Features of Distribution Systems and Substation Equipment Flashcards
Identify the three broad classes of HV distribution systems
- Radial
- Loop or Ring
- Network
Which of the three classes of HV distribution systems is the least expensive and the simplest?
Radial
Identify the three classes of HV distribution systems in terms of their levels of reliability
From least reliable: radial, ring, network
Which of the three classes of HV distribution systems requires the most comprehensive protection system?
Network
A rural overhead distribution line is most likely to be a _________ distribution system
Radial
What is a substation?
A substation is an area that contains CBs, disconnects, lightning arresters, transformers and other associated equipment
What is a unit substation?
A unit substation is a modular-constructed enclosure housing the HV cable termination, bus bars, CB, transformer, low voltage CBs, instrument transformers, etc
What is the purpose of viewing-windows in unit substations?
For visible indication of a switch being open or closed
HV equipment must always be installed in a vault. True or False?
False
What is the primary purpose of a series reactor in an HV system?
To limit the magnitude of fault current
How can the use of series reactors reduce the cost of substation installations?
By allowing the use of CBs with lower ampacity ratings
What is the function of a surge arrester?
To protect against overvoltages
What are the main parts of a surge arrester?
Air gap and thyrite material
What are the two functions of instrument transformers in an HV system?
- To monitor the voltage and current levels
- To isolate monitoring devices from the HV system
What is the most common secondary voltage of a VT?
120V
