JPH0228461Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a ground voltage detector that detects the ground voltage of a high-voltage distribution line.

In general, in high-voltage distribution lines, it is possible to locate the ground fault point by the distribution of zero-sequence current, and the direction of the ground fault point can be located by comparing the phases of zero-sequence voltage and zero-sequence current. It has been known. It is accurate to detect zero-phase voltage using a zero-phase transformer that can be installed all at once on three-phase distribution lines, but
Since it is extremely difficult to install this type of zero-phase transformer on existing three-phase distribution lines, the common method is to install a ground voltage detector on each phase overhead line and combine the respective outputs. It is being

A conventional ground voltage detector used for this type of purpose is constructed as shown in FIG.
FIG. 1 is a longitudinal cross-sectional view of a ground voltage detector mounted on an overhead wire, and in the figure, reference numeral 1 denotes a wire having an insulating coating 1b on the outer surface of a core wire 1a. Reference numeral 2 denotes a ground voltage measuring electrode having an arc-shaped cross section facing the outer peripheral surface of the overhead wire 1, and this ground voltage measuring electrode is formed in a resin molded part 3 shaped into a semi-cylindrical shape.
The electrode 2 and the molded part 3 constitute a first detector half 4. Similarly, a ground voltage measuring electrode 2' having an arcuate cross-section is embedded in a semi-cylindrical molded part 3' to constitute a second detector half 4', and a second detector half 4' is configured. and 4′
A ground voltage detector 5 is configured. 1st
The second detector halves 4 and 4' are configured to be butt-connected to each other, and an overhead wire through-hole 7 is formed between them for allowing the overhead wire to be measured to loosely pass through them in the butt-connected state. It is becoming more and more common. This detector is connected to the first
The detector half 4 is placed on the overhead wire 1 of the distribution line to be measured and mounted on the overhead wire. The earth voltage measuring electrodes 2, 2' are connected to each other by a lead wire 6, and the capacitances C ₁ and C 1 ' between the core wire 1a and the earth voltage measuring electrodes 2, ₂ ' cause the earth voltage to be measured according to the earth voltage. The sum of the voltages induced in the voltage measuring electrodes 2, 2' appears at the terminal 6a connected to the lead wire 6 as a detected voltage.

By the way, in this type of ground voltage detector, in order to improve workability during installation, it is necessary to form the inner diameter of the overhead wire insertion hole 7 of the detector larger than the outer diameter dimension of the overhead wire 1. 4 is mounted on the overhead wire 1, it is inevitable that a gap will be created between the overhead wire 1 and the second detector half 4' disposed below it. If a gap is created below the overhead wire 1 in this way, rainwater W accumulates at the lower part of the inner circumferential surface of the overhead wire insertion hole 7 during rain, surrounding the upper and lower halves of the overhead wire 1 as shown in FIG. When the ground voltage measuring electrodes 2 and ₂ ' are arranged as shown in FIG. The induced voltage increases,
There was a risk that errors would occur in the measured values of ground voltage in rainy weather.

An object of the present invention is to provide a voltage-to-ground voltage detector for power distribution lines that prevents errors in measuring the voltage to the ground even if rainwater accumulates inside the second half of the detector located at the bottom. It is in.

In order to achieve the above object, in the present invention, in order to measure the ground voltage of the overhead wire to be measured, a first detector half disposed on the upper side has a ground voltage measuring electrode facing the outer peripheral surface of the overhead wire to be measured. A voltage corresponding to the ground voltage is induced by the capacitance between the ground voltage measuring electrode and the core wire of the overhead wire to be measured.

If the ground voltage measuring electrode is provided only in the first half of the detector located on the upper side, even if rainwater collects inside the second half of the detector, the voltage to the ground will not be affected by the rainwater. It is possible to measure voltage and prevent measurement errors from occurring in rainy weather.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ground voltage detector of the present invention will be explained in detail below with reference to the illustrated embodiments.

FIG. 2 is a vertical cross-sectional view schematically showing an installed state of an embodiment of the present invention, and in the same figure, reference numeral 10 denotes an overhead wire to be measured in which the outer peripheral surface of a core wire 10a is covered with an insulating coating 10b. Reference numeral 20 denotes a ground voltage measuring electrode embedded in a semi-cylindrical resin molded part 30 having a relatively short axial length.
0 is formed in a dimension that faces approximately half the circumference of the outer peripheral surface of the overhead wire 10. The ground voltage measuring electrode 20 is formed by, for example, curving a conductive plate such as a copper plate or an aluminum plate, and is arranged concentrically with the inner peripheral surface of the molded part 30 and separated from the inner peripheral surface by an appropriate distance. There is. The ground voltage measuring electrode 20 and the mold part 30 constitute a first detector half 40 .

40' is a mold part 3 formed to have the same size and shape as the mold part 30 of the first detector half part 40.
0' is the second detector half. The first and second detector halves 40 and 40' constitute a ground voltage detector 50, which
The circumferential ends of the first and second detector halves 40 and 40' are arranged opposite to each other so as to surround the detector, and the detector halves are butt-joined to be mounted on the overhead wire. Although the structure for joining the detector halves 40 and 40' is not particularly shown, the structure for joining the two detector halves is formed integrally on the outer periphery of both circumferential ends of the mold parts 30 and 30'. A structure in which the flanges are screwed together and a structure in which the mold parts 30 and 3
The mold parts 30, 30' can be opened and closed by pivoting one end side in the circumferential direction of the mold parts 30, 30'.
Any structure can be adopted, such as a structure in which the other ends of the mold parts 30' are coupled by a coupling member such as a screw, or a structure in which an insulating band is wrapped around the outer periphery of the molded parts 30, 30'.

One end of a lead wire 60 is connected to the ground voltage measuring electrode 20, and this lead wire is led out from the molded part 30, and a terminal 60 at the other end of the lead wire 60
The detection voltage is obtained at point a.

The ground voltage detector 50 configured as described above,
As shown in the figure, when the first detector half 40 is mounted on the overhead line with the upper side, the capacitance C 10 between the core wire 10a of the overhead line 10 and the ground voltage measuring electrode ₂₀ causes the ground voltage measuring electrode 20 to A voltage corresponding to the ground voltage of the overhead wire 10 is induced. Therefore, the ground voltage can be measured by connecting a predetermined voltage measuring device to the terminal 60a at the end of the lead wire.
Since there is no ground voltage measuring electrode below the overhead wire, even if rainwater W accumulates at the bottom of the overhead wire insertion hole 70 during rain, the voltage value induced in the ground voltage measuring electrode 20 will not change. To accurately measure ground voltage regardless of the weather.

Although the above embodiment has been explained using a detector that detects only ground voltage as an example, the present invention can be applied in exactly the same way to the ground voltage detection section of a detector that simultaneously detects overhead line current as well as ground voltage. Of course, the present invention is not limited to the structure of the above embodiment.

As described above, according to the present invention, in order to measure the ground voltage of the overhead wire to be measured, the ground voltage measuring electrode facing the outer peripheral surface of the overhead wire to be measured is placed in the first half of the detector disposed on the upper side. Even if rainwater collects inside the second detector half, the voltage to ground can be measured without being affected by the rainwater, and the voltage to the ground can always be measured stably and accurately regardless of the weather. It has the advantage of being able to measure ground voltage.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view showing a conventional ground voltage detector installed on an overhead wire, and FIG. 2 is a vertical cross-sectional view schematically showing an installed state of an embodiment of the ground voltage detector of the present invention. It is a diagram. 10... Overhead line, 20... Ground voltage measurement electrode, 3
0, 30'... Mold part, 40, 40'... Detector half, 50... Ground voltage detector, 60... Lead wire, 70... Overhead wire insertion hole, W... Rainwater, C ₁₀ ...
...Capacitance.

Claims (1)

[Claims for Utility Model Registration] First and second wires are configured to be butt-connected to each other, and have an overhead wire through-hole formed therebetween for allowing the overhead wire to be measured to pass through the wire loosely in the butt-connected state. a detector half;
In a voltage-to-ground voltage detector for a distribution line that is installed on the overhead wire to be measured with half of the detector placed on the overhead wire to be measured, in order to measure the voltage to the ground of the overhead wire to be measured. A ground voltage detector for a distribution line, characterized in that a ground voltage measuring electrode facing the outer peripheral surface of the overhead wire to be measured is provided only in the first half of the detector.