US2261712A - Circuit breaker - Google Patents

Circuit breaker Download PDF

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Publication number
US2261712A
US2261712A US365821A US36582140A US2261712A US 2261712 A US2261712 A US 2261712A US 365821 A US365821 A US 365821A US 36582140 A US36582140 A US 36582140A US 2261712 A US2261712 A US 2261712A
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US
United States
Prior art keywords
breaker
insulator
rod
grading
potential
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US365821A
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English (en)
Inventor
Behringer Joseph
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CBS Corp
Original Assignee
Westinghouse Electric and Manufacturing Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Westinghouse Electric and Manufacturing Co filed Critical Westinghouse Electric and Manufacturing Co
Application granted granted Critical
Publication of US2261712A publication Critical patent/US2261712A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
    • H01H33/02—Details
    • H01H33/24—Means for preventing discharge to non-current-carrying parts, e.g. using corona ring

Definitions

  • the present invention relates to high-voltage circuit breakers, and, more specifically, to a circuit breaker whose movable contact-making member is provided in the form of a rod that is actuated with the aid of another rod that is made of insulating material.
  • a circuit breaker of this particular type is especially well adapted to be structurally combined with a hollow column-type insulator for supporting its parts, the most advantageous arrangement being obtained in this case when said rod of insulating material is located inside the hollow insulator.
  • the arrangement has to be such that if a high overvoltage--for instance, in the form of a surge-wave-should reach the breaker, there will occur a flashov'er along the outer surface of the insulator before the dielectric stress in the interior of the latter can increase to a magnitude high enough to result in a ⁇ dielectric breakdown along the surface oi' said rod of insulating material, the lower end of this rod of insulating material being preferably linked to an operating mechanism. whose metal parts are connected to ground.
  • the internal ilashover distance (along the surface of said rod of insulating material) becomes shorter.
  • the dielectric strength inside the hollow insulator can be further increased by mounting inside this insulator, at the lower end of the switching rod when this rod is in the off position, a grading cap for making the distribution of the electric field at this point more uniform.
  • the grounded flange belonging to the supporting structure of the breaker mechanism can be so shaped that it will have on the dielectric stresses an equalizing effect similar to that of a grading cap. But all these measures are not sufficiently effective Ito 'enable the designer to drastically reduce the overall height of the breaker structure.
  • the present invention discloses how the overall height of a breaker structure of the kind just referred to can be reduced to a quite considerable extent without resorting to complicated measures.
  • a grading cap to which voltage is applied only (Cl. 20G-48) when the breaker is in the off position; when the breaker is in the closed position, this grading cap acquires a floating potential somewhere between the line-potential and the ground-potential.
  • This grading cap must be so supported that it will be insulated from all other breaker parts; it can be suspended, for instance, from the breaker structure with the aid of a tube of insulating material.
  • the arrangement can then be such that when the breaker is in the open position, a spring will establish contact between the switching rod and the grading cap, so that no arcing will occur between these two members when the switching rod approaches its 01T position.
  • the switching rod when the switching rod is in the on position, its lower end must be located at such a distance from the grading cap that the flow of capacitive current from the switching rod to the grading cap cannot give rise to a discharge inthe form of an arc-over.
  • the grading cap will then acquire a floating potential somewhere between the line-potential and the ground-potential.
  • the proposed arrangement offers the advantage that when the breaker is in the closed position, the entire axial distance inside the hollow post-type insulator is available for establishing the required dielectric strength (the entire axial distance in question being the distance from the upper iiange of the support insulator down to the point inside this insulator where the grounded parts of the operating mechanism are linked to the insulating rod to which the switching rod is connected).
  • the entire axial distance in question being the distance from the upper iiange of the support insulator down to the point inside this insulator where the grounded parts of the operating mechanism are linked to the insulating rod to which the switching rod is connected.
  • the present invention makes it possibleV to make one further step in improving the breaker-design, insofar as this invention discloses that the breaker structure can be so arranged that the members (such as levers) of the operating mechanism will only extend into the interior of the hollow insulator when the breaker is in the closed position, whereas, when the breaker is in the open position, said members will be located outside the hollow insulator.
  • the high-voltage current is supplied to the breaker shown through a terminal I secured to a metal fiange 2 located in the intervening space between two hollow insulators 3 and 4 that are placed one above the other.
  • insulator 3 In insulator 3 is mounted an interrupter assembly comprising, for instance, a switch chamber 5, while the other insulator 4 accommodates the actuating parts.
  • the switching chamber 5 for example may be of the resilient expansion type and encloses a stationary contact assembly 6 at its upper end.
  • a coacting switching or contact rod 1 is operable through the chamber 5 and is slidably connected to the flange 2 by spring pressed contacts 8 disposed in a suitable casing mounted upon the flange, as shown.
  • the current then flows through a contact rod 1 through the stationary contact assembly 6, and finally leaves the breaker at the terminal 9. Consequently, when the breaker is in the closed position, the terminals I and 9 carry both the high supply-line voltageamounting, for instance, to 100 kv.-and the full potential-difference existing between the terinal I and ground.
  • a curved metal grading cap I 0 Inside the lower insulator 4 is mounted a curved metal grading cap I 0 with rounded-off edges which is preferably composed of sections of a sphere, and is provided for the purpose of making the distribution of the electric field more uniform. It is a feature covered by the present invention that the line-voltage is applied to this grading cap only when the breaker is in the open position; when the breaker is in the closed position, the grading cap acquires a floating potential somewhere between the line-potential and the ground-potential.
  • the grading cap I0 In order to enable the grading cap I0 to acquire said potentials, it is supported by means of a tube II made of an insulating material that may have a fibrous or a laminated structure. pended from the flange 2 located between the two insulators. Since the dielectric stresses to be taken up by said tube of insulating material are essentially perpendicular to the direction of its laminations, the use of such a tube is
  • the grading cap I0 can be mounted within the tube II of insulating material and can then be fastened to this tube by screws or bolts I2, so that it will be readily removable.
  • the screws or bolts can also be used for fastening the springs I3 which, for instance, may be disposed inside the grading cap I0.
  • the arrangement is such that the springs I3 will not interfere with the motion of an operating rod I4 of insulating material that establishes the connection between the contact rod 1 and the breaker operating mechanism.
  • the rod I4 of insulating material is operable inside the tube II of insulating material to actuate the contact rod 1 to open and closed positions and has considerable clearance from the inner wall of the insulating tube II.
  • the springs I3 come into contact with and are spread apart by a metal sleeve (or some other similar part) I5, fastened to the lower end of the contact rod 1, and has a diameter larger than the diameters of the rod 1 and the rod I4 of insulating material.
  • a metal sleeve or some other similar part
  • the grading cap I0 is charged by a capacitive current and acquires a oating potential somewhere between the line potential and the ground potential but when the breaker is in the open position, the grading cap I0 becomes electrically connected with the breaker terminal I, so that its potential is raised to that of the line without any occurrence of sparking between the contact rod 1 and the grading cap I0.
  • the springs I3 can be provided in the form of curved blade-springs, spiral or helical springs, or may consist of a plurality of individually bent strips of metal and can be arranged like sliding contacts, surrounding the rod I4 of insulating material in a manner such as to leave sufficient clearance for the switching motions of said rod.
  • the hollow insulator 4 in which the grading cap I0 is located is preferably filled with an insulating liquid but may be filled with a solidified, or with a granulated or pulverized insulating material in order to increase the dielectric strength still further.
  • the contact rod 1 can be actuated by means of a rocker arm 2
  • the shaft IB is operatively mounted in a grounded metal casing I1 which also serves to support the hollow insulator 4.
  • the rod I4 can be guided with the aid of a cross-head I8 that is
  • the tube II can be susrigidly attached to it, which may be provided on both sides with slots that can loosely engage and slide along two guide-rails I9 made of an insulating material and having a rectangular or a dovetail-shaped cross-section.
  • This arrangement for the operating members is such that no metal parts of the drive will be positioned inside the hollow insulator 4 when the breaker is in the open position, and only when the breaker is in the closed position will grounded metal parts of the actuating mechanism be located inside the insulator 4. Moreover, when the breaker is in the open position, the grounded metal parts of the actuating mechanism will be electrically protected by a grounded metal flange supported by the casing II and having a configuration to provide an electrostatic grading cap or shield.
  • the present invention is applicable to any high-voltage switching device, and more particularly to high-voltage circuit breakers. of applying the invention to an expansion-type breaker as above described, it is equally feasible to apply it to a gas-blast breaker that receives the required quantities of compressed gas from an outside source, or to a self-generated gas blast breaker in which the extinguishing gases are liberated from a solid insulating material, preferably provided in the form of tubular members. Furthermore, the invention can be applied to any other type of breaker, single-pole or multi-pole, v
  • circuit interrupting means including separable contacts disposed within said casing adjacent the other end thereof, an electrostatic stress grading member disposed within said casing between said contacts and ground, and means electrically connecting one of said contacts with said stress grading member when said contacts are in the open circuit position, said stress grading member being' so arranged that when said contacts are in the closed circuit position said member is disconnected from said contact and acquires a floating potential between line potential and the ground potential.
  • a high voltage circuit breaker having a hollow supporting insulator one end of which is maintained at ground potential, separable contact means in said insulator including a contact rod, an operating rod of insulating material disposed within said insulator for actuating said contact rod to open and closed positions, a potential grading member disposed within said hollow insulator between said contact rod and ground, and means for electrically connecting said contact rod to said grading member when said contact rod is in its open circuit position, said grading member being disconnected from said contact rod when said rod is in the closed circuit position and caused to acquire a potential intermediate the potential of said contact member and ground.
  • a high voltage circuit breaker having a hollow supporting insulator one end of which is maintained at ground potential, separable contact means in said insulator including a contact rod, an operating rod of insulating material disposed within said insulator for actuating said contact rod to open and closed positions, a potential grading member disposed within said hollow insulator between said contact rod and ground, metallic operating mechanism disposed adjacent the grounded end of said hollow insulator and connected to the lower end of said operating rod, said mechanism having only portions thereof extending into said hollow insulator when the breaker is in the closed position and being wholly outside said hollow insulator when the breaker is in the open circuit position, and a metallic grading shield disposed between said operating mechanism and said potential grading member for equalizing the dielectric stresses between said member and the operating mechanism.
  • circuit interrupting means carried by said metallic closure, said circuit interrupting means including a contact movable through said closure to open and closed positions, operating mechanism disposed in said base, an insulating operating rod extending from said mechanism through said hollow insulator and operatively coupled to said movable contact to actuate the latter, a tubular insulator suspended from said metallic closure and disposed in surrounding spaced relation with respect to said operating rod, a generally spherical potential grading member carried by said tubular insulator, and means operative upon moving said contact to open circuit position for connecting said contact to said potential grading member, said potential grading member causing a more uniform distribution of electrical stresses between said contact and said grounded metallic base.
  • circuit interrupting means carried by said metallic closure, said circuit interrupting means including a contact movable through said closure to open and closed positions, operating mechanism disposed in said base, an insulating operating rod extending from said mechanism through said hollow insulator and operatively coupled to said movable contact to actuate the latter, a tubular insulator suspended from said metallic closure and disposed in surrounding spaced relation with respect to said operating rod, a generally spherical potential grading member carried by said tubular insulator, and means operative upon moving said contact to open circuit position for connecting said contact to said potential grading member, and a grounded potential grading member disposed within said hollow insulator between said operating mechanism and said rst potential grading member for more uniformly distributing the dielectric stresses between said contact and said grounded base.

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  • Insulators (AREA)
  • Arc-Extinguishing Devices That Are Switches (AREA)
US365821A 1939-11-26 1940-11-15 Circuit breaker Expired - Lifetime US2261712A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES34964D DE921518C (de) 1939-11-26 1939-11-26 Hochspannungsschalter

Publications (1)

Publication Number Publication Date
US2261712A true US2261712A (en) 1941-11-04

Family

ID=5831171

Family Applications (1)

Application Number Title Priority Date Filing Date
US365821A Expired - Lifetime US2261712A (en) 1939-11-26 1940-11-15 Circuit breaker

Country Status (4)

Country Link
US (1) US2261712A (de)
CH (1) CH218202A (de)
DE (1) DE921518C (de)
FR (1) FR869509A (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH654138A5 (de) * 1981-06-30 1986-01-31 Sprecher & Schuh Ag Hochspannungs-leistungsschalter.
DE102015216153A1 (de) 2015-08-25 2017-03-02 Bayerische Motoren Werke Aktiengesellschaft Verbesserter Hochspannungsschalter

Also Published As

Publication number Publication date
CH218202A (de) 1941-11-30
DE921518C (de) 1954-12-20
FR869509A (fr) 1942-02-04

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