Output short circuit and internal overload protections in a "Regulated High Voltage Power Supply" (80 kV, 130A)

Regulated High Voltage Power Supplies (RHVPS) are developed at the Institute for Plasma Research (IPR) for Neutral beam and RF heating applications of Steady-state Superconducting Tokomak (SST-1) up to 80 kV, 130A rating. They deliver power to loads that have very low fault energy tolerance; thereby protection of load is mandatory. At each stage special diagnosis is necessary to protect power supply components. Also, output fault protection is done so that fault energy is not more than 10J. Multi-secondary transformers (2 numbers, each at 5.6 MVA rating with 40 outputs) may get damaged even for overload at any one of their secondary, while remaining secondaries carry very less current or no current. Special technique is applied to sense and diagnose this fault in addition to routine overload sensing. Electronic means are used for fast detection and isolating RHVPS from utility supply. This paper describes overall RHVPS power scheme along with output fault protection and internal fault diagnosis system and test results thereof.