The SEL-501 Dual Universal Overcurrent Relay is two complete sets of protection; both can be configured as one of five basic relays.
Universal Protection—Provide simple and economical protection for transformers, breakers, motors, capacitor banks, feeders, and other apparatus, with two independent three-phase overcurrent relays in a single compact package. The relay provides numerous protection schemes that are enabled by user settings.
Application Versatility—Set each side of the dual relay to correspond to a different application. For example, set one side for a feeder application and the other side for a breaker failure application.
Complete Feeder Protection—Install two SEL-501/501-2 Dual Universal Overcurrent/Dual Overcurrent Relays in two-high breaker switchgear to protect two separate feeders. This provides primary and backup protection for each feeder.
Transformer Protection—Connect one side of the dual relay to the transformer high-side CTs for transformer overload and overcurrent protection. Connect the other side of the relay to the neutral CT on the wye side of a delta-wye transformer for sensitive internal ground fault protection and backup external fault protection.
Two independent three-phase relays (X and Y) in a single compact package simplify two-high switchgear installations with reduced wiring, enhanced protection, and simplified settings. Each relay is configurable for one of several relay applications.
Flexible Applications Eliminate Settings
Complexity Settings menu includes individual selections for Feeder (FDR), Overcurrent (OC1), Motor (MOT), Breaker Failure (BFR), and Timer (TMR) relay applications. Feeder and overcurrent applications include phase, negative-sequence, and residual ground instantaneous, definite-time, and time-overcurrent elements. The breaker failure application includes breaker failure initiate, retrip, and breaker failure time-delayed operation. The timer relay application includes independent pickup and dropout settings for two outputs driven from a single control input.
Motor Protection Application
The motor relay application includes a patented motor thermal model for applications not requiring resistive temperature device (RTD) inputs. The motor thermal model automatically switches between starting and running conditions, and requires only basic information about the motor.
The relay stores 20 event report summaries and 12 fifteen-cycle event reports. The event summaries and the last two event reports are stored in nonvolatile memory.
Configuration and Control
Easily configured and controlled from the local front panel or through the EIA-232 communications port ASCII/binary interface using off-the-shelf terminal emulation software.