Protective and monitoring relays could fall into one of several categories. Protective relays and monitoring relays may be categorized as a voltage sensitive relay, power (phase) sensitive relay, current sensitive relay, and frequency se. Protective and monitoring relays could fall into one of several categories. Protective relays and monitoring relays may be categorized as a voltage sensitive relay, power (phase) sensitive relay, current sensitive relay, and frequency sensitive relay.SpecificationsImportant sensing and measuring specifications to consider when searching for protective relays and monitoring relays include: 1. Voltage sensing range- Voltage-sensing range applies to power (phase), voltage, voltage/frequency, and paralleling (synchronous) sensing relays. 2. Current sensing range- Current-sensing range applies to power (phase) and current-sensing relays. 3. Line voltage range-Line-voltage range applies to power (phase) sensing relays. 4. Line voltage mode-(line-to-line or l. Additional FunctionsOther protective functions include: Time delay- Time delay, where the relay can h. BS EN 50216-3- Power transformer and reactor fittings - Part 3: protective relay for hermetically sealed liquid-immersed transformers and reactors without gaseous cushion IEEE C37.113- Guide for protective relay applications to transmission lines MIL-PRF-32484- Protective relays and attachments, medium voltage vacuum circuit breaker applicationsSleva, Anthony F. Protective Relay Principles. Boca Raton: CRC, 2009. Print. Van Cortlandt Warrington, Albert R. Protective Relays: Their Theory and Practice. Vol.2. London: Chapman & Hall, 1978. Print. Steven Engineering - Phase Failure Relays.
