JPH0413980A - Apparatus for measuring insulation deterioration of cable line - Google Patents

Abstract

PURPOSE:To achieve measuring work accurately and safely by housing a high voltage part of a remote controller which performs a balance adjusting operation of a bridge circuit by a remote control into a box body having limited pointed protrusions on the surface thereof. CONSTITUTION:An adjustment signal of a slide resistor 3 inputted by a measuring person is applied to a balance adjusting mechanism to move a position of a slide end 3c. The position of the slide end 3c is also detected with an encoder and transmitted to a remote control section 1B via a photo converter 6 and a light emitting/receiving section 5 to be displayed, which allows enabling the determination of a distance from a display value as given when a balancing is held. In this manner, the measuring person can carry out a measurement without touching a high voltage part 1A to which a high voltage is applied. In addition, as the box body 7 with the high voltage section 1A housed has no pointed protrusion on the surface thereof, a corona discharge into the air is hard to occur.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a cable line insulation deterioration measuring instrument for locating insulation deterioration points on a power cable line.

[Conventional technology] When locating fault points or defective points on power cable lines, compared to measuring fault points where insulation breakdown has already occurred, it is better to measure insulation deterioration, etc. in order to prevent accidents. In order to locate the fault in a cable, it is necessary to apply a high voltage to the cable under test.

[Problem to be solved by the invention] When such a high voltage is applied, the inside of the measuring device also has a high potential, which may cause electrical discharge with the ground or corona discharge in the atmosphere, causing measurement problems. Not only may the adjustment not be carried out correctly, but there is even a risk of danger such as electric shock for the person adjusting the measuring device.

The purpose of the present invention is to provide accurate and safe measurement methods without the risk of electrical discharge to the ground or the atmosphere or electric shock to the person performing measurements when applying a high potential to locate defective points where insulation has deteriorated. An object of the present invention is to provide an instrument for measuring insulation deterioration of cable lines that can perform the following.

[Means for Solving the Problem] In order to achieve the above object, the cable line insulation deterioration measuring device according to the present invention is a measuring device that locates the insulation deterioration point of the power cable line using a high voltage bridge circuit. The present invention is characterized in that a high-voltage part of a remote control device for controlling the balance of the bridge circuit by remote control is housed in a casing having few protrusions on its surface.

[Function] The cable line insulation deterioration measuring device having the above configuration has the following features:
The remote control device allows the measurer to perform measurements without touching high-voltage parts, and the casing with few sharp edges prevents corona discharge into the atmosphere, increasing the reliability of measured values.

[Example] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a circuit diagram, and the locating device consists of a high voltage section IA and a remote control section IB. The high voltage section IA is provided with specimen connection ends 2a, 2b and a high voltage input terminal 2c.
is connected through resistors 3a and 3b of the slide resistor 3, and a galvanometer 4 is connected in parallel with this slide resistor 3, while the slide end 3C of the slide resistor 3 is a high voltage input terminal. Connected to 2c. The high voltage section IA also includes a light emitting device that transmits and receives optical signals to and from the remote control section IB.
A light receiving section 5 and an optical converter 6 that converts an optical signal into an electrical signal are provided, and a zero point (not shown) such as a Stella Pink motor that adjusts the zero point of the galvanometer 4 based on the output of the optical converter 6 is provided. An adjustment mechanism, a balance adjustment mechanism (not shown) that similarly moves the slide end 3c of the slide resistor 3 based on the output of the optical converter 6, and a balance adjustment mechanism (not shown) that detects the position of the slide end 3c and sends a detection signal to the optical converter 6. It is provided with an equilibrium position detector (not shown) for inputting garlic or the like, and a vibration direction detector (not shown) which detects the vibration direction of the galvanometer 4 and manually inputs a detection signal to the optical converter 6. Further, a battery (not shown) is provided as a power source for the light emitting/light receiving section 5, the optical converter 6, each adjustment mechanism, and each detector.

This high voltage section A is housed in a casing 7 without sharp protrusions as shown in FIG. The housing 7 is made of aluminum, for example, and its outer surface is coated with synthetic resin and molded smoothly, and the upper surface has the specimen connection ends 2a, 2b.
A connector for connecting the specimen with
An optical signal window 10 is provided to reach the light receiving section 5, and a battery exchange port 11 for exchanging batteries is provided on the bottom surface. Here, the specimen connection connector, high voltage input end 2c,
The power switch 9 and the battery exchange port 11 are molded by recessing the housing 7 inward so that they do not protrude from the contour of the housing 7. Furthermore, during measurement, the housing 7 is placed on the insulator tubes Ga and Gb at the ends of the test cables Ca and Cb by means of a mounting member 12 made of an insulating material such as an acrylic plate, as shown in FIG. Connection ends 2a, 2b
Lead wires Ra and Rb are connected to the high voltage input terminal 2C, respectively, and a high voltage DC power source E is connected to the high voltage input end 2C by a lead wire Rc.

On the other hand, the remote control unit IB includes a display unit that receives an optical signal from the high voltage unit IA and displays the deflection direction of the galvanometer 4 and the position of the slide end 3C of the slide resistor 3, and a display unit that displays the deflection direction of the galvanometer 4 and the position of the slide end 3C of the slide resistor 3. It is provided with manual transmission means for transmitting the zero point adjustment signal of the flow meter 4 and the balance adjustment signal of the slide resistor 3 as optical signals to the high voltage section IA.

When locating a deterioration point using the above-mentioned locating device, as shown in Fig. 1, a test cable C having a deterioration phase Ca to be measured and a sound phase Cb without deterioration is connected to the cable from the measurement end. At the far end of the length, the cable conductors of both phases Ca and Cb are short-circuited by a shorting line S, and at the measurement end, the deteriorated phase Ca is connected to the connection end 2a, and the healthy phase Cb is connected to the connection end 2b. Further, a high voltage DC power source E is connected to the high voltage input terminal 2c, and a high voltage of up to about 60 kV is applied to the ground. At this time, the deterioration point P of the deterioration phases C and a has a lower insulation resistance to ground than other parts of the cable, and can be considered to have a ground fault via the deterioration point resistance RP.

Therefore, the resistance R1 from the slide end 3c of the slide resistor 3 to the connection end 2a side, the resistance R2 from the slide end 3c to the connection end 2b side, the healthy phase cb from the connection end 2b, and further deteriorate through the short circuit at the far end. This is a so-called Wheatstone bridge consisting of a conductor resistance R3 of the cable C up to the deterioration point P of the phase Ca and a conductor resistance R4 of the cable C from the deterioration point P to the connection end 2a.

Therefore, by adjusting the position of the slide end 3C of the slide resistor 3 and making the deflection of the galvanometer 4 zero, the bridge circuit can be balanced, as is well known, R1・R3=R2・R4 The relationship holds true. Here, assuming that the distance from the measurement end to the deterioration point P is 2 and the cable conductor resistance is uniform, R1・(2・L−2)=R2・Flood, that is, flood=2・L −R1/ (R1+R2), R1+
R2 is constant, R1 is the slide end 3C of the slide resistor 3
The distance β can be determined based on the position of .

In addition, in the locating apparatus of this embodiment, finding the balance of the bridge circuit is performed by remote control. That is, the deflection direction of the galvanometer 4 is determined by the deflection direction detector, the optical converter 6, the light emitting
The signal is transmitted from the light receiving section 5 to the remote control section IB and displayed on the display means, allowing the measuring person to know the deflection direction of the galvanometer 4. On the other hand, the slide resistor 3 manually made by the measurer
The adjustment signal is given to the balance adjustment mechanism through the reverse path, and the position of the slide end 3c is moved. In addition, the position of the slide end 3C is also detected by the encoder, and is sent to the remote control unit IB via the optical converter 6 and the light emitting/receiving unit 5 and displayed, so the distance °C can be calculated from the displayed value when equilibrium is established. It becomes possible to ask for it. In this way, the measurer can perform measurements without touching the high voltage section IA to which a high voltage is applied.

In addition, since the casing 7 housing the high voltage part IA has no sharp protrusions on its surface, corona discharge into the atmosphere is unlikely to occur.Furthermore, when placed on the insulator tubes Ga and Gb by the mounting member 12, the casing 7 Good insulation between 7 and the earth is also ensured.

In addition, in the above-mentioned embodiment, it was decided to use light for information transmission between the high voltage section IA and the remote control section IB, but ultrasonic waves or radio waves may also be used. Further, as described above, it is desirable to use a battery as the driving power source for the high voltage section IA to improve insulation from the ground and increase safety. Furthermore, the method for fixing the casing 7 is not limited to the above-mentioned mounting member 12;
For example, a method such as suspending the device in the air using an electrically insulating wire or the like may be used.

[Effects of the Invention] As explained above, the cable line insulation deterioration measuring device according to the present invention uses a housing without sharp protrusions and is operated by remote control, so it can safely detect insulation deterioration points of power cables. It is possible to accurately and accurately locate the structure, and insulation breakdown accidents can be prevented.

[Brief explanation of the drawing]

The drawings show an embodiment of the cable line insulation deterioration measuring device according to the present invention, and FIG. 1 is a measurement circuit diagram using a locating device;
Figure 2 (a) is a plan view of the housing, (bl is a side view, (C)
3 is a bottom view, and FIG. 3 is a side view of the case placed on a placing member. Symbol IA is a high voltage section, IB is a remote control section, 2a and 2b are specimen connection terminals, 2C is a high voltage input terminal, 3 is a slide resistor, 4 is a galvanometer, 8 is a housing, 1a is a mounting member , C is a test cable, and E is a high voltage DC power supply.

Claims (1)

[Claims] 1. A measuring device for locating the insulation deterioration point of a power cable line using a high voltage bridge circuit, the high voltage part of the remote control device which performs the balance adjustment operation of the bridge circuit by remote control, is equipped with a sharp protrusion on the surface. An instrument for measuring insulation deterioration of cable lines that is housed in a small housing.