3 Phase Power

• 2012 After having problems with UPS & Gen set failure due to Neutral failure, did some investigation.

  • Failure of Switch-over box.
• Features
  • double conversion technology - separates the input ac power from the output power
    • Less desirable design is off-line, line-interactive or delta
• Important factor
  • input power factor of the UPS

  • Efficiency at <50% especially important if dual UPS used in data-center.

• Installation factors to consider.
  • UPS installation design - space cabling etc.
  • Redundant configuration n+1
  • Downstream earthing system: TN-S if transformer is in ownership and TT if it is not
  • Neutral section equal or double to phases
  • Different protection to UPS grid connection and by-pass connection
  • Over voltage protections downstream and upstream UPS
  • Disconnecting switch at UPS output to easy replacement
  • Air conditioning system

Switch box's / commutation

• Switch from mains power to generator in case of failure or testing.
• commutation between the grid connection and the generator

• Important neutral schemes

• four-pole breaker and therefore, the neutral wire is also sectioned.
  • During neutral switching spikes can be experienced, as neutral floats until connected to generator.
  • Sollution is to use transformer isolation downstream of UPS, generating new independent neutral.
    • adding a transformer in the by pass (static and dynamic)
• Makes
  • TELYS
  • NEXYS

Battery's

• BACS - Battery Analyze & Care System

  • Some can retrofit on current system, add unit to each battery.
• Alternate
  • Flywheel DC storage system.
    • Riello Fly Wheel 215KW - spinning at 36,000 RPM

Generator

• Standby Rating, Prime Power, Continuous Rating.
• Things to check
  • Sizing and selection
  • Electrical factors
  • Cooling
  • Ventilation
  • Fuel storage
  • Noise
  • Exhaust
  • Starting systems

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