US3637965A - Electrical switch utilizing compressed gas for arc extinction - Google Patents

Electrical switch utilizing compressed gas for arc extinction Download PDF

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Publication number
US3637965A
US3637965A US21021A US3637965DA US3637965A US 3637965 A US3637965 A US 3637965A US 21021 A US21021 A US 21021A US 3637965D A US3637965D A US 3637965DA US 3637965 A US3637965 A US 3637965A
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United States
Prior art keywords
pressure
low
pressure section
section
gas
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Expired - Lifetime
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US21021A
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English (en)
Inventor
Wolfgang Schmitz
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BBC Brown Boveri AG Germany
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Bbc Brown Boveri & Cie
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    • 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
    • H01H33/53—Cases; Reservoirs, tanks, piping or valves, for arc-extinguishing fluid; Accessories therefor, e.g. safety arrangements, pressure relief devices
    • H01H33/56—Gas reservoirs

Definitions

  • An electrical switch structure utilizing a compressed gas such as SP for arc extinction comprises a high-pressure section, a [Zl] Appl. No.: 21,021 low-pressure section and a switching point controlled by a blast valve located intermediate the highand low-pressure 3 Foreign Appficafion Priority Data sections.
  • the gas flows in a closed circuit from the high-pressure section through the switch contacts to the low-pressure P 1969 m ny l 1 7 section, thence to a compressor which'recompresses the gas and thence back to the high-pressure section.
  • a compressor which'recompresses the gas and thence back to the high-pressure section.
  • r ti is a buffer vessel which operates at a pressure Field of Search 143 4 143 B higher than that .of the high-pressure section, and the necessary pressure reduction is attained by means of an interposed References Cited reducing valve. Another reducing valve is located in a line extending from the buffer vessel to the low-pressure section.
  • UNITED STATES PATENTS Operation of the compressor is controlled solely as a function 3,009,042 1 1/1961 Schrameck et al ..200 14s B of the Pressure level in the low-Pressure Section I 5 Claims, 2 Drawing Figures BUFFER VESSEL REL PATENTED m5 1912 SHEET 2 BF 2 INVENTOk.
  • the present invention relates to a compressed gas switch or a compressed gas-insulated switching plant with a highand a low-pressure section and closed gas cycle, where the high pressure section is connected with the low-pressure section over at least one switching point provided with a blast valve and/or over a safety valve which responds at a maximum permissible pressure in the high pressure section, and where the gas return from the low-pressure section to the high pressure section occurs by means of one or more compressors.
  • German patent 1,226,684 it has been proposed in German patent 1,226,684 to avoid the known temperature-compensated control switches by using several temperature-independent pressure monitors, one of which is rendered operative through a thermostat, depending on the temperature. This, however, results in a multiplication of the number of pressure monitors, so that cost and trouble proneness cannot be reduced to the desired extent.
  • German patent 1,261,220 relates to the control of a compressed gas switch with a closed gas circuit and provides that the pressure-dependent locking members required for the switch can be actuated by a temperature-independent pressure monitor for each in the highand low-pressure sections of the gas circuit, the two pressure monitors being so adjusted in their working ranges that one picks up the critical values at high temperatures, the other at low temperatures.
  • This arrangement is made to fit the special case referred to. Besides, just as in the previously mentioned proposal, it results in unsteadiness in the operating characteristics, which may be undesirable.
  • the problem underlying the invention is that of making available in electric switch plants and compressed gas switches of the above-named kind, with simplest means, the high pressure required for extinguishing the arc and for driving the switch or respectively the required pressure difference as well as the low pressure needed for insulating, rated according to the required minimum gas density, and so controlling them solely as a function of the pressure levels that the pressures do not drop below the required minimum and the permissible maximum values are not exceeded.
  • FIG. 1 shows in schematic arrangement the gas circulation of the switch or switch plant according to the invention
  • FIG. 2 a diagram in which are represented the pressuretemperature state variations of sulfur hexafluoride (SP at constant volume, with the preferred operating characteristics of the switch or switch plant according to the invention.
  • the compressed gas switch or respectively the switch plant S has a high-pressure section HI) and a low-pressure section ND. Between them is arranged a switching point with respective blast valve V,, which during switching operations permits the gas of the high-pressure section to flow via the switching point to the low-pressure section.
  • the low-pressure section as well as the high-pressure, section are connected via their own reducing valves V,, V, to a buffer vessel P of a pressure higher than the-high-pressure section.
  • the high-pressure section is then further connected via a safety valve V with the low-pressure section. Thereby the maximum occurring pressure is limited and the dimensions of the high-pressure section can be reduced accordingly.
  • the low-pressure section is connected to a compressor K, which via another filter Fi feeds into the buffer vessel P, whereby the gas circuit is closed.
  • a safety valve V connected to the low-pressure section
  • a safety valve V connected to the buffer vessel P
  • a spare gas vessel F connected to the bufier vessel via another reducing -valve V
  • the low and high pressure sections are each provided with a common pressure monitor W, and W respectively.
  • the invention proceeds fromthe necessity of providing in the low-pressure section a certain minimum gas density p,,,,,, (cf. FIG. 2) to maintain the insulation.
  • a certain minimum pressure P,,,,,, is correlated to this minimum gas density. It follows from this that in the low-pressure section a lower operating pressure P, must always exist, which is above the minimum pressure P,,,,,,,. This lower operating pressure P is always available from the buffer vessel P via the reducing valve V,.
  • a sufficient pressure difference determined by a minimum pressure level P, in the high-pressure section.
  • This minimum pressure level P depends, of course, on the greatest possible upper operating pressure P, in the low-pressure section, that is, it must be high enough in relation to P and is held in continuous readiness by the reducing valve V, through which the high-pressure section is connected to the buffer vessel.
  • the buffer vessel is adjusted to a pressure level P which must be sufficiently above a highest permissible pressure value P, of the high-pressure section,
  • the safety valve V connected to the low-pressure section is adjusted to a pressure P. above the upper operating pressure P and sees to it that in case of disturbance e.g., failure of the compressor) the pressure in the low-pressure section cannot rise too high.
  • the magnet value V closes the line leading from the low-pressure section to the compressor when in case of disturbance (compressor running through) the minimum pressure P is reached, thus seeing to it that the compressor cannot draw too much gas from the low-pressure section.
  • the safety valve V connected to the buffer vessel P responds at a maximum pressure limit P permissible for the buffer vessel and, if necessary, lets the compressed gas escape into the open.
  • an additional gas supply F connected via a reducing valve V to the buffer vessel P and which is adjusted to the nominal pressure P, of the buffer vessel, sees to it that any gas losses in the switch or respectively in the switch plant can be compensated.
  • the advantages achieved with the invention thus consist chiefly in that, by simple means, the pressure levels required for extinguishing the are at the switching point and for driving the switch, or respectively the necessary pressure differences, as well as the low pressure needed for insulating, are made available, the pressure levels especially in the low-pressure section being arranged so that the minimum gas density required for sufficient insulation is provided, and this without having to resort to temperature compensation devices or gas density measurements for the control of the gas circulation. It is quite sufficient in the invention to control the compressor by way of a simple control scheme by means of the pressure monitor W simply as a function of the two pressure levels P and P of the low-pressure section.
  • the alternation between inflow and outflow of gas caused by the change in temperature has the further advantage that the gas can be guided over filters independently of switching operations and can thus be purified and dehumidified. Thereby a positive flushing of the insulators arranged in the low-pressure section is achieved, which is of great advantage for the life of the installation.
  • the automatic gas circulation, independent of switching operations can be extended by placing the pressure level (normal pressure P responsible for the shutting off of the compressor below the response pressure (lower operating pressure P )of the reducing valve V Then, of course, a time relay, for example, is needed to turn off the compressor, By this measure, however, an extended positive flushing of the insulation parts in the low-pressure section under voltage stress is obtained.
  • an electrical switch structure utilizing compressed gas for are extinction comprising a high-pressure section, a low-pressure section, a switching point controlled by a blast valve intermediate said highand low-pressure sections whereby upon operation of said blast valve the gas passes from said high-pressure section through said switching point to said low-pressure section, a closed gas circuit extending from said low-pressure section to said high-pressure section for gas flow between said sections, said gas circuit including in series a compressor and a buffer vessel having a pressure higher than that which exists in said high-pressure section and which is obtained by means of a first reducing valve located in said circuit between said buffer vessel and said high-pressure section, the inlet to said compressor being connected to said low-pressure section, the outlet from said compressor being connected to said buffer vessel and said compressor being controlled solely by the level of the pressure m said low-pressure section, an auxiliary gas flow line extending directly from said buffer vessel to said low-pressure section, and a second reducing valve located in said auxiliary gas flow line for maintaining a minimum pressure in said low pressure section

Landscapes

  • Gas-Insulated Switchgears (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
US21021A 1969-04-01 1970-03-19 Electrical switch utilizing compressed gas for arc extinction Expired - Lifetime US3637965A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19691916560 DE1916560A1 (de) 1969-04-01 1969-04-01 Druckgasschalter oder druckgasisolierte Schaltanlage

Publications (1)

Publication Number Publication Date
US3637965A true US3637965A (en) 1972-01-25

Family

ID=5729956

Family Applications (1)

Application Number Title Priority Date Filing Date
US21021A Expired - Lifetime US3637965A (en) 1969-04-01 1970-03-19 Electrical switch utilizing compressed gas for arc extinction

Country Status (8)

Country Link
US (1) US3637965A (de)
JP (1) JPS5125585B1 (de)
CH (1) CH499218A (de)
DE (1) DE1916560A1 (de)
FR (1) FR2042223A5 (de)
GB (1) GB1300845A (de)
NL (1) NL7004510A (de)
SE (1) SE353180B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3849618A (en) * 1972-05-16 1974-11-19 Bbc Brown Boveri & Cie Gas supply plant for compressed gas-insulated switchgear

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3009042A (en) * 1958-04-18 1961-11-14 Westinghouse Electric Corp Circuit interrupters
CA696066A (en) * 1960-06-17 1964-10-13 The English Electric Company Limited Gas blast circuit-breakers

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3009042A (en) * 1958-04-18 1961-11-14 Westinghouse Electric Corp Circuit interrupters
CA696066A (en) * 1960-06-17 1964-10-13 The English Electric Company Limited Gas blast circuit-breakers

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3849618A (en) * 1972-05-16 1974-11-19 Bbc Brown Boveri & Cie Gas supply plant for compressed gas-insulated switchgear

Also Published As

Publication number Publication date
SE353180B (de) 1973-01-22
CH499218A (de) 1970-11-15
GB1300845A (en) 1972-12-20
NL7004510A (de) 1970-10-05
DE1916560A1 (de) 1970-10-15
FR2042223A5 (de) 1971-02-05
JPS5125585B1 (de) 1976-07-31

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