JPH022544B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for measuring conductor current in electrical equipment.

Conventionally, in measuring conductor current using a magnetic sensor, a coil or a cylinder processed into a coil shape is used as the current conductor, a magnetic sensor is placed inside, and an axis created by the current flowing through the coil is used. Current measurement devices that detect directional magnetic fields have been considered. When this is applied to electrical equipment through which a large current flows, the conductor including the coil portion must be made large in terms of heat generation due to the current and mechanical strength against the electromagnetic force generated by the current. In addition, the magnetic flux detected by the magnetic sensor forms a magnetic circuit that crosses these coils or conductors, but as the proportion of the conductor in the magnetic path increases, the eddy current in the conductor increases depending on the frequency. Because of this change, the magnetic flux detected by the magnetic sensor is affected, resulting in a disadvantage that the frequency characteristics of the current measuring device deteriorate. In addition, when applied to electrical equipment in which multiple conductors are placed adjacent to each other, at the position of the magnetic sensor within each conductor, not only the magnetic field due to the current of each conductor itself but also the magnetic field due to the current of other conductors exists. . Each magnetic sensor detects them simultaneously, so the output of the magnetic sensor is
In addition to the current components of the corresponding conductor to be measured, current components of other conductors are mixed in at a considerably large proportion, resulting in a disadvantage that sufficient measurement accuracy cannot be obtained.

In the present invention, both ends of a magnetic sensor arranged in a spiral conductor so as to detect magnetic flux in the axial direction of the conductor and both ends of a U-shaped magnetic member are respectively opposed to each other, and the conductor is connected in a magnetic path of the magnetic member. By surrounding the conductor, a current measuring device with good frequency characteristics and high accuracy is provided which is not affected by eddy currents in the conductor.

1 and 2 show an embodiment of the present invention.
FIG. 1 is a configuration diagram thereof, and FIG. 2 is a sectional view. 1
is a conductor having a hollow part, and is provided with two holes 1a and 1b that pass through the inside and outside at a predetermined distance in the axial direction. A spiral cavity 1c is provided that extends around the hole 1b. 2 is a magnetic sensor that modulates light according to the magnetic field, and is installed so that its sensitivity direction faces the direction of the conductor axis. 3 is a U-shaped ferromagnetic member, with both ends 3a and 3b having holes 1.
a and 1b and face each other with the magnetic sensor 2 interposed therebetween.

The conductor current crosses the magnetic path of the ferromagnetic member 3 due to the gap 1c provided in the conductor 1, and the magnetic flux generated by the current passes through the path indicated by the symbol 4, so the position of the magnetic sensor 2 In this case, an axial magnetic field proportional to the magnitude of the conductor current is obtained. By detecting this magnetic field with a magnetic sensor 2 made of a Faraday element or the like and passing it through a photoelectric conversion/amplification section (not shown in the figure), an electrical output proportional to the current to be measured can be obtained.

In this embodiment, since the ferromagnetic member 3 forms a magnetically closed circuit inside and outside the conductor, most of the magnetic flux detected by the magnetic sensor 2 passes through the ferromagnetic member 3 and does not cross the conductor 1. do not have. Therefore, deterioration of frequency characteristics due to the influence of eddy currents generated when crossing the conductor 1 does not occur, and if a magnetic material with excellent high frequency characteristics such as a laminated core or ferrite core is used as the ferromagnetic member 3, , it becomes possible to measure the frequency characteristics well.

In addition, because the magnetic sensor inside the enclosure is surrounded by a ferromagnetic material and shielded from external magnetic fields, many conductors are placed adjacent to each other in the same container, and each conductor through which multiphase current flows. Even if applied to the case of measuring current, it is possible to obtain a small and highly accurate current measuring device that is less susceptible to the influence of magnetic fields caused by multiphase currents.

In carrying out the present invention, the internal space of the conductor containing the magnetic sensor and the conductor void are filled with a resin such as epoxy and solidified, and the entire detection section is covered with a supporting insulator made of epoxy or the like to hold the conductor. By simultaneously embedding the optical cable leading from the magnetic sensor to the outside in the supporting insulator and maintaining airtightness, an advantage arises in that an airtight optical connector is not required.

FIGS. 3 and 4 show other embodiments of the invention. In other embodiments, the hole 1d,
Spiral gap 1f provided between 1e and hole 1
The conductor is configured in a spiral shape by a spiral gap (not shown) provided between g and 1h, and the two ferromagnetic members 5 and 6 are arranged to face each other.

Further, the present invention can also be constructed by arranging two or more ferromagnetic members in parallel at equal intervals in the circumferential direction of the conductor 1.

As described above, according to the present invention, both ends of a magnetic sensor arranged in a spiral conductor so as to detect magnetic flux in the axial direction of the conductor and both ends of a U-shaped magnetic body are respectively opposed to each other, and the magnetic body By surrounding the conductor with a magnetic path, frequency characteristics can be improved and measurement accuracy can be improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view of one embodiment of the present invention, FIG. 2 is a sectional view of FIG. 1, FIG. 3 is a perspective view of another embodiment of the invention, and FIG. 4 is a sectional view of FIG. 3. It is. In the diagram,
1 is a conductor, 2 is a magnetic sensor, and 3 is a magnetic member. Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. Both ends of a magnetic sensor arranged in a spiral conductor to detect magnetic flux in the axial direction of the conductor and both ends of a U-shaped magnetic member are respectively opposed to each other, and the magnetic member A current measuring device characterized in that the conductor is surrounded by a magnetic path. 2. The current measuring device according to claim 1, wherein the magnetic sensor is a magneto-optical element that modulates light according to magnetism. 3. The current measuring device according to claim 1 or 2, characterized in that the conductor is composed of a plurality of conductors.