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

2. 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)

3. Zoning Concept mm

4. Zoning Concept mm

5. 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.

6. 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.

7. 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

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

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

10. 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.

11. 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)

12. 1. Grounding mesh in halls D01 to D03
ACC

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

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

15. 2 - 4. Connections to metallic structure

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

17. Preferred connection points
Level 090
D01
D06
Level 100

18. Reservation of space in the installation pathways

19. 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

20. Alternative: Connection points in galleries D01-D03

21. Alternative: Connection points at pillars E01/E02

22. Thanks!

23. 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 -

24. CF Grounding Map (West Sector, long Instr.)

25. CF Grounding Map (Other Sectors)

26. 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)

27. 1. Connection points on outer walls

28. 2. Connection points in galleries D01-D03

29. 2. Connection points in galleries D01-D037m 2m 5m

30. 3. Connection points for the bunker in D01

31. 4. Connection points at pillars E01/E02

32. 5. Connection points in the substations

33. The grounding symbols (IEC 60417)