EG1 CH.9 Flashcards
What is the typical max distance distribution reaches?
50 miles
What can the distribution be visualized as?
streets
What is the average distribution span length?
300 ft
What is the typical material used for distribution lines?
Aluminum
What in the primary type of current for distribution?
AC
What is the purpose of the distribution system?
To deliver power safely, with acceptable quality and reliability, and with a minimum loss of power.
T or F: Circuit design on distribution lines has little impact on reliability.
False
What is the term for an energized line?
Phase
What is another name for main lines?
Feeder Mains
T or F: Three phase main line may or may not have a neutral.
True
What type of lines do distribution circuits consist of?
Main and Tap lines
In regards to the wires, what is the difference between main lines and tap lines?
Main lines are larger than tap lines.
What is another name for a WYE circuit?
Star system
Describe the construction of a WYE system?
Four wires, three phase with a neutral conductor
What is V phase construction?
it is a two phase tap line with a neutral that serves light three-phase loads
On what circuit type is V phase construction commonly found?
WYE system
Distribution lines consist of three main elements or levels. What are they?
Primary, secondary, and service
Describe a primary line.
High voltage distribution line
Describe a secondary line.
Low voltage lines pole to pole lines
On an overhead system secondary runs pole to pole, what is the underground equivalent?
padmount to pedestal
Describe a service line.
low voltage lines pole or pedestal to customer
Underground systems are normally designed so each transformer can be served from two directions, What is this known as?
Loop design
What are the two benefits of a loop design?
improves reliability and convenient for line crews to work on the system
What is the voltage range for secondary?
120-480 V
What determines the number of customers on a circuit?
density of area, type of customers, and capacity of circuit
Utilities have four classifications of customers. What are they?
Residential, commercial, agricultural, and industrial
What are utilities obligated to provide to customers?
Acceptable voltages at the meter
What is the acceptable voltage range at the meter?
114-126 V
How much more expensive are underground systems compared to overhead?
4x
T or F: Most circuits are either entirely overhead or entirely underground.
False, MOST circuits are a combination of both.
What is the height range for distribution poles?
35 - 55
What materials can distribution poles be made from?
Fiberglass, wood, and steel
T or F: Primary lines are only found on the main line.
False
Name the distribution component being described.
Made from either wood of fiberglass and supported by braces/brackets.
Crossarms
Name the distribution component being described.
Made from porcelain or polymer and used to support the conductor.
Insulator
Name the distribution component being described. Made from porcelain or polymer and offers more contact area at the point of attachment and used with larger conductors.
Post insulator
Conductor sizes have increased over the years. Why?
Deliver larger amounts of power and reduce line loss
As the number of customers decreases down the line what happens to the conductor?
Gets smaller
The ultimate destination of nearly all power lines and is more than meets the eye.
Transformer or transformer bank
What category do the following components belong to? Fused cutout switches, reclosers, sectionalizers, and lightning arresters
Protective equipment
Name the distribution component being described. Protects from faults, burns out and falls open. Allows linemen to quickly find faults.
Fused Cutout Switch
Name the distribution component being described. An in-line device that can determine whether a fault is temporary or permanent by performing its function up to four time.
Recloser
Name the distribution component being described. Installed to clear faulted sections from the line and are coordinated with reclosers.
Sectionalizers
Name the distribution component being described. Used to protect the line from surges by diverting them to the ground.
Lightning or Surge Arresters
Name the distribution component being described.
Can automatically control voltage levels.
Voltage regulator
Name the distribution component being described. Used to improve the efficiency of the circuit. They reduce the flow of power that does not perform any useful function.
Capacitors
Name the distribution component being described. Used to counteract the negative effects of inductive reactance. Can be manually or automatically controlled.
Capacitors
Name the distribution component being described. Placed throughout the main line to redirect power or sectionalize a portion of a line. Can only be used manually.
Gang Operated Switches
What are the common classifications for underground equipment?
padmounted or subsurface
The term for underground lines.
Cable
Most utilities install underground cables in what?
Conduit
Broad term used to classify various types of concrete, fiberglass, or composite-type housing, which are used to splice cables, terminate cables, or house equipment.
Enclosures
Name the underground component being described. Larger concrete structures, which are typically installed in larger cities to house heavy cables and equipment.
Manholes
Name the underground component being described. Above ground and are used to splice low voltage secondary and service conductors.
Pedestals
Name the underground component being described. Classified as either padmount or subsurface, the single-phase units are combined into one three-phase unit.
Transformer
Term used to identify a pole where there is a transition from an overhead circuit to an underground circuit or vice versa.
Riser/Dip pole
T or F: A utility does not need to get legal rights to construct and maintain lines.
False
Name the circuit design being described. In this design, the circuits are independent and radiate into the service area. This design is the least reliable.
Radial
Name the circuit design being described. In this design the circuits can be connected together automatically or manually at one or more points and can be fed from adjacent circuits.
Radial Tie
Name the circuit design being described. In this design, the circuits are connected together as well as transformers and runs low-voltage three-phase. Extremely reliable.
Network Grid Design
The most reliable but also the most expensive circuit design.
Network Grid Design
