JPS6351010A - Insulator for current detection - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) This invention relates to a current detection insulator used for regulating the current in an electric line.

(Prior Art) Conventionally, current measurement, which is one of the information gathering methods for power supply on electric lines, has been carried out using a magnetic field sensor placed close to the electric wire 5, as shown in FIGS. 3(a) and 3(b). 41 is arranged, the magnetic field sensor 41 detects the magnetic field (shown by the chain line) due to the current in the electric line, and the current value is directly measured via a measuring device.

(Problem to be Solved by the Invention) However, since the conventional current detection device directly detects the magnetic field of the electric line and measures the current, in a three-phase electric line, etc., the 61st current of the phase to be measured is The field tends to change due to the interference of magnetic fields of other phases, resulting in a decrease in lateral oscillation, and the magnetic field sensor 41 has drawbacks such as being able to measure only a certain current range due to its measurement capability. This poses a problem in measuring wide areas such as fault currents in power lines, and to cover this problem, it is necessary to install various sensors for each current area.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention has an optical fiber that is connected to a measuring instrument inserted into the insulator body, and a similar A current transformer is attached to surround the electric wire supported on the insulator body, and a current proportional to the electric current flowing through the electric wire is installed between the tip of the optical fiber and the winding wound around the iron core of the current transformer. A method is adopted in which a secondary i-carrying resistor and a voltage sensor or a current sensor are connected to convert a change in current into a change in light intensity.

(Function) By adopting the above-mentioned means, this invention generates a magnetic field in the iron core of the current transformer due to the current in the electric line, and a secondary current is generated in the winding in proportion to the magnitude of this magnetic field. A secondary current is applied to the secondary load resistor and the voltage sensor or current sensor, and light modulated according to the magnitude of the current generated in the electric wire from the voltage sensor or current sensor is transmitted to the measuring instrument through the optical fiber. be done. At this time, the magnetic field is focused on the iron core surrounding the wire of the phase to be measured, and the interference of magnetic fields of other phases is shielded, so that an accurate secondary current proportional to the primary current of the wire is induced in the winding. . Further, by increasing or decreasing the resistance value of the secondary load resistor connected to the winding, it is possible to convert a current in a wide range into a voltage in a predetermined range, so that detection of a current in a wide range can be maintained with high accuracy. The modulated light is converted into an electrical signal by a measuring device, thereby measuring the current in the wire.

(Example) An example embodying this invention will be described below with reference to FIGS. 1 and 2.
To explain based on the diagram, a base metal fitting 2 is fitted and fixed to the lower end of an insulator body 1 made of magnet 2: A split-type current transformer 6, which also functions as a clamp member for clamping the electric wire 5, is mounted in the fitting recess 4a formed on the upper surface of the cap fitting 4.

This current transformer 6 includes a lower clamp member 7 made of an insulating material such as rubber or resin, which is screwed into the fitting recess 4a of the cap fitting 4 or fixed with an adhesive, and is joined to the upper surface of the lower clamp member 7. , an upper clamp member 9 tightened and fixed by a port 8, and a pair of iron cores 10.1 embedded in both clamp members 7.9 so as to surround the electric wire 5.
1 and a winding 12 wound around a lower iron core 10.

The winding 12 is disposed inside the lower part of the lower clamp member 7.
A secondary burden resistor 13 connected to both ends of the winding 12 and for converting the secondary current induced in the winding 12 into voltage; A voltage sensor 14 is embedded and fixed for converting changes in voltage applied to the line 12 into intensity of light. This voltage sensor 1
4 will be explained with reference to FIG. 1. An electro-optical element 16 made of a Pockels element is placed inside an insulating case 15, and a wave plate 17 and a reflecting mirror 18 are adhesively fixed to its upper surface, and a Rondo lens 19 is adhesively fixed to its lower surface. , and more Rondo Lens 19
A polarizer 20 is adhered to. Further, optical fibers 21 for incident light and emitted light having high insulation properties and non-inductive properties are connected to this polarizer 20 as a transparent body serving as an optical transmission path, and are led out from the insulating case 15. . Internal electrodes 22a and 22b are adhesively fixed to the electro-optical element 16,
Both ends of the winding 12 are connected to the internal electrodes 22a and 22b.

The optical fiber 21 is fixed to the polarizer 20 and the insulating case 15 by fixing members 23 and 24, and the insulating case 1
The void within 5 is filled with an insulator 25 .

On the other hand, the optical fiber 21, which is a transparent body, is inserted into the insertion hole 1a formed through the center of the insulator body 1, and its lower end is connected to the optical connector 2 attached to the center of the base metal fitting 2.
6. Note that the transparent body is the optical fiber 21
In addition, an optical fiber cable (not shown) whose outer periphery is coated with a PVC sheath or the like may also be used. The polarizer 20 or the optical connector 26 may be bonded to the end of a magnetic ceramic (not shown), etc. An optical fiber cable 27 is connected to the optical connector 26, and the base end thereof is installed on a utility pole or the like. The measuring device 32 is connected to a light source 29 made of a light emitting diode and a photodetector 30 made of a photodiode, for example, through an optical branching device 28 , and the photodetector 30 is connected to an arithmetic and control unit 31 .

Note that the cap fitting 4 is provided with a cover 3 that covers the current transformer 6.
3 is installed.

Next, the operation of the current detection insulator constructed as described above will be explained.

Now, when a current flows through the electric wire 5, a magnetic field is generated in the iron core 10, 11, a secondary current proportional to the magnitude of the magnetic field is induced in the winding 12 by the magnetic field, and this current is caused by the secondary burden resistance 13. The voltage is converted into a voltage, and the same voltage is applied to the electro-optic element 16 of the voltage sensor 14.

Further, in the present invention, the secondary burden resistor 13 is connected to the winding 12, and if the resistance value is adjusted to increase or decrease as appropriate depending on the magnitude of the secondary current induced in the winding 12, it can be applied over a wide area in the electric line. Since the current can be selectively converted to a voltage value within a certain range, a common voltage sensor can be used without using sensors for each current range. Note that the resistance value of the secondary load resistor 13 may be set in advance according to the applied current and then assembled to the insulator, but if it is of a variable type that can be adjusted from the outside, versatility will be increased.

On the other hand, light is transmitted from the light source 29 to the optical fiber 21 which is an optical transmission path inside the insulator body 1 through the optical fiber cable 27 via the optical connector 26, and further while passing through the voltage sensor 14. Due to the Pockels effect of the electro-optical element 16, the open light undergoes phase modulation according to the voltage described in 111, that is, the current of the electric wire 5, and is intensity-modulated by the polarizer 20 and the A-wave plate 17 to become a light intensity signal. The optical signal is transmitted from the outside via an optical fiber 21 at 7f! [j
It is transmitted without receiving the A conductor, is guided to the light receiver 30 of the measuring device 32 via the optical connector 26, and then becomes an electric signal and the current generated in the electric wire 5 is measured.

Incidentally, in this embodiment, the electro-optical element 16 of the voltage sensor 14 has a current detection error as low as ±1% in a temperature range of -20°C to 100°C, for example.

In other words, by using a Pockels element with good temperature characteristics and high weather resistance, and by connecting a secondary burden resistor 13 to the measurement circuit, it is possible to measure the current with one opening compared to the conventional one. The n degree is improved and the reliability is increased. Further, the electro-optical element 16, the optical fiber 21 and the optical fiber cable 27 are all insulative and non-inductive, and
Since a current detection part with a wire support function is provided on the head of the insulator body 1 made of porcelain, the structure is simple, and it is easy to handle and install, eliminating the influence of surrounding conditions.
It allows for highly accurate measurements and is highly safe.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can also be embodied as follows.

(1) In the above embodiment, the voltage change generated at both ends of the winding 12 is changed to the intensity of light, but a light emitting diode is used as a current sensor for the winding 12 to change the current change to the intensity of light. At the same time, connect an optical fiber to the light emitting diode.

(2) Although not shown, an arrester is connected in parallel with the secondary negative trI resistor 13 to provide overvoltage protection.

(3) Although not shown, a thermistor may be connected in series or in parallel with the secondary burden resistor 13 to compensate for the temperature and further improve the temperature characteristics.

Effects of the Invention As detailed above, the present invention integrates the current detection section into the support insulator of the electric wire to reduce the installation space, has a simple structure, is easy to manufacture and install, and is also safe. This has the excellent effect of realizing highly accurate current measurement.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main part showing an embodiment of the present invention, Fig. 2 is a semi-dark sectional view of the central part showing the entire current detection insulator, and Fig. 3(a) shows a conventional current detection device. Figure 4, Figure 3 (
b) is a front view showing the same conventional current detection device. 1... Insulator body, 5... Electric wire, 6... Current transformer, 7
... lower clamp member, 9 ... upper clamp member,
10゜11... Iron core, 12... Coil, 13...
Secondary material 1 resistance, 14... voltage sensor, 16... electro-optical element, 21... optical fiber, 26... optical connector, 27... optical fiber cable, 32... measuring instrument. Patent applicant Chubu Electric Power Co., Ltd. Nippon Insulators Co., Ltd. Takamatsu Electric Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. An optical fiber (21) connected to a measuring device (32) is inserted into the insulator body (1), and the same is inserted into the insulator body (1).
1), the electric wire (1) supported on the insulator body (1)
A current transformer (6) is attached so as to surround the optical fiber (21) and the iron core (1) of the current transformer (6) is connected to the tip of the optical fiber (21).
0, 11) and a secondary burden resistor (13) for converting a change in current proportional to the current flowing through the electric wire (5) into a change in light intensity. A current detection insulator characterized in that a voltage sensor (14) or a current sensor is connected. 2. An electro-optical element (
The current detection insulator according to claim 1, wherein 16) is a Pockels element. 3. The current detection insulator according to claim 1, wherein the current sensor is constituted by a light emitting diode.