Advantages of static relays
• Due to the amplification of energizing signals obtainable, the sources need only provide low power. Therefore the size of the associated current and voltage transformers could be reduced.
• Improved accuracy and selectivity.
• Fast operation of relays and hence fast clearance of faults.
• Flexibility of circuitry would allow new and improved characteristics.
• The relays would be unaffected by the number of operations.
Basic circuits employed
• Timers
• Phase comparators
• Amplitude Comparator
• Level detectors
• Integrators
• Polarity detectors
High reliability operational amplifiers are used for realizing the basic components of static relays