ABB SPAD346C Integrated Differential Relay

Features

Integrated three-phase differential relay, overcurrent relay and earth fault relay

Stabilized three-phase differential relays provide winding short-circuit and turn-to-turn fault protection for two-winding transformers and generator-transformer units, and winding short-circuit protection for generators.

Earth fault protection for transformer windings on the HV and LV side according to the required principle:

Stabilized differential current principle, high impedance principle, calculated or measured residual current principle or neutral current principle

Three-stage overcurrent protection for transformer and generator as well as two-stage backup protection for earth fault protection.

Differential relays with operating characteristics that can be easily adapted to different applications Short operating times, stable operation even in the event of partial saturation of the current transformer.

Prevents unwanted operation in the event of faults and transformer inrush currents outside the protective field.

Blocking based on the ratio of the second harmonic to the fundamental component of the differential current prevents unwanted operation in the event of transformer inrush currents.

Blocking based on the ratio of the fifth harmonic to the fundamental component of the differential current prevents unwanted operation in the event of transformer overexcitation.

- If the ratio of the fifth harmonic to the fundamental component of the differential current increases at high overvoltages, this blocking condition can be eliminated

Double-winding transformer protection without transformers - digital vector group matching on HV and LV side

Wide range of CT ratio corrections - precise corrections via digital settings Sensitive phase current and phase angle displays for easy checking of measurement circuits

Four trip and four signal relay outputs

Five programmable external control inputs for displaying and forwarding alarm and trip signals from gas relays, oil temperature sensors and other transformer auxiliary equipment sensors

Adjustable CBFP runtime for increased operational reliability Integrated disturbance recorder for current and digital signals - Trigger signals optional Highly resistant to electrical and electromagnetic interference.

Continuous monitoring of hardware and software

Applications

The stabilizing differential relay SPAD 346 C is designed for the protection of two-winding transformers and generator-transformer installations against winding short-circuits, turn-to-turn faults, earth faults and short-circuits, as well as for the protection of generators against winding short-circuits.

as well as protecting generators against winding short-circuits and short-circuits. The relay can also be used to protect three-winding transformers, provided that 75% of the short-circuit power comes from the same direction.

Description

Operation

The integrated differential relay SPAD 346 C consists of three separate relay modules: The three-phase voltage stabilized differential relay module SPCD 3D53.

SPCD 2D55 and the combined overcurrent and earth fault relay module SPCJ 4D28.

The rated currents of the relays are 1 A and 5 A, respectively.

The same or different current ratings can be used for the HV and LV sides.