DE102008020371A1 - Method for overload protection of three-phase load by current monitoring sensor, involves applying current sensor for determining difference of two phase currents, where three-phase motors are provided with motor coils - Google Patents
Method for overload protection of three-phase load by current monitoring sensor, involves applying current sensor for determining difference of two phase currents, where three-phase motors are provided with motor coils Download PDFInfo
- Publication number
- DE102008020371A1 DE102008020371A1 DE102008020371A DE102008020371A DE102008020371A1 DE 102008020371 A1 DE102008020371 A1 DE 102008020371A1 DE 102008020371 A DE102008020371 A DE 102008020371A DE 102008020371 A DE102008020371 A DE 102008020371A DE 102008020371 A1 DE102008020371 A1 DE 102008020371A1
- Authority
- DE
- Germany
- Prior art keywords
- phase
- sensor
- current
- current sensor
- overload protection
- 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.)
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Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/09—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against over-voltage; against reduction of voltage; against phase interruption
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
- G01R15/181—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers using coils without a magnetic core, e.g. Rogowski coils
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0038—Details of emergency protective circuit arrangements concerning the connection of the detecting means, e.g. for reducing their number
Landscapes
- Protection Of Generators And Motors (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren sowie eine Sensor-Messschaltung zum Überstromschutz eines Drehstromverbrauchers durch sensormäßige Stromüberwachung. Das Verfahren und die Sensor-Messschaltung können beispielsweise zum Schutz eines Drehstrommotors vor blockiertem Läufer Verwendung finden.The The invention relates to a method and a sensor measuring circuit for overcurrent protection of a Three-phase consumer through sensor-based current monitoring. The procedure and the sensor measuring circuit can For example, to protect a three-phase motor from blocked runner Find use.
Drehstrommotoren unterliegen der Gefahr von Überhitzung der Motorwicklungen. Überlastung, schlechte Netzqualität (Unterspannung/Überspannung) und blockierter Läufer zählen zu den häufigsten Ursachen, wobei schlechte Netzqualität (Unterspannung/Überspannung) im folgenden der Einfachheit halber als Überlastung betrachtet wird. So steigt beispielsweise bei blockiertem Läufer durch mechanische Blockierung, bei zu großer Drehmomentbelastung oder bei Phasenverlust der Strom der Phasenleitungen auf ein Mehrfaches des Nennwertes, so dass sich die Motorwicklungen sehr rasch auf unzulässige Werte erhitzen. Von einer gewissen Nennleistung an müssen daher Motoren und andere Drehstromverbraucher gegen Überstrom geschützt werden.AC motors are at risk of overheating the motor windings. Overload, bad power quality (Undervoltage / overvoltage) and blocked runner counting the most common Causes, where poor power quality (undervoltage / overvoltage) hereinafter, for the sake of simplicity, will be considered overloading. Thus, for example, with a blocked rotor, mechanical locking increases, too big Torque load or, in the case of phase loss, the phase line current at a multiple of the rated value, so that the motor windings very quickly to inadmissible Heat values. From a certain nominal power must therefore Motors and other three-phase consumers are protected against overcurrent.
Zu
diesem Zweck sind Sensor-Messschaltungen der in
Nachteilig bei dieser bekannten Art des Überstromschutzes ist das Erfordernis von zwei Stromsensoren.adversely in this known type of overcurrent protection is the requirement of two current sensors.
Der Erfindung liegt daher die Aufgabe zugrunde, ein Verfahren sowie eine Sensor-Messschaltung zum Überstromschutz eines Drehstromverbrauchers durch sensormäßige Stromüberwachung zu realisieren, die nur einen einzigen Stromsensor benötigen.Of the Invention is therefore based on the object, a method and a sensor measuring circuit for overcurrent protection to realize a three-phase current consumer by means of sensor-based current monitoring, that only need a single current sensor.
Diese Aufgabe wird erfindungsgemäß bei dem Verfahren nach Anspruch 1 und bei der Sensor-Messschaltung nach Anspruch 2 durch einen einzigen Stromsensor gelöst, der die Differenz von zwei Phasenströmen ermittelt.These Task is according to the invention in the Method according to claim 1 and in the sensor measuring circuit according to Claim 2 solved by a single current sensor, which determines the difference of two phase currents.
Zweckmäßige Ausgestaltungen
der Erfindung sind Gegenstand der Unteransprüche
In der Zeichnung zeigenIn show the drawing
Die
erfindungsgemäße Sensor-Messschaltung
gemäß
Die
Funktion der Sensor-Messschaltung gemäß
- i1(t), i2(t) und i3(t):
- der in der jeweiligen Phasenleitung in Richtung zum Drehstromverbraucher (beispielsweise Motor) fließende Versorgungsstrom,
- im(t):
- der durch den Stromsensor erfasste Strom,
- I1, I2 und I3:
- die jeweilige Amplitude von i1(t), i2(t) und i3(t),
- Im:
- die Amplitude von im(t),
- Ioverload:
- die Amplitude von ii(t), i2(t) und i3(t) bei Überlastung,
- ILR1:
- die Amplitude von i1(t), i2(t) und i3(t) bei blockiertem Läufer ohne Phasenverlust (wobei die Phasenasymmetrie vernachlässigt ist),
- ILR2:
- die Amplitude von i1(t), i2(t) und i3(t) bei blockiertem Läufer mit Verlust einer Phase,
- I ⇀x:
- der Stromvektor von ix(t).
- i 1 (t), i 2 (t) and i 3 (t):
- the supply current flowing in the respective phase line in the direction of the three-phase load (for example motor),
- i m (t):
- the current detected by the current sensor,
- I 1 , I 2 and I 3 :
- the respective amplitude of i 1 (t), i 2 (t) and i 3 (t),
- I m :
- the amplitude of i m (t),
- I overload :
- the amplitude of i i (t), i 2 (t) and i 3 (t) in case of overload,
- I LR1 :
- the amplitude of i 1 (t), i 2 (t) and i 3 (t) with blocked rotor without phase loss (the phase asymmetry being neglected),
- I LR2 :
- the amplitude of i 1 (t), i 2 (t) and i 3 (t) with blocked phase loss rotor,
- I ⇀ x :
- the current vector of i x (t).
In
der Sensor-Messschaltung gemäß
Mittels
Vektordiagramm (
Im
Normalbetrieb gilt gemäß (2) und
Im
Fall einer Überlastung
gilt:
Bei
blockiertem Läufer
ohne Phasenverlust ergibt sich gemäß (2) und
Bei
blockiertem Läufer
mit Verlust von Phase 3 ergibt sich gemäß (2) und
Bei
blockiertem Läufer
mit Verlust von Phase 1 oder Phase 2 ergibt sich gemäß (2) und
Der
Strom ILR1 und ILR2 bei
blockiertem Läufer ist
viel größer als
der Strom I1, I2 oder
I3 im Normalbetrieb, in der Regel beträgt er das
2- bis 8-Fache. Bei jedem blockierten Betrieb erfasst somit der
Stromsensor gemäß
Bei
dem Ausführungsbeispiel
der
Im Rahmen der Erfindung bestehen verschiedene Möglichkeiten zur Realisierung der Sensor-Messschaltung. Wesentlich ist dabei, dass
- • die Frequenz des Versorgungsstroms i1(t), i2(t) und i3(t) in dem vom Stromsensor erfassbaren Bereich liegt,
- • der effektive Messbereich des Stromsensors die sich in (2) bis (6) ergebenden Stromwerte von Im einschließt und
- • das Ausgangssignal des Stromsensors eine injektive Funktion des erfassten Stroms im(t) ist, wobei die Messgenauigkeit ausreichend hoch für eine eindeutige Unterscheidung zwischen Normalbetrieb nach (3) und Gefahrbetrieben nach (4), (5), (6) und (7) sein muss.
- The frequency of the supply current i 1 (t), i 2 (t) and i 3 (t) lies in the range detectable by the current sensor,
- The effective measuring range of the current sensor includes the current values of I m resulting in (2) to (6) and
- The output signal of the current sensor is an injective function of the detected current i m (t), the measurement accuracy being sufficiently high for a clear distinction between normal operation according to (3) and hazard operations according to (4), (5), (6) and (7 ) have to be.
Anhand der Ausgangsgröße des Stromsensors lässt sich eindeutig feststellen, in welchem Betrieb sich der überwachte Drehstromverbraucher (z. B. Motor) befindet. Die angeschlossene Schutzvorrichtung löst dann ein entsprechendes Signal aus.Based the output of the current sensor let yourself clearly establish in which operation the supervised Three-phase consumer (eg motor) is located. The connected Protection device triggers then a corresponding signal.
Claims (5)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102008020371.8A DE102008020371B4 (en) | 2008-04-23 | 2008-04-23 | Method and sensor measuring circuit for overcurrent protection of a three-phase load |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102008020371.8A DE102008020371B4 (en) | 2008-04-23 | 2008-04-23 | Method and sensor measuring circuit for overcurrent protection of a three-phase load |
Publications (2)
Publication Number | Publication Date |
---|---|
DE102008020371A1 true DE102008020371A1 (en) | 2009-10-29 |
DE102008020371B4 DE102008020371B4 (en) | 2019-11-14 |
Family
ID=41111678
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE102008020371.8A Active DE102008020371B4 (en) | 2008-04-23 | 2008-04-23 | Method and sensor measuring circuit for overcurrent protection of a three-phase load |
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DE (1) | DE102008020371B4 (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1817152U (en) * | 1959-01-30 | 1960-08-25 | Licentia Gmbh | TRIGGER FOR THE PROTECTION OF THREE-PHASE CURRENT CONSUMERS WITH STARTING LINKS FOR PHASE LOSS AND OVERCURRENT PROTECTION |
US4683513A (en) * | 1986-04-07 | 1987-07-28 | Westinghouse Electric Corp. | Dual current transformer current sensing method and sensor |
WO1990010940A1 (en) * | 1989-03-09 | 1990-09-20 | SIEMENS AKTIENGESELLSCHAFT öSTERREICH | Current transformer arrangement for three-wire three-phase systems, especially to detect the actual current for controlled dc consumers powered via current rectifiers |
-
2008
- 2008-04-23 DE DE102008020371.8A patent/DE102008020371B4/en active Active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1817152U (en) * | 1959-01-30 | 1960-08-25 | Licentia Gmbh | TRIGGER FOR THE PROTECTION OF THREE-PHASE CURRENT CONSUMERS WITH STARTING LINKS FOR PHASE LOSS AND OVERCURRENT PROTECTION |
US4683513A (en) * | 1986-04-07 | 1987-07-28 | Westinghouse Electric Corp. | Dual current transformer current sensing method and sensor |
WO1990010940A1 (en) * | 1989-03-09 | 1990-09-20 | SIEMENS AKTIENGESELLSCHAFT öSTERREICH | Current transformer arrangement for three-wire three-phase systems, especially to detect the actual current for controlled dc consumers powered via current rectifiers |
Also Published As
Publication number | Publication date |
---|---|
DE102008020371B4 (en) | 2019-11-14 |
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