Distribution Systems & Infrastructure Flashcards
7 cards from real PECO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Distribution Systems & Infrastructure flashcards as text
Which type of cable insulation is most commonly used in PECO's underground distribution system for medium-voltage circuits?
Answer: Cross-linked polyethylene (XLPE)
Cross-linked polyethylene (XLPE) is the predominant insulation for modern medium-voltage underground distribution cables due to its superior thermal and electrical properties.
What does the acronym 'URD' stand for in the context of PECO distribution infrastructure?
Answer: Underground Residential Distribution
URD stands for Underground Residential Distribution, referring to the system of underground cables and pad-mounted transformers that serve residential subdivisions.
A PECO feeder circuit experiences a permanent three-phase fault. Which protection device at the substation is the first to respond?
Answer: Substation feeder breaker
The substation feeder breaker is the first-line protection device and will trip on a permanent three-phase fault at the substation level before downstream devices operate.
What is the main advantage of a looped (ring-bus) distribution system over a radial distribution system for PECO's service area?
Answer: Improved supply reliability through alternate feed capability
A looped or ring-bus distribution system allows power to be rerouted from an alternate feed point during a fault or maintenance, improving service reliability compared to a radial system.
PECO installs capacitor banks on distribution feeders primarily to accomplish which of the following?
Answer: Provide reactive power compensation and improve power factor
Capacitor banks supply reactive power (VARs) locally on the feeder, improving power factor, reducing I²R losses, and helping maintain acceptable voltage levels.
In the context of PECO distribution operations, what is a 'pad-mounted transformer'?
Answer: A ground-level, tamper-resistant transformer in a locked enclosure set on a concrete pad
A pad-mounted transformer is a ground-level distribution transformer housed in a locked, tamper-resistant metal enclosure bolted to a concrete pad, commonly used in URD systems.
Which conductor configuration is most commonly used for PECO overhead distribution primary lines to reduce line losses and improve voltage regulation?
Answer: Balanced three-phase three-wire or four-wire configuration
PECO overhead primary distribution lines are predominantly configured as balanced three-phase three-wire or four-wire (with neutral) circuits to efficiently distribute power with minimized losses.