| 1. |
- de Haan, J. E. S., et al.
(författare)
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Stabilising system frequency using HVDC between the Continental European, Nordic, and Great Britain systems
- 2016
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 5, s. 125-134
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Tidskriftsartikel (refereegranskat)abstract
- For future efficiency improvement of the frequency containment process (primary control) within European power systems, cooperation between (multiple) synchronous areas using their controllable HVDC interconnections is optioned. However, the differences in system size, HVDC interconnection capacity, and the balancing performance per individual system will have its specific system frequency effect for each different balancing cooperation concept. Consequently, without alignment on cooperation, HVDC balancing might lead to disproportional support between systems, to frequency oscillations, reserve unreliability and non-compliancy, and to network constraints. Therefore, this work assesses frequency quality and associated DC power flows for several balancing arrangements, using a developed load-frequency control model with frequency interdependency for coupled power system. For a trilateral balancing cooperation case study, it is found that certain cooperation concepts result in undesired frequency oscillation and poor frequency quality. However, cooperation where especially fast-response services are shared, such as virtual inertia, show improved system frequency performance. For the case where power imbalances are proportionately distributed among the systems, it is concluded that power transfers over HVDC interconnections are limited and additional control optimisation can be performed. Those concepts with aligned central or coordinated control show best results for a future cooperation for balancing between synchronous areas.
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| 2. |
- Belitsky, Victor, 1955, et al.
(författare)
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ALMA Band 2 Cold Cartridge Assembly Design
- 2022
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Ingår i: 32nd International Symposium of Space Terahertz Technology, ISSTT 2022.
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Konferensbidrag (refereegranskat)abstract
- As part of the ALMA development, we present the design of the ALMA Band 2 Cold Cartridge Assembly (CCA). The Band 2 is the last band that completes the suit of the 10 receiver channels of ALMA. The originally planned ALMA Band 2 receiver cartridge should cover the RF band of 67 - -90 GHz. The recent progress in technology, optics, OMT design and mm-wave amplifiers, however allowed to implement receiver that has an extended RF band up to 116 GHz. Furthermore, the Band 2 receiver pursues 2SB layout and provides 4-18 GHz IF band for two sidebands in a dual-polarization configuration. Here, we describe the design of the Band 2 CCA that includes optics, amplifier assembly, internal RF transport, mechanics and cryogenics. The downconverter part and performances are described elsewhere.
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| 3. |
- Belitsky, Victor, 1955, et al.
(författare)
-
ALMA Band 5 receiver cartridge: Design, performance, and commissioning
- 2018
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 611
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Tidskriftsartikel (refereegranskat)abstract
- We describe the design, performance, and commissioning results for the new ALMA Band 5 receiver channel, 163-211 GHz, which is in the final stage of full deployment and expected to be available for observations in 2018. This manuscript provides the description of the new ALMA Band 5 receiver cartridge and serves as a reference for observers using the ALMA Band 5 receiver for observations. At the time of writing this paper, the ALMA Band 5 Production Consortium consisting of NOVA Instrumentation group, based in Groningen, NL, and GARD in Sweden have produced and delivered to ALMA Observatory over 60 receiver cartridges. All 60 cartridges fulfil the new more stringent specifications for Band 5 and demonstrate excellent noise temperatures, typically below 45 K single sideband (SSB) at 4 K detector physical temperature and below 35 K SSB at 3.5 K (typical for operation at the ALMA Frontend), providing the average sideband rejection better than 15 dB, and the integrated cross-polarization level better than -25 dB. The 70 warm cartridge assemblies, hosting Band 5 local oscillator and DC bias electronics, have been produced and delivered to ALMA by NRAO. The commissioning results confirm the excellent performance of the receivers.
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