Earthing at Data Centre Facilities

Power demands at data centres has exponentially increased over the years. Today a 50MW facility is a common size with plans by data centres to build between 80MW-500MW facilities in future in Australia. This is similar to energy consumption of a whole small city in the past. As a comparison the daytime energy consumption of Tasmania and South Australia is 1000MW.

In a facility with such high density of power in a relatively small area, there are several things in the design and construction of such a facility that need to given special consideration. These include consideration on methods of power transmission and distribution, methods of cooling, power cabling and busway systems, earthing systems, standby generation, fire protection system, other safety and security systems.

In this paper we will look at the earthing systems that will exist as a data center and also pay attention to how these systems are interconnected.

• Indoor grounding system for data and communication equipment that are almost all AC LV powered. The relevant standards for this are TIA607D and AS/IEC30129 Information technology – Telecommunications bonding networks for buildings and other structures.
• Outdoor grounding electrode system. There is no known standard for the outdoor grounding system and methods have developed over the years by the electrical engineering industry. These electrode system provide all the functions of earthing for both the telecommunications and the LV AC equipment.
• High Voltage and Medium Voltage Earthing system for substation and transformers. The high power density has necessitated the need for some of the MV transformers to be housed within the building and in many cases at several floor levels at a data centre facility.
• Interconnection and coordination of HV, LV and Communications earthing systems. While standards exist that provide guidance on some aspects of interconnection, there is generally lack of standards in this area.