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A Dual output (27 kV & 15 kV), 3 MW Ion Cyclotron High Voltage Power Supply (IC-HVPS) has been installed and integrated with a Diacrode based RF source to be used for ICRF (Ion Cyclotron RF) system. The IC-HVPS Controller is based on LabVIEW Real-time PXI controller, which supports all control and monitoring operations of the PSM based power supply. The controller supports all essential features like, fast dynamics, low ripple and protection for source and loads. EPICS (Experimental Physics and Industrial Control Systems) is an open source software widely accepted in scientific community as supervisory distributed control system including CODAC (Control, Data Access and Communication) for ITER. However interface with LabVIEW RT systems is not fully mature yet. Evolving interface requirements of platforms like EPICS with IC-HVPS control has been assessed and implemented for monitoring purpose. A test case was implemented to identify compatibility, feasibility, consistency and performance of EPICS server with Input Output Controller (IOCs) implemented in Real-time controller. This paper discusses integration of EPICS IOCs and LabVIEW based Real-time Controller along with an analysis on limitations imposed by such integration.

Mega watt particle accelerators like Neutral Beam Injectors draw electrical power for Plasma formation, Ion Extraction at elevated potential of ~100kV, infact the water cooling lines, gas feed lines are also floating at 100kV. Usually power supplies, hydraulic/gas feed station of typical Injector are placed in a separate building/location. In such a scenario, large coaxial transmission lines are used to support power transport, hydraulic & gas feed lines, providing electrical isolation of 100kV. This paper presents electrostatic analysis for the complex configuration of large transmission line. Specially designed profiles to provide electrical isolation within permissible limits of electric stress. Further HVDC test results showing behaviour of Transmission line over longer exposure of 3600s are also presented.

The realization of the ITER Neutral Beam Test Facility (NBTF) and the start the experimental phase are important tasks of the fusion roadmap, since the target requirements of injecting to the plasma a beam of Deuterium atoms with a power up to 16.5 MW, at 1MeV of energy and with a pulse length up to 3600s have never been reached together before. The ITER NBTF, called PRIMA (Padova Research on ITER Megavolt Accelerator), is hosted in Padova, Italy; it includes two experiments: MITICA, the full-scale prototype of the ITER injector and SPIDER, the full-size negative ion source. The realization promoted by the ITER organization is carried out with the contribution of the European Union, channeled through the Joint Undertaking for ITER (F4E), of the Consorzio RFX which hosts the Test Facility, the Japanese and the Indian ITER Domestic Agencies (JADA and INDA) and several European laboratories, such as IPP-Garching, KIT-Karlsruhe, CCFECulham, CEA-Cadarache. The early start of operation of PRIMA experiments is urgent because sufficient experimental time is necessary to face and solve the issues related to the achievement of the desired performance in time for the ITER operation, requiring NBI since the beginning. Substantial progresses have been recently achieved: the buildings construction, begun in October 2012, has been completed by the end of 2015 and the installation of some components has been started since the end of 2014. The SPIDER realization is well advanced: the installation phase is proceeding in good agreement with the general plan; it is expected to be almost completed by the end of 2016. In parallel, the commissioning of the SPIDER power supply (PS) and auxiliary plant systems is being proceeding. Tests at full power and remote control are planned, including also those addressed to reproduce the grid breakdowns and to test the relevant protections. The design of the MITICA injector components was completed in 2015their procurement is being made through a number of tenders, some of them already launched. The HV Power Supply system of the MITICA 1MV accelerator, provided by JADA, was delivered on site in December 2015. The challenging installation of these components, including the step-up transformers and the SF6 gas insulated transmission line, started soon after and will go on throughout 2016. The present phase, with the PRIMA buildings continuously filled with new components, with the installation activities progressing and with also the commissioning and testing phase starting represents a substantial step forward toward the main target. The paper will describe the main challenges the Project Team has dealt during this phase and the important feedback derived for the ITER HNB systems both from the technical and the organizational standpoints.

The ITER Neutral Beam Test Facility (NBTF), called PRIMA (Padova Research on ITER Megavolt Accelerator), is hosted in Padova, Italy and includes two experiments: MITICA, the full-scale prototype of the ITER heating neutral beam injector, and SPIDER, the full-size radio frequency negative-ions source. The NBTF realization and the exploitation of SPIDER and MITICA have been recognized as necessary to make the future operation of the ITER heating neutral beam injectors efficient and reliable, fundamental to the achievement of thermonuclear-relevant plasma parameters in ITER. This paper reports on design and R&D carried out to construct PRIMA, SPIDER and MITICA, and highlights the huge progress made in just a few years, from the signature of the agreement for the NBTF realization in 2011, up to now - when the buildings and relevant infrastructures have been completed, SPIDER is entering the integrated commissioning phase and the procurements of several MITICA components are at a well advanced stage

Regulated high-voltage power supplies (RHVPSs) are important power sources in high-power heating and current drive systems for a tokamak. Along with high power at output, these power supplies meet the requirements of fast dynamics (on the order of few microseconds), low ripple factor, and good output regulation. A development overview is presented for RHVPS ranging from 14 to 80 kV at several-megawatt power with typical output results. Having extensive tests performed with an 80-kV 75-A RHVPS, it is being regularly used for a neutral beam injector (NBI) at the Institute for Plasma Research (IPR). A large number of identical and series-connected switched power modules (SPMs) are fed from multisecondary transformers. Pulse step modulation control applied to an insulated-gate bipolar transistor switch within SPMs regulates output. Different rise and fall times of voltage can be set from few microsecond to millisecond range. Fast detection of instantaneous overcurrent reduces turnoff time within 2 μs. Due to higher frequency of ripple at higher voltages, output filter component value is of smaller order, which, in turn, limits fault energy below 10 J. The development of RHVPS at IPR started by making a functional prototype at lower rating (14 kV; 35 A) to have an experience in testing design concepts. This was divided in various activities like selection of topology, selection and design of different subparts, e.g., control, switching power converters with protections, and multisecondary transformers. Having successful results and testing all functional parameters on prototype, a series of RHVPSs at higher ratings (up to 80 kV), are developed and installed for NBI and radio-frequency heating system. The design details for each subsystem along with results are discussed.

High voltage power supply (HVPS) based on pulse step modulation (PSM) topology has already demonstrated its ability for broadcast transmitters, accelerators using radio frequency (RF) source and neutral beam injectors. Typical ion cyclotron resonant heating (ICRH) system composed of cascaded connection of driver stage and end stage would need two power supplies. A novel concept of tapping two outputs from single PSM based HVPS is attempted for the first time. A PSM based HVPS is developed with dual output to feed driver and end stages of a high power RF amplifier. This article discusses the development of a HVPS, capable to provide 14–18 kV, 250 kW to driver stage and 16–27 kV, 175–105 A, 2800 kW to end stage RF amplifier chain. Here dual output are controlled independently by single FPGA based PXI controller which support all pros of PSM based HVPS like low ripple, fast dynamics and very short time to turn-off. Discussed HVPS supports non-linear demand from ICRH system i.e. lower current (105 A) at higher voltage (27 kV) and higher current (175 A) at lower voltage (18 kV), which developed as indoor compact solution. As an add-on specification, HVPS facilitates 1 kHz RF power modulation. The HVPS is composed of two cast resin multi-secondary transformers (CRT), 48 numbers of switched power supply (SPS) modules; FPGA/real time based controller and other auxiliaries including passive protection devices. Present article describes technical details of HVPS components which are manufactured to IEC standards. HVPS with dual output is an effective replacement to conventional solutions, as it offers optimized solution for equipment bulk as well as economy.

The diagnostic neutral beam (DNB) line shall be used to diagnose the He ash content in the D–T phase of the ITER machine using the charge exchange recombination spectroscopy (CXRS). Implementation of a successful DNB at ITER requires several challenges related to the production, neutralization and transport of the neutral beam over path lengths of 20.665 m, to be overcome. The delivery is aided if the above effects are tested prior to onsite commissioning. As DNB is a procurement package for INDIA, an ITER approved Indian test facility, INTF, is under construction at Institute for Plasma Research (IPR), India and is envisaged to be operational in 2015. The timeline for this facility is synchronized with the RADI, ELISE (IPP, Garching), SPIDER (RFX, Padova) in a manner that best utilization of configurational inputs available from them are incorporated in the design. This paper describes the facility in detail and discusses the experiments planned to optimise the beam transmission and testing of the beam line components using various diagnostics.

The RF heating and current drive (H&CD) systems to be installed for the ITER fusion machine are the electron cyclotron (EC), ion cyclotron (IC) and, although not in the first phase of the project, lower hybrid (LH). These systems require high voltage, high current power supplies (HVPS) in CW operation. These HVPS should deliver around 50 MW electrical power to each of the RF H&CD systems with stringent requirements in terms of accuracy, voltage ripple, response time, turn off time and fault energy. The PSM (Pulse Step Modulation) technology has demonstrated over the past 20 years its ability to fulfill these requirements in many industrial facilities and other fusion reactors and has therefore been chosen as reference design for the IC and EC HVPS systems. This paper describes the technical specifications, including interfaces, the resulting constraints on the design, the conceptual design proposed for ITER EC and IC HVPS systems and the current status.

The RF heating and current drive (H&CD) systems that are to be installed in ITER during the construction phase, are the electron cyclotron (EC) and ion cyclotron (IC) systems. They are complex assemblies of high voltage power supplies (HVPS), RF generators, transmission lines and antennas. Their design and integration are constrained by many interfaces, both internal, between the subsystems, and external, with the other ITER systems. In addition, some components must be compatible with a nuclear environment and are classified as Safety Important Component. This paper describes the processes implemented in ITER to ensure proper integration.

An ion extractor system has been designed for the steady state superconducting tokamak (SST-1) neutral beam injector (NBI) for an experiment using a prototype ion source with fully integrated regulated high voltage power supply (RHVPS) and data acquisition and control system (DACS) developed at Institute for Plasma Research (IPR) to obtain experience of NB operation. The extractor system is capable of extracting positive hydrogen ion beam of ∼10 A current at ∼20 kV. This paper presents the beam optics study for detailed design of an ion extraction system which could meet this requirement. It consists of 3 grid accel–decel system, each of the grid has 217 straight cylindrical holes of 8 mm diameter. Grids are placed on a specially designed G-10 block; a fiber reinforc plastic (FRP) isolator of outer diameter of 820 mm and 50 mm thickness. Provisions are made for supplying high voltage to the grid system through the embedded feed-throughs. Extractor system has been fabricated, mounted on the SST-1 neutral beam injector and has extracted positive hydrogen ion beam of 4 A at 20 kV till now.

Multisecondary transformers are used at the input stage of modular high voltage power supplies. These power supplies are used in various steady state and pulsed applications, typical examples are neutral beam injectors, rf and microwave devices [N. Tomljenovic et al., Solid power supplies for Gyrotron and NBI sources, Fusion Technol., 1992; H.-U. Boksberger et al., The solid state TEXTOR high voltage neutral beam accelerator power supplies, in: Proceedings of the 11th SOFE, Austin, 1985, p. 679]. This paper presents a systematic study of the interactions of the transformer secondary winding stray capacitances [S. Austen Stigant, The J&P Transformer Book, Butterworths, London, 10th ed., pp. 498–500] and their behavior on the switching frequency of the power supply. Results from simulation and experiments on a pair of 300 kV A, 415/330 V (20 secondaries), 30 kV dc isolation transformers used for generating a regulated 14 kV dc, 35 A output are presented. Additional dielectric losses ∼13% of the total transformer loss and voltage swings at the switching frequency of the semiconductor devices are observed. Possible effects on the performance of the transformer and the design considerations are discussed. Constructional features and other observations related to the multisecondary transformers are also discussed.

The neutral beam injector of steady state superconducting tokamak (SST1-NBI) at IPR is designed for injecting upto 1.7 MW of neutral beam (Ho, 30-55 keV) power to the tokamak plasma for heating and current drive. Operations of the positive ion source (PINI or Plug-In-Neutral-Injector) of SST1-NBI were carried out on the NBI test stand. The PINI was operated at reduced gas feed rate of 2-3 Torr l/s, without using the high speed cryo pumps. Experiments were conducted to achieve a stable beam extraction by optimizing operational parameters namely, the arc current (120-300 A), acceleration voltage (16-40 kV), and a suitable control sequence. The beam divergence, power density profiles, and species fractions (H(+):H2(+):H3(+)) were measured by using the diagnostics such as thermal calorimetry, infrared thermography, and Doppler shift spectroscopy. The maximum extracted beam current was about 18 A. A further increase of beam current was found to be limited by the amount of gas feed rate to the ion source.

The paper presents the complete engineering design of steady neutral beam injector, with emphasis on the deviation in the design from conventional short pulse injectors.

A positive ion neutral injector capable in delivering 5MW (55kV, 90A) ion beam power is being operated for SST-1 neutral beam injection (NBI). SST-1 Neutral beam injection systems has various components on beam line like ion source, neutralizer, deflection magnet, ion dump, beam dump etc. A Thermocouples based diagnostics is being used for Power density distribution, Beam alignment and System protection. Temperature of beam line components rises when beam passes through them. In order to measure the rise in temperature and estimating beam power profile, beam line components are instrumented with thermocouples (TCs). The thermocouples, which are all K (nickel-chromium/nickel-aluminum) type, have their hot junctions on ground so as to respond quickly to temperature changes. Here `the ground' means beam line components, which in turn are connected to the single reference point of the electrical circuit. The beam itself is dumped on these parts so TCs are subject to severe voltage transients up to few hundred volts. We developed a signal conditioning and data acquisition system to measure the voltage developed across the thermocouples due to rise in temperature. This signal conditioning and data acquisition system is capable in truly producing the temperature rise in presence of voltage transients, high voltage switching during breakdowns. Raw signal from each of these thermocouples is first processed in signal condition cards and then acquired on data acquisition system. This paper presents the scheme of signal conditioning system and obtained results in detailed.

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.

The Ion Cyclotron Heating and Current Drive (IC H & CD) system for ITER will provide Radio frequency (RF) heating and current drive to the ITER plasma. This system is designed to provide 20 MW into the plasma using frequencies in the range of 40 MHz to 55 MHz, which could be upgraded to 40 MW in future. This paper presents the recent development of the IC H&CD system configuration in the ITER Tokamak complex & auxiliary buildings with developed interfaces.

Regulated High Voltage Power Supplies (RHVPS) are commonly used in high-energy particle accelerators. RHVPS is a modular power supply in which kV level modules (40 or 80#) are cascaded to generate desired level of voltage/power [1]. One of the most challenging tasks involved is to provide input power to number of rectifier modules with required isolation (inter-winding and winding to ground). This is accomplished by deploying multi-secondary (large numbers, say 40 secondaries) transformers. This RHVPS concept was realized for the first time in the country with development of oil filled multi-secondary transformer. A pair of 3.3MVA, 11kV/ (940Vx40) has been successfully demonstrated, isolation of 6kVDC (inter-winding) and 160kVDC (all secondary to ground) tested. The next generation power supplies are unitized with indoor installations. This has created the demand for dry type multi-secondary transformers in compliance with safety regulations. This paper presents manufacturing issues and testing of the prototype resin cast coil. On the manufactured prototype, inter-winding isolation is tested up to 6kVDC and 125kVDC with respect to ground.

This paper presents operational experience of integrated control of the arc-filament and High-voltage power supply of Steady State Tokamak (SST)-1 NBI system using Versa Module Europa (VME) system on prototype Ion source. The control algorithm is implemented on the VxWorks operating system using 'C' language. This paper also describes the operating sequence and controls on power supply system. Discharge and Filament power supplies are controlled in such a way so that necessary discharge current can be available in Ion Source. The discharge current is controlled by manipulating the filament current. Close loop control is implemented on each filament power supply with feedback from Discharge Current to control the overall discharge inside the ion source. Necessary actions for shut OFF and subsequent Turn ON are also taken during breakdowns between the Grids of the ion source. Total numbers of breakdowns are also monitored. Shot is terminated, if the breakdown count is higher than the set value. This control system can be programmed to restart High-voltage power supply within 5mS after breakdown occurs. This control system is capable to handle the all types of dynamics in the system. This paper also presents results of experiment.