AN ELECTRICAL ISOLATOR FOR WATER COOLED HIGH VOLTAGE SYSTEMS

A MAGNETOHYDRODYNAMIC (MHD) COMBINED-CYCLE POWERPLANT PROMISES TO BE ONE OF THE MOST EFFICIENT AND LEAST ENVIRONMENTALLY INTRUSIVE COAL-FUELED POWER GENERATING SYSTEMS. TO ACHIEVE THIS POTENTIAL, THE MHD COAL COMBUSTOR MUST BE COOLED WITH HIGH PRESSURE (1,200 PSI), HIGH TEMPERATURE (450 DEGREES FAHRENHEIT) BOILER FEED WATER. BECAUSE THE COMBUSTOR IS AT A HIGH NEGATIVE POTENTIAL (TENS OF KILOVOLTS) RELATIVE TO THE GROUNDED BOILER, THERE MUST BEBETWEEN THEM A HIGH RESISTANCE ELECTRICAL ISOLATOR WHICH PASSES THE BOILER FEED WATER WITH MINIMUM PRESSURE DROP. THE OBJECTIVE OF THIS RESEARCH IS TO DEVELOP SUCH AN ISOLATOR. THE ISOLATOR IN ITS BASIC FORM CONSISTS OF A SERIES OF ALTERNATING METALLIC AND DIELECTRIC RINGS THAT FORM A STACK SUFFICIENTLY LONG THAT IT CAN SUPPORT THE IMPOSED VOLTAGE WITHOUT EXCESSIVE CURRENT LEAKAGE THROUGH THE BOILER FEED WATER FLOWING WITHIN IT. DETAILED ANALYSIS OF THIS CONCEPT AND ITS VARIATIONS, AS WELL AS THE ISOLATOR DESIGN AND THE DESIGN OF A LONG DURATION TEST FACILITY, ARE BEING PERFORMED IN PHASE I. THE PROTOTYPE ISOLATOR AND THE TEST FACILITY ARE TO BE CONSTRUCTED IN PHASE II. LONG DURATION TESTS WILL DETERMINE THE ISOLATOR PERFORMANCE AND LIFETIME BEFORE ITS DELIVERY TO THE DOE-OWNED MHD TEST FACILITY IN BUTTE, MONTANA.