3. 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 ~ = = ~
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11. 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
12. 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
13. 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
14. 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
15. 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
16. 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
17. 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
18. 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
19. 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
20. 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
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27. 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.
28. 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
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30. 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 ?
31. System in normal operation Provisioning - Redundancy 100A Battery Charging Capacity approx 150A, thus “N + 1” Load 100A
32. System has no redundancy Increased recharge time Provisioning - Redundancy Load 100A Can the batteries charge ? 100A Capacity approx 120A ?
33. System has no redundancy and reduced standby time Provisioning - Redundancy 10A Load 100A Discharging the batteries 100A Capacity approx 90A
34. 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.
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