GB2175156A - Overvoltage protection device - Google Patents

Overvoltage protection device Download PDF

Info

Publication number
GB2175156A
GB2175156A GB08609528A GB8609528A GB2175156A GB 2175156 A GB2175156 A GB 2175156A GB 08609528 A GB08609528 A GB 08609528A GB 8609528 A GB8609528 A GB 8609528A GB 2175156 A GB2175156 A GB 2175156A
Authority
GB
United Kingdom
Prior art keywords
protection device
voltage
overvoltage
overvoltage protection
resistors
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.)
Withdrawn
Application number
GB08609528A
Other versions
GB8609528D0 (en
Inventor
Bertalan Dombi
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.)
Zellweger Uster AG
Original Assignee
Zellweger Uster AG
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 Zellweger Uster AG filed Critical Zellweger Uster AG
Publication of GB8609528D0 publication Critical patent/GB8609528D0/en
Publication of GB2175156A publication Critical patent/GB2175156A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • H02H9/06—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage using spark-gap arresters

Landscapes

  • Emergency Protection Circuit Devices (AREA)

Abstract

A first voltage dependent resistor 6 is connected between the two leads 1,2 of the supply input of an electronic apparatus and each of the two leads 1,2 is connected to ground or earth through another voltage dependent resistor 7, 8 and a gas filled overvoltage diverter 9 is arranged between the ground or earth and the other voltage dependent resistors 7, 8. The overvoltage protection device (US) ensures a high insulation level, maintenance of the required operating voltage in the event of a trouble incidence and a suppression of the secondary current after the overvoltage has died down. <IMAGE>

Description

SPECIFICATION Overvoltage protection device for electrical installations, in particular for electronic apparatus This invention relates to an overvoltage protection device for electric installations, in particularfor electronic apparatus, in which a firstvoltage dependent resistor is connected between the two leads of the supply input and each of these two leads is connected to ground or earth through another voltage dependent resistor.
It is well known that electronic apparatus and electric low voltage installations, i.e. installations having a nominal or operating voltage of up to about 1000 V, are at risk from overvoltages. These have their origin in, for example, atmospheric or nucleardischarges direct contacts, capacitive or inductive coupling with other electric installations carrying higher voltages, or switching processes in the low voltage installations themselves.
The use of voltage dependentresistorsforovervol- tage protection devices is known. Such resistors, in particularvaristors, i.e. resistors in which the resistance has a negative voltage exponent, are distinguished by the fact that their resistance decreases with increasing voltage. They are therefore particularly suitable for protecting against overvoltages.
The above mentioned characteristic of voltage dependent resistors is also utilized in an overvoltage protection device ofthetype mentioned above disclosed in DE-OS 3,109,883 which has, however, the disadvantagethatthe required insulation level,for example, of at least 2 kV, is not assured since the voltage dependent resistors are directly connected to ground or earth.
The invention is provided to improve this known overvoltage protection device in that it ensures the suppression of high energy overvoltages as well as ensuring a high insulation level. At the same time, it is intended to ensure that in the event of a mishap, the operating voltage of the electronic apparatus will not fall below the level necessary for maintaining the functional efficiency ofthe apparatus.
This problem is solved according to the invention by thearrangementofa gasfilled overvoltage diverter between the aforesaid other voltage dependent resistors and ground or earth.
The use ofgasfilled overvoltage diverters in overvoltage protection devices is known per se. Thus, for example, DE-AS 2,355,421 and DE-OS 2,538,919 each describes an overvoltage protection device with a gas filled overvoltage diverter and a voltage dependent resistor connected in parallel thereto.
These arrangements, however, are notcapable of solving the problems set out above, since as soon as the gas filled overvoltage diverter has responded, the operating voltage breaks down to its sa-cal led arc maintenance voltage, which is about 10to 25V. This meansthatin all apparatus requiring higher operating voltages, the voltage is interrupted due to short circuiting with melting ofthe fuse, which puts the apparatus out of action.
Another major advantage of the overvoltage protection device according to the invention lies in the suppression of secondary currents. This means that when the overvoltage has died down, the gas filled overvoltage diverter does not, as in most known devices, continueto burn so longe asthevoltage applied exceeds the necessary maintenance voltage or the excess current protection responds but is extinguished duetothe action ofthetwo additional voltage dependent resistors.
The invention will now be described in more detail with reference to an exemplary embodiment illustrated in the single figure which is a schematic circuit diagram of an overvoltage protection device accord ing to the invention.
The supply input of an electronic apparatus which is to be protected against overvoltage is shown in the figure. The supply voltage amounting, for example, to 220 V, is applied to two supply leads 1 and 2 and the supply input is composed ofthree stages, as illustrated: An overvoltage protection device US, a low pass filterTP and a stage PT for potential separation, from which leads 3 and 4 branch offto the consuming device.
Stage PTfor potential separation,which,asillus- trated, has an inductively acting transformer 5, is assumed to be common knowledge and will therefor not be further described here. Although the low pass filterTP which is installed for reasons of electro- magnetic compatability assists the protective action ofthe overvoltage protection device US by reducing the high frequency resdues ofthe overvoltage peaks, its contribution to the protective action is only of secondary importance.
The overvoltage protection device US consists, as illustrated, of a total ofthree ZN R resistors 6,7 and 8 and a gas filled cell 9. The first ZNR resistor 6 is connected between the two supply leads 1 and 2. The two additional ZNR resistors 7 and 8 are connected into a second branch which connects the two supply leads 1 and 2 from which another lead 11 is branched offatthejunction 10 betweenthetwo resistors 7 and 8 to be earthed or connected to ground by way of the gas filled cell 9.
The overvoltage protection device US is effective against both types of overvoltages, i.e. both those which act in phase opposition againsttheterminal and zero conductor and those which act in phase synchronism on terminal and zero conductorwith respect to ground.
Phase opposition overvoltages are conducted away through the resistor 6 which becomes conductive, as in a bipolar Zener diode, when the overvoltage exceeds the value of its threshold voltage.
A phase synchronism overvoltage causes the gas filled cell 9 to ignite and current is therefore conducted away to earth through the resistors7 and 8. As soon as the overvoltage has died down, the gas filled cell 9 becomes extinguished because the resistors 7 and 8 are no longer conductive atthe then prevailing operating voltage ofthe supply network and the arc in the gas filled cell 9therefore breaks down due to the lack of current. Due to the gas filled cell 9 being connected in series with the resistors 7 and 8, no secondary current can occur in spite ofthe slight maintenancevoltageofthegasfilledcell9.
The following are typical values for the ZNR resistors 6,7 and 8 and the gas filled cell 9: resistors 6, 7, 8: Threshold voltage 470 V/1 ma -Gasfilled cell 9: Ignitionvoltage 1500V Maintenance voltage 15V.
The overvoltage protection device US described above may be used both for apparatus with protective earthing - insulation 2 kV8ff- and forthose with protective insulation -4 kVeff. To testthe insulation, all that is necessary is to remove the gasfilled cell 9.

Claims (4)

1. Overvoltage protection device for electric installations, in particularfor electronic appar- atus, in which a first voltage-dependent resistor is connected betweenthetwo leads of the supply in put and these two leads are connected to ground or earth through anothervoltage-dependent resistor, wherein a gas filled overvoltage diverter is arranged between said othervoltagedependent resistors and ground or earth.
2. Overvoltage protection device according to claim 1,wherein the voltage dependent resistors are formed by ZNR resistors.
3. Overvoltage protection device according to claim 2,wherein the ZNR resistors have a threshold voltage of about470 W1 ma and in that the gas filled overvoltage diverterhas an ignition voltage of about 1500 V and a maintenance voltage of about isv.
4. Overvoltage protection device substantially as herein described and as illustrated in the accompanying drawing.
GB08609528A 1985-05-03 1986-04-18 Overvoltage protection device Withdrawn GB2175156A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1881/85A CH668516A5 (en) 1985-05-03 1985-05-03 OVERVOLTAGE PROTECTION DEVICE FOR ELECTRICAL SYSTEMS, ESPECIALLY FOR ELECTRONIC APPARATUS.

Publications (2)

Publication Number Publication Date
GB8609528D0 GB8609528D0 (en) 1986-05-21
GB2175156A true GB2175156A (en) 1986-11-19

Family

ID=4220765

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08609528A Withdrawn GB2175156A (en) 1985-05-03 1986-04-18 Overvoltage protection device

Country Status (5)

Country Link
AU (1) AU5651286A (en)
CH (1) CH668516A5 (en)
DE (1) DE3611793A1 (en)
GB (1) GB2175156A (en)
IT (1) IT1191881B (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2609580A1 (en) * 1987-01-08 1988-07-15 Finzel Jean Luc Lightning-arrester module for protection against industrial overvoltages
WO1990003058A1 (en) * 1988-09-07 1990-03-22 W J Furse & Co Ltd Apparatus suitable for use in protecting electrical installations from transients
GB2305030A (en) * 1995-08-31 1997-03-26 Long Trevor William Filter circuit for connection across the input of a power supply
WO2005071813A1 (en) * 2004-01-09 2005-08-04 Emerson Electric Co. Low cost surge protection

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3606287A1 (en) * 1986-02-27 1987-09-03 Dehn & Soehne Overvoltage protection arrangement
DE3834514C2 (en) * 1988-10-11 1996-02-01 Asea Brown Boveri Circuit arrangement for protecting electrical devices and systems against overvoltages
NZ237923A (en) * 1990-04-26 1993-11-25 Australian Telecomm Telecommunication line protector with varistor and gas discharge tube
DE4020646C2 (en) * 1990-06-29 1996-04-18 Oels Wolf Dieter Dr Ing Protection circuit for the protection of electrical consumers
FR2716044B1 (en) * 1994-02-09 1996-05-10 Soule Sa Device for protecting electronic and / or electrotechnical equipment on T-T type networks.

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB638903A (en) * 1945-02-12 1950-06-21 British Thomson Houston Co Ltd Improvements in and relating to excess voltage protective systems for electric windings
GB2050719A (en) * 1979-05-25 1981-01-07 Bowthorpe E M P Ltd Surge arrester
GB1594313A (en) * 1977-01-28 1981-07-30 Communic & Equip Consult Equipment for power line surge eliminator
EP0092052A1 (en) * 1982-04-20 1983-10-26 ANT Nachrichtentechnik GmbH Device for the protection of appliances connected to lines against overvoltages or disturbances
US4571656A (en) * 1984-01-13 1986-02-18 Dynatech Computer Power, Inc. Electrical circuit for protection against surge overvoltage of transients

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB638903A (en) * 1945-02-12 1950-06-21 British Thomson Houston Co Ltd Improvements in and relating to excess voltage protective systems for electric windings
GB1594313A (en) * 1977-01-28 1981-07-30 Communic & Equip Consult Equipment for power line surge eliminator
GB2050719A (en) * 1979-05-25 1981-01-07 Bowthorpe E M P Ltd Surge arrester
EP0092052A1 (en) * 1982-04-20 1983-10-26 ANT Nachrichtentechnik GmbH Device for the protection of appliances connected to lines against overvoltages or disturbances
US4553189A (en) * 1982-04-20 1985-11-12 Ant Nachrichtentechnik Gmbh Surge protection device
US4571656A (en) * 1984-01-13 1986-02-18 Dynatech Computer Power, Inc. Electrical circuit for protection against surge overvoltage of transients

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2609580A1 (en) * 1987-01-08 1988-07-15 Finzel Jean Luc Lightning-arrester module for protection against industrial overvoltages
WO1990003058A1 (en) * 1988-09-07 1990-03-22 W J Furse & Co Ltd Apparatus suitable for use in protecting electrical installations from transients
GB2223894A (en) * 1988-09-07 1990-04-18 Furse W J & Co Ltd Protecting electrical installations from transients
US5157572A (en) * 1988-09-07 1992-10-20 W. J. Furse & Co. Ltd. Apparatus suitable for use in protecting electrical installations from transients
GB2223894B (en) * 1988-09-07 1992-11-18 Furse W J & Co Ltd Apparatus suitable for use in protecting electrical installations from transients
GB2305030A (en) * 1995-08-31 1997-03-26 Long Trevor William Filter circuit for connection across the input of a power supply
WO2005071813A1 (en) * 2004-01-09 2005-08-04 Emerson Electric Co. Low cost surge protection
US7312970B2 (en) 2004-01-09 2007-12-25 Emerson Electric Co. Low cost surge protection

Also Published As

Publication number Publication date
IT1191881B (en) 1988-03-23
CH668516A5 (en) 1988-12-30
GB8609528D0 (en) 1986-05-21
DE3611793A1 (en) 1986-11-06
IT8647972A0 (en) 1986-04-30
AU5651286A (en) 1986-11-06

Similar Documents

Publication Publication Date Title
US4023071A (en) Transient and surge protection apparatus
CA1332074C (en) Surge protection device
US5854730A (en) Transient and voltage surge protection system and method for preventing damage to electrical equipment
US4119866A (en) High voltage electrical network with DC ice-melting device and current return through ground
EP0186939A2 (en) Circuit arrangements
EP3550581B1 (en) Methods and apparatus for dc arc detection/suppression
MX2007001043A (en) Overvoltage protection device with improved leakage-current- interrupting capacity.
US3737725A (en) Circuit overvoltage protector
US6778375B1 (en) Hybrid MOV/gas-tube AC surge protector for building entrance
US10944252B2 (en) Surge protection device
GB2175156A (en) Overvoltage protection device
EP2226914B1 (en) Systems and methods for protecting a series capacitor bank
Morton Circuit breaker and protection requirements for DC switchgear used in rapid transit systems
CN104410059B (en) Discharge gap arc extinguishing method of intrinsically safe inductive circuit
US4232351A (en) High-voltage crowbar circuit with cascade-triggered series ignitrons
US3889158A (en) Series capacitor protection equipment with dual sparkover feature
EP0677910B1 (en) Overvoltage protection
US20210079894A1 (en) Smart wind turbine blade with active components comprising a lightning protection system
US3629685A (en) Static converter station connected to a dc transmission line over a dc reactor with lightning arrester protection means
JPS6132375A (en) Device for protecting electric furnace
RU2085414C1 (en) Device to protect ac traction circuit in case of insulation faults in poles non-grounded to rails
SU892572A1 (en) Device for earthing transformer neutral wire
KR102582296B1 (en) Surge protection apparatus for LED
US20220085579A1 (en) Spark gap arrangement with ignition apparatus for protecting a high-voltage device and ignition apparatus therefor
KR100273599B1 (en) Thunderbolt identification control apparatus and method

Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)