WHAT CAUSED THE EXPOSION OF THE POWER TRANSFORMER(S)IN MANHATTAN’S ELECTRICAL SUBSTATION AT THE HEIGHT OF SANDY HURRICANE WAS INDEED A NIGHTMARE AND WHICH RESULTED INTO BIG HEADACHES TO ALL NOTWITHSTANDING THE HARM IT DOES IN THE POPULACE AS POWER WAS CUT-OFF BRINGING THOUSANDS IN DARK DESPAIR. THERE ARE MANY CAUSES OF THESE POWER TRANSFORMERS EXPLODING WHICH MAY BE MAN MADE, BY NATURE AND OVERLOADING AND EVENTUALLY SHORT CIRCUITS BOTH EXTERNAL AND INTERNAL INTO IT.
THE MOST PROBABLE CAUSE MIGHT BE THE L-G FAULT AT THE TRANSFORMERS HIGH SIDE TERMINALS WHICH ARE EXPOSED TO THE ENVIRONMENT AS THE RAINS DUE FROM SANDY WERE DAMPING ON THESE TERMINALS CAUSING A CREEPING VOLTAGE BRIDGING THE GAP BETWEEN THE INSULATED HIGH VOLTAGE TERMINAL BUSHING DOWN THE TO THE TRANSFORMER’S METALLIC FRAME AND TANK CONNECTED TO EARTH AS THE FRAME IS (SINCE MOST OFTEN THAN NOT ALL OR MOST OF THESE POWER TRANSFORMERS ARE INSTALLED OUTDOOR WHICH ARE EXPOSED FROM THE ELEMENTS SUCH AS RAIN OR SMALL ANIMALS)AND SINCE SALTY RAIN WATER IS CONDUCTIVE AND AS IT DRIPS DOWN SO DOES A DIRECT SHORT CIRCUIT WILL HAPPEN AND WILL CAUSE HIGH CURRENTS TO FLOW TO THE TRANSFOMER FRAME BODY WHICH INTURN CAUSES EDDY CURRENTS OF HIGH FREQUENCY TO FLOW IN THE TANK AND HEATING THE TANK, ITSELF. THEN AS IT HEATS UP, THE BIG VOLUME OF OIL INSULATION INSIDE THE TRANSFORMER TANK ALSO HEATS UP (ACTING NOW JUST LIKE INDUCTION PAN) WHICH DEVELOPS HIGH PRESSURE INSIDE. THERE IS USUALLY AN OVERPRESSURE DEVICE WHICH SENSE THIS ABNORMALITIES THERBY IT ACTS TO QUICKLY DE-ENERGIZED THE TRANSFORMER INPUT POWER BUT AS THIS MAY HAVE ACTED SLOWLY THE RESULTING RATE OF RISE OF OVERPRESSURE BUILDS-UP RATHER QUICKLY AND OVERTOOK IT AND THEN EXPLOSION WAS TRIGGERED DUE TO OVERPRESSURE AND HIGH TEMPERATURE COMBINED. NOW HERE’S THE LESSON TO LEARN. THESE MAIN POWER TRANSFORMERS SHOULD HAVE BEEN PROVIDED WITH SUNSHADE OR CANOPY JUST AS GOOD ENOUGH FOR THESE TRANSFORMERS TO BE PROTECTED FROM THE FALLING RAIN SPECIALLY DURING HIGH WINDY RAINS CAUSED BY HURRICANE AND EVEN DURING NORMAL RAINY DAYS. THESE CANOPYS ARE NOT COSTLY BUT IT DO PREVENT MOSTLY SUCH INCIDENTS THEREBY SAVING AND ABBETING THE CAUSE AND EFFECT OF SUCH KIND. FURTHER, POWER TRANSFORMER’S ARE NOT PROGRAMMED TO DETECT BY ITSELF BUT ONLY THE BUILT-IN DEVICES SUCH AS BUCHHOLZ RELAY, OVERTEMPERATURE SENSOR DEVICE, ETC. AND THE PROTECTION RELAYS WHICH DETECTS ELECTRICAL FAULTS AND OF COURSE, NOT WITHSTANDING THE ASSOCIATED C.T.DEVICES.