EMP Electrical Systems & Power Quality

Question 1

What is power factor in an electrical system?

Accepted Answer

The ratio of real power to apparent power

Answer

The ratio of reactive power to real power

Answer

The ratio of apparent power to reactive power

Answer

The ratio of voltage to current

Question 2

What is the typical minimum acceptable power factor for commercial and industrial facilities before utility penalties apply?

Accepted Answer

0.85

Answer

0.50

Answer

0.70

Answer

0.99

Question 3

Which device is most commonly installed to improve power factor in commercial and industrial electrical systems?

Accepted Answer

Capacitor bank

Answer

Step-up transformer

Answer

Inductor coil

Answer

Voltage regulator

Question 4

What does Total Harmonic Distortion (THD) measure in an electrical system?

Accepted Answer

The ratio of the sum of all harmonic components to the fundamental frequency component

Answer

Total power loss across all distribution feeders

Answer

The efficiency rating of electrical transformers under full load

Answer

The variation in supply voltage measured over a 24-hour period

Question 5

Which of the following is the most common cause of voltage sags in commercial electrical distribution systems?

Accepted Answer

Starting of large motors or heavy industrial equipment

Answer

Capacitor bank switching on the distribution feeder

Answer

Addition of voltage regulation equipment upstream

Answer

Reduced impedance in distribution transformers

Question 6

What is the primary purpose of a power quality analyzer used in energy management?

Accepted Answer

To measure and record electrical parameters such as voltage, current, and harmonics to identify power quality issues

Answer

To regulate voltage fluctuations in distribution circuits in real time

Answer

To convert AC power to DC power for sensitive equipment

Answer

To distribute electrical load evenly across all three phases

Question 7

What is a demand charge in utility billing for commercial and industrial customers?

Accepted Answer

A charge based on the highest peak power demand recorded during the billing period

Answer

A fee assessed on reactive power consumption measured in kVAR

Answer

The cost per kilowatt-hour of electricity consumed during a billing period

Answer

A surcharge applied to electricity used during off-peak hours