JPH0357973A - Device for monitoring insulation of electrical machinery and apparatus - Google Patents

Abstract

PURPOSE:To make it possible to monitor insulation without remodeling a container and the inside thereof by using for this purpose a current transformer existing in the container as an internal antenna. CONSTITUTION:A current transformer 6 provided beforehand inside a container 1 is used also for an internal antenna 8. By connecting a central conductor of a coaxial cable 10 to one through terminal 7A joined to one end of this current transformer 6 and by connecting an external conductor of the cable 10 to the container 2, an antenna signal output from the current transformer 6 is inputted to a tuning amplifier 11. It is preferable in this case that a choke coil 14A is connected between a node of connection of the central conductor of the cable 10 to the terminal 7A on one side and a secondary-side apparatus of the current transformer 6 so that noise from the secondary-side apparatus of the current transformer 6 may not be inputted to the central conductor of the cable 10. A choke coil 14B may advisably be connected to a through terminal 7B when the choke coil for the current transformer 6 is not sufficient.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an insulation monitoring device for monitoring the internal insulation of electrical equipment such as gas-insulated switchgear.

[Conventional technology In electrical equipment such as cogas insulated switchgear, when an internal corona occurs, electromagnetic waves are generated due to its high frequency vibration.

By detecting this electromagnetic wave, it is possible to monitor the insulation of electrical equipment.

Conventionally, insulation monitoring of such electrical equipment has been carried out as shown in FIG. That is, in the electrical equipment 1, an electrical equipment main body 3 is built in a container 2, a pushing 4 is provided through the container 2, and a conductor 4a of the pushing 4 is connected to a high voltage side energizing part of the electrical equipment main body 3. It is connected. The grounding side power charging section of the electrical equipment main body 3 is grounded via the grounding wire 5 and the container 2. In the container 2, the conductor 4a has a
A current transformer 6 is attached to detect the current flowing through the container 2, and the output of the current transformer 6 is taken out of the container 2 through a pair of through terminals 7A and 7B.

The insulation monitoring device is installed inside the container 2 and includes an internal antenna 8 such as a loop antenna or a rod antenna that detects electromagnetic waves or electric vibrations based on internal corona generation, and takes out the output of the internal antenna 8 to the outside of the container 2. A pair of through terminals 9A, 9B, a tuning amplifier 11 that amplifies the antenna signal outputted from the through terminals 9A, 9B through a coaxial cable 10, and the tuning amplifier (2).
A determination unit that determines the occurrence of internal corona based on the antenna signal amplified in step 1 and outputs a determination output to an alarm output terminal 12.

In such an insulation monitoring device for electrical equipment, when an internal corona occurs inside the container 1, the electromagnetic waves are received by the internal antenna 8, and are transmitted to the through terminals 9A, 9B and the coaxial cable 1.
0, is received by the tuning amplifier 11, judged by the judgment unit 13, and a judgment output is output to the alarm output terminal 12, so that the occurrence of internal corona can be detected.

[Problems to be Solved by the Invention] However, in such a conventional insulation monitoring device, an internal antenna 8 and through terminals 9A, 9 dedicated for monitoring are used.
B, it is necessary to modify the inside of the container 2 and the container 2 itself, resulting in high costs and problems in that the insulation monitoring device cannot be installed within a short delivery time.

An object of the present invention is to provide an insulation monitoring device for electrical equipment that can perform insulation monitoring without modifying the container or its interior.

[Means for Solving the Problems] To explain the structure of the present invention to achieve the above-mentioned object, the present invention eliminates electromagnetic waves caused by the internal corona generation of an electrical device in which the main body of the electrical device is built in a container. The insulation monitoring device for electrical equipment monitors insulation by detecting it with an internal antenna installed in the container, characterized in that a current transformer present in the container also serves as the internal antenna.

[Operation] By using the current transformer inside the container as an internal antenna in this way, insulation monitoring can be performed without modifying the container or its interior. Therefore, it becomes possible to install the insulation monitoring device in a short delivery period.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. Note that parts corresponding to those in FIG. 2 described above are designated by the same reference numerals.

In this embodiment, a current transformer 6 previously provided inside the container 1 is also used as an internal antenna 8.

To output the antenna signal from the current transformer 6, connect the center conductor of the coaxial cable 10 to one of the through terminals 7A connected to one end of the current transformer 6, and connect the outer conductor of the coaxial cable 10 to the container 2. The signal is input to the tuning amplifier 11 by the following. In this case, in order to prevent noise from the secondary side equipment (not shown) of the current transformer 6 from being input to the center conductor of the coaxial cable 10, the connection point where the center conductor of the coaxial cable 10 is connected to one through terminal 7A is connected to the transformer. It is preferable to connect the choke coil 14A between the flow device 6 and the secondary side equipment. In addition, noise from the secondary side equipment of the current transformer 6 may be input to the center conductor of the coaxial cable 10 via the other through terminal 7B and the current transformer 6, but in this case, the current transformer 6
The reactance acts as a choke coil to prevent noise from entering. In addition, if the choke coil provided by the current transformer 6 is insufficient, a through terminal 7B may be used as shown in the figure.
It is sufficient to connect the choke coil 14B to the same.

Furthermore, if necessary to insulate the current transformer 6 and the center conductor of the coaxial cable 10, a capacitor 15 is added as shown in the figure.
It is sufficient to intervene.

[Effects of the Invention] As explained above, in the insulation monitoring device for electrical equipment according to the present invention, the current transformer inside the container also serves as an internal antenna, so there is no need to modify the container or its inside. Therefore, there is an advantage that the insulation monitoring device can be installed in a short delivery time and at low cost.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing a schematic configuration of an insulation monitoring device for electrical equipment according to the present invention, and FIG. 2 is a vertical sectional view showing a schematic configuration of a conventional insulation monitoring device. DESCRIPTION OF SYMBOLS 1... Electrical equipment, 2... Container, 3... Electrical equipment body, 4... Bushing, 4a... Conductor, 5... Grounding wire, 6... Current transformer, 7A, 7B...Through terminal, 1
0... Coaxial cable, 11... Tuning amplifier, 12... Alarm output terminal, 13... Judgment unit,
14A, 14B... Choke coil, 15... Capacitor. (1 other person) ゛゛′Question]ノ

Claims (1)

[Claims] In an insulation monitoring device for electrical equipment that monitors insulation by detecting electromagnetic waves due to internal corona generation of an electrical equipment whose main body is built in a container with an internal antenna installed in the container, the internal antenna may be used as the internal antenna. An insulation monitoring device for electrical equipment, characterized in that the container also serves as a current transformer.