Large Scale Common-Mode Current Rejection

"STOP THE SATURATION!! That is the message from the entirety of the technical literature regarding solar magnetic disturbances (SMD) and electromagnetic pulse (EMP). These phenomena produce a quasi-DC current in the earth that enters the powertransmission system via ground-induced currents (GIC). This current saturates power transformers and produces a host of undesirable results leading up to, and including, complete system collapse.During Phase I, Engineering Matters has advanced three innovative solutions to this vexing problem. Two of these solutions are based upon switch-mode power supply principles driving currents in the neutral lead, and the third solution consists of magneticcancellation in the transformer core, i.e., instead of current cancellation, this is direct field cancellation. All solutions are focused on eliminating the magnetic saturation of the transformer. These solutions will be demonstrated on a 120 VACsingle-phase basis during Phase I.The Phase II work effort will consist of extending the design, analysis, and testing of the Phase I work to a three-phase 14 kV system with autotransformers. The extension will increase the system operating voltage; test the solutions in the field,including the E3 environment; perform a manufacturing cost reduction analysis, and optimize the design of each of the solutions."