EETC Power Distribution 4

Question 1

In power distribution, 'load factor' is defined as:

Accepted Answer

Average load divided by peak demand over a given period

Answer

Load factor = average load / peak load over a period, indicating how efficiently the system capacity is utilized; a higher load factor means more uniform loading.

Question 2

What is the typical voltage range for 'primary distribution' circuits in the United States?

Accepted Answer

2.4 kV to 35 kV

Answer

Primary distribution operates at medium voltages, typically 2.4 kV to 35 kV (most commonly 4, 13.2, 13.8, or 25 kV), between the substation and distribution transformers.

Question 3

Which type of fault produces the highest fault current on a three-phase power system?

Accepted Answer

Bolted three-phase fault

Answer

A bolted (zero impedance) three-phase symmetrical fault produces the highest fault current because all three phases are involved symmetrically with no fault impedance.

Question 4

A distribution recloser is set for a '2 fast, 2 delayed' sequence. What does this mean?

Accepted Answer

It opens twice quickly, then twice after a time delay, and locks out after the 4th operation

Answer

The '2 fast, 2 delayed' sequence means the recloser trips twice on a fast (instantaneous) curve, then twice on a slower time-delay curve before locking out after the fourth operation if the fault persists.

Question 5

Underground residential distribution (URD) cables most commonly use which insulation material?

Accepted Answer

Cross-linked polyethylene (XLPE) or EPR

Answer

Modern URD cables use XLPE or EPR insulation for their superior electrical properties, moisture resistance, and long service life compared to older materials.

(EETC) Electrical Technician Certification Practice Test

(EETC) Electrical Technician Certification Practice Test

EETC Power Distribution 4