JPS5855735B2 - Element failure detection device in high voltage converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an element failure detection device in a high voltage converter using a light guide method.

A high voltage converter, for example, an oil-filled AC/DC converter (oil-cooled thyristor valve), as shown in FIG. It is composed of columns 3 and the like that support these frames 2 which are stacked in several tiers.

4 indicates an oil tank. Since a high voltage AC/DC converter has tens or hundreds of thyristors connected in series depending on the rated voltage, the method of detecting failure of the thyristor element 1 becomes a major problem.

One method that is currently common is to install a light emitting element 5 on each pedestal 2 on the high voltage side, and create a circuit configuration in which a potential difference will occur if one or several thyristors 1 on the pedestal 2 fail. This potential difference is input to the light emitting element 5, and the emitted light is sent to the light receiving element 7 provided on the low voltage side through a guide 6 made of quartz glass, glass fiber light guide, or other material with good transmittance. There is a method of detecting a failure of the element 1 by converting an optical signal into an electrical signal using the light receiving element 7.

In this system, an amplifier 8 is provided to amplify input and output on the light emitting and light receiving sides, and when a mechanically fragile material such as quartz glass is used for the light guide 6, a protective tube 9 is provided to protect it.

Since this protection tube 9 provides insulation between the high voltage side of the high voltage charging section and the low voltage side of the tank potential, a high insulation resistance material such as epoxy resin or FRP with relatively good insulation performance is used.

Also, in order to improve the withstand voltage of this protection tube 9, metal shields 10 and 11 are attached to the high voltage side and the low voltage side.
Further, on the low voltage side, a ground plate 12 is provided as a noise countermeasure, and the low voltage side of the light guide 6 is collectively received.

Although such a light guide type element detection method is characterized in that each pedestal 2 is insulated from the ground potential, this method has the following drawbacks.

(1) It is necessary to insulate each frame 2 on the high-voltage side from the ground plate 12 at ground potential, and this requires creeping insulation, which increases insulation weaknesses.

Particularly with respect to DC voltage, uneven distribution of charges on the surface of the protective tube 9 may adversely affect insulation.

(2) A protection tube 9 that mechanically protects the light guide 6, and a shield 10.1 for improving the withstand voltage along the surface of the protection tube 9.
1 and a ground plate 12 for noise prevention are required, and the manufacturing and installation of these parts requires a large number of man-hours.

In particular, when the low-voltage side shield 11 is a paper-wrapped shield, the paper-wrapping operation becomes considerably difficult because the shield itself is small.

(8) Protective tube 9, shields 10 and 11, and ground plate 1
2 is required, and as mentioned above, the number of man-hours required to install these parts increases, making the light guide device expensive.

In view of these points, the present invention makes it possible to eliminate the protective tube for protecting the light guide, the shield for increasing withstand voltage, and the grounding plate for noise prevention, thereby making it possible to reduce costs and reducing insulation weaknesses. It is an object of the present invention to provide an element failure detection device for a high voltage converter, which is configured to improve the reliability of the device.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 2, 21 is a large number of high voltage, large current thyristor elements connected in series, 22 is a multi-stage pedestal for receiving these thyristor elements 21, and 23 is a frame 22 made of an insulating material such as FRP or epoxy resin. Fallen trees are provided with hollow cylindrical supports that support the cylinders at approximately equal intervals, and these are housed in the oil tank 24 and constitute an oil-cooled silisk valve.

The hollow support 23 has a required number for mechanical strength to several tens of meters.
It has a wall thickness of m, and each frame 22 has a hole 25, so that insulating oil enters inside.

In the present invention, a flexible glass fiber light guide is used as the light guide 27 when transmitting the optical signal emitted from the light emitting element 26 of each mount 22 to the light receiving side using a light guide. is made to pass through the hollow part of the support column 23.

On the other hand, on the light receiving side, the same number of light receiving elements and amplifiers as the number of light guides 27 will be provided, but these will be housed in a shield box 28 outside the device and stored all at once.

In this way, if the insulating column 23 supporting the pedestal 22 is made hollow and the light guide 27 is sent through the insulating oil in the column 23 to the low-voltage side, the light guide can be protected, which was previously necessary. Costs can be reduced by eliminating the need for tubes, shields to improve withstand voltage, and ground plates to prevent noise.Also, since there is no protective tube with creeping insulation, insulation weaknesses can be eliminated, making the equipment easier to use. Reliability can be improved.

Furthermore, since the pedestal 22 becomes a high voltage section, a presspod barrier may be provided on the pedestal 22 side in order to insulate it from the tank.

At this time, the conventional method had the drawback that the light guide device became an obstacle and the installation of the presspod barrier required a considerable amount of time.

However, in the present invention, since there are no obstacles, the work can be completed in a relatively short time.

Furthermore, since the amplifier on the light receiving side uses a lot of electronic equipment, it is susceptible to surges and electrostatic and electromagnetic effects from other lines and equipment.

In contrast, in the present invention, the light receiving side is housed all together in the electrostatic shielding box 28, so it is possible to reduce the electrostatic influence from surges and other lines.

Also, one of the electromagnetic effects is the problem of the connection line between the light receiving element and the amplifier, but as in the present invention, the light receiving element and the amplifier are connected together.
If the cables are housed in one shield box 28, the connection lines can be shortened, which has the advantage of reducing the electromagnetic influence caused by the connection lines.

In the above embodiment, it has been explained that FRP or epoxy resin is used as the support column 23, but a porcelain insulator may also be used instead.

Also, as the light guide 27, in addition to the above, quartz glass,
Clad rods and other materials may also be used.

Further, in the above embodiment, an example was shown in which a large number of light guides 27 are passed through one support 23, but they may be passed through two or more support pillars 23 separately.

Furthermore, in the above embodiment, an oil-filled type transducer was explained, but the SF6. It can also be applied to AC/DC converters insulated with a medium such as air.

In addition, the shield box 28 on the light receiving side may be divided into several parts for convenience of use, and if the lowest part of the pedestal 22 is insulated with a support insulator 29 as shown by the dotted line in FIG. The present invention can also be applied by utilizing the cavity within the insulator 29.

In the present invention described above, in order to detect an element failure using the light guide method, a hollow support is used as an insulator to support the mount that receives the conversion element, and a light guide from the light emitting side of the mount is installed inside the support. An element failure detection device in a high voltage converter that sends a low-voltage side optical signal through the ground, reducing the number of parts and reducing costs, as well as reducing insulation weaknesses and improving equipment reliability. can be provided.

[Brief Description of the Drawings] Fig. 1 is a sectional view of a main part showing an element failure detection device using a conventional light guide method in an oil-cooled silisk valve, and Fig. 2 is a sectional view of a main part showing an embodiment of the present invention. It is. 1.21; Thyristor element, 2, 22; Frame, 23
;Hollow pillar, light emitting element, 2γ; Shield box. 24; tank, 25; hole, 26; light guide, 28; light receiving side

Claims (1)

[Claims] 1. Failure of the conversion element in a high voltage converter is caused by the failure of the light emitting element,
In detection using a light guide method consisting of a light guide and a light receiving element, a hollow support is used as an insulator to support the mount that receives the conversion element, and the light guide from the light emitting side of the mount is passed through the support above the ground. An element failure detection device in a high voltage converter that sends an optical signal to the low voltage side and has a light receiving device placed on the low voltage side.