13-EHS- Section 6

Question 1

According to the Electrical Safety Hand Book, . What is the primary purpose of substations?
a. Power generation
b. Voltage reduction
c. Emergency response
d. Equipment storage

Answer 1

B
Substations use transformers to reduce the
voltage and send it along distribution lines to users.

Question 2

According to the Electrical Safety Hand Book, Why are substations equipped with automatic signal systems?
a. To regulate voltage
b. To summon utility personnel in emergencies
c. To control transformers
d. To prevent fires

Answer 2

B
Although most substations are unattended, they are equipped with automatic signal systems which summon electrical utility personnel in an emergency.

Question 3

According to the Electrical Safety Hand Book, What is the common insulating material used in transformer coils?
a. PVC
b. Paper
c. Sulphuric acid
d. PCB

Answer 3

D
Some of these oils may also contain small quantities of PCBs

Question 4

According to the Electrical Safety Hand Book, What is the purpose of a conservator in a transformer?
a. To cool the oil
b. To store energy
c. To expand and contract with cooling oil
d. To prevent explosions

Answer 4

C
These large tanks located at the top of transformers (see diagram, Section 6.1.2) allow for expansion and contraction of the cooling oil when the transformer is carrying load

Question 5

According to the Electrical Safety Hand Book, What is the flash point of the cooling insulating oil in transformers?
a. 295°C (563°F)
b. 145°C (295°F)
c. 1000°C (1832°F)
d. 450°C (842°F)

Answer 5

B
They usually contain large volumes
of cooling insulating oil which is combustible and has a lash point of 145°C (295°F).

Question 6

According to the Electrical Safety Hand Book, What do explosion vents in transformers help prevent?
a. Overheating
b. Pressure buildup
c. Voltage fluctuations
d. Short circuits

Answer 6

B
These are large vertical pipes (see diagram, Section 6.1.2) with rupturable discs fitted to the transformer tops and are intended to relieve pressure in the event of an internal transformer fault. It is unlikely to be a hazard to the people fighting a fire.

Question 7

According to the Electrical Safety Hand Book, What do bus bars in a substation carry?
a. Water
b. Electricity
c. Oil
d. Gas

Answer 7

B
These are metal conduits or pipes (see diagram, Section 6.1.12) that are used within substations to carry the electricity from transformers to other devices inside the substation. These bus bars are energized but insulated from the steel support
structures by insulators.

Question 8

According to the Electrical Safety Hand Book, What is the purpose of porcelain bushings in a substation?
a. high voltage transformer connections
b. To generate electricity
c. To store oil
d. To cool the equipment

Answer 8

A
These simply enable high voltage transformer connections to pass through the grounded metal tank without energizing it. Typically they contain the same insulating material found in transformers - paper and oil. When subjected to high temperatures, the porcelain material can explode, resulting in lying projectiles and more oil as fuel for the ire

Question 9

According to the Electrical Safety Hand Book, What are cable trenches used for in substations?
a. To carry cables
b. To store equipment
c. To cool transformers
d. To prevent fires

Answer 9

A
Cable trenches carry the control cables previously mentioned. In the event of a substation fire, cable trenches can carry transformer oil that may have leaked from a burning transformer or a broken porcelain bushing. Thus, a ire can be carried to adjacent equipment fairly readily. To reduce this type of hazard, some cable trenches may be filled with sand.

Question 10

According to the Electrical Safety Hand Book, Which component in a substation may contain polychlorinated biphenyls (PCBs)?
a. Bushings
b. Explosion vents
c. Capacitors
d. Bus bars

Answer 10

C
Some of the capacitors contain polychlorinated
biphenyl’s (PCBs) which can be hazardous to your health and the environment. In the event of a spill, extreme caution should be exercised, while containing and then cleaning up PCBs.

Question 11

According to the Electrical Safety Hand Book, What is the purpose of substation ground grids?
a. To support insulators
b. To protect personnel from high voltage during fault conditions
c. To store energy
d. To cool transformers

Answer 11

B
An extensive grounding grid system is located under the gravel in all distribution and trans-mission substations, and all equipment including the fence is connected to it. The grids function is to protect personnel from high voltage levels during fault conditions on the power lines outside the substations. For example, should lightning strike a power line it could cause an insulator arc-over at the station, which would raise the ground voltage several thousand volts.

Question 12

According to the Electrical Safety Hand Book, What is the primary concern when fighting fires in substation control buildings?
a. Toxic gases from PVC insulation
b. Explosive gas buildup
c. Containment of oil spills
d. Energization

Answer 12

A
Fires inside substation control buildings may
involve PVC cable insulation as a fuel. The
combustion gases given of by PVC are extremely toxic and corrosive. Self contained breathing apparatus must be worn when entering a control building to fight fires, and special attention given to clean-up and decontamination of equipment.

Question 13

According to the Electrical Safety Hand Book, In firefighting inside electrical substations, what type of water application is safest?
a. Straight stream
b. Water fog or spray at a 30° angle
c. High-pressure jets
d. Water cannons

Answer 13

B
Fog or water spray at minimum of 30° useing with a minimum pressure of 700 Kpa (100 psi) at the nozzle is safest

Question 14

According to the Electrical Safety Hand Book, Why is water discharge in the form of a straight stream not recommended near electrical equipment?
a. It causes explosions
b. It may conduct electricity
c. It increases the risk of PCB exposure
d. It promotes corrosion

Answer 14

B
Maintain the minimum
recommended distance (10 m, 33 t) for the use of water fog or spray on electrical equipment. Water must never be discharged in the form of a straight stream.

Question 15

According to the Electrical Safety Hand Book, What is the minimum recommended distance for using water fog or spray on electrical equipment?
a. 5 meters
b. 10 meters
c. 15 meters
d. 20 meters

Answer 15

B
Maintain the minimum recommended distance (10 m, 33 t) for the use of water fog or spray on electrical equipment

Question 16

According to the Electrical Safety Hand Book, What is the primary concern with combustible insulating oil in substation fires?
a. Low flash point
b. High toxicity
c. Rapid combustion
d. Environmental contamination

Answer 16

A and D
This insulating oil has a minimum lash point of 145°C (293°F) and will generate temperatures in excess of 1000°C (1850°F) in the immediate ire zone.Attempt to establish containment to minimize the environmental impact from the oil spill. Electric utility personnel have been trained to contain oil spills and can be relied upon to provide assistance to contain the oil and runoff.

Question 17

According to the Electrical Safety Hand Book, What precaution should be taken when dealing with privately owned substations?
a. Enter immediately for rescue operations
b. Wait for utility personnel before entering
c. Ignore potential hazards
d. Disconnect the incoming supply yourself

Answer 17

B
If the privately owned substation is required to be isolated and de-energized contact the utility to disconnect the incoming supply at the right-of-way

Question 18

According to the Electrical Safety Hand Book, What precaution should be taken when dealing with PCB-contaminated equipment during a fire?
a. Use water extensively
b. Minimize the use of water
c. Increase the pressure of water jets
d. Call for additional firefighting units

Answer 18

B
PCB contaminated equipment (transmission and distribution) that has spilled oil and is burning, will result in the wide distribution of trace PCB contamination in the environment. Where safe alternatives to water are available (carbon dioxide [CO2], dry chemical), they should be used. If non-water alternatives are not an option, the quantities of water should be minimised to the extent possible to limit the spread of contamination

Question 19

According to the Electrical Safety Hand Book, What should responders wear when dealing with suspected PCBs in a fire?
a. Regular firefighting gear
b. SCBA and full turnout gear
c. Chemical-resistant suits
d. No protective gear is required

Answer 19

B
Wear full turnout gear and SCBA

Question 20

According to the Electrical Safety Hand Book, In case of an injured utility worker in a substation, what is the recommended action for emergency responders?
a. Evacuate the area immediately
b. Wait for utility personnel to arrive
c. Provide first aid without contacting the utility
d. Disconnect the power supply yourself

Answer 20

B
ACTION
1. Calmly, tell the person to move to the
fence if they are able.
2. Call the local electrical utility for
assistance and follow their instructions
including waiting for their arrival.
3. When electrical utility personnel arrive,
initiate rescue under their direction