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Dc Principal Dc Principal Presentation Transcript

  • Nov’07 DC Power Principles
      • Why DC Power
      • DC Power System – Overview
      • DC Output Current flow
      • Terminology
      • Provisioning considerations
    DC Power System Principles
  • Types of Power Systems DC OUTPUT DC/DC CONVERTER AC INPUT POWER SUPPLY OR RECTIFIER BATTERY CHARGER Battery UPS INVERTER ~ = DC OUTPUT DC INPUT = = AC OUTPUT DC INPUT = ~ DC OUTPUT AC INPUT ~ = AC OUTPUT Battery DC AC INPUT ~ = = ~
    • Provide reliable DC Power for Telecom Equip.
    No. 1 2 3 4 5 Battery DC OUTPUT AC INPUT ~ =
    • Most telecom equipment is designed to operate with DC input voltage.
    Why choose DC Power ?
    • Provide equipment power when AC is absent
    No. 1 2 3 4 5
    • When the AC supply (mains) is absent, DC supply must come from a stored energy source.
    • Currently, DC batteries are the cheapest and most efficient way to store electrical energy.
    Battery DC OUTPUT AC INPUT ~ = Why choose DC Power ?
    • Charge the Batteries
    No. 1 2 3 4 5
    • When the AC supply (mains) is restored, the batteries must be recharged.
    • Currently, DC batteries can only be charged by DC Power.
    Battery DC OUTPUT AC INPUT ~ = Why choose DC Power ?
    • Filter out noise and protect from surges
    No. 1 2 3 4 5
    • A DC supply will act as a line filter thus shielding the telecom equipment from AC system and phase noise.
    • A DC supply can also be configured with Over Voltage Protection to prevent high voltage surges from damaging the telecom equipment
    Battery DC OUTPUT AC INPUT ~ = Why choose DC Power ? ~ ~ ~
    • Monitor and Control the power
    No. 1 2 3 4 5 Battery DC OUTPUT AC INPUT ~ =
    • Equipment operators can configure and control what power is being supplied to the various telecom equipment.
    • Alarming is also provided to monitor the power system’s operation
    Why choose DC Power ?
  • In summary
    • The reasons for a DC Power System are :
    • Convert AC power to DC for telecom equipment
    • Provide power when AC is absent.
    • Charge the batteries when mains is restored.
    • Provide filtering and surge protection.
    • Provide monitoring and control of power.
  • DC Power System Principles
      • Why DC Power
      • DC Power System – Overview
      • DC Output Current flow
      • Terminology
      • Provisioning considerations
  • DC Power System - Components G DIESEL GENERATOR AC input Typically AC Mains between 110 – 480V, however other sources of supply can include generators, UPS etc. AC Input
  • DC Power System - Components G OVP MAINS FUSES DIESEL GENERATOR Input protection Can be provided by either; in-line fuses, Over Voltage Protection or other such devices. AC Input
  • Rectifier #1 Rectifier #2 Rectifier #n G OVP MAINS FUSES REDUNDANT RECTIFIER SYSTEM AC/DC DIESEL GENERATOR Rectifier #n Rectifier A Power supply which converts Alternating Current to Direct Current; typical output below 60V. AC Input DC Power System - Components
  • ALARM MODULE Rectifier #1 Rectifier #2 Rectifier #n G OVP MAINS FUSES REDUNDANT RECTIFIER SYSTEM AC/DC DIESEL GENERATOR Rectifier #n Monitor & Control Unit (Alarm module) Monitors the system and generates alarms if an event occurs outside of normal operation. AC Input DC Power System - Components
  • ALARM MODULE Rectifier #1 Rectifier #2 Rectifier #n G OVP MAINS FUSES BATTERY BANK REDUNDANT RECTIFIER SYSTEM AC/DC DIESEL GENERATOR Rectifier #n BATTERY BANK Battery Bank / String A battery bank is 1 or more battery strings. A battery string is a number of batteries connected in series to provide the required operating voltage AC Input DC Power System - Components
  • ALARM MODULE Rectifier #1 Rectifier #2 Rectifier #n G OVP MAINS FUSES LVBD BATTERY BANK REDUNDANT RECTIFIER SYSTEM AC/DC DIESEL GENERATOR Rectifier #n BATTERY BANK Low Voltage Battery Disconnect To prevent deep discharging of the batteries. Operated by the MCU when a user-configured low battery voltage point is reached. AC Input DC Power System - Components
  • ALARM MODULE Rectifier #1 Rectifier #2 Rectifier #n G OVP MAINS FUSES LVBD BATTERY BANK REDUNDANT RECTIFIER SYSTEM AC/DC DIESEL GENERATOR Rectifier #n LVLD BATTERY BANK Low Voltage Load Disconnect Reduces the drain on the batteries by non-priority loads. Operated by the MCU when a user-configured low battery voltage point is reached. AC Input DC Power System - Components
  • ALARM MODULE Rectifier #1 Rectifier #2 Rectifier #n G OVP MAINS FUSES BATTERY DISTRIBUTION BATTERY BANK REDUNDANT RECTIFIER SYSTEM AC/DC DIESEL GENERATOR Rectifier #n LVLD BATTERY BANK Distribution System hardware for distributing the DC power to the load. Hardware can include; battery breakers, MCB or blade fuses. AC Input DC Power System - Components LVBD
  • NONE PRIORITY LOAD LOAD (pc’s or different voltage) ALARM MODULE Rectifier #1 Rectifier #2 Rectifier #n G OVP MAINS FUSES BATTERY DISTRIBUTION BATTERY BANK DC-DC or DC/AC REDUNDANT RECTIFIER SYSTEM AC/DC DIESEL GENERATOR Rectifier #n LVLD PRIORITY LOAD BATTERY BANK Load Any equipment connected to the distribution of the DC system. AC Input DC Power System - Components LVBD
  • Load Any equipment connected to the output of the DC system. NONE PRIORITY LOAD LOAD (pc’s or different voltage) ALARM MODULE Rectifier #1 Rectifier #2 Rectifier #n G OVP MAINS FUSES LVBD BATTERY DISTRIBUTION BATTERY BANK DC-DC or DC/AC REDUNDANT RECTIFIER SYSTEM AC/DC DIESEL GENERATOR Rectifier #n LVLD PRIORITY LOAD BATTERY BANK BATTERY CHARGER Battery DC OUTPUT AC INPUT ~ = AC Input DC Power System - Overview
      • Why DC Power
      • DC Power System – Overview
      • DC Output Current flow
      • Terminology
      • Provisioning considerations
    DC Power System Principles
  • Eltek Power System Battery Bank DC OUTPUT AC INPUT DC Power System – Current Flow AC Input OK AC Input Outage AC Input restored
    • Load supplied by DC Power System
    • Voltage is at Float Voltage to maintain the charge on the batteries.
  • Eltek Power System Battery Bank DC OUTPUT AC INPUT DC Power System – Current Flow AC Input OK AC Input Outage AC Input restored
    • Load supplied by Battery Bank
    • Small amount of current to System for alarm and monitoring devices.
  • Eltek Power System Battery Bank DC OUTPUT AC INPUT DC Power System – Current Flow AC Input OK AC Input Outage AC Input restored
    • Load supplied by DC Power System
    • Batteies recharged by DC Power System. Initially maximum allowable/available current supplied, then reduces as battery charge level increases.
      • Why DC Power
      • DC Power System – Overview
      • DC Output Current flow
      • Terminology
      • Provisioning considerations
    DC Power System Principles
    • W = I x V
    • I = W / V
    • V = W / I
    Terminology – Power Triangle Current (I) Power (W) Voltage (V)
  • Terminology – Output Characteristics Constant Power : if the voltage is varied, the current value will be conversely adjusted to maintain a constant power output. Constant Current : If the voltage is varied, the power output will be corresponding adjusted to maintain a constant current output. Constant Voltage : If the current is varied, the power output will be corresponding adjusted to maintain a constant voltage output.
  • Terminology - Abbreviations PR : Power Rack; a shelf where rectifiers are inserted. MCB : Miniature Circuit Breaker BB : Battery Breaker MTBF : Mean Time Before Failure; Calculated value of the probability of failure rates
      • Why DC Power
      • DC Power System – Overview
      • DC Output Current flow
      • Terminology
      • Provisioning considerations
    DC Power System Principles
  • NONE PRIORITY LOAD Rectifier #1 Rectifier #2 Rectifier #n LVBD BATTERY BANK Rectifier #n PRIORITY LOAD BATTERY BANK ALARM MODULE MAINS FUSES BATTERY DISTRIBUTION LVLD AC Input Provisioning : 6 Key Questions 1. System Voltage ? (+24/-48/-60/other) Rectifier #1 Rectifier #2 Rectifier #n Rectifier #n 3. No. of Outputs ? NONE PRIORITY LOAD PRIORITY LOAD 2. Max Load ? BATTERY BANK BATTERY BANK 5. Back-up Time ? Rectifier #1 Rectifier #2 Rectifier #n Rectifier #n 4. Rectifier Recharge time / Redundancy ? LVBD 6. End Voltage ?
  • System in normal operation Provisioning - Redundancy 100A Battery Charging Capacity approx 150A, thus “N + 1” Load 100A
  • System has no redundancy Increased recharge time Provisioning - Redundancy Load 100A Can the batteries charge ? 100A Capacity approx 120A ?
  • System has no redundancy and reduced standby time Provisioning - Redundancy 10A Load 100A Discharging the batteries 100A Capacity approx 90A
  • Provisioning – Battery Breakers 800Ah Battery bank Capacity approx 150A Load 100A LVBD What is the most suitable rating of the BB ? Too small and it will trip during normal operation; but too big and you waste money ? Charging : 150A – 100A = 50 A max Discharging : 100A load max Thus 150A will suit, though 125A is possible if nec.
  • Provisioning – Earthing Types Clean Earth CABINET Exchange Link CABINET
  • End of Presentation Let’s us know if you found this presentation useful or would like more information. Eltek values your feedback. Thank you