DC high voltage

Data centres are increasingly relying on direct current (DC), as many of their components, such as UPS systems, batteries, processors and memories, work with DC. Renewable energies such as photovoltaics also generate direct current, which suggests using a centralised DC grid. The advantage: There is no need to convert alternating current (AC) to direct current, which can increase efficiency by up to 10 %.

DC systems require fewer components than AC-based solutions: Transformers, rectifiers and inverters can be eliminated in most applications. This simplifies the current path and reduces energy losses, maintenance costs and space requirements. Smaller cable cross-sections also enable better resource utilisation with the same performance, especially when using copper. This saves costs and simplifies cable management, which also has a positive effect on costs for rented infrastructure.

Retrofitting existing systems is often uneconomical, HVDC is becoming increasingly important for new buildings. Needless to say, safety is just as important as efficiency and cost-effectiveness - especially where people come into direct contact with the power supply, e.g. of IT racks.

E-T-A’s "PDB-HVDC-D08-R" Power D-Box is one example of such a solution. The power distribution system is designed for use in DC 400 V applications and offers a redundant structure. It is possible to connect two separate power supplies to maintain the power supply in the event of malfunctions or faults on one power path. The system offers space for up to eight pluggable, double-pole 8365-T circuit breakers. They trip reliably and precisely even in the event of malfunctions in both the positive and negative paths. 

The circuit breakers can protect loads up to 25 A and are characterised by a magnetic-hydraulic tripping characteristic. Circuit breakers with magnetic tripping react almost immediately to short-circuit currents by disconnecting the faulty circuit quickly and reliably. This tripping characteristic is ideal for applications that require precise, temperature-insensitive tripping, as is the case in communications technology. Their hydraulic trip elements provide delayed tripping in the event of an overload making these circuit breakers an extremely reliable and safe solution. This ensures a high level of operational reliability, even in the event of cooling system or air conditioning failures. 

The mechanically coded supply connectors prevent the power supply from being inadvertently swapped. SAF-D-GRID®-connectors are available for the load outputs. Their enclosures suppress arcs in case the connector is plugged or removed under voltage. Several earthing connections also facilitate the integration of insulation monitors, which provide additional safety. The power distribution system can be used in all applications that are supplied by a current-limiting power supply unit (PSU).