Applications

The RET670 provides fast, selective protection, monitoring and control of two- and three-winding transformers, autotransformers, step-up transformers and generator transformer sets.

transformer units, phase shifters, special railroad transformers and shunt reactors.

This IED operates normally over a wide frequency range to accommodate power system frequency changes during disturbances, generator startup and shutdown.

The RET670 features fast, low-impedance differential protection with very low CT requirements. Differential protection function

Differential protection features 2nd dcs-sis.com harmonic and waveform block suppression to avoid CT saturation and transformer inrush current tripping, as well as 5th harmonic suppression.

It also has a 5th harmonic suppression function to avoid transformer overexcitation trips.

Differential functions provide high sensitivity to low-level internal faults through the use of sensitive differential protection based on amplitude measurement of the negative sequence component and direction comparison.

A variety of low impedance restricted earth fault protection functions are available as sensitive and fast primary protection against winding earth faults.

This function includes an internal/external fault discriminator for increased safety.

In addition, it has a high-impedance differential protection function. It can be used for different applications that

These include limiting earth fault protection as winding protection, autotransformer differential protection, shunt reactor protection, T-feeder protection, busbar protection and generator differential protection.

Six software packages are defined for the following applications:

– Transformer backup protection (A10)

– Voltage control (A25)

– Single-breaker, two-winding transformers (A30)

– Double-winding transformers with multiple circuit-breaker arrangement (B30)

– Three-winding transformers in single-breaker dcs-sis.com arrangement (A40)

– Triple-winding transformer in multi-breaker arrangement (B40)

The optional functions are not configured, but a maximum configuration with all optional functions is available as a template in the graphical configuration tool.

Templates for alternative configurations for auto-transformers are also available.

The analog and trip I/O are pre-defined for basic use and come standard with one binary input module and one binary output module.

The binary I/O can be added at the time of ordering, depending on the needs of the application. the other signals need to be set up according to the needs of the different applications.