220 Volt DC Power for Telecom NZ

WSP Opus helped Telecom NZ move to 220 volt DC power – a move which has brought a range of benefits. WSP Opus has done many upgrade projects involving traditional 50 volt DC systems in Telecom buildings as part of the engineering asset management services we provide to Telecom NZ.

However traditional solutions are becoming unsuitable due to issues associated with increasing equipment power densities, limited building space and building floor loading limitations.

We provided Telecom with consultancy services to find alternative solutions, including:

• Identifying initial and ultimate system power requirements
• Determining battery reserve capacity, and size and weight requirements
• Structural analysis of buildings to identify floor loading limitations
• Identifying suitable DC power equipment locations in buildings
• Developing an alternative DC solution using a central 220V DC design
• Sourcing and specifying suitable equipment associated with a high voltage DC solution
• Producing pre-development reports and detailed design briefs
• Project management during installation and final testing/commissioning of the completed installation

The 220V solution was developed to provide a range of benefits. There is now the ability to locate 240V AC to 220V DC rectifier banks and DC battery reserve remotely from communication equipment without the need for a large DC bus to maintain voltage drop limits. Heavy batteries can be located in parts of buildings capable of handling heavy weights, usually on ground floor or lower levels where seismic related issues are lessened.

We provided for 220V DC to 50V DC rectifiers to be located close to equipment load. There was a reduction in cable sizes traditionally needed to minimise voltage drop as 50V supply is maintained throughout battery discharge. The new solution enabled modular system cable, and an isolated 220V supply.