1-2 Grounding Principles and CF Infrastructure in Instruments Halls Grounding Implementation Workshop Lund, 29th August 2018 Thomas Gahl - Group Leader Motion Control & Automation -

Overview ESS Grounding principles Application on instruments The zoning concept Basic requirements for implementation on ESS instruments Application on instruments Long, medium, short Ground connections inside a zone How to connect to infrastructure? Existing CF infrastructure Preferred ground connection points + alternatives Instruments zoning map (proposal)

Zoning Concept mm

Zoning Concept mm

L1 - High level requirements The grounding installations shall be divided into three greater grounding zones, following the different power supply zones in the D- and E-buildings. The grounding of NSS instruments shall be implemented in a way that interferences from in- and outside the instrument through air, power cables or grounding bonds shall not compromise the availability, functionality and performance of the single instrument (e.g. by introducing isolated instruments grounding zones). The number of grounding zones shall be minimized. Lessons learned from other facilities shall be included in the design of the grounding installations. Grounding shall fulfill functional, EMC and safety requirements to ESS and European standards.

L2 requirements The cave zone with the detector equipment is the most sensitive area of an instrument. Instruments grounding potential shall be independent from any outside influences, especially from the accelerator and the target. Each instrument should have its own grounding zone (s) isolated from each other. Grounding zones are following the different power supply zones. Grounding zones shall as much as possible follow “natural” borders like walls, shieldings etc. The number of grounding zones shall be minimized. It shall be possible to define common grounding areas among instruments if advantageous. Inside a grounding zone sensitive equipment like detector electronics shall have its own “clean earth” return. Grounding shall fulfill at the same time functional, EMC and safety requirements of European standards.

Long Instruments Target A B C D03 Building E02 Building Bunker Bunker Wall B Building Wall Instruments perimeter Grounding zone boundaries C Zone barrier: Isolation of instruments components

Medium Instruments ? Target A B C D01 Building Bunker Bunker Wall Instruments perimeter Grounding zone boundaries Zone barrier: Isolation of instruments components

Short Instruments Target A C D03 Building Bunker Bunker Wall Building Wall Instruments perimeter Grounding zone boundaries Zone barrier: Isolation of instruments components

Grounding connections inside a zone Equipotential bonding bar (EBB) for standard safety and functional grounding “Clean Earth” connections for sensitive equipment connecting directly to the ground reference point of the zone.

CF Grounding Infrastructure In Instruments halls: Grounding mesh 5x5m of conductor Fe 3x30, regularly connected to the rebar. Regular connection to the ring conduit around the whole ensemble of buildings Connections of all metallic infrastructure to this mesh (pillars, facade structure etc.) Flexible connection to bridge the dilatation joint between D01/D03 and D02. Areas of connection points to CF grounding Access to the grounding mesh with “yellow” connection points along the outer walls of the halls (every 5m) Access to the grounding mesh in the gallery of halls D01 and D03 (every 3m) Access to the grounding mesh at the bunker walls of D02 Access to the grounding mesh at each pillar between E01 and E02 Access to the grounding mesh of the substation buildings (D05, D06 and E05) in the power distribution rooms for instruments of that buildings (one ground connection per instrument zone)

1. Grounding mesh in halls D01 to D03 ACC

1. Grounding mesh in halls D01 to D03 ~ 10-15cm ~ 60cm Concrete armouring

2. Circuit conduit around D- and E-buildings ACC

2 - 4. Connections to metallic structure

5. Areas of connection points to CF grounding Level 090 D01 D06 Level 100

Preferred connection points Level 090 D01 D06 Level 100

Reservation of space in the installation pathways

Installation preparations (22 Instruments) Assumption: Two zones per instrument + common bunker zone Each zone has a power cable and an additional ground cable to connect to the substation Power cable type: FXQJ EMC Power cable sizes 4x6/6 to 4x70/35 Ground cable sizes 35mm2 Lengths from 40m to 280m Prepared ground connections in substation: D05: 20 D06: 21 E05: 16

Alternative: Connection points in galleries D01-D03

Alternative: Connection points at pillars E01/E02

Thanks!

Grounding Implementation Workshop Lund, 29th August 2018 Grounding Principles and CF Infrastructure in Instruments Halls - Additional slides - Grounding Implementation Workshop Lund, 29th August 2018 Thomas Gahl - Group Leader Motion Control & Automation -

CF Grounding Map (West Sector, long Instr.)

CF Grounding Map (Other Sectors)

CF Grounding Infrastructure II Access to the grounding mesh with “yellow” connection points along the outer walls of the halls (every 5m) Access to the grounding mesh in the gallery of halls D01 and D03 (every 3m) Access to the grounding mesh at the bunker walls of D02 Access to the grounding mesh at each pillar between E01 and E02 Access to the grounding mesh of the substation buildings (D05, D06 and E05) in the power distribution rooms for instruments of that buildings (one ground connection per instrument zone)

1. Connection points on outer walls

2. Connection points in galleries D01-D03

2. Connection points in galleries D01-D03 7m 2m 5m

3. Connection points for the bunker in D01

4. Connection points at pillars E01/E02

5. Connection points in the substations

The grounding symbols (IEC 60417) https://incompliancemag.com/article/the-grounding-symbols/