Consumer

1
Consumers Main Switchroom Main L.V.
Switchboard

• Learning outcome from this topic, the student is
  able to
• state the functions and requirements of a main
  switchroom
• state the functions and requirements of a main
  switchboard
• sketch a single-line LV supply diagram from a
  main switchboard to different parts of a building
• describe different tests for a switchboard (the
  type tests and routine tests)

2
Consumers Main Switchroom

• General requirements for main switchroom
• Sufficient space for work and to house the main
  switchboard and other distribution equipment
  (600mm for switchgear 100A, 900mm for those
  gt100A)
• Next to transformer room
• Supply taking from a LV network, the room should
  be at the building entrance
• Clear access
• Good ventilation
• Minimum illumination Floor 150 lx, wall 120
  lx
• No water or drainage pipes inside

3
Consumers Main Switchroom

• Function of a main switchroom
• power is taken from a transformer room
• power distribution to different parts of a
  building and for different usages
• separate the consumer side from the power company

4
Layout of cubicle-type main switchboard

• Components in a main switchboard
• Body built with 2 mm-thick steel and coated with
  suitable paint
• A busbar compartment with hard drawn copper and
  high conductivity to BS1432 or BS1433
• Compartment for the incoming and outgoing cables
  
• Neat internal wiring and with sufficient
  clearance
• A compartment housing ACB, MCCB, fuseswitch,
  motor starter, capacitor bank, auto-changeover
  switch
• A meter compartment to show the energy
  consumption or maximum demand

5
Layout of cubicle-type main switchboard

• Components in a main switchboard
• Measuring CTs and protection CTs
• Meters showing current, voltage, power factor
  (and max. demand), etc. Now A digital
  multi-purpose is used for all
• IDMT relays for overcurrent and earth-fault
  protection (Now a digital relay)
• Charger and battery for closing/tripping of ACBs
• Phase indication lamps
• Anti-condensation heaters
• Spare compartments

6
Layout of cubicle-type main switchboard

• The main switch in a switchboard
• For three-phase 4-wire supply, a triple-pole
  neutral (TPN) main switch (or circuit breaker)
  is used
• The TPN switch should interrupt all the phase
  conductors (R/Y/B)
• A link (fixed by bolts or screws) should be
  inserted in the neutral conductor
• For single-phase installations, a double-pole
  (DP) main switch should be used

7
Layout of cubicle-type main switchboard

• If the supply is taken directly from a
  transformer room, the main incoming ACB
• should be of draw-out type
• should have a breaking capacity at least 40 kA
• should be equipped with overcurrent
  earth-fault protective relays
• For an overall installation serving more than
  one building, the installation in each building
  should be treated as a separate installation.
  Each building should have a main switch.

8
Load Distribution in a Building

• Refer to slide 10 for illustration
• Tenant Supply Board
• Connection to a transformer
• Main incoming circuit breaker (ACB/MCCB) for
  overload and fault protections to the whole
  installation
• Busducts leading to different load centres in
  the building
• Bus section switch interconnects adjacent busbar
  section
• Non-essential Public Supply Board
• Bus section for the power supply to public
  facilities
• Plumbing and drainage pumps, passenger lifts,
  non-essential lighting, A/C plant and spares, etc
• Cable risers to different loads in the building
• Protective devices for cable overload protection
• Bus section switch interconnects adjacent busbar
  section

9
Load Distribution in a Building

• Emergency Supply Board
• Connection with an emergency generator / UPS
• ACB, MCCB, fuseswitch for overload and / or
  fault protections to essential loads
• Automatic changeover switch
• Two mutually exclusive switches
• Normal open (N/O)
• Normal close (N/C)
• Switch ON/OFF
• Sprinkler pumps, hydrant / hose reel pumps,
  firemens lifts, emergency lighting and spares,
  etc
• A single-line low voltage schematic for the
  power distribution to different loads in a
  building is shown on slide 11

10
A single-line LV schematics
11
L.V. Switchboard
12
Air Circuit Breaker (ACB)
13
(No Transcript)
14
(No Transcript)
15
(No Transcript)
16
(No Transcript)