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1. CA2229073 - GROUND SKEW PROTECTION METHOD AND APPARATUS

Office
Canada
Application Number 2229073
Application Date 14.01.1997
Publication Number 2229073
Publication Date 31.07.1997
Grant Number
Grant Date 23.04.2002
Publication Kind C
IPC
H02H 1/04
HELECTRICITY
02GENERATION, CONVERSION, OR DISTRIBUTION OF ELECTRIC POWER
HEMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
1Details of emergency protective circuit arrangements
04Arrangements for preventing response to transient abnormal conditions, e.g. to lightning
H02H 9/08
HELECTRICITY
02GENERATION, CONVERSION, OR DISTRIBUTION OF ELECTRIC POWER
HEMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
9Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
08Limitation or suppression of earth fault currents, e.g. Petersen coil
H04B 3/30
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
BTRANSMISSION
3Line transmission systems
02Details
30Reducing interference caused by unbalance current in a normally balanced line
CPC
H04B 3/30
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
BTRANSMISSION
3Line transmission systems
02Details
30Reducing interference caused by unbalance current in a normally balanced line
Applicants ONEAC CORPORATION
Inventors MCCARTNEY, THOMAS
FISH, LAURENCE H.
Priority Data 08589980 23.01.1996 US
Title
(EN) GROUND SKEW PROTECTION METHOD AND APPARATUS
(FR) PROCEDE ET APPAREIL DE PROTECTION CONTRE LES DIFFERENCES DE POTENTIEL A LA TERRE
Abstract
(EN) A method and apparatus are provided for protecting a non-isolated data communications cable against ground skew used with an AC power source. A current summing transformer (20) is coupled to an AC power source. The current summing transformer includes a single transformer core (20A) and a plurality of coils. One of the coils is connected in series with each phase, neutral (if present) and ground line in the AC power source. The plurality of coils are substantially identical. Each coil has an identical number of turns and an identical direction of winding on the transformer core (20A). The current summing transformer (20) is only needed in the power path to one of two or more interconnected systems (22). The current summing transformer (20) introduces a high impedance to surge current in the data cable ground of one or many non-isolated data cables attached to the system and at the same time offers substantially zero impedance to the normal power currents including leakage and fault ground currents.