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SEL 787


Complete protection for two windings - Differential protection for two windings, with percentage differential function with two slopes and phase, negative sequence, residual and neutral overcurrent elements, for backup protection. Use circuit breaker failure protection for two three-pole circuit breakers. Also use the SEL-787 to protect autotransformers.

In addition to basic transformer protection - Get comprehensive transformer protection with the optional single-phase, sensitive REF input and three-phase voltage inputs. Eliminate the need for external measuring devices through integrated measurement, which includes harmonics, power, phase voltages and currents, neutral current, and positive, negative and zero sequence voltages and currents.

Low-cost monitoring for transformers - Extend the life of your transformer by monitoring the installation environment, load switch (LTC), and transformer oil temperature with 4-20 mA analog inputs (optional) or RTD inputs. Monitoring of through faults, accumulated I2t, and the duration of faults, to determine the frequency and impact of external faults on the transformer and prevent faults.

Reliable protection in harsh environments - The SEL-787 operates in extreme temperature conditions (–40° to +85°C) and is also designed and tested to exceed applicable standards, including vibration, electromagnetic compatibility, and harsh environmental conditions. Additionally, the SEL-787 is ATEX and Underwriters Laboratories (UL) Class I/Zone2 certified for use in hazardous and potentially explosive environments.

Fan bank control -provide fan bank control and protection with the optional single-phase CT channel plus RTD thermal elements.

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