×

METHOD AND APPARATUS FOR PROTECTING POWER TRANSFORMERS FROM LARGE ELECTRO-MAGNETIC DISTURBANCES

  • US 20130285671A1
  • Filed: 01/08/2013
  • Published: 10/31/2013
  • Est. Priority Date: 04/25/2012
  • Status: Active Grant
First Claim
Patent Images

1. A system for protecting a transformer having:

  • (a) an input winding, (b) at least one output winding intended to be coupled to a load, and (c) having a neutral line returned to ground, and wherein when the transformer is subjected to electro-magnetic conditions excessive currents can flow in the neutral line and cause the core of the transformer to saturate, the protective system including;

    (a) circuitry for sensing the level of the current flowing in the neutral line, hereafter referred to as “

    IN

    , and for determining whether the of level IN is above a predetermined value for more than a predetermined time period and for generating a first signal alarm when this condition occurs;

    (b) circuitry for sensing selected even and odd harmonics of the current flowing in the output winding coupled to the load and processing the selected harmonics to determine whether certain relationships pertaining to the harmonics indicative of core saturation are present for a preselected time duration and producing a harmonics status signal corresponding thereto; and

    (c) circuitry responsive to the first signal alarm and to the harmonics status signal for producing a second alarm signal.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×