The INFRA SA Consortium is responsible for the design of the Infrastructure & Power Sub-elements for SKA1-mid in South Africa. This includes Access (roads, civil works), Buildings, Communication, Site Monitoring, Security, Antenna Foundations, Vehicles, Power, Water and Sanitation.
The Consortium has updated the Level 2 requirements based on the Level 1 Rev 11 requirements. A few partial/non-compliant requirements are being discussed with the SKAO.
Good progress has been made on all the Level 3 requirements for each sub-element as well as internal interface definition.
There has also been good progress on updates to the external Interface Control Documents, with only the TM/INFRA ICD remaining the least mature.
The Consortium has submitted an ECP to the SKAO to update the Stage 2 Milestones and Deliverables.
The SKAO Configuration Board has approved the ECP which considers the trade-off in life cycle costs between providing stand-alone PV plants as opposed to overhead power distribution lines to the last 5 dishes in each spiral arm (design baseline).
A PV design engineer and RFI specialist have been appointed by INFRA SA to undertake the detailed design of the PV plants.
Aurecon South Africa has been undertaking further Digsilent modelling to look at what upgrades are required to the existing 33kV overhead power line. Further discussions have also been held with the South African power utility, Eskom regarding the Notified Maximum Demand which can be made available to the SKA at the Karoo substation.
Further work is underway on the structuring loading of the overhead power lines and the first draft of the RAM/ILS modelling for the power system has been submitted for review.
SKA1-mid ANTENNA FOUNDATION PROTOTYPE
The SKA1-mid antenna foundation prototype stability testing was undertaken on the 2nd of August and the 20th of September 2017. The measured tilt from the first test ranged from 2.473 to 2.681 arcsec while the results from the second test ranged from 2.063 to 2.269 arcsec, both below the 10.4 arcsec specified for the operational conditions. It should however be noted that the governing case is the lateral stiffness, not tilt. For the maximum applied load (calculated for both MeerKAT and SKA antennas) the displacement on MeerKAT antennas was in the order of 11 arcsec, while for the SKA prototype foundation it is 3.919 arcsec when subjected to a 25ton load (refer figure below).
The detailed design of the antenna foundations has now been finalised and an internal review date will be confirmed in due course.
UPGRADE TO CENTRAL PROCESSING AND POWER FACILITY
A preliminary design review has taken place on the proposed solutions to the Central Processing Facility and Power Facility. Work is now progressing on the detailed design of the upgrades required to both facilities.
SKA1-mid PHYSICAL CONFIGURATION
The Consortium has submitted proposed changes to the SKA1-mid physical configuration following interaction with the power line route surveyor and landowners in the spiral arms. The Consortium will submit an ECP to the CCB for approval.
SITE CHARACTERISATION STUDIES
The geotechnical contractor has completed the Phase 2 drilling on site as an input to the detailed design of the antenna foundations. The geo-hydrological contractor has been on site determining yield values from boreholes as an input to the geo-hydrological modelling and Water & Sanitation sub-element.
EMC/EMI CONTROL PLANS
The Consortium has developed an overarching EMC/EMI Control Plan which has been reviewed and approved by the SKAO.
HEALTH & SAFETY HAZARD ANALYSIS
Work has commenced on a detailed hazard analyses for the infrastructure and power products. This work will be discussed with the SKAO to ensure compliance to the SKA requirements.
COST PLAN UPDATES
The Consortium submitted its updated Cost Plan to the SKAO on the 2 October 2017. Capital costs have decreased as a result of the implementation of the ECP from the Cost Control Project on the introduction of stand-alone PV plants for the last 5 dishes on each arm.
DETAILED DESIGN WALKTHROUGH
The Consortium will be undertaking a detailed design walkthrough from the 4-8 December 2017 in South Africa. Detailed design drawings and reports will be reviewed, general progress assessed as well as possible gaps identified in the design which still need to be addressed.
E.C. HORIZON 2020 SUBMISSION AND CDR SUBMISSION
The Consortium will be submitting its detailed design packs to the EC Horizon 2020 at the end of January 2018 (funding was received for Stage 2 from the EC Horizon 2020). A meeting will be held in Brussels on the 14th March 2018 to assess the completeness of deliverables.
The Consortium will be submitting its Critical Design Review pack to the SKAO at the end of April 2018. This will be followed by CDR in June/July 2018.