ABB Transformer Protector RET670 Controller Accessories

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 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.

Trip and alarm signals from the pressure relief, Buchholz and temperature devices can be sent directly to the RET670 via the binary input channels for alarm and standby.

The binary inputs are highly stable against interference and prevent incorrect operation due to, for example, capacitive discharges in the DC system or DC ground faults.

The distance protection function serves as backup protection against faults within the transformer and in the connected power system.

Positive-, negative- and zero-sequence overcurrent functions (selectable direction and/or voltage control) provide further back-up protection.

Thermal overload, overexcitation, overvoltage/undervoltage and overfrequency/underfrequency protection functions are also provided.

A circuit breaker fault protection function for each transformer circuit breaker allows high-speed backup tripping of surrounding circuit breakers.

A built-in disturbance and event recorder provides the user with valuable data on status and operation for post-fault disturbance analysis.

The RET670 can also be optionally equipped with a full range of control and interlocking features, including a synchronization check function for integration of primary or local standby control functions.

The RET670 also features pole slip protection, which detects and evaluates pole slips occurring in the power system and takes the necessary action.

Sections of the power system that are swinging away from each other can be separated by the line closest to the center of the power swing, allowing the two systems to remain stable when separated.

The RET670 can be used with the IEC 61850-9-2LE process bus with up to six Merge Units (MUs).

Advanced logic functions allow user logic to be programmed with graphical tools to enable special applications such as automatic opening of disconnect switches in multi-breaker arrangements, closing of breaker loops and load transfer logic.

Logic can be monitored and debugged online in real time for testing and commissioning.

Communication via fiber optic connections ensures immunity to interference.

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 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.