US3612894A - Ac supply system - Google Patents

Ac supply system Download PDF

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Publication number
US3612894A
US3612894A US3612894DA US3612894A US 3612894 A US3612894 A US 3612894A US 3612894D A US3612894D A US 3612894DA US 3612894 A US3612894 A US 3612894A
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US
United States
Prior art keywords
current supply
load
assemblies
main
standby
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
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English (en)
Inventor
Jurgen Schmidt
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.)
Licentia Patent Verwaltungs GmbH
Original Assignee
Licentia Patent Verwaltungs GmbH
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
Priority claimed from DE19691935206 external-priority patent/DE1935206C/de
Application filed by Licentia Patent Verwaltungs GmbH filed Critical Licentia Patent Verwaltungs GmbH
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Publication of US3612894A publication Critical patent/US3612894A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/20—End-user application control systems

Definitions

  • ABSTRACT The voltage stablhty of an AC supply system having a plurality of AC current supply assemblies connected in parallel to a common load is improved when a malfunction gg p g i z is detected in one of the current supply assemblies by first conalms raw 3 necting the load to a standby AC main with which the current U.S.Cl 307/60, supply assemblies are synchronized, disconnecting the mal- 307/64 functioning current supply assembly from the load, and, after Int. Cl H02j 9/06 adjusting the properly functioning current supply assemblies Field of Search 307/64, 60, to supply the total power output prior to the malfunction,
  • This invention relates to an improved AC supply system of the type including a plurality of individual current supply assemblies connected in parallel to a common load. More particularly, this invention relates to a method and apparatus for improving voltage stability of such a system when one of the current supply assemblies is malfunctioning.
  • At least two current supply assemblies are provided which, when the system is operating normally, individually feed identical partial loads which are separated from one another but which together form the total load.
  • the two current supply assemblies are also designed to be able to individually supply the current for the total load. Whenever a malfunction is detected in one of the current supply assemblies, the respective partial load is automatically switched without interruptions in the current supply, by means of an electronic switching device, directly to the output of the properly functioning current supply assembly. If the latter current supply assembly should then also malfunction, so that both assemblies are then inoperative, the entire load is switched automatically and without interruption to the standby AC main.
  • a single current supply assembly feeds the load under normal conditions and a substitute assembly and a standby AC main are available for emergencies.
  • the substitute assembly is automatically put into operation and the load is switched by means of electronic switching devices, and in particular an electronic switch common to both assemblies and a switch connected to the standby AC main which are switched with overlapping closing times, first temporarily to the standby AC main and then to the substitute assembly.
  • an AC supply system having a plurality of current supply assemblies, e.g. thyristor inverters, which operate in parallel for a single load in order to increase the output or dependability of the system.
  • a malfunction occurs in one of the current supply assemblies, the load voltage may deviate greatly from the rated or desired value due to the influence exerted on the parallelly operating current supply assemblies, depending on the type of malfunction, until the malfunction assembly is separated or disconnected from the load.
  • This large voltage deviation is produced due to the fact that the malfunctioning assembly represents a short circuit type load for the properly operating assembly or assemblies.
  • a continuously constant supply voltage is an absolute must and accordingly, this type of supply system can not normally be used for such loads.
  • this object is achieved in that whenever a malfunction of one of the current supply assemblies is detected, the common output of the current supply assemblies and hence the load is switched to the standby AC main, with which the assemblies are synchronized, through the aid of an electronic switch and, after separation of the malfunctioning assembly from the system by opening the associated switching device connected in the respective output line of the assembly, and after stabilization of the remaining assemblies not affected by the malfunction to the total power output provided by the system prior to the malfunction, the remaining properly functioning current supply assemblies are again disconnected from the standby AC main.
  • energy storage devices e.g. chokes and capacitors of filter circuits
  • These energy storage devices ensure that the load voltage will not suddenly change when an internal malfunction of one of the current supply assemblies occurs, but rather remains al most constant until the malfunction is detected and the electronic switching triggered. Due to the synchronism between the AC supply assemblies and the standby AC main, switching can occur at any moment.
  • the current supply assemblies are monitored for the occurrence of internal malfunctions as well as for undue deviations in the load voltage so that switching to the standby AC main without interruptions is performed upon the malfunctioning of one of the current supply assemblies as well as when there is an undue deviation in the voltage, caused, e.g., by an external short circuit.
  • a plurality of electronic switches which are individually associated with the current supply assemblies and which are disposed between the standby AC main and the common output of the system are utilized.
  • the individual current supply assemblies can each be separately monitored by a monitoring member and the monitoring thus becomes simpler than with central monitoring of the entire system.
  • FIG. 1 is a block diagram of one embodiment of an AC supply system according to the invention utilizing a central monitoring and control device.
  • FIG. 2 is a block diagram of a further embodiment ofan AC supply system according to the invention utilizing separate monitoring and control devices for each of the current supply assemblies.
  • FIG. 1 there is shown a block circuit diagram of an AC supply system having two AC current supply or inverter assemblies 1, 2 whose outputs are connected in parallel to a common load 3.
  • the inverters l and 2 which may, for example, be static single phase or three phase inverter circuits containing thyristors, bipolar thyristors or transistors, are controlled by a common control unit 4 which is synchronized with a standby AC main N by means of a synchronizing device 5, thus also synchronizing the inverter assemblies 1 and 2 with the standby AC main N.
  • an energy store El or E2 Connected in the output line of each of the current supply assemblies 1 and 2 in a known manner, is an energy store El or E2, respectively, which may, for example, be the capacitors or inductances of a filter, and a switch S1 or S2, respectively.
  • the switches 81 and S2 are indicated as mechanical switches, it is to be understood that they can also be electronic switches.
  • a central monitoring and control member 6 is provided having, for this purpose, signalling lines a1, 02 leading from the current supply assemblies 1 and 2, respectively, and a further signalling line leading from the control unit 4.
  • the control lines a1 and a2 are schematic in nature and may in fact contain a plurality of separate lines which monitor not only the input and output voltages of the current supply assemblies, but also internal operations of the assemblies, for malfunctions.
  • the system is further provided with a switch 8, preferably electronic, which is connected between the common output line 9 of the system and the standby AC main N. Closure of this switch in the event of a malfunction will thus have the effect of connecting the common output line 9 and hence the load to the AC main N.
  • the monitoring and control member 6 is provided with control lines d1 and d2 for the switches S1 and S2, respectively, for the switch 8, and e] and 22 for the inverters l and 2, respectively. These latter control lines el and e2 are utilized to adjust the output of the functioning inverter when a malfunction in the system is discovered.
  • the switch 8 remains temporarily closed until the malfunctioning inverter 1 has been separated or disconnected from the load 3 by opening its switch S1 and the inverter 2 has been adjusted to produce the total supply power. These latter functions are carried out by means of two actuating signals which are produced by the circuit 6 almost simultaneously with the actuation signal to the switch 8, and are transmitted via signalling lines d1 and e2 to the switch S1 and the inverter 2, respectively. After opening contactor SI and adjusting the inverter 2, the monitoring and control circuit 6 transmits a further actuating signal via signalling lines 0 to the switch 8 which causes it to return to the open position, thus disconnecting the load 3 from the AC main N.
  • inverter 2 now also ceases to function properly due to a malfunction, this malfunction is signalled to the monitoring and control circuit 6 via signalling line a2 and a new closing signal is then transmitted through signalling line 0 to the switch 8 and an opening signal is transmitted through line d2 to the switch S2. Since in this condition the standby AC main N feeds the load 3 by itself, the switch 8 remains closed and the load 3 remains connected to the standby AC main N. After repair of one or more of the inverters, the load 3 can be switched back to the current supply assemblies according to known methods which need not be discussed here in detail. Of course, in the event of a malfunction in the control circuit 4, indicating that the entire system is malfunctioning, the signal transmitted to the circuit 6 via line b will also cause the switch 8 to be closed and connect the load 3 to the AC main N.
  • FIG. 2 there is shown another embodiment of the invention wherein in place of a single malfunction control switch 8 and a central monitoring and control circuit 6, separate malfunction switches and monitoring and control circuits are provided for each current supply assembly or inverter in the system.
  • a second switch 8' is provided which is disposed, as is the switch 8, between the standby AC main N and the common assembly output line 9 having the load 3 connected thereto.
  • switches 8, 8' one of them, for example switch 8, as indicated, is associated as to its function with inverter 2 and the other, switch 8', is associated with inverter 1. This is intended to mean that when inverter 2 experiences a malfunction, the load 3 is temporarily connected to the standby AC main N by means of switch 8 and when inverter l is malfunctioning such a switching is accomplished by means of switch 8'.
  • a second control circuit 6' is provided so that the circuits 6 and 6 are associated with the inverters 2 and 1, respectively.
  • each of the monitoring and control circuits 6'. 6 need only monitor one of the inverters l or 2, respectively, and accordingly, they are connected to their associated inverters by means of monitoring or input signal lines a'l and a2, respectively.
  • the circuits 6 and 6' are also provided with monitoring signal lines b and b, respectively, for monitoring the control circuit 4.
  • each of the circuits 6, 6' is provided with a respective control line a or c for controlling the switches 8 and 8, respectively, a control line d2 or d'l, respectively, for controlling the respective switches S2 and S1 associated with the associated inverter being monitored, and a control line e1 or e2 for adjusting the power output of the other inverter in the circuit.
  • a control line a or c for controlling the switches 8 and 8, respectively
  • a control line d2 or d'l respectively, for controlling the respective switches S2 and S1 associated with the associated inverter being monitored
  • a control line e1 or e2 for adjusting the power output of the other inverter in the circuit.
  • the respective switches 8 and 8' can be bridged in a known manner by means of an emergency contactor S8 or S8, respectively, and the synchronizing device 5 monitored by a separate monitoring device 5.
  • the monitoring member 5 initiates a signal via a signalling line f, f which causes the switches 8, 8 to be blocked and a relay SN in the standby AC main to be opened. Switches 8 and 8' can then no longer be closed when one of the inverters l or 2 malfunctions.
  • the monitoring member 6 or 6' initiates a signal over lines d2 or d'l, respectively, and sends it to the associated switch S8 or S8 causing it to close, so that the load 3 can be connected to the standby AC main N at least with an interruption in its supply voltage.
  • all of the current supply assemblies may be controlled by a common control unit 4 which may be synchronized by means of a synchronizing oscillator 5 with the standby AC main N.
  • each assembly can be controlled by a separate control unit which can be synchronized with the standby AC main by means of a common synchronizing oscillator 5.
  • the separate control units should be so designed that they have a limited influence on each other as concerns their frequencies.
  • a method of improving the voltage stability of an AC supply system including a plurality of current supply assemblies which are synchronized with an AC main and which are connected in parallel via individual energy storage devices to a common load upon the malfunction of one of said current supply assemblies comprising the steps of:
  • An AC current supply system comprising, in combinatron:
  • first normally closed switch means for individually connecting said current supply assemblies to said load
  • control means responsive to the malfunctionings of one of said current supply assemblies for: load to said standby AC main;
  • said second switch means comprises a plurality of individual switches, one for each of said current supply means, each of which is connected between the common output to said current supply assemblies and said standby AC main.
  • control means responds to voltage drops and/or excess voltages at the inputs of said current supply assemblies.

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  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Stand-By Power Supply Arrangements (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
US3612894D 1969-07-11 1970-07-13 Ac supply system Expired - Lifetime US3612894A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19691935206 DE1935206C (de) 1969-07-11 Verfahren zur Verbesserung der Span nungskonstanz von im Parallelbetrieb ar beitenden Stromversorgungsaggregaten

Publications (1)

Publication Number Publication Date
US3612894A true US3612894A (en) 1971-10-12

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ID=5739495

Family Applications (1)

Application Number Title Priority Date Filing Date
US3612894D Expired - Lifetime US3612894A (en) 1969-07-11 1970-07-13 Ac supply system

Country Status (6)

Country Link
US (1) US3612894A (xx)
AT (1) AT300133B (xx)
CH (1) CH528167A (xx)
FR (1) FR2055015A5 (xx)
GB (1) GB1316763A (xx)
SE (1) SE371553B (xx)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3703644A (en) * 1971-03-24 1972-11-21 Asea Ab Synchronizing device
US3971957A (en) * 1975-05-30 1976-07-27 Hase A M Electrical load transfer control system
US4096394A (en) * 1975-03-25 1978-06-20 A.G. fur industrielle Elektronic AGIE Apparatus for supplying electrical energy to a load
US4176320A (en) * 1978-09-28 1979-11-27 Victor Leshkowitz Transmission trunk powering system
US4281376A (en) * 1978-06-22 1981-07-28 Siemens Aktiengesellschaft Protected converter arrangement
US4644238A (en) * 1983-11-16 1987-02-17 Mitsubishi Denki Kabushiki Kaisha Airflow control apparatus
US4667116A (en) * 1984-10-31 1987-05-19 Mitsubishi Denki Kabushiki Kaisha Inverter control circuit
EP0419015A2 (en) * 1989-09-22 1991-03-27 Kabushiki Kaisha Toshiba Power supply system

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
HU190049B (en) * 1982-12-15 1986-08-28 Eroemue Es Halozattervezoe Non stop supply source of transformer
DE102006050289B4 (de) * 2006-10-23 2015-11-12 Rittal Gmbh & Co. Kg Leistungsversorgungseinrichtung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3351770A (en) * 1964-03-12 1967-11-07 Technical Operations Inc A. c. power system having d. c. driven standby power supply
US3500166A (en) * 1968-05-23 1970-03-10 Lorain Prod Corp Integrated three phase inverter system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3351770A (en) * 1964-03-12 1967-11-07 Technical Operations Inc A. c. power system having d. c. driven standby power supply
US3500166A (en) * 1968-05-23 1970-03-10 Lorain Prod Corp Integrated three phase inverter system

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3703644A (en) * 1971-03-24 1972-11-21 Asea Ab Synchronizing device
US4096394A (en) * 1975-03-25 1978-06-20 A.G. fur industrielle Elektronic AGIE Apparatus for supplying electrical energy to a load
US3971957A (en) * 1975-05-30 1976-07-27 Hase A M Electrical load transfer control system
US4281376A (en) * 1978-06-22 1981-07-28 Siemens Aktiengesellschaft Protected converter arrangement
US4176320A (en) * 1978-09-28 1979-11-27 Victor Leshkowitz Transmission trunk powering system
US4644238A (en) * 1983-11-16 1987-02-17 Mitsubishi Denki Kabushiki Kaisha Airflow control apparatus
US4667116A (en) * 1984-10-31 1987-05-19 Mitsubishi Denki Kabushiki Kaisha Inverter control circuit
EP0419015A2 (en) * 1989-09-22 1991-03-27 Kabushiki Kaisha Toshiba Power supply system
EP0419015A3 (en) * 1989-09-22 1992-05-06 Kabushiki Kaisha Toshiba Power supply system
EP0599814A2 (en) * 1989-09-22 1994-06-01 Kabushiki Kaisha Toshiba Power supply system
EP0599814B1 (en) * 1989-09-22 1997-04-16 Kabushiki Kaisha Toshiba Power supply system

Also Published As

Publication number Publication date
GB1316763A (en) 1973-05-16
DE1935206B2 (de) 1971-09-02
AT300133B (de) 1972-07-10
FR2055015A5 (xx) 1971-05-07
CH528167A (de) 1972-09-15
DE1935206A1 (de) 1971-05-27
SE371553B (xx) 1974-11-18

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