CN1282287C - Surge arrester having disconnector by end cap - Google Patents

Abstract

An apparatus includes a surge arresting element, first and second end caps, an arrester housing, and a fault disconnector. The surge arresting element is arranged to conduct in the presence of the surge on a power line. The first and second end caps are arranged to be electrically connected to the surge arresting element, and the second end cap forms a disconnector housing. The arrester housing is arranged to house the surge arresting element and the first and second end caps so that the disconnector housing is accessible from an exterior of the arrester housing. The fault disconnector is arranged to electrically disconnect the surge arresting element from the power line in the event of a fault, and the fault disconnector is housed within the disconnector housing formed by the second end cap. A fastener is arranged to fasten the surge arresting element, the first and second end caps, the arrester housing, and the fault disconnector to a mounting bracket so as to wedge the arrester housing between the mounting bracket and the second end cap in order to form a seal.

Description

Surge arresters with circuit breakers built into end caps

related application

This application is a continuation-in-part of US Patent Application Serial No. 08/907,327, filed August 6,1997.

technical field

The invention relates to a surge arrester for shunting electrical surges to ground. More specifically, the surge arrester of the present invention may have a circuit breaker capable of disconnecting the surge arrester from ground in the event of a malfunction of the surge arrester.

Background technique

An overvoltage surge that travels along an electrical distribution system and is not properly diverted or diverted, often damaging transformers and other electrical equipment in the electrical distribution system, as well as the residential, commercial, and industrial users supplied by the electrical distribution system electrical equipment. Therefore, surge arresters are often used in a power distribution system to shunt overvoltage surges to system grounds before they can damage electrical equipment connected to or connected to the power distribution system.

Common surge arresters used in power distribution systems can fail in an uncontrolled condition. When such a fault occurs, the surge arrester can explode, potentially damaging nearby equipment and anyone who happens to be near it. Therefore, it is common in the prior art to provide surge arresters with a fault circuit breaker capable of opening a circuit containing a faulty surge arrester. Usually, a fault circuit breaker is connected between its corresponding surge arrester and ground, so that when the surge arrester fails and activates the fault circuit breaker, the fault circuit breaker can connect the surge arrester to ground. Connector detached. This split ground connection not only isolates the faulty surge arrester from the power distribution system, but it also indicates to the utility lineman that the surge arrester has failed.

A typical fault interrupter includes a case which may contain a predetermined amount of explosive which is heated when the surge arrester begins to malfunction. When the box heats up sufficiently, it explodes to disconnect the surge arrester from the ground connection. The amount of powder used in the box is sufficient to cause this disengagement, but not sufficient to cause damage or injury to people or animals.

The box and other components of the fault circuit breaker are housed in a circuit breaker base, which is a separate component of the surge arrester and has an internally threaded hole for mating with a housing of the surge arrester. threaded connection and also has an externally threaded grounding connector connected to the grounding conductor. As another component of the fault circuit breaker, a resistor built into the circuit breaker base is electrically connected between a surge arrester terminal and the ground connection of the circuit breaker. Thus, when the surge arrester fails, the current through the resistor increases abnormally, generating enough heat to energize the box, causing it to break the breaker mount and separate the ground from the surge arrester.

The use of a separate circuit breaker base increases both the part count of a surge arrester and the manufacturing cost of the surge arrester. The object of the invention is directed to a surge arrester which reduces the number of parts.

Contents of the invention

According to one aspect of the present invention, there is provided a surge arrester comprising:

a surge blocking element, wherein the surge blocking element is configured to conduct electricity when a surge occurs;

a first end cap configured to electrically connect the surge blocking element to a first electrical wire;

a second end cap electrically connected to the surge blocking element, wherein the second end cap has first and second ends, the first end is directly electrically connected to the surge blocking element, and the second end cap is electrically connected to the surge blocking element. the second end of the two-end cap is recessed to form a circuit breaker base, the second end cap being entirely conductive; and

a fault interrupter configured to electrically connect the second end cap to a second electrical line, wherein the fault interrupter is configured to disconnect the surge blocking element from the second electrical line in the event of a fault , the fault circuit breaker is received in the circuit breaker housing formed by the second end cap.

Description of drawings

These and other features and advantages of the present invention will become more apparent when the invention is considered in detail and in conjunction with the accompanying drawings. The attached drawings are:

Figure 1 shows a first embodiment of a surge arrester comprising a fault circuit breaker according to the invention;

Fig. 2 is an exploded view of the fault circuit breaker shown in Fig. 1;

Figure 3 is an enlarged view of a second embodiment of a surge arrester according to the present invention;

Figure 4 shows a third embodiment of a surge arrester according to the invention; and

Fig. 5 shows a fourth embodiment of a surge arrester according to the invention.

Detailed ways

As shown in FIG. 1 , a surge arrester 10 includes a first terminal 12 and a second terminal 14 . The first terminal 12 includes a first connector 16 for electrically connecting the surge arrester 10 to a first wire. The second terminal 14 includes a second connector 18 for connecting the surge arrester 10 to a second wire. The first wire can be, for example, a conductive wire that connects the first connector 16 to a high voltage wire of a power distribution system, and the second wire can be a conductive wire that connects the second connector 18 to ground. However, alternatively, the first wire can be, for example, a conductive wire connecting the first connector 16 to ground, and the second wire can be a conductive wire connecting the second connector 18 to a high voltage wire of a power distribution system.

The first connector 16 is screwed to a first end cap 20, and the second connector 18 is electrically connected to a second end cap 22 in a manner to be described below. The first and second end caps 20 and 22 are electrically conductive and may, for example, be made of aluminum. A first surge blocking element 24 is in electrical contact with the first end cap 20, a second surge blocking element 26 is in electrical contact with the first surge blocking element 24, and a third surge blocking element 28 is in electrical contact with On the second surge blocking element 26 , a fourth surge blocking element 30 is electrically connected to the third surge blocking element 28 and the second end cap 22 . Therefore, a series circuit is formed between the first and second end caps 20 and 22 . The surge blocking elements 24-30 may be, for example, metal oxide varistor blocks which conduct electricity in the event of a surge to transfer surge energy in the power distribution system between the first and second terminals 16 and 18. shunt.

An arrester housing 32 houses the first and second end caps 20 and 22 and the surge blocking elements 24, 26, 28 and 30 therein. The arrester housing 32 may be an insulating polymeric or porcelain housing having a plurality of polymeric or porcelain porcelain water sheds 34, as is well known. In order to install and support the surge arrester 10 on a utility pole or other equipment of a power distribution system, a mounting bracket 36 is specially provided.

As shown in FIGS. 1 and 2 , the second end cap 22 has a first end 40 in electrical contact with the fourth surge arresting element 30 . The second end cap 22 also has a second end 42 including a wall 44 forming a recess 46 . A fault interrupter 47 includes a cartridge 48 contained within an end 50 of the second connector 18 . The fault circuit breaker 47 also includes a first conductive washer 52 close to the end 50 of the second connector 18, a second conductive washer 54 close to an inner wall 58 of the second end cap 22, and a Resistor 56 between first and second conductive washers 52 and 54 . When the fault interrupter 47 is assembled as shown in FIG. 1 , a plastic cap 59 contains the first and second conductive washers 52 and 54 and the resistor 56 . As such, the plastic cap 59 insulates the resistor 56 and the first and second conductive washers 52 and 54 from the wall 44 of the second end cap 22, facilitating fault current flow from the second end cap 22 through the second conductive washer 54, resistor 56 . The first conductive gasket 52 and the second joint 18 .

The wall 44 of the second end cap 22 has a circumferential groove 60 formed therein. During assembly of the surge arrester 10 , the surge blocking elements 24 , 26 , 28 and 30 are stacked between the first and second end caps 20 and 22 . A fiberglass fabric is wrapped around the pile formed by the surge arresting elements 24, 26, 28 and 30 and the first and second end caps 20 and 22 so that the surge arresting elements 24, 26, 28 and 30 and first and second end caps 20 and 22 remain within the stack. Arrestor housing 32 (shown in FIG. 1 ) is attached to the exterior of the wrapped stack of surge blocking elements 24 , 26 , 28 and 30 and first and second end caps 20 and 22 . For example, the arrester housing 32 may be molded directly over the wrapped studs of the surge blocking elements 24 , 26 , 28 and 30 and the first and second end caps 20 and 22 .

The arrester housing 32 is mounted to the mounting bracket 36 by inserting the wall 44 through a hole 62 in the mounting bracket 36 as shown in FIG. 1 . The mounting bracket 36 may have a first recess 64 and a second recess 66 disposed concentrically with each other. The first recess 64 is formed by a generally cylindrical wall 68 of the mounting bracket 36 . The generally cylindrical wall 68 may have an internal taper. When the second end cap 22 is pushed into and through the hole 62 in the mounting bracket 36, a flange 70 of the second end cap 22 enters the second recess 66 of the mounting bracket 36, and the taper of the generally conical wall 68 An end 72 of the arrester housing 32 is squeezed between the generally cylindrical wall 68 and the flange 70 of the second end cap 22 . Due to this compression, the end portion 72 acts as a gasket or seal at the second terminal 14 to isolate the inner walls of the arrester housing 32 from the external environment. When the arrester housing 32 is fully pressed into the opening 62 of the mounting bracket 36 so that the circumferential groove 60 can be contacted, a snap ring 73 is snapped into the circumferential groove 60 on the wall 44 of the second end cap 22 , so that the surge arrester 10 is clamped to the mounting bracket 36 with sufficient force, and the seal between the generally cylindrical wall 68 and the flange 70 of the second end cap 22 is maintained by the end portion 72 .

By inserting the heat release element 48 into the end 50, inserting the second joint 18 through the plastic cap 59 until the plastic cap 59 abuts against a flange 76 at the end 50 of the second joint 18, and by inserting the second joint 18 A subsection 74 is formed by inserting a conductive washer 52 into the plastic cap 59 until the washer 52 abuts against the flange 76 at the end 50 of the second connector 18 . The resistor 56 is inserted into the plastic cap 59 until it abuts the first conductive washer 52 and the second conductive washer 54 is placed on top of the resistor 56 . Then, the sub-component 74 is inserted into the recess 46 of the second end cap 22 until the second conductive gasket 54 abuts against the inner wall 58 leaving a space 78 (as shown in FIG. 1 ). The space 78 is filled with an epoxy potting material to maintain electrical contact between the sub-component 76 and the second end cap 22 .

Thus, the recess 46 in the second end cap 22 forms a breaker mount for a fault interrupter 47, eliminating the need for an additional separate housing for the fault interrupter.

Instead of using a snap ring 73 in the circumferential groove 60 of the second end cap 22 to clamp the first and second end caps 20 and 22, the surge arresting elements 24, 26, 28 and 30 and the arrester housing 32 to the mounting The bracket 36 allows the second end cap 22 to be screwed onto the mounting bracket 36 . To this end, external threads can be machined in a region 80 on the outside of the second end cap 22 as shown in FIG. 3 .

As shown in FIG. 1, the arrester housing 32 is formed over the first end cap 20 and engages a flange of the first connector 16 to provide a seal. This seal at the first terminal 12 isolates the interior of the arrester housing 32 from the external environment. Alternatively, the arrester housing 32 may be configured with an integral O-ring 92 as shown in FIG. 4 . The integral O-ring 92 fits in an annular groove 94 surrounding a first end cap 20A to provide a seal at the first terminal 12 that isolates the interior of the arrester housing 32 from the external environment. open.

Instead of forming an integral O-ring according to the integral O-ring 92 shown in FIG. 4, an integral O-ring 100 may be provided as shown in FIG. The O-ring 100 is integrally formed on the top of the arrester housing 32 and forms a bore 102 through which the first connector 16 extends so that it can be threaded into the first end cap 20 . The integral O-ring 100 fits within an annular groove 104 formed on a flange 106 of the first joint 16 . When the first connector 16 is screwed into the first end cap 20, the integral O-ring 100 is squeezed tightly into the annular groove 104 and cooperates with the flange 106 to provide A seal that seals off the interior of the arrester housing 32 from the external environment.

Certain variations on the present invention are discussed above. Those skilled in the field of practice of the present invention may also have other variable designs. For example, the first connector 16 and the first end cap 20 are shown separate. Alternatively, the first contact 16 and the first end cap 20 may be formed as a single integral conductive element.

Also, four surge blocking elements 24 , 26 , 28 and 30 shown in FIG. 1 are electrically connected between the first and second end caps 20 and 22 . However, any number of surge blocking elements may be disposed between the first and second end caps 20 and 22, depending on the voltage carried by the power distribution system and/or the particular configuration of the surge blocking elements.

In addition, as mentioned above, this surge arrester 10 is assembled according to the following procedures. First, the surge arresting elements 24, 26, 28, and 30 are stacked between the first and second end caps 20 and 22, and then the surge arresting elements 24, 26, 28, and 30 are wrapped with fiberglass fabrics. And the first and second end caps 20 and 22 form the heap to be wound up, and then the arrester housing 32 is installed on the wrapped surge arresting elements 24, 26, 28 and 30 and the first and second end caps. End caps 22 and 22 are stacked on the post. In a second step, the structure is then secured to the mounting bracket 36 . In a third step, the subassembly 74 is mounted on the second end cap 22 . If not, the surge arrester 10 can be assembled in any desired sequence. For example, all surge arresting elements 24, 26, 28 and 30 can be stacked between the first and second end caps 20 and 22 first, and then the surge arresting elements 24, 26, 28 and 30 and the stack column formed by the first and second end caps are wrapped, and then the arrester housing 32 is installed to the stacked surge arresting elements 24, 26, 28 and 30 and the first and second end caps. end caps 20 and 30. In a second step, the subsection 74 can be mounted to the second end cap 22 . In the third step, the formed structure is then fixed to the mounting bracket 36 .

Furthermore, the first and second end caps 20 and 22 may be considered as surge blocking elements as long as they facilitate the above-mentioned surge discharge function.

Additionally, the plastic cap 59 can be made from any number of electrically insulating materials that are not plastic.

Also, a conductive spring, such as a spring washer, can be inserted between the second conductive washer 54 and the inner wall 58 .

Therefore, the foregoing description of the present invention is to be considered as illustrative only, and its purpose is to teach those skilled in the art the best mode of carrying out the invention. The specific structure may be changed obviously without departing from the spirit of the invention, and the full use of all design changes within the scope of the appended claims is reserved.

Claims (12)

1. a surge arrester comprises:

One electric surge blocking element, wherein, this electric surge blocking element is set to when surge occurring and just can conducts electricity;

One first end cap, this first end cap are set to electric surge blocking element are electrically connected on one first electric wire;

One second end cap, this second end cap is electrically connected on electric surge blocking element, wherein, this second end cap has first and second ends, first end directly is electrically connected on electric surge blocking element, second end of second end cap be indent to form a breaker base, second end cap all conducts electricity; And

One stoppage circuit breaker, this stoppage circuit breaker is set to second end cap is electrically connected on one second electric wire, wherein, this stoppage circuit breaker is set to when breaking down the electric surge blocking element and second electric wire is disconnected, and this stoppage circuit breaker is placed in the breaker base that is formed by second end cap.

2. according to the surge arrester of claim 1, it is characterized in that first electric wire is a supply lines, second electric wire is a ground connection.

3. according to the surge arrester of claim 1, it is characterized in that first and second end caps are in electrical contact with electric surge blocking element.

4. according to the surge arrester of claim 1, it is characterized in that electric surge blocking element is a metal oxide variable resistor.

5. according to the surge arrester of claim 1, it is characterized in that, also comprise an installation bracket, it is set to can support electric surge blocking element, first and second end caps and stoppage circuit breaker.

6. according to the surge arrester of claim 5, it is characterized in that, also comprise a securing member, it is set to and electric surge blocking element, first and second end caps and stoppage circuit breaker can be anchored on installation bracket, and this installation bracket is clamped between second end cap and this securing member.

7. according to the surge arrester of claim 6, it is characterized in that the discharger shell is set to when installation bracket is clamped between second end cap and the securing member and is wedged between the installation bracket and second end cap, make to form a sealing.

8. according to the surge arrester of claim 6, it is characterized in that, installation bracket has first and second recesses, first recess is formed by a wall of this installation bracket, this wall is tapered, second recess is set to a flange that can place second end cap, and the discharger shell is set between the flange of the tapered wall that is wedged in this installation bracket when installation bracket is clamped between second end cap and this securing member and second end cap, so that form a sealing

9. according to the surge arrester of claim 1, it is characterized in that electric surge blocking element comprises a plurality of electric surge blocking elements.

10. according to the surge arrester of claim 1, it is characterized in that, also comprise the discharger shell of being arranged to hold the electric surge blocking element and first and second end caps.

11. the surge arrester according to claim 1 is characterized in that, the discharger shell has a projection that is O shape cast formula, and this projection is arranged to a sealing with respect to first end cap.

12. the surge arrester according to claim 1 is characterized in that, first end cap has first and second ends, and second end is electrically connected on electric surge blocking element, and the discharger shell forms a sealing on first end of first end cap.

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