JPH03223678A - Transmission line current sensor - Google Patents

Abstract

PURPOSE:To prevent the generation of corrosion due to the contact between different kinds of metal and to perform highly reliable measurement by simplifying a structure and facilitating mounting by receiving a coil in a metal tube composed of the same material quality as the surface of a transmission line conductor in an insulated state. CONSTITUTION:A transmission line current sensor 1 is mounted to a transmission line 2 as shown by a drawing. In this case, the transmission line current sensor 1 performed in a spiral shape can be mounted to the outer periphery of the transmission line 2 in a close contact state and it not detached because it is self-supported by the elasticity of a metal tube 14 receiving a coil 13. The transmission line 2 is ACSR (steel core aluminum stranded wire) employed in a transmission line widely and generally and, since the material quality of the line 2 being in contact with the transmission line current sensor 1 is made of the same aluminum as the metal tube 14, the corrosion due to the contact with a different kind of a metal is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a current sensor, and particularly to a power transmission line current sensor in which a Rogowski type coil is attached to a power transmission line.

[Prior Art] As a sensor for measuring current, a current transformer conventionally called a CT or a hollow core coil called a Rogowski coil is used. Among these, the Rogowski type coil is free from magnetic saturation of the core and has excellent high frequency characteristics, so it is used, for example, for measuring high frequency impulse large currents such as plasma current.

Rogowski coils are made by winding wire around a hollow core.
By winding this in a donut shape around the conductor whose current is to be measured, a winding output corresponding to the wire current can be obtained as shown by the following equation.

v=μo, us −A −n −dl /dt However,
■=Coil output voltage.

μ0: Vacuum permeability.

μS: Relative magnetic permeability (μS・1 in vacuum).

A: Coil cross-sectional area.

n: coil winding density.

rat style represents.

[Problem U to be Solved by the Invention] However, in order to apply the Rogowski type coil of this prior art to a power transmission line, a dedicated fixing device is required and the structure of the sensor becomes complicated.

Therefore, the sensor itself can be self-supported by the power line.
! There was a strong need for a simple sensor.

Furthermore, since the sensor using the Rogowski type coil described above has a differential output, it is susceptible to noise, and the coil itself needs to be sufficiently shielded. Usually, metal shielding is considered, but there is a problem in that using a metal different from the surface of the conductor to be installed may cause corrosion.

Further, current sensors using a coil usually have a complicated #I design in which a metal shield is molded, and there is a drawback that the mounting cannot be easily changed depending on the dimensions of the conductor.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a current sensor for a power transmission line that has a simple structure, can be self-supported to the power transmission line, and has high reliability.

[Means for Solving the Problems] A first form of the present invention includes winding an electric wire around a hollow core,
In a power transmission line current sensor in which a Rogowski type coil is arranged along the circumferential direction around a power transmission line conductor, the wire at the winding end is returned to the winding start end and taken out together with the winding start end. The coil is insulated and housed inside a metal tube made of the same material as the surface of the power transmission line conductor.

In the second embodiment, a metal tube containing a Rogowski-type coil is preformed into a spiral shape according to the dimensions of the power transmission line conductor, so that it can be self-supported on the power transmission line conductor.

In the third embodiment, the Rogowski type coil is shielded by an inner insulated metal laminate sheath made of the same material as the surface of the power transmission line conductor.

The fourth form differs from the third form in that a conductive metal tube is used as the hollow core around which the Rogowski coil is wound, the electric wire at the end of the coil winding is attached to the metal tube, and the electric wire at the end of the coil winding is attached to the metal tube. The configuration is such that the output of the Rogowski type coil is obtained from the metal tube and the @ wire at the beginning of the winding.

[Operation] In the first form, the material of the metal tube that houses the Rogowski coil is the same as the metal material of the surface of the power transmission line to be installed, so corrosion due to contact between dissimilar metals does not occur. .

In addition, in the second form, the Rogowski-type coil is housed in a metal tube, and the metal tube is preformed to match the dimensions of the power transmission line on which it will be installed, ensuring self-support to the power transmission line. can be set.

In the third form, the coil winding is wound on a metal tube to form a Rogowski-type coil, and a metal laminate sheath is used to shield this.Although it is a simple sensor structure, it can be adjusted to match the installed conductor. Can easily change shape. The material of the metal laminate sheath that shields the Rogowski-type coil is Since it is made of the same metal material as the surface of power transmission lines, corrosion due to contact between dissimilar metals will not occur.

In the fourth embodiment, a metal tube is used as a hollow core, and the end of the coil winding is electrically drawn out toward the start end of the winding, so that a simpler sensor structure can be obtained.

[Example] Hereinafter, the power transmission line current sensor of the present invention will be described in detail based on the illustrated example.

FIG. 1 is a sectional view showing an embodiment of the power transmission line current sensor of the present invention.

A winding 11 made of an insulated wire is wound around the outside of a hollow core 12 made of plastic to form a coil 13. This coil 13 is housed in a metal tube 14 made of aluminum. The winding wire 11 wound around the hollow core 12 has its winding end end passed through the center of the coil 13 and returned to the winding start end, and is taken out of the metal tube 14 together with the wire at the winding start end. That is, the coil as a whole constitutes a Rogowski type coil.

Figure 2 shows that this power line current sensor is preformed to match the dimensions of the power line to be installed.
This is an example in which the power transmission line current sensor 1 is previously formed into a spiral shape so as to be in close contact with the outer periphery of the power transmission line 2.

FIG. 3 shows the situation in which the power transmission line current sensor 1 is attached to the power transmission line 2. The power transmission line current sensor 1, which is preformed in a spiral shape as shown in FIG. It can be attached closely to the coil 1.
The electric wire 2 is self-supported by the elasticity of the metal tube 14 that houses the electric wire 3, and will not fall off. Since the material of the surface portion of the electric wire 2 that the electric wire current sensor 1 comes into contact with is made of aluminum, which is the same as the metal tube 14, corrosion due to contact between dissimilar metals does not occur.

FIG. 4 shows a power transmission line current sensor 1 installed on an overhead ground wire 21 of a power transmission line to construct a failure point locating system for a power transmission line 22. The transmission line current sensor 1 of the present invention is installed on the overhead ground wire 21 at two locations remote from each other,
A surge current induced in the overhead ground wire 21 when a failure occurs in the power transmission line 22 is measured. This measurement result is input to the location device 4 installed in the steel tower section 3 to locate the point where the failure has occurred, and the location of the failure point can be realized with an extremely simple sensor structure.

According to the above embodiment, a power transmission line current sensor that is extremely simple to use and easy to install can be obtained, and it is also possible to measure the current of a power transmission line with high reliability.

Although the metal tube 14 made of aluminum is used in the above embodiment, it is of course possible to construct the metal tube 14 in a multilayer structure by making the outermost layer of aluminum. It is also possible to use a vapor deposited film as the outermost layer.

5 and 6 show other embodiments of power line current sensors.

As can be clearly seen from FIG. 5, in this power transmission line current sensor 5, the hollow core 2 is not made of plastic as shown in FIG. The coil 13 is formed by winding the insulation-coated winding 11 on the outside. Although the coil 13 is housed in the metal tube 111 in FIG. 1, in this embodiment it is covered with a rolled sheet-like aluminum laminate sheath 34 whose inside is insulated. Both end portions 35 of the rolled laminate sheath 34 overlap, and a portion of the circumferential direction is insulated at this portion.

Moreover, by applying heat, this overlapping portion 35 can be
The inner insulation part is designed to be bonded when melted.

In FIG. 6, the roll 1 wound on the aluminum tube 32
The winding end 15 of itllO is connected to the aluminum tube 32, and the electric wire 16 is connected to the aluminum tube 32 at the six winding start end side where the aluminum tube 32 is used as the unwinding line of the Rogowski type coil. Output is obtained between the electric wires 16. By using the metal tube made of the aluminum tube 32 as the hollow core 12 in this manner, appropriate rigidity can be provided.

FIG. 7 shows how the power transmission line current sensor 5 is attached to the power transmission line 2, and the power transmission line current sensor 5 is formed into a donut shape to match the shape of the power transmission line 2 and is attached.

Since the material of the four surface parts of the electric wire 2 that the power transmission line current sensor 5 comes into contact with is made of aluminum, which is the same as the laminate sheath 34, corrosion due to contact between dissimilar metals does not occur.

The shape of the power transmission line current sensor 5 is not limited to the donut shape shown in FIG. 7, but can be used in accordance with the shape of the conductor to be attached.

The power transmission line current sensor 5 has an extremely simple structure, can be mounted in any shape according to the installed conductor, and is highly economical.

[Effects of the Invention] As explained above, according to the present invention, a power transmission line current sensor that does not cause corrosion due to contact between dissimilar metals can be obtained. Furthermore, the structure is extremely simple and installation is easy, and highly reliable current measurement of power transmission lines is possible.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of a power transmission line current sensor according to an embodiment of the present invention, FIG. 2 is an external view showing an example of a shape obtained by preform molding the power transmission line current sensor of FIG. 1, and FIG. 3 Figure 4 shows an example of a transmission line fault location system constructed using the transmission line current sensor shown in Figure 2. 6 is a cross-sectional view showing the structure of a power transmission line current sensor according to another embodiment of the present invention, FIG. 6 is an overall configuration diagram of the power transmission line current sensor, and FIG. The installation is an external view showing the situation. In the figure, 1 is a power transmission line current sensor, 2 is an electric wire, 3 is a steel tower, and 4
is a location device, 11 is a winding, 12 is a hollow core, 13 is a coil, 14 is a metal tube, 15 is the end of the winding, 16 is a winding, 32 is an aluminum tube (hollow core), 34 is a laminate sheath, 35 indicates an overlapping portion.

Claims (4)

[Claims] 1. A Rogowski-type coil is created by winding a wire around a hollow core, returning the wire at the end of the winding to the beginning of the winding, and taking it out together with the wire at the beginning of the winding. A power transmission line current sensor, characterized in that the coil is insulated and housed in a metal tube made of the same material as the surface of a power transmission line conductor. 2. 2. The power transmission line according to claim 1, wherein the metal tube housing the Rogowski-type coil is preformed into a spiral shape according to the dimensions of the power transmission line conductor so that it can be self-supported on the power transmission line conductor. current sensor. 3. 2. The power transmission line current sensor according to claim 1, wherein the Rogowski type coil is shielded by an inner insulated metal laminate sheath made of the same material as the surface of the power transmission line conductor. 4. A conductive metal tube is used as the hollow core around which the Rogowski-type coil is wound, and the electric wire at the end of the coil is attached to the metal tube, and the Rogowski-type coil is formed from the metal tube at the end of the winding and the electric wire at the beginning of the winding. 4. The power transmission line current sensor according to claim 3, wherein the power transmission line current sensor obtains an output of .