EMP Electrical Systems & Power Quality 3

Question 1

What is the primary benefit of implementing power factor correction in an industrial facility?

Accepted Answer

It reduces reactive power demand from the utility, improving system efficiency and lowering utility charges

Answer

It eliminates voltage surges caused by switching transients in the electrical system

Answer

It removes harmonic currents generated by non-linear loads such as VFDs

Answer

It regulates output frequency in on-site distributed generation systems

Question 2

What does 'peak shaving' refer to in the context of facility energy management?

Accepted Answer

Reducing recorded peak demand by discharging stored energy or curtailing loads during high-demand periods

Answer

Permanently reducing the total connected load of a facility through equipment upgrades

Answer

Scheduling non-critical equipment to operate only during on-peak utility hours

Answer

Physically removing peak voltage transients from the electrical distribution system

Question 3

What transformer winding configuration is most commonly used in US commercial and industrial facilities to step down medium voltage to utilization voltage?

Accepted Answer

Delta-Wye with grounded neutral on the secondary

Answer

Delta-Delta with floating neutral

Answer

Wye-Delta with grounded primary neutral

Answer

Wye-Wye with ungrounded neutral

Question 4

What is the 'demand interval' as used in utility metering and billing?

Accepted Answer

The time window (typically 15 or 30 minutes) over which average power is measured to determine peak demand for billing

Answer

The number of days between successive utility meter reading dates

Answer

The required advance notice period before switching to a different utility rate schedule

Answer

The duration of monitored outages that the utility tracks for reliability reporting purposes

Question 5

Which of the following best describes an advantage of advanced metering infrastructure (smart meters) for facility energy management?

Accepted Answer

Smart meters enable real-time energy monitoring and provide interval-based time-of-use consumption data

Answer

Smart meters automatically correct power factor at the service entrance

Answer

Smart meters eliminate the need for any supplemental sub-metering systems throughout a facility

Answer

Smart meters automatically schedule equipment operation to minimize energy costs without operator input

Question 6

What is the primary purpose of an Uninterruptible Power Supply (UPS) system in a critical facility?

Accepted Answer

To provide seamless backup power during utility outages and condition power to protect sensitive equipment from power quality disturbances

Answer

To improve the power factor of sensitive electronic loads during normal operation

Answer

To convert single-phase incoming utility power to three-phase power for motor loads

Answer

To regulate and stabilize voltage supplied to fluorescent and LED lighting systems

Question 7

What is a 'ratchet clause' in a utility rate schedule, and why is it significant for energy managers?

Accepted Answer

A billing mechanism where a single high peak demand event can set minimum demand charges for 11 to 12 subsequent months

Answer

A provision allowing customers to request reduced rates based on demonstrated energy efficiency improvements

Answer

A penalty applied when a facility exceeds its contracted monthly energy consumption limit

Answer

A discount structure that rewards customers who shift consumption to off-peak hours