WO2000048287A1 - Ferroresonance-suppressing static transfer switch - Google Patents
Ferroresonance-suppressing static transfer switch Download PDFInfo
- Publication number
- WO2000048287A1 WO2000048287A1 PCT/CA2000/000130 CA0000130W WO0048287A1 WO 2000048287 A1 WO2000048287 A1 WO 2000048287A1 CA 0000130 W CA0000130 W CA 0000130W WO 0048287 A1 WO0048287 A1 WO 0048287A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- switch
- load
- power source
- voltage divider
- static transfer
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
- H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
- H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
- H02J9/062—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for AC powered loads
Definitions
- the present invention relates to a static transfer switch for switching a load between multiple power sources in response to a drop in quality of the power delivered from one of the power sources.
- the present invention relates to a ferroresonance- suppressing solid-state static transfer switch for switching a load from one medium- voltage primary power source to another medium- voltage secondary power source in
- a voltage spike, sag, brownout or other reduction in power quality (hereinafter referred to as a supply event) on the power lines feeding such high power consumers can
- the secondary source of power is derived from a secondary or backup power utility or onsite power generation system.
- the power distribution lines from the primary and the second power sources are coupled to the power consumer through a transfer switch which, until recently, consisted of a number of mechanical switches which switched the consumer from the primary power source to the secondary power source in response to a supply event in the power supplied by the primary power source.
- mechanical transfer switches can take up to 10 power cycles to effect the changeover between the primary and the secondary utility. Since industrial users of microprocessor-controlled
- STS state static transfer switches
- the switch consists of a pair of solid-state switches.
- the first solid-state switches connects and disconnects the power consumer to and from the primary power source, while the
- second solid-state switch connects and disconnects the power consumer to and from the
- GTO gated turn-off
- the power supplied by the primary power source is adequate for the power consumer
- control logic forces the first solid-state switch to conduct, thereby connecting the power consumer to the primary power source.
- the control logic prevents the first solid-state switch from conducting, thereby disconnecting the power consumer from the primary power source.
- the control logic forces the second solid-state switch to conduct, thereby connecting the power consumer to the secondary power source.
- SCR switches can conduct current, without the appropriate gating signals, if the rate of change of voltage drop across the SCR switch exceeds a threshold value. This characteristic can be problematic when, for example, a supply event occurs from the secondary power source while the power consumer is
- the first solid state switch generally includes a RC snubber circuit connected across the first switch for limiting the maximum rate of
- RC snubber circuit connected across the second switch for limiting the
- the solid-state SCR switches can be subjected to a large inrush of current when power is first
- the conventional STS generally includes a remotely-controlled motorized mechanical by-pass switch, connected across the solid-state SCR switches, to avoid exceeding the maximum tolerable rate of change of current through the solid-state SCR switches at initial application of power to the power consumer.
- the mechanical by-pass switch is kept closed until the current through the load has stabilized. Thereafter, the mechanical by-pass switch is opened to allow the solid-state SCR switches to control the transfer of power, as described above.
- motorized mechanical by-pass switches reduce the likelihood of damage to the solid-state SCR switch
- motorized mechanical by-pass switches increase the cost and size of the conventional STS. Therefore, for some time it has been desirable to eliminate motorized mechanical by-pass switches from the conventional STS without increasing the failure rate of the STS.
- SCR technology has evolved to the extent that SCRs are now able
- circuits comprising a capacitive element and an iron-cored inductive element, whereby line voltage harmonics present in the power source cause the resonant circuit to have sustained high voltage oscillations.
- Ferroresonance results from line voltage harmonics present in the power source causing the undamped circuit to oscillate at high voltage which, in turn, causes the magnetic flux generated in the iron core of the inductive element to saturate the iron core. As the iron core becomes saturated, the inductance of
- the inductive element varies which, in conjunction with the capacitive element, causes the resonant frequency of the circuit to vary. If harmonics are present in the power source at any of the new resonant frequencies, the undamped circuit will continue to oscillate at high voltage.
- the inventors have discovered that when the conventional STS circuit is coupled to an iron-cored load transformer and the load transformer is energized or de-energized at no
- the RC snubber leakage currents can increase the magnetic field of the load
- the solid-state static transfer switch comprises switch means for coupling a first and a second power source to a load, and an attenuator coupled to the switch means for suppressing series ferroresonance at the load by attenuating the power applied to the load when the switch means is open.
- ferroresonance occurring at the load transformer, at power-up and power-down of the load transformer, are substantially reduced.
- Fig. 1 is a schematic circuit diagram of a prior art solid-state static transfer switch
- Fig. 2 is a waveform diagram of AC source voltage and load voltage as a static transfer switch switches a load between two AC sources;
- Fig. 3 is a schematic diagram of a single-phase solid-state static transfer switch according
- Fig. 4 is a schematic diagram of a three-phase solid-state static transfer switch system according to a second embodiment of the invention.
- a conventional static transfer switch 10 is shown coupling a primary power source 12 and a secondary power source 14 to a
- the static transfer switch 10 comprises a first solid-state switch 18 for connecting and disconnecting the primary AC power source 12
- the first solid-state switch 18 comprises first and second silicon-controlled rectifier (SCR) switches 22, 24 connected together back-to-back such that the anode of the first SCR switch 22 is connected to the cathode of the second SCR switch 24, and the anode of
- the second SCR switch 24 is connected to the cathode of the first SCR switch 22.
- the second solid-state switch 20 comprises third and fourth SCR switches 26,
- the SCR switches 22, 24, 26, 28 are connected to control logic (not shown) for switching the load transformer 16 between the first and second AC power source 12, 14.
- the first solid state switch 18 includes a RC snubber circuit 30 connected across the first and second SCR switches 22, 24.
- the second solid state switch 20 includes a RC snubber circuit 32 connected
- the first solid-state switch 18 includes a mechanical by-pass switch 34 connected across the first and second SCR switches 22, 24, and the second solid-state switch 20 includes a mechanical by-pass
- the waveform diagram shown in Fig. 2 shows the voltage signals present in the conventional STS 10 shown in Fig. 1.
- the voltage signals V 12 , V 14 of the primary and secondary power source 12, 14 are shown in Fig. 2 as being substantially
- control logic During the interval T, control logic
- Vg 22 , Vg 24 which force the first and second SCR switches 22, 24 to conduct.
- the control logic drives the gate terminals of the third and fourth SCR
- the load transformer 16 is coupled to the primary power source 12 and is isolated from the secondary power source 14.
- a power brownout is shown occurring on the primary power source 12, causing the voltage N 16 at the load transformer 16 primary to drop.
- Sensors monitoring the quality of power delivered by the primary and secondary power source 12, 14 sense the drop in power quality.
- the control logic responds to the drop in power quality by driving the gate terminals of the first and second SCR
- interval T 2 represents a period of changeover between the
- the period T 2 is less than 4 ms, which is less than the generally accepted figure of 8.3 ms
- the interval T 2 may be shortened by forcing the third and fourth SCR switches 26, 28 to conduct earlier, at the risk of possibly damaging the secondary power source 14 by shorting the secondary power source 14 to the failed primary power source 12.
- a single-phase series fenoresonance-suppressing solid-state static transfer switch 110 is shown coupling a first single-phase power source 112 and a second single- phase power source 114 to a primary winding of a load transformer 116.
- the solid-state static transfer switch 110 comprises switch means 118 for connecting and disconnecting
- the switch means 118 includes a first input 118a for coupling the switch means
- a first mechanical by-pass switch (not shown) is connected between the first input 118a and the switch output 118c for maintenance purposes.
- a second mechanical by-pass switch (not shown) is connected
- Switch means 118 comprises a first solid-state switch 122 for coupling the first power source 112 to the load transformer 116 primary, and a second solid-state switch 124 for
- the static transfer switch 110 can be used for coupling to more than two power sources.
- the static transfer switch 110 would include as many solid-state switches as there were power sources.
- the first solid-state switch 122 comprises first and second silicon-controlled rectifier
- SCR solid-state switch
- GTO gated turn-off thyristors
- the first and second solid state switch 122, 124 could be replaced with mechanical switches, at the expense of reducing the speed of the static transfer switch 110.
- the first and second SCR switches 128, 130 are connected together back-to-back such
- the third and fourth anti-parallel SCR switches 132, 134 are connected together back-to-back such that the anode of the third SCR switch 132
- SCR switch 134 is connected to the cathode of the third SCR switch 132.
- terminals of the SCR switches 128, 130, 132, 134 are connected to control logic (not shown) for switching the load transformer 116 between the first and second AC power sources 112, 114.
- a snubber circuit 136 is connected across the first solid-state switch 122 for limiting the rate of change of voltage drop across the first solid-state switch 122.
- a snubber circuit 138 is connected across the second solid-state switch 124 for limiting the rate of change of voltage drop across the second solid-state switch 124.
- the snubber circuit 136 comprises a snubber resistive element R j connected in series with a snubber capacitive element C, and the snubber circuit 138 comprises a snubber resistive element R 2 connected in series with a snubber capacitive element C 2 .
- the resistance of the snubber resistive element R is equal to the resistance of the snubber resistive element R 2
- the capacitance of the snubber capacitive element C is equal to the capacitance of the snubber capacitive element C 2 .
- the snubber circuits 136, 138 are not essential elements of the invention. Since the snubber circuits 136, 138 merely serve to prevent the SCR switches 128, 130, 132, 134 from inadvertently conducting when subjected to large instantaneous changes in voltage drop, the snubber circuits 136, 138 can be eliminated from the static
- SCR switches 128, 130, 132, 134 are replaced with mechanical switches or other suitable forms of solid-state switches which are not subject to uncontrolled turn-on.
- the static transfer switch 110 would allow voltage harmonics, generated by the presence of other non- linear loads connected to the power sources 112, 114, to be applied to the load transformer 116 primary.
- the load transformer 116 and the SCR switches 128, 130, 132, 134 would then be subjected to high voltage series
- L the inductance of the unsaturated transformer 116 primary
- C the capacitance at the transformer 116, which includes the effective capacitance of C, and C 2 , plus any stray capacitance of the power distribution lines,
- the static transfer switch 110 includes an attenuator 120 coupled to the switch means 118 for attenuating the
- the attenuator 120 is shown connected between the load transformer 116 primary and the
- the attenuator 120 can be connected across the load transformer 116 primary.
- the attenuator 120 is shown comprising an attenuator resistor R N connected in series with an attenuator capacitor C N , with the capacitance of the attenuator capacitor C N being
- the capacitance of the attenuator capacitor C N should be greater than the series capacitance C.
- the attenuator 120 acts as a capacitive voltage divider dividing the voltage delivered from the first and second power sources 112, 114 between the
- second solid-state switches 122, 124 are both open, is reduced by the attenuator 120, thereby reducing the likelihood of load transformer 116 core saturation.
- the attenuator resistor R N acts as a high frequency oscillation suppressor which reduces the likelihood of high frequency oscillations being induced in the static transfer switch 110 should the static transfer switch 110 be subjected to high frequency transient impulses, such as those which would be induced if the static transfer switch 110 or the power distribution lines from the first or second power sources 112, 114 were struck by lightning. Therefore, in one variation of the invention, the attenuator resistor R N is eliminated from the attenuator 120, and the attenuator 120 comprises only the capacitor C N . This variation can be used where other means are used to protect the static transfer switch 110 from lightning impulses, or where such protection is not required. However, this variation is not preferred due to the possibility of oscillations developing in the static transfer switch 110 and the load transformer 116, and due to the possibility of damage to the capacitor C N from large instantaneous changes in voltage drop across the capacitor ⁇
- the attenuator 120 comprises only the resistor R N . In this variation,
- the attenuator 120 dampens any oscillations which might otherwise occur in the load transformer 116.
- this latter variation is not preferred due to the increased
- the solid-state static transfer switch 110 couples the first and second power sources 112, 114 to a capacitive load and an inductive element.
- the capacitance of the attenuator capacitor C N is much greater than the effective capacitance C of the load and the of snubber capacitive elements.
- a three-phase series ferroresonance-suppressing solid-state static transfer switch 210 is shown coupling the three phases 212a, 212b, 212c of a first three- phase power source 212, and the three phases 214a, 214b, 214c of a second three-phase power source 214 to the three phases 216a, 216b, 216c of the primary of a three-phase load transformer 216.
- the static transfer switch 210 comprises switch means 218 for
- the first and second three-phase power sources 212, 214 are shown in Fig. 4 as being wye-configured power sources coupled to ground. However, if desired, the first and second three-phase power sources 212, 214 may be delta-configured and/or left floating. Similarly, the load transformer 216 is shown in Fig. 4 as being a delta- wye load
- transformer comprising primary phases 216a, 216b, 216c, and secondary phases 216d
- the load transformer 216 may adopt some other
- the switch means 218 comprises a first switch 222 (comprising solid-state switches 222a,
- a second switch 224 (comprising solid-state switches 224a, 224b, 224c) for coupling the three- phases 214a, 214b, 214c of the second power source 212 to the three-phases 216a, 216b,
- the solid-state switch 222a of the first switch 222 includes input 225 a for coupling phase 212a of the first power source 212 to the load transformer primary phases 216a, 216c.
- the solid-state switch 222b of the first switch 222 includes input 225b for coupling phase
- the solid-state switch 222c of the first switch 222 includes input 225c for coupling phase 212c of the first power source 212 to the load transformer primary phases 216b, 216c.
- the solid-state switch 224a of the second switch 224 includes input 226a for
- the solid-state switch 224b of the second switch 224 includes input 226b for coupling phase 214b of the second power source 214 to the load transformer primary phase 216a, 216b.
- the solid-state switch 224c of the second switch 224 includes
- Solid-state switch 222a comprises SCR switches 228a, 230a, connected back-to-back.
- solid-state switch 222b comprises SCR switches 228b, 230b, connected back-
- solid-state switch 222c comprises SCR switches 228c, 230c, connected back-to- back
- solid-state switch 224a comprises SCR switches 232a, 234a, connected back-to-
- solid-state switch 224b comprises SCR switches 232a, 234a, connected back-to- back
- solid-state switch 224c comprises SCR switches 232a, 234a, connected back-
- the gate terminals of the SCR switches 228, 230, 232, 234 are connected to control logic (not shown) for switching the load transformer 216 between the first and second AC
- a snubber circuit 236a comprising a snubber resistive element in series with a snubber capacitive element, is connected across the solid-state switch 222a. Similar snubber circuits 236b, 236c, 238a, 238b, 238c are respectively connected across the solid state
- each snubber circuit 236, 238 is effectively in series with the respective transformer primary phases 216a, 216b, 216c.
- the attenuator 220 comprises three attenuator circuits 220a, 220b, 220c. Each attenuator
- circuit 220a, 220b, 220c comprises an attenuator resistor in series with an attenuator capacitor, with each attenuator capacitor having a capacitance greater than that of each snubber capacitive element.
- each attenuator capacitor having a capacitance greater than that of each snubber capacitive element.
- the load transformer 216 is exposed to other sources of capacitance C in series with the load transformer primary 216a, 216b, 216c sufficient to cause series
- the capacitance of each attenuator capacitor should be greater than the
- Attenuator circuits 220a, 220b, 220c may be replaced with resistor-only attenuator circuits, capacitor-only attenuator circuits, or other suitable attenuator circuits if desired.
- Attenuator circuit 220a is connected to the junction of the load transformer 216 primary
- Attenuator circuit 220b is connected to the junction of the load transformer 216 primary phases 216a, 216b at one end, and to ground at the other end.
- Attenuator circuit 220c is connected to the junction of the load transformer 216 primary phases 216b, 216c at one end, and to ground at the other end.
- each attenuator circuit 220a, 220b, 220c can be connected
- the static transfer switch 210 is coupled to 25 kilovolt power sources.
- Each snubber resistive element comprises 16 10-ohm resistors
- each snubber capacitive element comprises 16 1 -microfarad capacitors connected in series.
- each snubber resistive element has a resistance of 160 ohms and each snubber capacitve element has a capacitance of 62.5 nanofarads.
- Each attenuator resistor comprises a 100 ohm resistor, and each attenuator capacitor comprises a 125 nanofarad capacitor. In this implementation, the capacitance of the
- Attenuator capacitor is at least twice that of the snubber capacitive element.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002362163A CA2362163C (en) | 1999-02-12 | 2000-02-11 | Ferroresonance-suppressing static transfer switch |
EP00904751A EP1151518A1 (en) | 1999-02-12 | 2000-02-11 | Ferroresonance-suppressing static transfer switch |
AU26527/00A AU2652700A (en) | 1999-02-12 | 2000-02-11 | Ferroresonance-suppressing static transfer switch |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/248,900 | 1999-02-12 | ||
US09/248,900 US6560128B1 (en) | 1999-02-12 | 1999-02-12 | Ferroresonance-suppressing static transfer switch |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2000048287A1 true WO2000048287A1 (en) | 2000-08-17 |
Family
ID=22941171
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/CA2000/000130 WO2000048287A1 (en) | 1999-02-12 | 2000-02-11 | Ferroresonance-suppressing static transfer switch |
Country Status (5)
Country | Link |
---|---|
US (1) | US6560128B1 (en) |
EP (1) | EP1151518A1 (en) |
AU (1) | AU2652700A (en) |
CA (1) | CA2362163C (en) |
WO (1) | WO2000048287A1 (en) |
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US7755872B2 (en) | 2006-09-14 | 2010-07-13 | Schweitzer Engineering Laboratories, Inc. | System, method and device to preserve protection communication active during a bypass operation |
CN103248010A (en) * | 2013-04-27 | 2013-08-14 | 国家电网公司 | Method for suppressing phenomena of ferromagnetic resonance and fuse melting of voltage transformer |
WO2022106900A3 (en) * | 2020-11-20 | 2022-06-30 | Abb Schweiz Ag | Delta connected resonant turn off circuits |
Families Citing this family (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7064458B2 (en) * | 2003-03-18 | 2006-06-20 | Target Hi-Tech Electronics Ltd. | Method and system for transferring a load between AC voltage sources |
US20050207082A1 (en) * | 2004-03-17 | 2005-09-22 | Bosch Martin S | Dual bus static tie switch |
US7777600B2 (en) * | 2004-05-20 | 2010-08-17 | Powerpath Technologies Llc | Eddy current inductive drive electromechanical liner actuator and switching arrangement |
CA2620828A1 (en) * | 2005-09-19 | 2007-03-29 | Schweitzer Engineering Laboratories, Inc. | Method and apparatus for routing data streams among intelligent electronic devices |
US7940029B2 (en) * | 2008-07-02 | 2011-05-10 | American Superconductor Corporation | Static VAR corrector |
SE534975C2 (en) * | 2009-10-16 | 2012-03-06 | Tsc Innovation Ab | Method and apparatus for installing and repairing insulated pipe lines |
RU2447565C1 (en) * | 2011-02-17 | 2012-04-10 | федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Национальный исследовательский университет "МЭИ" (ФГБОУ ВПО "НИУ МЭИ") | Method for automatic switching-on of backup supply for consumers and device for this method implementation |
JP5784520B2 (en) * | 2012-02-08 | 2015-09-24 | 株式会社東芝 | Bidirectional uninterruptible power switching device |
US9806560B2 (en) * | 2012-10-04 | 2017-10-31 | Eaton Corporation | UPS with multiple independent static switches |
US20140247537A1 (en) * | 2013-03-01 | 2014-09-04 | Panduit Corp. | Medium Voltage Power Distribution in Data Centers |
RU2638571C1 (en) * | 2016-09-12 | 2017-12-14 | Акционерное общество "Проектно-изыскательский и научно-исследовательский институт по проектированию энергетических систем и электрических сетей "ЭНЕРГОСЕТЬПРОЕКТ" (АО "Институт "ЭНЕРГОСЕТЬПРОЕКТ") | Three-phase alternating current substation |
RU2660115C1 (en) * | 2017-08-24 | 2018-07-05 | Федеральное государственное автономное образовательное учреждение высшего образования "Национальный исследовательский Томский политехнический университет" | Device of automatic switching on of backup power with synchronism control on lowering substation with turbo-aggregates of low power |
US10734834B2 (en) * | 2018-06-04 | 2020-08-04 | Abb Schweiz Ag | Static transfer switch with resonant turn-off |
RU188256U1 (en) * | 2018-12-24 | 2019-04-04 | Павел Владимирович Илюшин | Power supply control device for an industrial energy district with distributed generation sources during a short circuit on a redundant section of substation buses |
RU2692758C1 (en) * | 2018-12-24 | 2019-06-27 | Павел Владимирович Илюшин | Method of power supply control for industrial power district with sources of distributed generation at short-circuit on reserved section of substation buses |
US10903649B1 (en) * | 2019-07-25 | 2021-01-26 | Abb Schweiz Ag | Static transfer switch with turn off circuit |
US11258296B1 (en) | 2020-11-20 | 2022-02-22 | Abb Schweiz Ag | Shared resonant turn off circuit |
WO2023131479A1 (en) * | 2022-01-06 | 2023-07-13 | Signify Holding B.V. | Modular ferroresonant led driver |
US20240063656A1 (en) * | 2022-08-17 | 2024-02-22 | Delta Electronics, Inc. | Dual power switching system and method of controlling the same |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4811163A (en) * | 1987-01-14 | 1989-03-07 | Varo, Inc. | Automatic power bus transfer equipment |
US5210685A (en) * | 1985-03-08 | 1993-05-11 | Westinghouse Electric Corp. | Uninterruptible power supply system and load transfer static switch for such a system |
EP0771059A1 (en) * | 1995-10-25 | 1997-05-02 | Eaton Corporation | Method and apparatus for transferring between electrical power sources with adaptive blocks transfer until load voltage decays to safe value |
Family Cites Families (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3509357A (en) * | 1967-05-10 | 1970-04-28 | Borg Warner | Static transfer switching system |
US3675110A (en) * | 1971-01-27 | 1972-07-04 | Gen Electric | Means for damping voltage oscillations in solid-state switching circuits |
US3750004A (en) * | 1972-02-23 | 1973-07-31 | Esb Inc | Instantaneous current control for static inverters |
US3932764A (en) * | 1974-05-15 | 1976-01-13 | Esb Incorporated | Transfer switch and transient eliminator system and method |
UST967008I4 (en) * | 1975-01-12 | 1978-02-07 | Westinghouse Electric Corporation | Capacitive voltage transformer with improved ferroresonance protection device |
US4410935A (en) * | 1981-03-23 | 1983-10-18 | General Signal Corporation | Current overload protection for inverter of uninterruptible power supply system |
US4409635A (en) * | 1981-06-18 | 1983-10-11 | Westinghouse Electric Corp. | Electrical power system with fault tolerant control unit |
US4527228A (en) * | 1983-09-19 | 1985-07-02 | Chi Yu Simon S | Wide band full duty cycle isolated transformer driver |
US4583004A (en) * | 1983-09-22 | 1986-04-15 | Solidstate Controls, Inc. | Current monitoring circuit for static switch of uninterruptable power system |
FR2574233B1 (en) * | 1984-12-05 | 1988-01-15 | Telemecanique Electrique | STATIC POWER SWITCHING APPARATUS |
JPS61254026A (en) * | 1985-04-30 | 1986-11-11 | 三菱電機株式会社 | Parallel operation control system of ac output converter |
DE3669816D1 (en) * | 1985-07-04 | 1990-04-26 | Bbc Brown Boveri & Cie | AC MOTOR FOR SYNCHRONOUS MACHINES. |
US5251120A (en) * | 1986-07-23 | 1993-10-05 | Steve Smith | Harmonic noise isolation and power factor correction network |
DE3627395A1 (en) * | 1986-08-13 | 1988-02-18 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | CONTROL CIRCUIT FOR A SWITCHING POWER SUPPLY WITH SINUS-SHAPED CURRENT RECEIVER FOR CONVERTING A SINUS-SHAPED AC VOLTAGE TO A REGULATED DC VOLTAGE |
US5138184A (en) * | 1990-01-22 | 1992-08-11 | Powertrol, Inc. | Solid state static power transfer mechanism |
US5283726A (en) * | 1991-12-20 | 1994-02-01 | Wilkerson A W | AC line current controller utilizing line connected inductance and DC voltage component |
JPH0698482A (en) * | 1992-06-10 | 1994-04-08 | Digital Equip Corp <Dec> | Supply device of electric power |
SE501046C2 (en) * | 1993-01-25 | 1994-10-24 | Lindmark Electric Ab | Power unit with self-rotating series resonant converter |
US5644175A (en) * | 1995-03-28 | 1997-07-01 | Cyberex, Inc. | Static switch method and apparatus |
US5907234A (en) * | 1995-08-04 | 1999-05-25 | Siemens Aktiengesellschaft | Thyristor-switched capacitor bank |
US5646459A (en) * | 1995-11-09 | 1997-07-08 | Lucent Technologies Inc. | Integrated maintenance bypass switch and method of operation thereof |
US5689410A (en) * | 1996-06-21 | 1997-11-18 | Lucent Technologies Inc. | Split-boost circuit having imbalance protection circuitry |
CA2249755C (en) * | 1998-10-02 | 2006-12-12 | Praveen K. Jain | Full bridge dc-dc converters |
-
1999
- 1999-02-12 US US09/248,900 patent/US6560128B1/en not_active Expired - Lifetime
-
2000
- 2000-02-11 CA CA002362163A patent/CA2362163C/en not_active Expired - Fee Related
- 2000-02-11 EP EP00904751A patent/EP1151518A1/en not_active Withdrawn
- 2000-02-11 AU AU26527/00A patent/AU2652700A/en not_active Abandoned
- 2000-02-11 WO PCT/CA2000/000130 patent/WO2000048287A1/en not_active Application Discontinuation
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5210685A (en) * | 1985-03-08 | 1993-05-11 | Westinghouse Electric Corp. | Uninterruptible power supply system and load transfer static switch for such a system |
US4811163A (en) * | 1987-01-14 | 1989-03-07 | Varo, Inc. | Automatic power bus transfer equipment |
EP0771059A1 (en) * | 1995-10-25 | 1997-05-02 | Eaton Corporation | Method and apparatus for transferring between electrical power sources with adaptive blocks transfer until load voltage decays to safe value |
Cited By (3)
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US7755872B2 (en) | 2006-09-14 | 2010-07-13 | Schweitzer Engineering Laboratories, Inc. | System, method and device to preserve protection communication active during a bypass operation |
CN103248010A (en) * | 2013-04-27 | 2013-08-14 | 国家电网公司 | Method for suppressing phenomena of ferromagnetic resonance and fuse melting of voltage transformer |
WO2022106900A3 (en) * | 2020-11-20 | 2022-06-30 | Abb Schweiz Ag | Delta connected resonant turn off circuits |
Also Published As
Publication number | Publication date |
---|---|
US6560128B1 (en) | 2003-05-06 |
EP1151518A1 (en) | 2001-11-07 |
AU2652700A (en) | 2000-08-29 |
CA2362163C (en) | 2007-04-17 |
CA2362163A1 (en) | 2000-08-17 |
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