DEVELOPMENT AND PERFORMANCE TESTING OF A 200 KVA DAMPERLESS SUPERCONDUCTING GENERATOR

A 200 kVA, 3000 RPM superconducting generator has been developed and t ested, The rotor has been wound. with superconducting wire of Nb-Ti al loy, A closed-circuit liquid helium system has been designed and insta lled for cooling the superconducting windings. The stator carries the air-gap type armature windings and a laminated-iron flux-shield. A new concept in the design of superconducting generators with high short-c ircuit ratio (more than 5) has been introduced, This eliminates the re quirement of Electro-magnetic Damper (EMD) and Quick Response Excitati on System (QRES). The generator has been comprehensively tested in sup erconducting state, Open-circuit and sustained short-circuit tests, 3- phase sudden short-circuit test, synchronization with grid and paralle l operation with power system have been conducted, The synchronous mac hine was operated up to its rated kVA in the four quadrants - as gener ator and as condenser with leading and lagging power factors, A few sp ecial tests on superconducting generator, which were not reported earl ier, such as direct-on-line starting of a 20 HP squirrel-cage inductio n motor and negative phase sequence tests have also been performed suc cessfully, Test results and conclusions are given in the paper.