Setting Guidelines - ABB REC670 Applications Manual

Section 12
System protection and control
12.1.3
12.1.3.1
270
• Overcurrent or overvoltage protection at specific frequency harmonic, sub-
harmonic, inter-harmonic etc.
• Presence of special railway frequencies (e.g. 16.7Hz or 25Hz) in the three-
phase power system
• Sensitive reverse power protection
• Stator or rotor earth fault protection for special injection frequencies (e.g.
25Hz)
• etc.
The filter output can also be connected to the measurement function blocks such as
CVMMXN (Measurements), CMMXU (Phase current measurement), VMMXU
(Phase-phase voltage measurement), etc. in order to report the extracted phasor
values to the supervisory system (e.g. MicroSCADA).
The following figure shoes typical configuration connections required to utilize this
filter in conjunction with multi-purpose function as non-directional overcurrent
protection.
IEC13000179 V1 EN-US
Figure 102: Required ACT configuration
Such overcurrent arrangement can be for example used to achieve the
subsynchronous resonance protection for turbo generators.

Setting guidelines

Setting example
A relay type used for generator subsynchronous resonance overcurrent protection
shall be replaced. The relay had inverse time operating characteristic as given with
the following formula:
K
= +
t T
op 01
I
s
EQUATION13000029 V1 EN-US
1MRK 511 401-UEN A
IEC13000179-1-en.vsd
GUID-5A3F67BD-7D48-4734-948C-01DAF9470EF8 v2
(Equation 104)
Bay control REC670 2.2 IEC
Application manual