Design & development of electrical system for TWIN source

Abstract

TWIN Source (TS) experimental setup is a stepping stone towards INTF, a test-bed to characterize ITER Diagnostic Neutral Beam (DNB) and its ion source. in IPR, India. The electrical system for TS experiments involves design of the scheme, layout, procurement activities, testing, installation & commissioning of power supplies, LT Panels, cables, High Voltage (HV) transmission line, HV deck, RF shielding, grounding and bonding for its safe, reliable and successful operation. The operation of TWIN source will try to mimic some operational features of INTF / DNB source like, 5Hz modulation with 3s ON 20s OFF duty cycle, Few kA current through Plasma Grid (PG) ,based transverse magnetic field electrical feedthroughs through high voltage bushing (HVB) and source operation in vacuum immersed condition. The control of those power supplies will be carried out through CODAC type data acquisition and control platform. The TS electrical system comprises of 180kW 1MHz RF Generator (RFG) system, Filament Heating power supply (16VDC, 10A), Filament Bias power supply (128VDC, 1A), Grid Bias power supply (60VDC, 333A), Filter field power supply (3VDC, 6kA), 150kVA 50Hz 100kVDC isolation transformer, HV transmission line, Air Circuit Breaker (ACB) based LT Panel of 1600A and 800A with 50kA breaking current capacity. This paper discusses the schematic layout of the electrical system, operational modes of 180kW 1MHz RFG including the interfaces with cooling water system and electrical interface with CODAC type Data Acquisition & Control System (DACS). It also discusses the design of HV transmission line & its prototype, shielding, grounding & bonding and highlights the design considerations to mitigate challenges of HV isolation during beam extraction & acceleration mode.