Stabilized Differential Relay ABB DSPAD/32/375

Description

The Stabilized Differential Relay ABB DSPAD/32/375 is an integrated differential relay that combines three-phase differential relay, overcurrent relay, and ground fault relay functions in one unit. Designed for protection of two-winding transformers, generator-transformer units, and generators, it provides winding short-circuit and inter-turn fault protection, as well as winding short-circuit protection for generators. It offers ground fault protection for transformer high and low voltage windings based on multiple principles, including stabilized differential current, high impedance, calculated or measured residual current, or neutral point current. Additional protection features include three-stage overcurrent protection for transformers and generators, and two-stage backup protection for ground faults.

Key performance features include short operating time, stable operation even with partial current transformer saturation, and prevention of unnecessary tripping during out-of-zone faults and transformer inrush currents. It uses second harmonic blocking to avoid tripping on transformer inrush currents, and fifth harmonic blocking to prevent tripping during harmless transformer overexcitation, with the ability to disable fifth harmonic blocking if the fifth-to-fundamental frequency ratio rises excessively under dangerous overvoltage. It supports wide CT ratio correction via digital settings, enables two-winding transformer protection without additional current transformers through high and low voltage side digital vector group matching, and includes four heavy-duty output relays for circuit breaker tripping, five signal output relays, and five programmable external control inputs. With high immunity to electrical and electromagnetic interference, integrated disturbance recording, and compatibility with ABB’s SPACOM product line and distribution automation systems, it meets EMC EC directive requirements with CE marking.