Basic Electrical Devices/Equipment

Question 1

List the Basic Electrical Devices/Equipment

Answer 1

A. Spudgers for lifting wires and aligning leads
B. Surgical scissors
C. Tweezers
D. Heat sinks
E. Wire strippers
F. Needlenose pliers
G. Screwdrivers
H. Nut drivers
I. Soldering Iron
J. Manual desoldering tool
K. Low-voltage pencil soldering iron
L. Desoldering bulb and soldering iron with hollow tip
M. Component lead former tool
N. Analog voltmeter
O. Digital voltmeter
P. Temperature-controlled soldering station

Question 2

The Structure of Electric Power Systems in the Philippines

Answer 2

• Generation
• Transmission
• Distribution
• End users

Question 3

______ Electric Power Systems and Equipment — Voltage Ratings (60 Hertz)

Answer 3

ANSI C84.1-2011

Question 4

System Voltage Classes

Answer 4

3.1 Low Voltage (LV)
3.2 Medium Voltage (MV)
3.3 High Voltage (HV)
3.4 Extra-High Voltage (EHV)
3.5 Ultra-High Voltage (UHV)

Question 5

A class of nominal system voltages 1000 volts or less

Answer 5

Low Voltage (LV):

Question 6

A class of nominal system voltages greater than 1000 volts and less than 100 kV.

Answer 6

Medium Voltage (MV):

Question 7

A class of nominal system voltages equal to or greater than 100 kV and equal to or less than 230 kV.

Answer 7

High Voltage (HV):

Question 8

A class of nominal system voltages greater than 230 kV but less than 1000 kV.

Answer 8

Extra-High Voltage (EHV):

Question 9

A class of nominal system voltages equal to or greater than 1000 kV.

Answer 9

Ultra-High Voltage (UHV):

Question 10

In Section ____ of the Philippine Electrical Code (PEC), it is mentioned that:
Where the voltage exceeds 600 volts, nominal, permanent and conspicuous warning signs shall be provided, reading as follows:
DANGER — HIGH VOLTAGE — KEEP OUT

Answer 10

1.10.3.5(c)

Question 11

Where the voltage exceeds 600 volts, nominal, permanent and conspicuous warning signs shall be provided, reading as follows:

Answer 11

DANGER — HIGH VOLTAGE — KEEP OUT

Question 12

Small commercial or residential buildings have a very simple power distribution system. The utility will own the ___ , which will sit on a ___ outside the building or will be attached to a ____.

Answer 12

transformer; pad; utility pole

Question 13

The transformer reduces the voltage from ___ down to _____ volts and then passes the electricity to a meter, which is owned by the utility and keeps a record of power consumption.

Answer 13

13.8kV ; 120/240 or 120/208

Question 14

After leaving the meter, the power is transmitted into the building at which point all wiring, panels, and devices are the property of the ____. Wires transfer the electricity from the meter to a ____, which is generally located in the basement or garage of a house.

Answer 14

building owner; panel board

Question 15

Power Distribution in Small Buildings:
In small commercial buildings, the panel may be located in a ____. The panel board will have a ____ and a series of circuit breakers, which control the flow of power to various circuits in the building. Each branch circuit will serve a ____ (some appliances require heavy loads) or a number of devices like convenience outlets or lights.

Answer 15

utility closet; main service breaker; device

Question 16

Large buildings have a much higher electrical load than small buildings; therefore, the electrical equipment must be ____

Answer 16

larger and more robust.

Question 17

Power Distribution in Large Buildings:
Large building owners will also purchase electricity at high voltages (in the US, 13.8kV) because it comes at a cheaper rate. In this case, the owner will provide and maintain their own ____, which lowers the voltage to a more usable level (in the US, 480/277 volts). This transformer can be mounted on a pad outside the building or in a transformer room inside the building.

Answer 17

step-down transformer;

Question 18

Power Distribution in Large Buildings:
The electricity is then transmitted to ____. The role of the ____ is to distribute electricity safely and efficiently to the various electrical closets throughout the building. The equipment has numerous safety features including circuit breakers, which allow power to be disrupted downstream - this may occur due to a____, but it can also be done intentionally to allow technicians to work on specific branches of the power system.

Answer 18

switchgear; fault or problem

Question 19

It should be noted that very large buildings or buildings with complex electrical systems may have multiple transformers, which may feed ____

Answer 19

multiple pieces of switchgear

Question 20

The electricity will leave the switchgear and travel along a _____ This is a heavy gauge conductor that can carry high amperage current throughout a building safely and efficiently. Tapped as needed and a conductor is run to an electric closet, which serves a zone or floor of a building

Answer 20

primary feeder or bus.

Question 21

Each electrical closet will have another step-down transformer - in the US, this will drop the power from ____ to _____ for convenience outlets. That transformer will feed a branch panel, which controls a series of branch circuits that cover a portion of the building.

Answer 21

480/277 volts to 120 volts

Question 22

Each branch circuit covers a subset of the electrical needs of the area - for instance:

Answer 22

• lighting,
• convenience outlets to a series of rooms,
• or electricity to a piece of equipment.

Question 23

Distribution Equipment

Answer 23

1. Distribution Transformer
2. Circuit Breaker
3. Lightning Arrester
4. Air Break Switch / Isolator
5. Insulator
6. Busbar
7. Capacitor Bank
8. Distribution Panel Board

Question 24

is a transformer that provides the final voltage transformation in the electric power distribution system, stepping down the voltage used in the distribution lines to the level used by the customer.

Answer 24

Distribution Transformer

Question 25

is a main and largest equipment of distribution substation.

Answer 25

Distribution Transformer

Question 26

is an equipment which automatically cut off power supply of the system when any fault or short circuit occurs in the system. It detect and isolate faults within a fraction of a second thereby minimizing the damage at the point where the fault has occurred.

Answer 26

Circuit Breaker

Question 27

are specially designed to interrupt the very high fault currents, which may be ten or more times the normal operating currents.

Answer 27

Circuit Breaker

Question 28

is a most important protective device of distribution substation to protect valuable equipment as well as working personnel. It arrests and discharges over voltage to earth during lightning strokes. These are installed between line and earth near equipment.

Answer 28

Lightning Arrester

Question 29

are used to isolate equipment for maintenance and also for transfer of load from one bus to another. Lay-out of substation depends upon type

Answer 29

Air Break Switch / Isolator

Question 30

These switches are of two types viz.

Answer 30

vertical break type or horizontal break type.

Question 31

TRUE OR FALSE:
Horizontal break type normally occupies more space than the vertical break type.

Answer 31

TRUE

Question 32

The main function of an ___ is to insulate live conductor or equipment at different voltages with reference to the ground structures as well as provide mechanical support.

Answer 32

insulator

Question 33

TRUE OR FALSE: Provision of adequate insulation in a substation is of only importance from the point of view of reliability of supply and safety of personnel

Answer 33

FALSE: Provision of adequate insulation in a substation is of primary importance from the point of view of reliability of supply and safety of personnel

Question 34

is a conductor used to connect two and more equipment located side-by-side when the currents are very high. These are usually rectangular, sometimes tubular, bare copper bars supported on insulators.

Answer 34

Busbar

Question 35

The outdoor busbars are either of the _____

Answer 35

rigid type or of the strain type.

Question 36

In the ____ , pipes are used for making connections among the various equipment.

Answer 36

rigid type

Question 37

The ____ busbars are an overhead system of wires strung between two supporting structures and supported strain type insulators.

Answer 37

strain type

Question 38

TRUE OR FALSE: Since the busbars are rigid, the clearances remain constant.

Answer 38

TRUE

Question 39

It is a series parallel combination of capacitors required to improve power factor of the system. They act as reactive power generators and provide the needed reactive power to accomplish active power in the circuit. This reduces the amount of reactive power, and thus total power (kVA) or the demand.

Answer 39

Capacitor Bank

Question 40

consists of MCCBs, control equipment, meters and relays are housed in the control room. The panel frame shall be connected to the earth grid by an earthing conductor. A rubber mat of prescribed size and quality shall lay in front of panel.

Answer 40

Distribution Panel Board