JPH0787151B2 - Optical fiber transformer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high voltage transformer having an optical fiber inside.

[Prior Art] Conventionally, since an optical fiber is strong against electromagnetic induction interference,
It is often used as a transmission line for transmitting information of various devices under the environment of power or high voltage and large current. In particular, in order to obtain information on the high-potential portion, since the dielectric strength of the high fiber is large, it has been attempted to directly arrange the optical fiber in the air or the insulating material from the high-potential portion to the ground potential. .

However, when the potential difference becomes large, a high electric field applied in the length direction of the optical fiber or the optical fiber cable including the exterior portion may cause obstacles such as so-called tracking and stain flashover. For this reason, it is necessary to store the optical fiber cable in a structure made of a material such as glass that is resistant to tracking and stains.

Therefore, for example, when receiving information transmitted via an optical fiber attached to a power transmission line section or receiving information from a high voltage section of a transformer by an optical fiber,
As shown in the figure, an optical fiber lowering porcelain tube 5 is prepared separately from the transformer bushing 2 of the transformer 1, inside which the optical fiber 4 is transmitted / received from the transmission line 3 or the transformer high potential portion to receive an optical signal of ground potential. Must be lowered to device 6.

However, when the voltage becomes several hundred thousand V or more, the installation area of the entire equipment increases to secure an insulating space around the optical fiber pulling down insulator 5, and the cost of the optical fiber pulling down insulator 5 also increases. It costs a lot to pull down the optical fiber from the voltage section.

On the other hand, it is conceivable to use the bushing 2 for pulling out the transformer without using the porcelain bushing dedicated to pulling down the optical fiber.
There is a part where a high electric field is locally generated inside the transformer bushing 2 in order to make it compact, and it is necessary to change the insulating design of the bushing in order to pull out the optical fiber from there to the ground potential part. is there. Therefore, considerable technical and economic difficulties are expected.

[Problems to be Solved by the Invention] As described above, it is seemingly easy to pull down an optical fiber to or from high-voltage equipment because the optical fiber is insulating. When applied to a practical device, it is not easy because it involves problems such as the structural design of the device body and restrictions on the installation location.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a transformer with an optical fiber in which an optical fiber can be easily pulled out from a high voltage section.

[Means for Solving the Problems] In the optical fiber-containing transformer of the present invention, an optical fiber for measuring the internal condition of a high-voltage transformer or for transmitting information from a high-voltage section of power transmission and distribution equipment is connected to the ground potential side. In order to pull it out, the optical fiber was placed inside the transformer from the high voltage part of the transformer almost along the potential of the winding, and was taken out to the outside of the ground potential only from the neutral point or the side close to the ground potential of the winding. It is configured.

[Operation] The purpose of using the optical fiber arranged in the optical fiber-containing transformer is to transmit an optical signal to the transformer from the transformer in the high-voltage section via an external power generation and transformation device, a switchgear, or a power transmission and distribution facility. And transmitting the information, measuring and monitoring the internal conditions of the windings and the iron core of the transformer itself, extracting the information, and using the information for both purposes.

In either case, it is desirable to install the optical signal receiver at a location of ground potential, from the viewpoint of actual use, inspection and maintenance, repair, etc., and it is necessary to place the optical fiber from the high voltage section to the ground potential section. .

As mentioned above, it is convenient in terms of transmission line configuration to pull down the optical fiber directly from the bushing of the transformer to the ground potential.However, even if the optical fiber has good dielectric strength, it is necessary to cooperate with the transformer insulation design. It is necessary to secure the insulation resistance characteristic. In particular, when oil or gas as an insulating medium of a transformer has a long electric field direction such as an optical fiber in the electric field direction, electric discharge is likely to occur along the surface thereof. That is, when an electric field is applied in the lateral direction of the optical fiber, even if a discharge occurs on the surface, oil and gas layers are immediately formed, so that the discharge is locally stopped, but the electric field is applied in the longitudinal direction of the optical fiber. In this case, discharge occurs over the entire length and discharges between high potential differences.Therefore, the discharge energy is large, which not only damages the optical fiber surface, but also causes fatal damage such as dielectric breakdown of the transformer. Is large.

Therefore, when arranging the optical fiber from the high voltage portion to the ground voltage portion, the creeping discharge should not occur as much as possible, the high electric field portion should not be passed, and the electric field direction should not be parallel to the high electric field portion especially at a distance. Need to do so.

In the present invention, when arranging the optical fiber inside the transformer, since the optical fiber is arranged along the potential drop of the winding part where the local potential difference is the smallest from the high voltage part, the optical fiber is laterally high. Although an electric field is applied, only a very low electric field is applied in the length direction, and the risk of creeping discharge in the length direction of the optical fiber is prevented. Also, when the end of this optical fiber is taken out of the high-voltage device, it is pulled out from the winding part of the ground potential or almost the ground potential, so that metal fittings for pulling out can be mounted relatively easily. The optical fiber can be easily arranged without affecting the insulation performance of the transformer, that is, the insulation design change of the high-voltage transformer can be minimized.

[Examples] The present invention will be described below based on illustrated examples.

FIG. 3 shows a partial cross section of an example of the internal structure of the optical fiber transformer.

In the transformer 1 shown in FIG. 3, the iron core 7 and the case 8 are at the ground potential, and the first high voltage winding 9 and the second high voltage winding 10 are as far away from them as possible, and the iron core 7 and the second high voltage winding 10 are separated from each other. An insulating partition wall 11 is provided between the voltage winding 10, the first high voltage winding 9 and the case 8. However, since there is a strong demand for reducing the size of the transformer itself, the insulating size between the high voltage windings 9 and 10 and the iron core 7 and the case 8 is reduced, and therefore a very high electric field is applied.

In order to pull down the optical fiber from the high-voltage winding portion, that is, the portion of the first high-voltage winding 9 in this example, to the ground, in general, the portion of high potential difference and high electric field is placed in the direction of the electric field. It will be placed through. Moreover, in some cases, the insulating partition 11 is penetrated, and the insulation performance of the transformer 1 is deteriorated.

On the other hand, in a normal high-voltage transformer, one end of the high-voltage winding serves as the highest voltage portion and is drawn out via the transformer bushing 2, but the other end of the high-voltage winding is normally at ground potential. In many cases. For example, in the case of the transformer 1 shown in FIG. 3, as shown by the dotted line in FIG. 1, the high-voltage winding 9 becomes a high voltage in order from the inner side to the outer side, and one end of the high-voltage winding 9 serves as the highest voltage portion in the transformer bushing 2. The other end reaches the neutral point connecting line 12. Alternatively, as shown by the dotted line in FIG.
In the form of windings 13 which are stacked in a disk shape from the lower side to the upper side, one end of the winding 13 also reaches the transformer bushing 2 as the highest voltage portion, and the other end thereof reaches the neutral point connecting wire 12.

Therefore, in a transformer in which the high-voltage windings 9 and 13 are arranged as shown in FIG. 1 or 2, when the optical fiber 4 is arranged along the potential of the high-voltage winding, the optical fiber 4 has a horizontal line in the drawing. Although a high electric field is applied in the direction, only a very low electric field is applied in the length direction, and the risk of creeping discharge in the length direction of the optical fiber 4 can be prevented. Further, even when the end portion of the optical fiber 4 is taken out of the high-voltage device, it is arranged to be pulled out from the winding portion of the ground potential or substantially the ground potential, so that the metal fittings for pulling out can be mounted relatively easily. This can be done without affecting the insulation performance of the transformer.

This situation is schematically shown in FIGS. 1 and 2 with reference numeral 4 of the optical fiber.

Even in the case where the high-voltage winding 9 has a high voltage from the inner side to the outer side as shown in FIG. 1 or in the case where the high-voltage winding 9 is stacked in a disk shape from the lower side to the upper side as shown in FIG. , The optical fiber 4 is arranged from the high voltage part bushing 2 to the low voltage part and the neutral point connection line 12 along the potential of the winding shown by the dotted line.

Depending on the type of transformer, the low voltage part is directly connected to the ground terminal, the three-phase transformer is connected to the ground terminal after forming the neutral point, the bushing for pulling out the neutral point and the neutral point grounding after forming the neutral point. There may be various connection forms such as one connected to a ground line via impedance, but the optical fiber 4 may be taken out from a portion close to the ground potential.

On the other hand, regarding the end of the high voltage part, for convenience of manufacturing and transportation,
For the convenience of connecting with the optical fiber on the power transmission and distribution equipment side after installing the transformer, the space for the connector part or the space for storing the connection part is located near the tip of the bushing for drawing out the high voltage part of the transformer or near the terminal part. It is desirable to secure in advance in the form of a storage box.

Further, when the optical fiber has a sensor function for measuring the internal condition of the winding or iron core of the transformer itself, for example, the optical fiber itself detects a temperature, strain, vibration, electric field, magnetic field, etc. When it has a function, reflection of light or the like, which is different from that of the fiber part in the middle, occurs at the most distal end, which may affect the measurement. Therefore, in the vicinity of the high voltage side tip of the optical fiber, the temperature to be detected,
It is preferable to secure a space in which distortion, vibration, electric field, magnetic field, etc. are almost uniform, and accommodate the extra length of the tip of the optical fiber.

It should be noted that storing a plurality of thin optical fibers requires much material and manufacturing cost. Therefore, one fiber having a sensor function is stored, and a combination of a sensor function and an information transmission function can be obtained by combining time division, wavelength, etc. It is preferable that the configuration of the transformer with the optical fiber is economical. The information transmission function here may be information transmission / reception with various switches other than the transformer, protective devices, or power transmission / distribution equipment.

[Effects of the Invention] As described above, according to the present invention, the risk of creeping discharge in the length direction of the optical fiber is prevented, and the insulation design of the high-voltage transformer is minimally changed to facilitate the operation. An optical fiber can be placed in the. Since it is technically and economically easy to pull out the optical fiber from the high voltage portion, the field of application of the optical fiber for high voltage or power can be expanded.

[Brief description of drawings]

1 and 2 are schematic diagrams showing the structure of windings in a transformer and the arrangement of the optical fiber according to the present invention from a high voltage portion to a low voltage portion,
FIG. 3 is a diagram showing an example of a partial cross-sectional structure inside the transformer, and FIG. 4 is a diagram showing a method of pulling down an optical fiber from a transformer high-voltage portion by a conventional method. In the figure, 1 is a transformer, 2 is a transformer bushing, 3 is a power transmission line, 4 is an optical fiber, 5 is an insulator for pulling down an optical fiber, 6
Is an optical signal receiving and transmitting device, 7 is an iron core, 8 is a case, 9 and 10 are high-voltage windings, 11 is an insulating partition wall, 12 is an intermediate contact connecting wire, and 13 is a high-voltage winding.

Claims (1)

[Claims] 1. An optical fiber for measuring the internal condition of a high-voltage transformer or for transmitting information from a high-voltage section of a power transmission facility to the ground potential side, so that the optical fiber is installed inside the transformer. An optical fiber-containing transformer characterized in that it is arranged substantially along the potential of the winding from the voltage section and is taken out to the outside of the ground potential only from the neutral point or the side close to the ground potential of the winding.