JPH07115006A - Arrester for power distribution - Google Patents

Abstract

PURPOSE:To provide a arrester for power distribution which prevents the increase of the tank size even if it is incorporated into a pole transformer and simplifies assembly work. CONSTITUTION:In zinc oxide type power distribution arresters 17a and 17b which are housed in a tank 1 of a pole transformer and submerged in an insulation oil 10 and connected to windings 2 and 3 of the pole transformer and the tank 1 at a grounding potential and applied to the windings 2 and 3, the arresters are designed to suppress surge voltages and comprise a high voltage side arrester connected to the primary winding 2 and a lower voltage side arrester connected to the secondary winding 3. What is more, both arresters are integrated into one unit by using a common ground terminal board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zinc oxide type surge arrester for power distribution built in a pole transformer.

[0002]

2. Description of the Related Art FIG. 4 is an internal wiring diagram of a well-known single-phase pole transformer having a built-in lightning arrester for distribution, and FIG. 5 is similar to that disclosed in, for example, JP-A-63-296315. It is sectional drawing which shows the mounting structure of the lightning arrester for distribution incorporated in the pole transformer. First, in FIG. 4, 1 is a pole transformer tank, 2 and 3 are high-voltage side primary windings and low-voltage side secondary windings respectively stored in tank 1, 4 is primary winding 2 and secondary winding Line 3
An iron core around which 5a and 5b are high voltage side bushings that penetrate the tank 1, 6a and 6b are low voltage side bushings that penetrate the tank 1, and 7a and 7b are zinc oxide type power distribution connected to the high voltage side conductor Lightning arresters, 8a and 8b are zinc oxide type distribution arresters connected to the conductor on the low voltage side, and 10 is insulating oil filled in the tank 1. Next, in FIG. 5, 40 is an iron core of a pole transformer, 41 is an insulating plate attached to the iron core 40, and tap switching terminals and the like are provided. Reference numeral 71 is a zinc oxide element forming the lightning arresters 7a and 7b for distribution, and is composed of deposition of three cylindrical zinc oxide blocks. 72 and 73 are terminal plates applied to both end surfaces of the zinc oxide element 71, 74 is an insulating rod inserted into the through holes of the zinc oxide element 71 and the terminal plate 72, 79 is a metal support fixed to the iron core 40, and 91 is a high voltage side. And a reference numeral 92 is a lead wire connected to the grounded tank 1.

Pole transformers used for distribution lines are required to be protected against the causes of accidents such as insulation deterioration, insulation breakdown, and burnout in order to supply electric power to consumers continuously. Lightning is the most important and frequently occurring cause of this, and the pole transformer has built-in surge arresters 7a, 7b on the high-voltage side and surge arresters 8a, 8b on the low-voltage side to protect against shock voltage caused by lightning. Insulation protection is performed between the primary winding 2 and the iron core 4 and the tank 1, between the secondary winding 3 and the iron core 4 and the tank 1, and between the primary winding 2 and the secondary winding 3 so It is designed to withstand a low shock voltage. By the way, the surge arresters 7a, 7b for distribution on the high voltage side are provided with terminal plates 72, 7a, 7b on both end surfaces of a zinc oxide element 71 formed by depositing three cylindrical zinc oxide blocks.
73, pass the insulating rod 74 through the through hole, fix it by tightening it at both ends, and support it with the support metal fittings 74 attached to the iron core 40, as well as the zinc oxide element 71, terminal plates 72, 73, lead wires.
Conductive contact between 91 and 92. Insulating oil 10 in tank 1
And the primary winding 2, the secondary winding 3, and the iron core 4 are immersed in the insulating oil 10. When surge voltage enters from the high voltage side line, the surge arresters 7a and 7b for distribution suppress it and discharge the surge current to the ground through the tank 1. At this time, the Joule heat generated in the zinc oxide element 71 is radiated to the insulating oil 10. The distribution surge arresters 8a, 8b on the low-voltage side are the same as the distribution arresters 7a, 7b on the high-voltage side, except that the zinc oxide element is composed of one cylindrical zinc oxide block.

[0004]

The conventional lightning arresters for distribution are as described above, and the lightning arresters 7a, 7b on the high voltage side and the lightning arresters 8a, 8b on the low voltage side are installed in the tank 1 of the pole transformer.
Since it is built in and is connected with lead wires 91 and 92, and the required insulation distance is provided between the phases and the ground, there is a problem to be solved such as the tank 1 becomes large and the assembly work is complicated. It was

The present invention has been made to solve the above problems, and an object thereof is to provide a lightning arrester for power distribution in which the pole transformer tank does not become large and the assembling work is simplified. To do.

[0006]

A lightning arrester for distribution according to the present invention is placed in a tank of a pole transformer and immersed in insulating oil.
In the zinc oxide type that suppresses the surge voltage applied to the winding by connecting to the winding of the pole transformer and the tank of ground potential, the surge arrester and secondary winding connected to the primary winding The lightning arrester connected to the low voltage side is quite common, and the two are integrated using a common ground terminal plate.

[0007]

According to the present invention, since the high-voltage side lightning arrester and the low-voltage side lightning arrester are integrated with each other by using the common ground terminal plate, the pole transformer tank is not upsized and the assembling work is simplified. .

[0008]

【Example】

Example 1. FIG. 1 is an internal connection diagram of a single-phase pole transformer with a built-in lightning arrester according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the embodiment of FIG. In FIG. 1, 1-4, 5a,
5b, 6a, 6b are the same as described with reference to FIG. 4 in the prior art. 17a and 17b are lightning arresters for power distribution that have a high-voltage side lightning arrester and a low-voltage side lightning arrester integrated. Further, in FIG. 2, reference numeral 171 is a stack of three zinc oxide blocks each having a cylindrical shape, which is a zinc oxide element forming a lightning arrester on the high voltage side.
172 is a ground terminal plate common to the zinc oxide element 171 and the zinc oxide element 181 described later, 175 is a cylindrical insulating case, 175a
Is the oil passage hole of the insulating case 175, 176 is the zinc oxide element 171,
A spring for elastically fixing 181 and the ground terminal plate 172 and making conductive contact, 177a and 177b are metal lids that close both end surfaces of the insulating case 175, and 178a and 178b are high-voltage side conductively connected to the zinc oxide elements 171 and 181 respectively. Terminal and low voltage side terminal,
Reference numeral 179 is a supporting metal fitting for supporting the ground terminal plate 172, and 181 is one cylindrical zinc oxide block which is a zinc oxide element forming a lightning arrester on the low voltage side.

The first embodiment is constructed as described above,
A high-voltage side zinc oxide element 171, a ground terminal plate 172, a low-voltage side zinc oxide element 181, and a spring 176 are housed in an insulating case 175, and both end surfaces of the insulating case 175 are closed with metal lids 177a and 177b. The zinc oxide element 171, the grounding terminal plate 172, and the zinc oxide element 181 are fixed by the elastic force of the spring 176 and are in conductive contact.
When 10 is satisfied, the zinc oxide element 171, the ground terminal plate 172, the zinc oxide element 18 penetrates through the oil passage hole 175a of the insulating case 175.
Soak 1 etc. The high-voltage side terminal 178a is connected to the primary winding 2 of the pole transformer, and the low-voltage side terminal 178b is connected to the secondary winding 3.
The ground terminal plate 172 is grounded. When surge voltage enters from the high voltage side line or the low voltage side line, the surge arrester 17a for distribution,
17b suppresses it and discharges surge current to the ground. At this time, the Joule heat generated in the zinc oxide elements 171 and 181 is radiated to the insulating oil 10 inside the insulating case 175 and naturally convects with the insulating oil inside the tank 1 through the oil passage holes 175a. According to this embodiment, the lightning arrester on the high voltage side and the lightning arrester on the low voltage side have an integrated structure, so that the tank 1 is compact and the tank 1 is not enlarged, and the assembling work is simplified.

Embodiment 2. FIG. 3 is a sectional view showing a second embodiment of the present invention. Zinc oxide element 271 on the high-voltage side, ground terminal plate 272, and zinc oxide element 281 on the low-voltage side are deposited, terminal plates 277a and 277b are applied to both end surfaces, and insulating rods 274 are inserted into the respective through holes, and at both ends. Tighten and fix and make conductive contact. This is put in the tank 1 of the pole transformer, filled with the insulating oil 10, and immersed. The high-voltage side terminal 278a is connected to the primary winding 2 of the pole transformer, the low-voltage side terminal 278b is connected to the secondary winding, and the ground terminal plate 272 is grounded. Similar effects can be expected in this embodiment as well.

[0011]

As described above, according to the present invention, the coil is housed in the pole transformer tank, immersed in insulating oil, and connected to the pole transformer winding and the ground potential tank. In a zinc oxide type surge arrester for power distribution that suppresses surge voltage applied to, a surge arrester connected to the primary winding and a surge arrester connected to the secondary winding, and a common ground terminal plate By using them as an integrated structure, the pole transformer tank does not become large and the assembly work becomes simple.

[Brief description of drawings]

FIG. 1 is an internal wiring diagram of a single-phase pole transformer with a built-in lightning arrester according to the present invention.

FIG. 2 is a sectional view showing the embodiment of FIG.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is an internal connection diagram of a conventional single-phase pole transformer with a built-in lightning arrester for distribution.

FIG. 5 is a cross-sectional view showing a conventional mounting structure for a lightning arrester for distribution.

[Explanation of symbols]

 1 Tank 2 Primary winding 3 Secondary winding 4 Iron core 10 Insulating oil 17a Distribution lightning arrester 17b Distribution lightning arrester 171 Zinc oxide element 172 Ground terminal plate 175 Insulation case 175a Oil passage hole 176 Spring 177a Metal lid 177b Metal lid 178a High voltage side Terminal 178b Low-voltage side terminal 181 Zinc oxide element 271 Zinc oxide element 272 Ground terminal plate 274 Insulation rod 277a Terminal plate 277b Terminal plate 278a High-voltage side terminal 278b Low-voltage side terminal 281 Zinc oxide element

Claims (2)

[Claims] 1. A pole transformer is placed in a tank and immersed in insulating oil, and the surge voltage applied to the winding is connected to the pole transformer winding and the ground potential tank. In a zinc oxide type surge arrester for distribution, which consists of a high-voltage side lightning arrester connected to the primary winding and a low-voltage side lightning arrester connected to the secondary winding, and a common ground terminal plate, both are integrated A surge arrester for power distribution characterized by the above. 2. A cylindrical zinc oxide element having a ground terminal plate sandwiched therein and a spring are housed in a cylindrical insulating case having oil passage holes, and both ends of the insulating case are closed by metal lids. 2. The lightning arrester for power distribution according to claim 1, wherein the zinc oxide element and the ground terminal plate are fixed by the elastic force of, and are brought into conductive contact with each other, and the both metal lids and the ground terminal plate are conductive terminals.