JPH0338705Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a current measuring device that measures the current of a conductor housed in a container.

1 and 2 show conventional current measuring devices. In the figure, containers 1, 2, and 3 are filled with insulating gas at a predetermined pressure to insulate conductors 4, 5, and 6 to which high voltage is applied.

In such a configuration, the magnetic field generated by the current flowing through the conductors 4, 5, 6 enters the containers 1, 2, 3 of the other phase, and the magnetic sensors 10, 11,
12, magnetic sensors 10, 11, 1
2 had the disadvantage of lowering the accuracy of current measurement.

This invention was made to eliminate the above-mentioned drawbacks, and provides a current measuring device with good current measurement accuracy using a magnetic sensor.

The figures will be explained below. In FIGS. 3 and 4, numerals 1, 2, and 3 are cylindrical containers for each of the three phases arranged substantially parallel on the same plane and filled with insulating gas. 4, 5, 6 are each container 1,
2 and 3 coaxially pass through each phase, and annular grooves 4a, 5a, and 6a are provided on the outer periphery. and,
A three-phase alternating current flows through the conductor 4 in the U phase, the conductor 5 in the V phase, and the conductor 6 in the W phase. 7, 8, 9 are each groove 4a,
5a, 6a, each conductor 4, 5, 6 is connected to a straight line that crosses each conductor 4, 5, 6.
Sky spaces 7a, 8a, and 9a are formed on substantially perpendicular lines passing through the center of the space 6, respectively. 10,
Magnetic sensors 11 and 12 are arranged in the air 7a, 8a, and 9a, and are configured to operate by a magnetic field in the circumferential direction of the conductors 4, 5, and 6 of the self-phase.

By providing the iron cores 7, 8, and 9, the air
The magnetic field in the circumferential direction due to the current in the self-phase conductors 4, 5, and 6 in a, 8a, and 9a increases. On the other hand, the magnetic field caused by the current flowing through the conductors 4, 5, and 6 of the other phases passes through the iron cores 7, 8, and 9, and hardly passes through the gaps 7a, 8a, and 9a. For this reason, magnetic sensor 1
The current detection accuracy of each conductor 4, 5, 6 by 0, 11, 12 is improved.

The magnetic field caused by the current flowing through the conductors 4, 5, and 6 has a large effect on the part of the iron cores 7, 8, and 9 of the other phases that are on the line connecting each conductor 4, 5, and 6, so position, i.e., conductor 4,
Magnetic sensor 1 is placed at a position on a perpendicular line passing through conductors 4, 6 and almost perpendicular to the straight line connecting between each conductor 4, 5, and 6.
0, 11, and 12 are provided to reduce the influence of magnetic fields of other phases.

Further, by embedding the iron cores 7, 8, and 9 in the grooves 4a, 5a, and 6a, concentration of the electric field is prevented.

That is, the containers 1, 2, and 3 are grounded and the conductors 4,
Since a high voltage is applied to conductors 5 and 6, an electric field E of equation (1) is applied to the surfaces of conductors 4 and 5.6.

E=V/a・1/logb/a (V/m)...(1) Here, V is the voltage applied to conductors 4, 5, and 6, a is the radius of conductors 4, 5, and 6, and b is container 1,
The inner diameter is 2 or 3.

Equation (1) above applies when the surface is smooth, and it is known that the electric field becomes stronger if there are protrusions on the surface.

For example, the distance between parallel plates with one side grounded is d
It is known that when there is a hemispherical protrusion on either side of parallel plates, the maximum electric field strength is expressed by equation (2).

Emax=V/d×3...(2) If there is a protrusion on a parallel plate like this, the electric field will be three times stronger than when there is no protrusion. Moreover, in the case of the above embodiment, since they are arranged coaxially, the rise in the electric field does not increase three times, but it becomes larger than the value calculated from the above equation (1).

In the above embodiment, the gaps 7a, 8a, 9a are provided at two locations in each of the iron cores 7, 8, 9. , 12 is also effective.

As described above, according to this invention, the iron core is placed in the groove provided on the outer periphery of the conductor so that the air gap is on a perpendicular line passing through the center of the conductor, and the magnetic sensor is placed within the air gap of the iron core, so the magnetic sensor It is possible to strengthen the magnetism caused by the current in the current phase that operates the current, reduce the influence of the magnetic field caused by the current in other phases, and improve measurement accuracy.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a conventional current measuring device, Fig. 2 is a sectional view of Fig. 1, Fig. 3 is a sectional view of an embodiment of this invention, and Fig. 4 is a summary of an embodiment of this invention. FIG. In the figure, 1, 2, 3 are containers,
4, 5, 6 are conductors, 7, 8, 9 are iron cores, 7a, 8
A and 9a are gaps, and 10, 11, and 12 are magnetic sensors. Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] A plurality of conductive cylindrical containers are arranged approximately in parallel, and a conductor is arranged within the container coaxially with each of the containers, and a line passing through the center of each conductor is approximately perpendicular to a straight line that crosses each of the conductors. A magnetic sensor for measuring the main current of each conductor is arranged on a perpendicular line, and an annular groove is provided on the outer periphery of the conductor, so that the hollow of the annular iron core has a hollow that extends from the center of the conductor. A current measuring device characterized in that the iron core is disposed in the groove so as to be on a perpendicular line passing through the groove, and the magnetic sensor is disposed within the space.