What is SEL 387?
Substation Battery Monitor for DC Quality Assurance. The SEL-387 measures and reports the substation battery voltage at the relay power supply terminals. The relay includes four programmable threshold comparators and associated logic for alarm and control.
Why differential relay is used in transformer?
The differential relay actually compares between primary current and secondary current of power transformer, if any unbalance found in between primary and secondary currents the relay will actuate and inter trip both the primary and secondary circuit breaker of the transformer.
Which relay is used in transformer protection?
The protection of a transformer against the overloads is performed by a dedicated protection usually called thermal overload relay. This type of protection simulates the temperature of the transformer’s windings.
How many relays does a transformer have?
Relays for Transformer Protection
| SL | Voltage Ratio and Capacity of Transformer | Common Relays |
|---|---|---|
| 9 | 400/220KV 315MVA | Differential Relay Overflux Relay Buchholz Relay OLTC Buchholz Relay PRV Relay OT Trip Relay WT Trip Relay Over Load (Alarm) Relay |
What is sel-387a current differential and Overcurrent relay?
The SEL-387A Current Differential and Overcurrent Relay is a low-cost solution for two-winding transformer protection. Beyond Typical Transformer Protection— Protect reactors, generators, large motors, and other multiterminal power apparatus. Provide backup distribution bus or feeder protection with low-side overcurrent elements.
What is the sel-387a?
The SEL-387A is a low-cost solution for two-winding transformer protection. Beyond Typical Transformer Protection— Protect reactors, generators, large motors, and other multiterminal power apparatus.
What is the sel-787 transformer protection relay?
Protect and monitor most industrial transformer applications with the versatile SEL-787 Transformer Protection Relay. Apply 2 three-phase winding inputs, an optional single-phase restricted earth fault (REF) input, and three-phase voltage inputs for comprehensive transformer protection.
What are the features of the sel-787-2-3-4?
The SEL-787-2/-3/-4 offers additional protection and communications options, such as protection for two-, three-, and four-winding transformers and EtherNet/IP. It is also available with a color touchscreen display.