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1. (WO2017064148) IMPROVEMENTS IN OR RELATING TO THE PROTECTION OF POWER TRANSFORMERS

Pub. No.:    WO/2017/064148    International Application No.:    PCT/EP2016/074517
Publication Date: Fri Apr 21 01:59:59 CEST 2017 International Filing Date: Thu Oct 13 01:59:59 CEST 2016
IPC: H02H 3/08
H02H 7/04
H02H 9/00
Applicants: GENERAL ELECTRIC TECHNOLOGY GMBH
Inventors: HA, Hengxu
WENG, Yu
BALAKRISHNAN, Gajendiran
Title: IMPROVEMENTS IN OR RELATING TO THE PROTECTION OF POWER TRANSFORMERS
Abstract:
In the field of power transformer protection there is provided a method of protecting a power transformer comprising the steps of: (a)monitoring an external fault indication signal (12A, 12B, 12C); (b)carrying out locally a fault determination; (c)carrying out locally an inrush current determination; and (d)issuing a final trip signal (48) to protect the power transformer if: (i)the external fault indication signal (12A, 12B, 12C) identifies that a fault has occurred and the locally carried out fault determination confirms that a fault has occurred; or (ii)the external fault indication signal (12A, 12B, 12C) identifies that a fault has occurred and the locally carried out fault determination identifies that no fault has occurred but after a predetermined delay the locally carried out inrush current determination confirms the absence of an inrush current.