coil 5 of the receiver B are electromagnetically coupled. The display device 7 for displaying the current of the receiver B may be placed on the tower 12 or may be pulled down from the tower 12 and placed at another position.

[0011]

As described above, the non-contact current sensor according to the present invention comprises the transmitter and the receiver, and the transmitter includes the current transformer and the current transformer connected to the current transformer. The receiving unit includes a secondary coil, and the receiving unit includes a secondary coil electromagnetically coupled to the primary coil of the transmitting unit, an amplification device that amplifies the current induced in the secondary coil, and a current amplified by the amplification device. Since it consists of a display unit that displays, it is hard to break down because of its simple structure and it is inexpensive, and since it does not require a power supply, it can supply power to overhead power lines to replace batteries and solar cells. The problem of periodic stoppages also disappears.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a usage state of the present invention.

[Explanation of symbols]

 A transmitter B receiver 1 current transformer 2 primary coil 5 secondary coil 6 amplification device 7 current display device 8 filter device 10 overhead power transmission line 11 insulator 12 steel tower 13 jumper line

Claims (1)

[Claims] 1. A transmission unit and a reception unit, wherein the transmission unit includes a current transformer and a primary coil connected to the current transformer, and the reception unit includes a primary coil of the transmission unit. A non-contact current sensor comprising a secondary coil electromagnetically coupled to a coil, an amplifying device for amplifying a current induced in the secondary coil, and a display section for displaying the current amplified by the amplifying device.