- Email: [email protected]
The High Voltage Deck 1 and Bushing for the ITER Neutral Beam Injector: Integrated design and installation in MITICA experiment
Fusion Engineering and Design 146 (2019) 1895–1898
Contents lists available at ScienceDirect
Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes
The High Voltage Deck 1 and Bushing for the ITER Neutral Beam Injector: Integrated design and installation in MITICA experiment
T
⁎
Marco Boldrina, , Muriel Simonb, Gerard Escudero Gomezb, Michael Krohnc, Hans Decampsd, Tullio Bonicellib, Vanni Toigoa a
Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova, Italy Fusion For Energy, c/ Josep Pla 2, 08019 Barcelona, Spain c Siemens AG, Process Industries and Drives Division, Large Drives, Industrial Applications PD LD AP S TA EL, Gleiwitzer Str. 555, 90475 Nürnberg, Germany d ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex, France b
A R T I C LE I N FO
A B S T R A C T
Keywords: ITER PRIMA MITICA Heating Neutral Beam Injector (HNB) High Voltage Deck 1 (HVD1) High Voltage Bushing Assembly (HVBA) Insulation design Seismic design Thermal design
MITICA is the full scale prototype of the ITER Heating Neutral Beam (HNB) currently under construction at the Neutral Beam Test Facility in Padova (Italy). In the ITER HNB, negative ions (H−/D−) are produced in the Ion Source (IS) polarized to ground at −1012 kV, then extracted and accelerated to ground at 1 MeV energy and finally neutralized. The complex power supply system feeding the IS includes two non-standard equipment, beyond the current industrial standard for insulation voltage level (-1 MVdc) and dimensions: 1) the High Voltage Deck1 (HVD1), a large air insulated Faraday cage (12.5 m (L) x 8.4 m (W) x 9.6 m (H)) hosting the IS power supplies and diagnostics; 2) the High Voltage Bushing Assembly (HVBA), a -1 MVdc air to SF6 Bushing which interfaces the HVD1 with the SF6 insulated Transmission Line (TL) connecting the Acceleration Grid Power Supply system with the IS, carrying inside its High Voltage electrode all IS power and diagnostics conductors. The HVD1 and HVBA are installed inside a large HV hall. The main design choices leading to the final hall layout, integrating the HV experimental equipment and the conventional building plants assuring the necessary clearance required by such very high electric insulation level, are presented. Moreover, the paper reports on the manufacturing design developed by the supplier, the factory type tests to validate the design of the HVD1, the factory tests carried out on the HVBA and the on-site installation, commissioning and testing activities.
1. Introduction To achieve ITER plasma burning conditions two Heating Neutral Beam Injectors (HNBs), designed to deliver to the plasma a power of 16.5 MW each with a pulse duration up to 1 h [1], are required. To comply with such very demanding ratings, the strategy for the construction and the development of the ITER project foresees the realization of a test facility called PRIMA (Padua Research on Injector with Megavolt Acceleration) [2] including two separate projects: SPIDER (Source for the Production of Ions of Deuterium Extracted from RF plasma) aimed at characterizing the high-energy negative neutral beam Ion Source (IS) and MITICA (Megavolt ITER Injector & Concept Advancement), the full-size prototype of the 1 MVdc beam injectors aimed at designing, installing, testing and optimizing the prototype of the HNB in order to reach the required parameters for the ITER operation. In the MITICA project will be tested the production, extraction, acceleration and neutralization of H− and D− ions. These ions are produced in the IS
⁎
polarized to ground at −1012 kVdc, then extracted by 12kVdc extraction voltage, accelerated at 1 MeV energy and finally neutralized. The complex power supply system feeding the IS (see Fig. 1) includes two very particular equipment, beyond the actual industrial standard for insulation voltage level (-1 MVdc) and dimensions, which are:
• the High Voltage Deck1 (HVD1), a large air insulated Faraday cage •
(12.5 m (L) x 8.4 m (W) x 9.6 m (H)) hosting all the Ion Source services, namely the Ion Source and Extractor Power Supplies (ISEPS [3]) and the cubicles for control and diagnostics; this equipment is fed by an insulating transformer during operation [4]; the High Voltage Bushing Assembly (HVBA), a -1 MVdc air to SF6 Bushing interfacing the HVD1 with the SF6 insulated Transmission Line (TL); the TL connects the Acceleration Grid Power Supply system (AGPS) with the IS, carrying inside its High Voltage electrode all ISEPS power and diagnostics conductors.
Corresponding author. E-mail address: [email protected] (M. Boldrin).
https://doi.org/10.1016/j.fusengdes.2019.03.059 Received 27 August 2018; Received in revised form 7 February 2019; Accepted 10 March 2019 Available online 18 March 2019 0920-3796/ © 2019 Elsevier B.V. All rights reserved.
Fusion Engineering and Design 146 (2019) 1895–1898
M. Boldrin, et al.
Table 1 Environmental conditions inside the HVH building. Temperature (min ÷ max) Room air humidity (min ÷ max) Dust class a
18 °C ÷ 35 °C 40% ÷ 60% 100.000 P/ft³a
Fed. Std. 209E, equivalent to ISO Class 8 according to ISO 14644-1.
minimum clearance of 5 m is required. To this purpose, electrical and air treatment services have been designed to assure such minimum clearance. The HVH walls are recessed from the pillars (around 1 m) to ensure that the lamps, fire detectors, loudspeakers and related distribution ducts, made of plastic pipes, as well as all electrical and interface cubicles (see red circled details in Fig. 2) installed on the walls, are at a distance greater than 5 m from the HVD1. The interconnecting electrical cables are routed inside corrugated pipes (not visible in Fig. 2) buried in the concrete floor to avoid the use of conventional metallic trays along HVH walls and consequent increase of the electric field. Similarly, the fibre optics tray and the cooling water pipes connected to the HVD1 Insulating breaks are laid in a dedicated narrow pit on the HVH floor (see green contoured detail P in Fig. 2). The air conditioning system, designed to assure the environmental conditions reported in Table 1, is an all-air type (indoor air circulation with partial reintegration and mixing with outdoor air). It consists of an air treatment unit, installed outside the HVH, provided with suitable microfilters to cope with the dust class requirements. The treated air is delivered through channels installed on HVH ceiling (detail A in Fig. 2) to two collectors (detail B in Fig. 2) placed on the upper side of opposite walls, just beneath the building ceiling, and diffused to ambient through motorized nozzles (remotely adjustable). Exhaust air is extracted from HVH bottom side by vertical air channels provided with suction grilles at the lower end (detail C in Fig. 2), then delivered back to the air treatment machine by means of two lateral ducts (detail D in Fig. 2) installed beneath the HVH ceiling. Finally, an adaptation of the HVH floor was necessary before the installation of the HVD1. In fact, the concrete slab of the HVH, designed and built before HVD1 design finalization, was unsuitable to withstand the forces transferred by the two plates of the HVD1 base frame laying on the other side of the TL pit (detail E in Fig. 2). Therefore, underneath those two plates the original floor was removed and replaced with two plinths designed to withstand the forces applied by the HVD1 structure.
Fig. 1. Overall view of the MITICA HV components.
Fig. 2. MITICA HVH layout.
2. High Voltage Hall integrated layout 3. Manufacturing design The HVD1 and HVBA are indoor installations, inside the MITICA High Voltage Hall (HVH) (26 m (L) x 29 m (W) x 21,4 m (H)); here ambient conditions (air temperature, humidity and dust level) are controlled. Underneath the HVD1 there is a pit where the HVBA is installed and interfaced with the TL (see Fig. 2). This configuration, described and analysed in [5,6], has been taken as reference for the procurement technical specification [7] mainly for its electrostatic reasons (HVBA installed in the uniform electric field produced underneath the HVD1). As a consequence, more free space for a functional layout of the equipment inside the HVH is made available. Furthermore a simpler seismic design (HVBA mechanically decoupled from HVD1) has been adopted. The insulating transformer bushing is installed aside the HVD1 and connected to it via a duct, acting also as corona shield. The duct hosts in a tray the medium voltage cables connected to the insulating transformer secondary which provides power supply to ISEPS equipment inside HVD1. The duct is realized to decouple mechanically the transformer bushing and the HVD1 to avoid force transmission during seismic events. The HVH will host also the AGPS dummy load, consisting in a series of high voltage resistors in air with taps for connections, to be connected to the HVD1 for on‐site testing of AGPS performance with a pulse length limited to 2 s. To avoid discharges from the HVD1 towards the ceiling and the walls (which inner surface is identified by the pillars inner face) of the HVH, a
The detailed design phase of HVD1 and HVBA was concluded in May 2016 [7]. The manufacturing design has been developed by the supplier using a 3D integrated model. Specific 2D drawings have been derived from the model to detail HVD1 and HVBA interfaces. Fig. 3, showing HVD1 base plates positions and drilling scheme for anchor bolts fixation on the HVH floor, is an excerpt of the set of drawings that, together with the specification of the forces transferred to the concrete floor under static and seismic conditions, were used for exchanges up to final clearance from PRIMA civil engineers prior to
Fig. 3. ISO view of HVD1 baseframe with baseplates and anchor bolts location. 1896
Fusion Engineering and Design 146 (2019) 1895–1898
M. Boldrin, et al.
HVD1 installation. Similar information was exchanged to allow verification of the HVBA. Additional 2D drawings have been produced: to detail the interface with ISEPS equipment (transformers, power and control cubicles) fixed on the supporting beams of HVD1 mechanical structure; to detail position and dimensions of interfaces with the Insulating Transformer and with the cooling plant pipes, connected to HVD1 insulating breaks at ground floor (see Fig. 2). A critical task, finalized through dedicated exchanges between European and Japanese Domestic Agency under ITER Organization coordination, consisted in defining, both from mechanical and electrical point of view, a design solution at the interface between the HVBA (procured by F4E) and the TL (procured by Japanese DA) reconciling the two individual designs and allowing a proper interconnection of the two components. 4. Factory acceptance tests 4.1. HVD1 tests A HVD1 mock-up with a reduced size of 4 m × 4 m × 4 m and only one floor, equipped with a door and supported by 4 full size post insulators, was built to perform the factory tests, developed with the Supplier based on the ratings reported in Table 2, to validate the design and release the manufacturing of the full-size HVD1. The tests were carried out on July 2016 at the High-Voltage laboratory of Hochspannungsgeräte GmbH (HSP) in Troisdorf (Germany) with a common tests setup requiring the mock-up installed in a corner of the test hall, at 5 m from the walls, with a 6.3 m x 6.3 m metallic frame installed 5 m above the deck and connected to ground potential to simulate the HVH ceiling (see Fig. 4). The post insulators were filled with N2 set at the minimum pressure value (250 kPa gauge). The following electrical tests, based on test standards IEC60060-1 (2010) and IEC60270 (2001), were successfully carried out (i.e. no disruptive discharge occurred on the test object): AC (960 kV) power frequency voltage withstand test, lightning impulse (2.1 MV) voltage withstand test and a long-duration DC voltage withstand test (5 h at -1.2 MVdc).
Fig. 4. HVD1 mock-up inside HSP laboratory in Troisdorf.
45°K [7], calculated with 40 °C ambient temperature after three daily operation at nominal duty cycle 1 h ON/3 h OFF) but below the admissible limit of ΔT = 100°K according to IEEE 65700−19-3 applicable standard.
4.2. HVBA tests 5. Installation at MITICA site As with the HVD1 post insulators [7], also for the HVBA dedicated materials tests followed by hydraulic pressure tests to achieve Italian National Body (INAIL) homologation for pressurized components were successfully held in October 2016. The same set of electrical tests described in Section 4.1 were carried out in January 2017 at HSP laboratory, as well as a polarity reversal test (according to applicable standard IEC/IEEE 65700−19-3) to test HVBA insulation capability to withstand the specific requirement in Table 2 and then the voltage withstand test of HVBA ISEPS conductors. Finally, a temperature rise test was carried out on February 2017. The HVBA was filled with SF6 at minimum pressure (450 kPa relative) and a set of thermocouples were fixed on the inner conductors. The test was carried out driving continuously along the two massive HVBA inner conductors (rated currents about 5kAdc [7]) an increased current of 6.6kAdc to take into account the losses of the remaining power conductors, in particular the RF lines [7], until reaching thermal stabilization (i.e. temperature variation less than 1°K/h). The hottest inner conductor heated up to 88 °C with 23 °C ambient temperature (ΔT = 65°K), above the simulated results (ΔT =
Installation onsite, carried out from mid-March to end October 2017, was preceded by a metrological survey supported by Consorzio RFX metrology team to locate precisely the positions of the HVD1 baseplates (Fig. 3) with reference to the interface point of the HVBA with the TL already installed in the pit. The HVBA already assembled (about 12 m tall), was delivered via special transport and installed in the pit as a unique piece using two truck cranes. Next was the assembly of the HVD1 baseframe (Fig. 3), composed of beams welded on baseplates in turn fixed to the HVH floor by anchor bolts and mortar, on which were fixed afterwards the eight post insulators (see Fig. 5). The cage lower frame (only the main beams) was preassembled at ground, lifted up by the HVH crane, connected to the top of the post insulators and then completed with secondary beams, floor grids, and bottom nested screens (inner EMI, outer electrical [7]). The side walls of the HVD1 cage were preassembled at ground in three vertical sections (metallic supporting structure completed with the outer electrical screen) lifted up sequentially for fixation on the cage lower frame. The assembly operations went on with the completion of the two outer screens, the installation of the additional equipment (insulating breaks for water and optical fibres, grounding switch, ventilation system [7]) and of the aluminium screen covering the baseframe. Being the HVD1 qualified as structural work, its compliance with Italian Norm for Construction (NTC2008) was monitored by the Director of Works, a chartered engineer involved both before installation (manufacturing design clearance, inspection of manufacturing, samples) and during installation. Another role prescribed by law is the static test inspector,
Table 2 Power supply system voltage withstand requirements. Rated voltage Short duration (3600 s) DC test voltage Long duration (5 hours) DC test voltage Pulsed voltage test starting from -1060kVdc Polarity reversal (up to 200 times per hour; total number of 450,000 during lifetime)
−1000 kVdc −1200 kVdc −1060 kVdc −1265 kV +300 kV
1897
Fusion Engineering and Design 146 (2019) 1895–1898
M. Boldrin, et al.
processing was done in the frequency domain by using ARTeMIS Modal 5.1 software suite to obtain validated estimates of the mode shapes, natural frequencies and damping ratios (procedure known as Operational Modal Analysis, OMA). In the significant range up to 20 Hz it was possible to identify 3 eigenfrequencies for the HVD1 and 5 for the HVBA deviating less than 20% (acceptance criteria) from the corresponding numerical results calculated by modelling and analysing the structures with ANSYS Workbench 16.1. This way, the experimental vibration measurements validated the HVD1 and HVBA numerical models. The insulating tests for the final acceptance of the HVD1 and HVBA, consisting in the execution of the Short and Long duration DC voltage tests and the Pulsed voltage test as reported in Table 2, are foreseen to be performed in Q4 of 2018 after connecting the HVBA to the TL. The tests will be carried out using a dedicated SF6 insulated Testing Power Supply generator (see Fig. 1) rated for -1.3MVdc and 10mAdc. 7. Conclusions
Fig. 5. HVD1 installed inside HVH.
After successful execution of the factory acceptance tests, the HVD1 and HVBA have been installed at PRIMA facility. Onsite acceptance tests have been positively carried out. The final acceptance tests at full voltage are foreseen to take place in Q4 of 2018 after connection to the TL.
whose duty is to prescribe and perform load tests on the structure or parts of it in order to verify its structural function before entry into service. The static test inspector prescribed a static test in-situ on one of the post-insulators, which verified with positive result the actual behaviour against the theoretical result derived from the finite element model used for the structural analysis.
Acknowledgement and Disclaimers
6. Onsite acceptance tests
The work leading to this publication has been funded partially by Fusion for Energy under the contract F4E-OPE-083. This publication reflects the views only of the author, and F4E cannot be held responsible for any use which may be made of the information contained therein. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization. The authors would like to thank the main subcontractors of Siemens who manufactured and installed at site: HSP Hochspannungsgeräte GmbH for the HVBA, Andreas KARL GmbH & Co. KG for the HVD1.
The following tests were successfully executed. A HVD1 electrical screen test (to assess the correct installation of the HVD1 electrical screen in particular regarding its EMI screening capabilities) consisted in a qualitative verification of the screening via a “leakage test” done using a 435 MHz power transmitter with suitable transmitting antenna, positioned in the HVH outside the HVD1, and a portable receiver moved along the connections and joints of the EMI screen inside the HVD1 to verify the absence of transmitted signal. The Insulating breaks for demineralised cooling water, provided with closing flanges, were pressurized and subjected to a water leakage test at 10 bar absolute maintained for 1 h. Functional tests were performed on the grounding switch using its operating mechanism and registering closing and opening operations times. The proper operation of the ventilation system and the provision of the required air flow (16 m3/s) were verified. The correct operation of the interlock mechanism of the HVD1 doors was demonstrated. The voltage withstand test of HVBA ISEPS conductors, already carried out in factory, was repeated including also the additional cables sections up to their interface point inside the HVD1. Finally, a seismic qualification was performed on both HVD1 and HVBA to validate the parameters of the models used for the seismic design of the structures. To this purpose, each equipment was provided in turn with accelerometers (24 piezoelectric accelerometers of different sensitivity on the HVD1 and 21 on the HVBA) and the signals, produced by the ambient vibration without needing any artificial excitation, were acquired and stored via a frontend to a laptop. Signals
References [1] ITER technical basis, IAEA, Vienna, ITER EDA, Doc. Series N. 24, Plant Description Document, Sec. 2.5.1. (2002). [2] V. Toigo, et al., The PRIMA Test Facility: SPIDER and MITICA test-beds for ITER neutral beam injectors, New J. Phys. 19 (2017). [3] M. Bigi, et al., Design, manufacture and factory testing of the Ion Source and Extraction Power Supplies for the SPIDER experiment, Fusion Engineering and Design 96-97 (2015) 405–410. [4] E. Gaio, et al., The alternative design concept for the Ion Source Power Supply of the ITER Neutral Beam Injector, Fusion Engineering and Design 83 (2008) 21–29. [5] M. Boldrin, et al., Design issues of the High Voltage Platform and feedthrough for the ITER NBI ion source, Fusion Engineering and Design 84 (2009) 470–474. [6] M. Boldrin, et al., Design status and procurement activities of the High Voltage Deck 1 and Bushing for the ITER neutral Beam Injector, Fusion Engineering and Design 88 (2013) 985–989. [7] M. Boldrin, et al., Final design of the High Voltage Deck 1 and Bushing for MITICA: The ITER Heating Neutral Beam Injector prototype, Fusion Engineering and Design 123 (2017) 395–399.
1898
Contents lists available at ScienceDirect
Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes
The High Voltage Deck 1 and Bushing for the ITER Neutral Beam Injector: Integrated design and installation in MITICA experiment
T
⁎
Marco Boldrina, , Muriel Simonb, Gerard Escudero Gomezb, Michael Krohnc, Hans Decampsd, Tullio Bonicellib, Vanni Toigoa a
Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova, Italy Fusion For Energy, c/ Josep Pla 2, 08019 Barcelona, Spain c Siemens AG, Process Industries and Drives Division, Large Drives, Industrial Applications PD LD AP S TA EL, Gleiwitzer Str. 555, 90475 Nürnberg, Germany d ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex, France b
A R T I C LE I N FO
A B S T R A C T
Keywords: ITER PRIMA MITICA Heating Neutral Beam Injector (HNB) High Voltage Deck 1 (HVD1) High Voltage Bushing Assembly (HVBA) Insulation design Seismic design Thermal design
MITICA is the full scale prototype of the ITER Heating Neutral Beam (HNB) currently under construction at the Neutral Beam Test Facility in Padova (Italy). In the ITER HNB, negative ions (H−/D−) are produced in the Ion Source (IS) polarized to ground at −1012 kV, then extracted and accelerated to ground at 1 MeV energy and finally neutralized. The complex power supply system feeding the IS includes two non-standard equipment, beyond the current industrial standard for insulation voltage level (-1 MVdc) and dimensions: 1) the High Voltage Deck1 (HVD1), a large air insulated Faraday cage (12.5 m (L) x 8.4 m (W) x 9.6 m (H)) hosting the IS power supplies and diagnostics; 2) the High Voltage Bushing Assembly (HVBA), a -1 MVdc air to SF6 Bushing which interfaces the HVD1 with the SF6 insulated Transmission Line (TL) connecting the Acceleration Grid Power Supply system with the IS, carrying inside its High Voltage electrode all IS power and diagnostics conductors. The HVD1 and HVBA are installed inside a large HV hall. The main design choices leading to the final hall layout, integrating the HV experimental equipment and the conventional building plants assuring the necessary clearance required by such very high electric insulation level, are presented. Moreover, the paper reports on the manufacturing design developed by the supplier, the factory type tests to validate the design of the HVD1, the factory tests carried out on the HVBA and the on-site installation, commissioning and testing activities.
1. Introduction To achieve ITER plasma burning conditions two Heating Neutral Beam Injectors (HNBs), designed to deliver to the plasma a power of 16.5 MW each with a pulse duration up to 1 h [1], are required. To comply with such very demanding ratings, the strategy for the construction and the development of the ITER project foresees the realization of a test facility called PRIMA (Padua Research on Injector with Megavolt Acceleration) [2] including two separate projects: SPIDER (Source for the Production of Ions of Deuterium Extracted from RF plasma) aimed at characterizing the high-energy negative neutral beam Ion Source (IS) and MITICA (Megavolt ITER Injector & Concept Advancement), the full-size prototype of the 1 MVdc beam injectors aimed at designing, installing, testing and optimizing the prototype of the HNB in order to reach the required parameters for the ITER operation. In the MITICA project will be tested the production, extraction, acceleration and neutralization of H− and D− ions. These ions are produced in the IS
⁎
polarized to ground at −1012 kVdc, then extracted by 12kVdc extraction voltage, accelerated at 1 MeV energy and finally neutralized. The complex power supply system feeding the IS (see Fig. 1) includes two very particular equipment, beyond the actual industrial standard for insulation voltage level (-1 MVdc) and dimensions, which are:
• the High Voltage Deck1 (HVD1), a large air insulated Faraday cage •
(12.5 m (L) x 8.4 m (W) x 9.6 m (H)) hosting all the Ion Source services, namely the Ion Source and Extractor Power Supplies (ISEPS [3]) and the cubicles for control and diagnostics; this equipment is fed by an insulating transformer during operation [4]; the High Voltage Bushing Assembly (HVBA), a -1 MVdc air to SF6 Bushing interfacing the HVD1 with the SF6 insulated Transmission Line (TL); the TL connects the Acceleration Grid Power Supply system (AGPS) with the IS, carrying inside its High Voltage electrode all ISEPS power and diagnostics conductors.
Corresponding author. E-mail address: [email protected] (M. Boldrin).
https://doi.org/10.1016/j.fusengdes.2019.03.059 Received 27 August 2018; Received in revised form 7 February 2019; Accepted 10 March 2019 Available online 18 March 2019 0920-3796/ © 2019 Elsevier B.V. All rights reserved.
Fusion Engineering and Design 146 (2019) 1895–1898
M. Boldrin, et al.
Table 1 Environmental conditions inside the HVH building. Temperature (min ÷ max) Room air humidity (min ÷ max) Dust class a
18 °C ÷ 35 °C 40% ÷ 60% 100.000 P/ft³a
Fed. Std. 209E, equivalent to ISO Class 8 according to ISO 14644-1.
minimum clearance of 5 m is required. To this purpose, electrical and air treatment services have been designed to assure such minimum clearance. The HVH walls are recessed from the pillars (around 1 m) to ensure that the lamps, fire detectors, loudspeakers and related distribution ducts, made of plastic pipes, as well as all electrical and interface cubicles (see red circled details in Fig. 2) installed on the walls, are at a distance greater than 5 m from the HVD1. The interconnecting electrical cables are routed inside corrugated pipes (not visible in Fig. 2) buried in the concrete floor to avoid the use of conventional metallic trays along HVH walls and consequent increase of the electric field. Similarly, the fibre optics tray and the cooling water pipes connected to the HVD1 Insulating breaks are laid in a dedicated narrow pit on the HVH floor (see green contoured detail P in Fig. 2). The air conditioning system, designed to assure the environmental conditions reported in Table 1, is an all-air type (indoor air circulation with partial reintegration and mixing with outdoor air). It consists of an air treatment unit, installed outside the HVH, provided with suitable microfilters to cope with the dust class requirements. The treated air is delivered through channels installed on HVH ceiling (detail A in Fig. 2) to two collectors (detail B in Fig. 2) placed on the upper side of opposite walls, just beneath the building ceiling, and diffused to ambient through motorized nozzles (remotely adjustable). Exhaust air is extracted from HVH bottom side by vertical air channels provided with suction grilles at the lower end (detail C in Fig. 2), then delivered back to the air treatment machine by means of two lateral ducts (detail D in Fig. 2) installed beneath the HVH ceiling. Finally, an adaptation of the HVH floor was necessary before the installation of the HVD1. In fact, the concrete slab of the HVH, designed and built before HVD1 design finalization, was unsuitable to withstand the forces transferred by the two plates of the HVD1 base frame laying on the other side of the TL pit (detail E in Fig. 2). Therefore, underneath those two plates the original floor was removed and replaced with two plinths designed to withstand the forces applied by the HVD1 structure.
Fig. 1. Overall view of the MITICA HV components.
Fig. 2. MITICA HVH layout.
2. High Voltage Hall integrated layout 3. Manufacturing design The HVD1 and HVBA are indoor installations, inside the MITICA High Voltage Hall (HVH) (26 m (L) x 29 m (W) x 21,4 m (H)); here ambient conditions (air temperature, humidity and dust level) are controlled. Underneath the HVD1 there is a pit where the HVBA is installed and interfaced with the TL (see Fig. 2). This configuration, described and analysed in [5,6], has been taken as reference for the procurement technical specification [7] mainly for its electrostatic reasons (HVBA installed in the uniform electric field produced underneath the HVD1). As a consequence, more free space for a functional layout of the equipment inside the HVH is made available. Furthermore a simpler seismic design (HVBA mechanically decoupled from HVD1) has been adopted. The insulating transformer bushing is installed aside the HVD1 and connected to it via a duct, acting also as corona shield. The duct hosts in a tray the medium voltage cables connected to the insulating transformer secondary which provides power supply to ISEPS equipment inside HVD1. The duct is realized to decouple mechanically the transformer bushing and the HVD1 to avoid force transmission during seismic events. The HVH will host also the AGPS dummy load, consisting in a series of high voltage resistors in air with taps for connections, to be connected to the HVD1 for on‐site testing of AGPS performance with a pulse length limited to 2 s. To avoid discharges from the HVD1 towards the ceiling and the walls (which inner surface is identified by the pillars inner face) of the HVH, a
The detailed design phase of HVD1 and HVBA was concluded in May 2016 [7]. The manufacturing design has been developed by the supplier using a 3D integrated model. Specific 2D drawings have been derived from the model to detail HVD1 and HVBA interfaces. Fig. 3, showing HVD1 base plates positions and drilling scheme for anchor bolts fixation on the HVH floor, is an excerpt of the set of drawings that, together with the specification of the forces transferred to the concrete floor under static and seismic conditions, were used for exchanges up to final clearance from PRIMA civil engineers prior to
Fig. 3. ISO view of HVD1 baseframe with baseplates and anchor bolts location. 1896
Fusion Engineering and Design 146 (2019) 1895–1898
M. Boldrin, et al.
HVD1 installation. Similar information was exchanged to allow verification of the HVBA. Additional 2D drawings have been produced: to detail the interface with ISEPS equipment (transformers, power and control cubicles) fixed on the supporting beams of HVD1 mechanical structure; to detail position and dimensions of interfaces with the Insulating Transformer and with the cooling plant pipes, connected to HVD1 insulating breaks at ground floor (see Fig. 2). A critical task, finalized through dedicated exchanges between European and Japanese Domestic Agency under ITER Organization coordination, consisted in defining, both from mechanical and electrical point of view, a design solution at the interface between the HVBA (procured by F4E) and the TL (procured by Japanese DA) reconciling the two individual designs and allowing a proper interconnection of the two components. 4. Factory acceptance tests 4.1. HVD1 tests A HVD1 mock-up with a reduced size of 4 m × 4 m × 4 m and only one floor, equipped with a door and supported by 4 full size post insulators, was built to perform the factory tests, developed with the Supplier based on the ratings reported in Table 2, to validate the design and release the manufacturing of the full-size HVD1. The tests were carried out on July 2016 at the High-Voltage laboratory of Hochspannungsgeräte GmbH (HSP) in Troisdorf (Germany) with a common tests setup requiring the mock-up installed in a corner of the test hall, at 5 m from the walls, with a 6.3 m x 6.3 m metallic frame installed 5 m above the deck and connected to ground potential to simulate the HVH ceiling (see Fig. 4). The post insulators were filled with N2 set at the minimum pressure value (250 kPa gauge). The following electrical tests, based on test standards IEC60060-1 (2010) and IEC60270 (2001), were successfully carried out (i.e. no disruptive discharge occurred on the test object): AC (960 kV) power frequency voltage withstand test, lightning impulse (2.1 MV) voltage withstand test and a long-duration DC voltage withstand test (5 h at -1.2 MVdc).
Fig. 4. HVD1 mock-up inside HSP laboratory in Troisdorf.
45°K [7], calculated with 40 °C ambient temperature after three daily operation at nominal duty cycle 1 h ON/3 h OFF) but below the admissible limit of ΔT = 100°K according to IEEE 65700−19-3 applicable standard.
4.2. HVBA tests 5. Installation at MITICA site As with the HVD1 post insulators [7], also for the HVBA dedicated materials tests followed by hydraulic pressure tests to achieve Italian National Body (INAIL) homologation for pressurized components were successfully held in October 2016. The same set of electrical tests described in Section 4.1 were carried out in January 2017 at HSP laboratory, as well as a polarity reversal test (according to applicable standard IEC/IEEE 65700−19-3) to test HVBA insulation capability to withstand the specific requirement in Table 2 and then the voltage withstand test of HVBA ISEPS conductors. Finally, a temperature rise test was carried out on February 2017. The HVBA was filled with SF6 at minimum pressure (450 kPa relative) and a set of thermocouples were fixed on the inner conductors. The test was carried out driving continuously along the two massive HVBA inner conductors (rated currents about 5kAdc [7]) an increased current of 6.6kAdc to take into account the losses of the remaining power conductors, in particular the RF lines [7], until reaching thermal stabilization (i.e. temperature variation less than 1°K/h). The hottest inner conductor heated up to 88 °C with 23 °C ambient temperature (ΔT = 65°K), above the simulated results (ΔT =
Installation onsite, carried out from mid-March to end October 2017, was preceded by a metrological survey supported by Consorzio RFX metrology team to locate precisely the positions of the HVD1 baseplates (Fig. 3) with reference to the interface point of the HVBA with the TL already installed in the pit. The HVBA already assembled (about 12 m tall), was delivered via special transport and installed in the pit as a unique piece using two truck cranes. Next was the assembly of the HVD1 baseframe (Fig. 3), composed of beams welded on baseplates in turn fixed to the HVH floor by anchor bolts and mortar, on which were fixed afterwards the eight post insulators (see Fig. 5). The cage lower frame (only the main beams) was preassembled at ground, lifted up by the HVH crane, connected to the top of the post insulators and then completed with secondary beams, floor grids, and bottom nested screens (inner EMI, outer electrical [7]). The side walls of the HVD1 cage were preassembled at ground in three vertical sections (metallic supporting structure completed with the outer electrical screen) lifted up sequentially for fixation on the cage lower frame. The assembly operations went on with the completion of the two outer screens, the installation of the additional equipment (insulating breaks for water and optical fibres, grounding switch, ventilation system [7]) and of the aluminium screen covering the baseframe. Being the HVD1 qualified as structural work, its compliance with Italian Norm for Construction (NTC2008) was monitored by the Director of Works, a chartered engineer involved both before installation (manufacturing design clearance, inspection of manufacturing, samples) and during installation. Another role prescribed by law is the static test inspector,
Table 2 Power supply system voltage withstand requirements. Rated voltage Short duration (3600 s) DC test voltage Long duration (5 hours) DC test voltage Pulsed voltage test starting from -1060kVdc Polarity reversal (up to 200 times per hour; total number of 450,000 during lifetime)
−1000 kVdc −1200 kVdc −1060 kVdc −1265 kV +300 kV
1897
Fusion Engineering and Design 146 (2019) 1895–1898
M. Boldrin, et al.
processing was done in the frequency domain by using ARTeMIS Modal 5.1 software suite to obtain validated estimates of the mode shapes, natural frequencies and damping ratios (procedure known as Operational Modal Analysis, OMA). In the significant range up to 20 Hz it was possible to identify 3 eigenfrequencies for the HVD1 and 5 for the HVBA deviating less than 20% (acceptance criteria) from the corresponding numerical results calculated by modelling and analysing the structures with ANSYS Workbench 16.1. This way, the experimental vibration measurements validated the HVD1 and HVBA numerical models. The insulating tests for the final acceptance of the HVD1 and HVBA, consisting in the execution of the Short and Long duration DC voltage tests and the Pulsed voltage test as reported in Table 2, are foreseen to be performed in Q4 of 2018 after connecting the HVBA to the TL. The tests will be carried out using a dedicated SF6 insulated Testing Power Supply generator (see Fig. 1) rated for -1.3MVdc and 10mAdc. 7. Conclusions
Fig. 5. HVD1 installed inside HVH.
After successful execution of the factory acceptance tests, the HVD1 and HVBA have been installed at PRIMA facility. Onsite acceptance tests have been positively carried out. The final acceptance tests at full voltage are foreseen to take place in Q4 of 2018 after connection to the TL.
whose duty is to prescribe and perform load tests on the structure or parts of it in order to verify its structural function before entry into service. The static test inspector prescribed a static test in-situ on one of the post-insulators, which verified with positive result the actual behaviour against the theoretical result derived from the finite element model used for the structural analysis.
Acknowledgement and Disclaimers
6. Onsite acceptance tests
The work leading to this publication has been funded partially by Fusion for Energy under the contract F4E-OPE-083. This publication reflects the views only of the author, and F4E cannot be held responsible for any use which may be made of the information contained therein. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization. The authors would like to thank the main subcontractors of Siemens who manufactured and installed at site: HSP Hochspannungsgeräte GmbH for the HVBA, Andreas KARL GmbH & Co. KG for the HVD1.
The following tests were successfully executed. A HVD1 electrical screen test (to assess the correct installation of the HVD1 electrical screen in particular regarding its EMI screening capabilities) consisted in a qualitative verification of the screening via a “leakage test” done using a 435 MHz power transmitter with suitable transmitting antenna, positioned in the HVH outside the HVD1, and a portable receiver moved along the connections and joints of the EMI screen inside the HVD1 to verify the absence of transmitted signal. The Insulating breaks for demineralised cooling water, provided with closing flanges, were pressurized and subjected to a water leakage test at 10 bar absolute maintained for 1 h. Functional tests were performed on the grounding switch using its operating mechanism and registering closing and opening operations times. The proper operation of the ventilation system and the provision of the required air flow (16 m3/s) were verified. The correct operation of the interlock mechanism of the HVD1 doors was demonstrated. The voltage withstand test of HVBA ISEPS conductors, already carried out in factory, was repeated including also the additional cables sections up to their interface point inside the HVD1. Finally, a seismic qualification was performed on both HVD1 and HVBA to validate the parameters of the models used for the seismic design of the structures. To this purpose, each equipment was provided in turn with accelerometers (24 piezoelectric accelerometers of different sensitivity on the HVD1 and 21 on the HVBA) and the signals, produced by the ambient vibration without needing any artificial excitation, were acquired and stored via a frontend to a laptop. Signals
References [1] ITER technical basis, IAEA, Vienna, ITER EDA, Doc. Series N. 24, Plant Description Document, Sec. 2.5.1. (2002). [2] V. Toigo, et al., The PRIMA Test Facility: SPIDER and MITICA test-beds for ITER neutral beam injectors, New J. Phys. 19 (2017). [3] M. Bigi, et al., Design, manufacture and factory testing of the Ion Source and Extraction Power Supplies for the SPIDER experiment, Fusion Engineering and Design 96-97 (2015) 405–410. [4] E. Gaio, et al., The alternative design concept for the Ion Source Power Supply of the ITER Neutral Beam Injector, Fusion Engineering and Design 83 (2008) 21–29. [5] M. Boldrin, et al., Design issues of the High Voltage Platform and feedthrough for the ITER NBI ion source, Fusion Engineering and Design 84 (2009) 470–474. [6] M. Boldrin, et al., Design status and procurement activities of the High Voltage Deck 1 and Bushing for the ITER neutral Beam Injector, Fusion Engineering and Design 88 (2013) 985–989. [7] M. Boldrin, et al., Final design of the High Voltage Deck 1 and Bushing for MITICA: The ITER Heating Neutral Beam Injector prototype, Fusion Engineering and Design 123 (2017) 395–399.
1898