GE Intro to protective Relaying Flashcards
What are the links of a power system?
Generator
Power Transformers
Switch Gear
Transmission lines
Distribution circuits
Utilization apparatus i.e. Load
What is the function of relays?
Reduce number or alternate links to avoid equipment damage/limits damage to a single unit
What is the difference between primary and secondary relaying?
Primary Relaying - First Line of Defense
Backup/Secondary Relaying - Isolates more portions of the system
What is a protective Relay
Device energized by suitable currents, voltages or both
Responds to magnitudes & relationships of these currents to indicate abnormal condition
What are the 4 relay elements?
Plunger, hinged armature, induction disk, induction cup
What element creates time delay?
Induction disk
What are the advantages of an induction cup relay?
Instantaneous operation w/ ability to monitor several electrical quantities
Time Delay
To avoid equipment damage from fire hazards
Most vulnerable portion of a power system?
Transmission lines
What is an operating characteristic graph?
Graph depicting relationships and quantities that will cause a relay to actuate
