The Residual Ion Dump Power Supply (RIDPS) is devoted to feed the Electrostatic Residual Ion Dump, a device which shall collect the residual ions at the output of the gas Neutralizer in the ITER Heating Neutral Beam Injectors (HNBI) and their full-scale prototype (MITICA), presently under construction in the Neutral Beam Test Facility (NBTF) in Padua, Italy. The procurement of the three RIDPS, part of the Procurement Arrangement signed between Fusion for Energy (F4E) and ITER Organization (IO) in 2009, has been committed by F4E to OCEM Energy Technology s.r.l. (OCEM). This power supply has to provide an average voltage of up to 25 kV, plus an ac low-frequency voltage component with maximum amplitude of 5 kV. The nominal output current is 60 A, and the maximum pulse duration is 1 hr. The selected topology is the Pulse-Step-Modulator (PSM), including a multi-winding dry type transformer and 42 water-cooled switching power modules, connected in series at the output. Among the various advantages of this technology, the most important for this application are the modularity, allowing redundancy at module level, and the light output filter and short switch-off time in case of fault, both limiting the energy delivered to possible arches among RID plates. The manufacturing of the RIDPS for MITICA has been concluded in summer 2018. The Factory Tests on the single components and on the full system were finished in October 2018 and in the same month started the Site Installation activities at NBTF. At the end of November the installations were completed and the Site Tests started, planned to be completed by beginning of 2019. A close follow-up of the whole procurement process has been carried out by both F4E and Consorzio RFX. Particular effort has been devoted to the verification of the design, the definition of the test procedures and the integration of the system with the existing installations, including the management of layout interferences and the detailed scheduling of site works. In particular, during the factory tests, some problems appeared, requiring the definition of proper solutions. For example, in the original specification the frequency of the ac component of the output voltage was set to 50 Hz, while it has been found that this caused unwanted input current peaks due to synchronization with the grid voltage, with possible saturation of the transformer. Electromagnetic immunity issues have output filter caused a voltage ripple slightly exceeding the limit with reversed polarity, solved with the improvement of the filtering action. Finally, a suitable test procedure has been devised for the Electromagnetic Emission Tests at Site. In this paper, the most significant issues faced during the design, integration and tests and the solutions identified will be described. The layout adopted in the final installation will be commented and the most interesting results of the Factory and Site Tests will be presented, with particular emphasis to those proving the compliance of the RIDPS with the most critical requirements.
Manufacturing, installation and commissioning of the Residual Ion Dump Power Supply for MITICA experiment
TOIGO Vanni;
2019
Abstract
The Residual Ion Dump Power Supply (RIDPS) is devoted to feed the Electrostatic Residual Ion Dump, a device which shall collect the residual ions at the output of the gas Neutralizer in the ITER Heating Neutral Beam Injectors (HNBI) and their full-scale prototype (MITICA), presently under construction in the Neutral Beam Test Facility (NBTF) in Padua, Italy. The procurement of the three RIDPS, part of the Procurement Arrangement signed between Fusion for Energy (F4E) and ITER Organization (IO) in 2009, has been committed by F4E to OCEM Energy Technology s.r.l. (OCEM). This power supply has to provide an average voltage of up to 25 kV, plus an ac low-frequency voltage component with maximum amplitude of 5 kV. The nominal output current is 60 A, and the maximum pulse duration is 1 hr. The selected topology is the Pulse-Step-Modulator (PSM), including a multi-winding dry type transformer and 42 water-cooled switching power modules, connected in series at the output. Among the various advantages of this technology, the most important for this application are the modularity, allowing redundancy at module level, and the light output filter and short switch-off time in case of fault, both limiting the energy delivered to possible arches among RID plates. The manufacturing of the RIDPS for MITICA has been concluded in summer 2018. The Factory Tests on the single components and on the full system were finished in October 2018 and in the same month started the Site Installation activities at NBTF. At the end of November the installations were completed and the Site Tests started, planned to be completed by beginning of 2019. A close follow-up of the whole procurement process has been carried out by both F4E and Consorzio RFX. Particular effort has been devoted to the verification of the design, the definition of the test procedures and the integration of the system with the existing installations, including the management of layout interferences and the detailed scheduling of site works. In particular, during the factory tests, some problems appeared, requiring the definition of proper solutions. For example, in the original specification the frequency of the ac component of the output voltage was set to 50 Hz, while it has been found that this caused unwanted input current peaks due to synchronization with the grid voltage, with possible saturation of the transformer. Electromagnetic immunity issues have output filter caused a voltage ripple slightly exceeding the limit with reversed polarity, solved with the improvement of the filtering action. Finally, a suitable test procedure has been devised for the Electromagnetic Emission Tests at Site. In this paper, the most significant issues faced during the design, integration and tests and the solutions identified will be described. The layout adopted in the final installation will be commented and the most interesting results of the Factory and Site Tests will be presented, with particular emphasis to those proving the compliance of the RIDPS with the most critical requirements.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
