Available Versions; Principle Of Operation - ABB Relion 670 Series Technical Reference Manual

1MRK 505 208-UEN B
5.1.1.1
5.1.2
Technical reference manual
The IED can detect all types of internal phase-to-phase and phase-to-earth faults in
solidly earthed or low impedance earthed power systems, as well as all internal multi-
phase faults in isolated or high-impedance earthed power systems.

Available versions

The following versions of the IED are available:
1. Three-phase version of the IED with two low-impedance differential
protection zones and four three-phase CT inputs.
• This version is available in 1/2 of 19" case. The version is intended for
simpler applications such as T-connections, meshed corners and so on.
2. Three-phase version of the IED with two low-impedance differential
protection zones and eight three-phase CT inputs.
• This version is available in full 19" case. The version is intended for
applications on smaller busbars, with up to two zones and eight CT inputs.
3. One-phase version of the IED with two low-impedance differential protection
zones and twelve CT inputs.
• This version is available in either 1/2 of 19" or full 19" case.
• The IED in 1/2 of 19" case is intended for applications without need for
dynamic Zone Selection. Typical examples are substations with single
busbar with or without bus-section breaker, one-and-half breaker or
double breaker arrangements. Three such IEDs offer cost effective
solution for such simple substation arrangements with up to 12 CT inputs.
• The IED in full 19" case is intended for applications in substation where
dynamic Zone Selection or bigger number of binary inputs and outputs is
needed. Such stations for example are double busbar station with or
without transfer bus with up to 12 CT inputs.
• This version can be optionally used with external auxiliary summation
transformers.
4. One-phase version of the IED with two low-impedance differential protection
zones and twenty-four CT inputs
• This version is available in full 19" case. The IED is intended for busbar
protection applications in big substation where dynamic Zone Selection,
quite large number of binary inputs and outputs and many CT inputs are
needed. The IED includes two differential zones and twenty-four CT
inputs.
• This version can be optionally used with external auxiliary summation
transformers.

Principle of operation

Busbar differential protection detects internal faults within the station. In order to
do that selectively it often incorporates more than one differential protection-
measuring element. These differential protection-measuring elements are often
Section 5
Differential protection
99