ABB Transformer protection IED RET 670  RET670

• A protection, control, and monitoring IED with extensive functional library and configuration possibilities and expandable hardware design to meet specific user requirements 

• For power transformers, autotransformers, shunt reactors, T-protection, generator transformer blocks, phase shifting transformers and small busbar systems 

• For two- and three-winding transformers with up to six stabilized inputs 

• For multi- or single-breaker arrangements 

• Transformer differential protection with: - Percentage bias restraint for through faults - Waveform and Second harmonic restraint for transformer inrush - Fifth harmonic restraint for overexcitation - High sensitivity for interturn faults 

• Restricted earth fault protection for all direct or low impedance earthed windings - Extremely fast operation - High sensitivity - High and low impedance based 

• Full scheme phase-to-phase and phase-to-earth distance protection with up to five zones: - Load encroachment feature 

• Instantaneous high speed short circuit function with low transient overreach 

• Directional overcurrent protection with four steps for each winding - Each step can be inverse or definite time delayed - Each step can be directional or non-directional 

• Instantaneous high speed earth fault function with low transient overreach 

• Directional earth fault protection with four stages for each winding

- Each step can be inverse or definite time delayed - Each step can be directional or non-directional - Each step can be blocked on second harmonic component 

• Synchrocheck function for single- or multi-breaker arrangements: - Selectable energizing direction - Two functions with built-in voltage selection 

• Selectable additional software functions such as breaker failure protection for each breaker, voltage protection, overexcitation protection, control and monitoring 

• Tripping from Buchholtz, temperature devices etc. through binary inputs stabilized against capacitive discharges