JPH0382107A - Ground transformer - Google Patents

Abstract

PURPOSE:To facilitate the maintenance and inspection works such as confirmation of voltage detection, phase detection and the like by a method wherein the riser cable from a buried high tension wiring ground cable is led to the upper part of a high-tension opening and closing device, the cable is coupled by an elbow type end terminal, a terminal arrangement is provided in front of a housing, and an air-tight stopper of high tension cutout is constituted in such a manner that the door of the housing is not closed in an open-circuit state. CONSTITUTION:The connection points of the high-tension cable, which is brought up from the ground, and a transformer are connected by the elbow type terminal 1 provided on the upper part of a high-tension opening and closing device 2, and the height of 650 to 700mm above the ground can be secured. Moreover, the mounting and dismounting of the cable can be conducted by moving it on the circular arc and tumbles it with the surface of the ground as the supporting point, and the cable can be connected by bringing it down, and the connection work becomes very easy. When an airtight stopper 14 is opened, the mounting position of a high-tension cutout 4 is arranged in such a manner that the door of a housing will not be closed by the sticking out of the open end of the airtight stopper 14 from the front of the housing 8. One-phase lacking and a phaseless operations are prevented by providing a three-pole interlocking low-tension circuit breaker 6 for power distribution on the low-tension side.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a transformer, and more particularly to an on-road transformer for high voltage transformation from underground distribution cables.

(Conventional techniques*) Power distribution equipment installed on roads is being lowered in height from the ground with the expansion of underground power distribution.
There is a strong demand for development from the side of equipment manufacturers from the viewpoint of maintaining street appearance and road safety management. When developing low-ground height equipment, it is necessary to ensure safety on the road, as well as workability and maintainability during equipment installation, and to ensure high reliability. In particular, underground cables have thick and strong insulating jacket layers due to functional requirements, so workability during cable routing and distortion correction cannot be said to be good.

The high-voltage side lead-in of conventional ground transformers is described in the Tokyo Electric Power Co., Inc. Electrical Equipment Material Specifications 6J-8F Ground Transformer Purchase Specifications for Large Capacity Ground Transformers.

Install a load break elbow that can be operated independently for each phase, or even one that has a built-in high voltage switchgear.

For example, as shown in Figure 10.11, an underground cable is connected to a transformer by means of its lower straight terminals. Therefore, in the former case, if the transformer is single-pole switching and a load is connected to the transformer, an open-phase state will occur, albeit for a short time. In addition, even if a high voltage switchgear is built in that can open and close all three phases at once, the high voltage cable connection point is located at the bottom and has a straight terminal.
If so-called low ground clearance is planned, the space required for cable connection work will become smaller. On the other hand, the protection method on the low pressure side is a low pressure current limiting fuse method, so 2
If the phase was not completely fused, open phase operation occurred on the load side.

(Problems to be Solved by the Invention) In the above-mentioned conventional technology, the narrowing of the cable connection work space reduces the workability for voltage detection and phase detection confirmation, and the open-phase operation results in a stable supply of electric power. There were problems such as loss of information. In addition, from a safety perspective, the height of the ground transformer is 1100, compared to the conventional product's 14501.
■The following six points have been proposed for consideration.The present invention has been made to solve the above-mentioned problems. The purpose of this invention is to provide a ground transformer that is easy to use and has excellent safety.

(Means for solving problems) The above objectives are achieved by:

A rise from a buried underground high-voltage wiring cable is guided to the upper part of the high-voltage switchgear and connected by an elbow-shaped terminal terminal, and the terminal array is provided on the front surface of the housing.

The door of the casing cannot be closed when the sealing stopper of the high-pressure cutout is open.

The low-voltage side protection means does not require a fuse for each phase, but instead provides a low-voltage circuit breaker for power distribution.

A branch terminal is provided at the bottom of the low-voltage circuit breaker for power distribution, allowing four circuits to be branched.

A communication cable with a plug-in structure at both ends is used to connect the high voltage switchgear and the transformer body.

(Function) With the above configuration, the high-voltage wiring cable can be easily attached and detached by moving it along an arc line centered on a point on the ground surface, and visual inspection can be performed from the front of the casing. It is possible to prevent forgetting to open the out sealing plug, and on the low pressure side, there is no need for one phase breakage due to fuse deterioration or a time lag for fuse blowouts, making it easier to handle.

(Example) An example of the present invention will be described with reference to the drawings. FIG. 5 shows a connection diagram inside the ground transformer according to the present invention, in which the high voltage side is led into the high voltage switchgear 2 via the elbow type plug-in terminal 1,
It is led to the transformer winding and core storage area via the communication cable 3. Power is transformed from inside the transformer main body through a high-voltage cutout 4 by a transformer 5 consisting of an iron core and windings, and is branched from a low-voltage branch terminal 7 through a distribution low-voltage circuit breaker 6 to be distributed to demand customers. Each has two branch ends, and can be branched into a total of four circuits with two circuits and two branches. The above arrangement is incorporated into the transformer housing 8 shown in Figure 6.7. Fig. 6 shows a front view of the casing 8, and Fig. 7 shows a side view of the casing 8 as viewed from arrow C, where 9 is a high-pressure side door and 10 is a low-pressure side door.
The structure and arrangement of each part inside the casing 8 of the present invention are shown in FIGS. 1 to 4. The connection point between the high-voltage cable pulled up from underground and the transformer is connected by an elbow-shaped terminal 1 provided on the top of the high-voltage switchgear 2, and in this embodiment, the connection point is 650~
It is possible to secure a dimension of 700 m. In addition, the cable can be attached and detached by moving it on a circular arc with the ground as a fulcrum and tilting it down, as shown by arrow K in Figure 2, and the operation is extremely easy compared to the conventional linear terminal 11 in Figure 10. becomes. As shown in Fig. 8, the structure of the high-voltage side elbow-type terminal is that a voltage detection terminal 13 is provided on the back. If so, it can be easily checked visually.

The high-voltage cutout 4 is installed in such a way that when the sealing stopper 14 is opened, the open end of the podium stopper 14 protrudes from the front of the housing 8, and the high-voltage cutout 4 is positioned so that it cannot be closed, as shown in FIG. It is set up. On the low voltage side, a three-pole interlocking power distribution low voltage circuit breaker 6 is provided to prevent one phase from being disconnected and to avoid open phase operation. As shown in Figure 0, the connecting cable 3 connecting the high voltage switchgear 2 and the transformer 5 has a plug-in structure in which both ends can be attached and detached, which is advantageous for maintenance and inspection, especially for electrode wear. This makes it easy to independently trip the high voltage switchgear 2, which is a concern.

(Effect of the invention) By implementing the present invention, the following effects can be obtained.

(a) By placing the one-pull lead-in part on the high voltage side above the high voltage switchgear and adopting an elbow-type terminal, the cable can be connected and disconnected without providing extra length for the cable pull 10, and the height above the ground is high. A distance of 650 to 700 meters is ensured, and there will be no problem in drawing in the GV cable with a cross-sectional area of 150 am2.

(b) By arranging the elbow-shaped terminals at the front of the housing, the voltage detection terminal provided on the back of the elbow-shaped terminals can be confirmed when the high-voltage side door is open, improving the efficiency of maintenance and inspection work.

(e) If you forget to tighten the sealing plug of the high pressure cutout,
Since it is not possible to close the high voltage side door, electrical insulation and dust resistance are maintained and the reliability of the equipment is improved.

(d) The three-pole interlocking distribution circuit breaker prevents open-phase operation, and along with ε, which contributes to a stable supply of power, maintainability is improved and contributes to accident prevention during live line work.

(8) High-voltage switchgear The continuous cable that connects the transformer main body ε has a plug-in structure at both ends, making it possible to easily attach and detach the high-voltage switchgear and prevent electrode wear. This simplifies inspection and improves assembly work efficiency.

[Brief explanation of drawings]

Figure 1. Figures A to 4 show the configuration ε arrangement inside the casing of the ground transformer according to the present invention, where Figure 1 is a front view, Figure 2 is a side view as seen from arrow A in Figure 1, and Figure 3 is a 4 is a top view, FIG. 5 is a connection diagram inside the ground transformer according to the present invention, FIG. 6 is a front view of the cylindrical body of the ground transformer according to the present invention, and FIG. The figures are a side view taken in the direction of arrow C in Figure Ω, Figure 8 is a cross-sectional view of the elbow-shaped terminal terminal according to the present invention, Figure 0 is a cross-sectional view of a part of the communication cable according to the present invention, and Figure 10 is a cross-sectional view of a part of the communication cable according to the present invention. The figure shows the high-voltage side layout of a conventional ground transformer. 1... Elbow type terminal terminal 3... Communication cable 5... Transformer 7... Low voltage branch terminal 9... High voltage side door] 3... Voltage detection terminal Figure 11 is the same low voltage side Arrangement 2... High voltage switchgear 4... High voltage cutout 6... Low voltage circuit breaker for power distribution 8... Housing 10... Low voltage side door

Claims (1)

[Claims] 1. In a ground transformer equipped with a high-voltage switchgear and a high-voltage cutout in the housing, a low-voltage distribution circuit breaker with a branch terminal and high-voltage power from a cable buried underground are introduced from the top of the high-voltage switchgear. It includes an elbow-shaped terminal terminal and a communication cable having a plug-in structure at both connection ends that connects the high-voltage switch and the high-voltage cutout, and closes the housing door only when the sealing plug of the high-voltage cutout is closed. The sealed wire is provided on the front surface of the casing, and the connection point of the high voltage cable connected to the transformer via the high voltage cutout is provided on the front surface of the casing. Ground transformer.