Transformer Protection Terminal RET 521 ABB for Power Systems

Description

The ABB RET 521 is a numerical microprocessor-based protection terminal that provides advanced transformer protection functions in a compact design. It is engineered to safeguard two-winding and three-winding transformers, generator-transformer blocks, and reactors. Moreover, it integrates multiple protective features such as inrush restraint, overexcitation protection, and zero-sequence current elimination. In addition, the RET 521 supports flexible breaker arrangements without requiring interposing current transformers, making installation and configuration straightforward. Its design emphasizes operational security and productivity, ensuring that transformers operate safely under varying load conditions. Therefore, it is trusted in both industrial plants and utility substations where continuous reliability is essential.