A method for preventing an extraordinary electromagnetic pulse from reaching and rendering inoperative a magnetic-winding containing electrical component of an electrical power system, the magnetic-winding containing electrical component being located in a conductive path of said electrical component of said electrical power system that receives said extraordinary electromagnetic pulse, the electrical power system being a system for generating electrical power, transmitting the power over short to long distances and distributing the power to a plurality of end users; the method comprising the steps of: a) detecting the presence of said extraordinary electromagnetic pulse (22, 28) in said conductive path prior to the pulse reaching and rendering inoperative said electrical component (16, 18); and b) diverting said pulse around the electrical component by creation of a low inductance, high current capacity short-circuit across the electrical component, so as to thereby collapse the magnetic field in said winding before the pulse can reach and render the electrical component inoperative; said low inductance, high current capacity short-circuit (36, 38) comprising÷ a high-voltage cold-cathode field-emission vacuum electron tube (44, 45a) including a cylindrical inner electrode (100, 106), at least one cylindrical grid (102, 110) encircling the inner electrode, and a cylindrical outer electrode (104, 112) encircling the at least one cylindrical grid; the inner and outer electrodes and the at least one cylindrical grid sharing a common main axis; the radial spacing from either the inner electrode (100, 106) or the outer electrode (104, 112) to one of the at least one cylindrical grid (102, 110) being such as to create therebetween a circular waveguide supporting the transverse electromagnetic mode; said pulse being a transient pulse arising from a nuclear electromagnetic pulse event, a non-nuclear electromagnetic pulse event creating the extraordinary electromagnetic pulse having a rise time of less than 500 picoseconds and a field strength sufficient to reach and render inoperative components of the electrical power system, or a geomagnetically-induced current as a result of either coronal mass ejections from a solar storm or another electromagnetic pulse event. a) detecting the presence of said extraordinary electromagnetic pulse (22, 28) in said conductive path prior to the pulse reaching and rendering inoperative said electrical component (16, 18); and b) diverting said pulse around the electrical component by creation of a low inductance, high current capacity short-circuit across the electrical component, so as to thereby collapse the magnetic field in said winding before the pulse can reach and render the electrical component inoperative; said low inductance, high current capacity short-circuit (36, 38) comprising÷ a high-voltage cold-cathode field-emission vacuum electron tube (44, 45a) including a cylindrical inner electrode (100, 106), at least one cylindrical grid (102, 110) encircling the inner electrode, and a cylindrical outer electrode (104, 112) encircling the at least one cylindrical grid; the inner and outer electrodes and the at least one cylindrical grid sharing a common main axis; the radial spacing from either the inner electrode (100, 106) or the outer electrode (104, 112) to one of the at least one cylindrical grid (102, 110) being such as to create therebetween a circular waveguide supporting the transverse electromagnetic mode; said pulse being a transient pulse arising from a nuclear electromagnetic pulse event, a non-nuclear electromagnetic pulse event creating the extraordinary electromagnetic pulse having a rise time of less than 500 picoseconds and a field strength sufficient to reach and render inoperative components of the electrical power system, or a geomagnetically-induced current as a result of either coronal mass ejections from a solar storm or another electromagnetic pulse event.