Transformer protection relay Schweitzer Engineering Laboratories

Multi-Winding Current Differential Protection

Use the SEL-387 Relay for protection, monitoring, and automation applications for important transformers, generators, and other power apparatus. Apply the SEL-387 Relay for protection of two-, three- or four-winding power transformers. Use overcurrent elements from combined CT inputs for backup protection. Use the thermal element to activate a control or issue a warning or alarm when the transformer overheats or is in danger of excessive insulation aging or loss of life. Capture current, hourly or daily, data about your transformer using the thermal event report. Perform predictive maintenance based on accumulated through-fault duty as compared to transformer capability as defined in ANSI Standard C57.109. Use recorded fault values or an alarm set point to initiate an evaluation of transformer maintenance needs.

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