PROTECTIVE RELAY

In electrical engineering, a protective relay is an electromechanical apparatus, often with more than one coil, designed to calculate operating conditions on an electrical circuit and trip circuit breakers when a fault is detected. Unlike switching type relays with fixed and usually ill-defined operating voltage thresholds and operating times, protective relays have well-established, selectable, time/current (or other operating parameter) operating characteristics. Protection relays may use arrays of induction disks, shaded-pole magnets, operating and restraint coils, solenoid-type operators, telephone-relay contacts, and phase-shifting networks. Protection relays respond to such conditions as over-current, over-voltage, reverse power flow, over- and under- frequency. Distance relays trip for faults up to a certain distance away from a substation but not beyond that point. An important transmission line or generator unit will have cubicles dedicated to protection, with many individual electromechanical devices. The various protective functions available on a given relay are denoted by standard ANSI Device Numbers. For example, a relay including function 51 would be a timed overcurrent protective relay.

PESERTA :
Application engineers, design engineers and electrical engineers from industrial or municipal distribution systems with complex protective relay

COURSE CONTENT

1.      Introduction to Power Systems Relaying
•    System Planning
•    Power System Studies
•    Phasor Fundamentals
•    Relaying Principles
•    Review of Short Circuit Calculations
•    Fundamentals of Coordination

2.      Power Systems Grounding
•    Symmetrical Components
•    Ungrounded Systems
•    Solidly-Grounded Systems
•    Resistance-Grounded Systems
•    Ground Fault Detection Methods

3.      Current Transformers
•    Types, CT Ratios, Polarity
•    Burden, Accuracy Classes, Saturation Calculations

4.      Protection Fundamentals
•    Line, Cables, Feeders
•    Medium Voltage Motors
•    Power Transformers

5.      Protective Relay Schemes
•    Directional Relays
•    Differential Relays
•    Ground Relays