CHAPTER 18 QUESTIONS AND
ANSWERS WITH SOLUTONS 2024
Power Generation and transmission - ANSWER Power Station
- Houses equipment to generate electricity
- 1 Megawatt (MW) = 1,000,000 W
- Power is generated between 2.4 kV and 13.2 kV
- Transmission over power lines 115kV to 765 kV, with
1100 kV being explored
Power Substation
- Reduces transmission voltages to safer distribution
levels
Generation and Transmission - ANSWER Distribution lines:
- 4160 V, 4800 V, 6900 V, or 13.2 kV
Distribution Transformer (USA and Canada):
- 120/240 V single phase
- 120/208 V three phase
- 480Y/277 V three phase
Building Electrical Service Equipment - ANSWER Service Entrance Conductors
- Service drop (overhead)
- Service lateral (underground)
Service Entrance Equipment
- Electric Meter
- Service disconnect
Switchboards - ANSWER Large cabinet or assembly of metal cabinets
Typically floor mounted
, Access usually through front or rear
Includes disconnect switches, overcurrent
protection devices (OCP), other protective
devices and instruments
Designed to divide large amounts of electrical
current into smaller amounts of current used by
electrical equipment
Rated at 1200-6000 A, and voltages below 600 V
panelboards - ANSWER One or more metal cabinets that serve as a
single unit
Includes buses, automatic OCPs
Equipped with or without switches for the control
of light, heat, and power circuits
Placed in or against a wall or partition that is
accessible from the front
Load center is a panelboard containing a
preassembled disconnect and the necessary
circuit breakers
Building transformers - ANSWER Used in transmitting and distributing power from
the power plant to a substation
Change voltage, current, and phase of electrical
power
Nearby and within a building
Rated in kVA
Typical ratings used in buildings: 3, 6, 9, 15, 25,
30, 37.5, 45, 50, 75, 112.5, 150, 225, 300, 500,
750, 1000, 1500 kVA and larger
ANSWERS WITH SOLUTONS 2024
Power Generation and transmission - ANSWER Power Station
- Houses equipment to generate electricity
- 1 Megawatt (MW) = 1,000,000 W
- Power is generated between 2.4 kV and 13.2 kV
- Transmission over power lines 115kV to 765 kV, with
1100 kV being explored
Power Substation
- Reduces transmission voltages to safer distribution
levels
Generation and Transmission - ANSWER Distribution lines:
- 4160 V, 4800 V, 6900 V, or 13.2 kV
Distribution Transformer (USA and Canada):
- 120/240 V single phase
- 120/208 V three phase
- 480Y/277 V three phase
Building Electrical Service Equipment - ANSWER Service Entrance Conductors
- Service drop (overhead)
- Service lateral (underground)
Service Entrance Equipment
- Electric Meter
- Service disconnect
Switchboards - ANSWER Large cabinet or assembly of metal cabinets
Typically floor mounted
, Access usually through front or rear
Includes disconnect switches, overcurrent
protection devices (OCP), other protective
devices and instruments
Designed to divide large amounts of electrical
current into smaller amounts of current used by
electrical equipment
Rated at 1200-6000 A, and voltages below 600 V
panelboards - ANSWER One or more metal cabinets that serve as a
single unit
Includes buses, automatic OCPs
Equipped with or without switches for the control
of light, heat, and power circuits
Placed in or against a wall or partition that is
accessible from the front
Load center is a panelboard containing a
preassembled disconnect and the necessary
circuit breakers
Building transformers - ANSWER Used in transmitting and distributing power from
the power plant to a substation
Change voltage, current, and phase of electrical
power
Nearby and within a building
Rated in kVA
Typical ratings used in buildings: 3, 6, 9, 15, 25,
30, 37.5, 45, 50, 75, 112.5, 150, 225, 300, 500,
750, 1000, 1500 kVA and larger
