JPH02257607A - Oil-filled electric apparatus - Google Patents

Abstract

PURPOSE:To prevent an insulating oil from being moved between a main-body part and a cable-connection part, to limit a part where a trouble has been formed and to reduce a period of time and a cost for investigating the part where the trouble has been caused by a method wherein the main-body part and the cable-connection part are united via a diaphragm-system conservator under a uniform pressure. CONSTITUTION:A diaphragm-system conservator 25 whose inside is divided into a first chamber 27 and a second chamber 28 by using a flexible film 26 so as to be airtight and oiltight is installed for a cable-connection part 11; the first chamber 27 is used as an oil chamber and is connected to the cable-connection part 11; while the second chamber 28 is connected to a main-body part 1. Accordingly, while a pressure inside the first chamber 27 and that of the second chamber 28 are changed appropriately, they are always kept at an identical value; also on pressures on both sides of a connection terminal 14 are set at a nearly identical value; it is possible to prevent an insulating oil from being moved between the main-body part 1 and the cable- connection part 11. Thereby, when it is detected that a trouble has been caused by analyzing the oil, it is possible to clearly limit which of the main-body part 1 and the cable-connection part 11 is defective; it is possible to reduce the period of time and cost for investigating the trouble.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to cable-directly connected oil-filled electrical equipment filled with insulating oil, such as transformers and shunt reactors installed in underground substations, etc. It is.

[Conventional technology]

Oil-filled electrical equipment installed outdoors is of m construction with bushings attached to the top or side of the main tank, but substations in urban areas are often underground or installed in narrow spaces. In such cases, most of the power transmission lines are cables. When the power transmission line is capped, oil-filled electrical equipment such as transformers and shunt reactors are often directly connected to cables so that live parts are not exposed to the atmosphere.

Figure 3 is a sectional view showing the structure of a conventional direct cable connection type installed in such an underground substation.
3) is housed inside the main body tank along with insulating oil (4), and (5) is a diaphragm type conservator installed above the main tank (1), which has a flexible membrane inside. A rubber bag (6) is provided, and the outside of the rubber bag (6) communicates with the main tank (1) via a connecting pipe (7).
(8) is a breather containing a moisture absorbent inside, and the connecting pipe (
9) to the inside of the rubber bag (6) of the conservator (5). σ1 is a valve provided in the middle of this connecting pipe (9).

OJ is a connection chamber as a cable connection part that accommodates the cable end (end) of the cable (transmission) on the high voltage side together with insulating oil (4), and 041 is a connection chamber between the main body tank (1) and the connection chamber Qη. This is a connection terminal that separates the two in oil and electrically connects them, and because a high level of insulation reliability is required, we developed an insulator obtained by molding a craft valve and this insulator. A conductor a provided through the
It is composed of Q. (171 is the lead that connects the high voltage side of the coil (2) and the conductor t* (G), (to) is the lead that connects the cable end (to) and the conductor σQ. ) and the connecting chamber (ll)
(1) is a valve provided in the middle of the connecting pipe that communicates with J. (2) is a connection chamber in which the cable end 4 of the low voltage side cable (E) is accommodated together with insulating oil (4), and between it and the main tank (1) is an oil-submerged bushing (C). The cable end 0 is connected to the low pressure side of the coil (2) via this oil-in-oil bushing.

Next, the operation, particularly the behavior of the insulating oil (4) when the transformer is operated, will be explained. Now that the transformer is running, there is no oil (
When the temperature of the insulating oil (4) increases, the volume of the insulating oil (4) increases, and the increased insulating oil (4) is transferred to the conservator (5).
) and reduce the internal volume of the rubber bag (6). Therefore, the air inside the rubber bag (6) is released into the atmosphere through the breather (8). The insulating oil (4) in the connection chamber θυ also increases in volume due to the temperature rise, and flows into the conservator (5) via the connection pipe Ql. And the same team as above,
It works to reduce the internal volume of the rubber bag (6).

When the transformer stops operating and the temperature of the insulation part (4) drops, its 441 decreases, and the breather (8) sucks air from the atmosphere and sends it into the rubber bag (6) to absorb its contents. The volume of the insulating oil (4) is guaranteed to decrease by increasing the volume of the insulating oil (4).

Note that the connection chamber tn for the low voltage side cable @ is filled with insulating oil (4
) has a structure that absorbs changes in volume.

[Problem to be solved by the invention]

By the way, in the case of large-capacity, high-voltage oil-immersed transformers connected to the power system, ensuring their long-term reliability is an extremely important $ point. In other words, extremely rare coils (
2), the iron core (3), or inside the connection chamber ση, local heating may occur in the energized parts, and so-called partial discharge may occur in the insulated parts. These local heating and partial discharges may expand over time and lead to short-circuit or ground fault accidents in the transformer, and it is necessary to detect phenomena such as the above-mentioned local heating as early as possible, which can be considered as precursor phenomena.

For this reason, a gas detection device is installed on the upper part of the main body tank (1) and the connection chamber α1, and the insulation part (
4) is decomposed and gasified, this decomposed gas can be detected. In addition, if the energy for local heating is small and the decomposed gas is dissolved in the insulating oil (4), periodically collect the insulating oil (4) from each part,
A method has been adopted in which the precursor phenomenon is detected by analyzing the components of the dissolved gas.

However, as shown in Figure 3, conventional oil-immersed transformers
The main body tank (1) and the connection chamber Qη are connected through a connection pipe o1 and are in communication. For this reason, even if oil analysis detects a result that indicates an internal malfunction, it is difficult to determine whether the malfunction is occurring in the main tank (1) or in the connection chamber aυ. As a result, the location of the problem cannot be determined unless the entire oil-immersed transformer is investigated, resulting in an increase in investigation time and expense.

However, a method can be considered in which a dedicated conservator is newly attached to the connection chamber αυ without providing the connection pipe a11.

However, in this case, there is a difference in the oil pressure on both sides of the connection terminal Q4, and due to this pressure difference, the oil (4) penetrates through the insulation material of the connection terminals α and υ and is connected to the main body tank (1). Even if there is a difference in degree of movement between the chamber aη and the chamber aη, the above-mentioned problem cannot be solved.

This invention was made to reliably solve the following problems. When a malfunction is detected by oil analysis, it is possible to determine whether the malfunction is in the main body or in the cable connection part. The purpose of the present invention is to provide oil-filled electrical equipment that can clearly limit the investigation period and reduce costs.

[Means to solve the problem]

The oil-filled electrical equipment according to the present invention is provided with a diaphragm-type conservator for the cable connection portion, which divides the inside into an airtight and oil-tight partition into a first chamber and a second chamber by a flexible membrane of 0IJ. 1
The chamber serves as an oil chamber and is communicated with the cable connecting portion, and the second chamber of 1 is communicated with the main body portion.

[For production]

The pressure in the first chamber of the conservator communicating with the cable connection part and the pressure in the second chamber of the conservator communicating with the main body part are always kept at the same value by appropriate deformation of the membrane. As a result, the oil pressure on both sides of the connection terminal has approximately the same value, and there is no movement of insulating oil from this area due to penetration. Since there is no other communication path, movement of insulating oil between the main body portion and the cable connection portion is prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a cross-sectional view showing the structure, and in the figure, (1) to Q
I'9.3 sword (c) is the same as the conventional one. 4 is a diaphragm type conservator for absorbing the volume fluctuation of the insulating oil (4) in the connection chamber aη, and there is a town inside! A rubber bag (E), which is a membrane, is provided, and the outside thereof is a first chamber, and the inside thereof is a second chamber (support), which is divided airtight and oil-tight.

The first chamber @ communicates with the connection chamber (Q1) via the oil chamber and the connecting pipe (Q1), and the second chamber (to) also communicates with the connection pipe (Q1) as an oil chamber.
1), it communicates with the upper part of the main tank (1).

With the above configuration, the #: and product variation components of the insulating oil (4) in the connection chamber (B) go in and out of the first chamber of the conservator, and are distributed in the rubber bag (housing) according to the difference. ) is deformed. According to the deformation of the rubber bag (e), the insulating oil in the second chamber (to) flows into and out of the main body tank (1).

In this way, the insulating oil (4) in the main body tank +1) and in the connection chamber Qη are maintained under the same pressure while being isolated. Therefore, the insulating oil (4) is applied to the insulators (
7) It does not penetrate and move.

Fig. 2 shows another embodiment of the present invention, in which the second chamber (to) of the diaphragm type conservator is used as an air chamber and the air is connected to the main body side of the ``conservator'' via a connecting pipe (31). 5)
It communicates with the inside of the rubber bag (6). (2) is a valve provided in the middle of this connecting pipe 6υ.

In this example, the insides of the rubber bags (6) and 2) of both conservators (5) and 2) were connected with a connecting pipe θυ so that the pressure was the same, so that both conservators (5) and 2)
By keeping the same mounting level, there is no pressure difference between the main body part and the cable connection part, and it is possible to prevent the insulating oil (4) from moving from the connection terminal Q4i as in the embodiment shown in Figure 1. .

In the above embodiment, the first chamber (2) of the conservator (G)
) is the outside of the rubber bag, and the second chamber is the inside of the rubber bag.However, conversely, the first chamber may be the inside of the rubber bag, and the second chamber may be the outside of the rubber bag. The material is not limited to a rubber bag, but any material, such as a metal bellow-like material, may be used as long as it partitions the compartment in an airtight and oil-tight manner and deforms without pressure to change its volume.

Further, in the above embodiment, a diaphragm type conservator is also provided in the main body portion, but other types may be used.

〔Effect of the invention〕

As mentioned above, the main body part and the cable connection part are connected under equal pressure through the diaphragm type conservator, so 1 ml of the image part is connected to the connection terminal using an oil-immersed insulator. Even if a structure in which the parts are separated is adopted, movement of the insulating oil between the two parts is prevented. Therefore, if an internal malfunction is detected from oil analysis, the location of the malfunction can be limited to either the internal or external parts, and the time and cost required to investigate the malfunction location can be reduced.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an oil-immersed transformer according to an embodiment of the present invention, FIG. 2 is a sectional view showing another embodiment of the invention, and FIG. 3 is a sectional view showing a conventional oil-immersed transformer. FIG. In the figure, (1) is the main body tank as the main body part, (
2) and (3) are the coil and iron core as the main body of the device, (4) is the insulating oil, α is the connection chamber as the cable connection part, Q is the cable end, Q4 is the connection terminal, and (7) is the absolute , atS is a conductor, ni) is a diaphragm conservator, (
E) is a rubber bag as a flexible membrane, (B) is the first chamber, (
C) is the second chamber, and port 41 is a connecting pipe. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] A main body part that accommodates the main body of the device together with insulating oil, and a cable connection part that accommodates the cable end along with insulating oil, and includes an oil-impregnated insulator and a cable connection part that is provided through an oil-impregnated insulator. In oil-immersed electrical equipment that is directly connected to a cable, the above-mentioned two parts are separated in oil by a connection terminal consisting of a conductor, and an electrical connection is made between the above-mentioned two parts. A diaphragm type conservator is provided for the cable connection portion that is airtightly and oiltightly divided into a second chamber, the first chamber serves as an oil chamber and communicates with the cable connection portion, and the second chamber communicates with the main body portion. An oil-filled electrical device characterized in that the hydraulic pressures applied to the connection terminal at both parts are approximately equal.