ABB REG670 Applications Manual page 441

1MRK 502 071-UEN -
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual
should be based on neutral point 3
operation.
UNFund>: UNFund> gives the operation level for the fundamental frequency
residual voltage stator earth fault protection. The setting is given as % of the rated
phase-to-earth voltage. A normal setting is in the range 5 – 10%.
UT3BlkLevel:UT3BlkLevel gives a voltage level for the 3rd harmonic voltage level at
the terminal side. If this level is lower than the setting the function is blocked. The
setting is given as % of the rated phase-to-earth voltage. The setting is typically 1 %.
t3rdH: t3rdH gives the trip delay of the 3
setting is given in seconds. Normally, a relatively long delay (about 10 s) is acceptable
as the earth fault current is small.
tUNFund: tUNFund gives the trip delay of the fundamental frequency residual
voltage stator earth fault protection. The setting is given in s. A delay in the range 0.5
– 2 seconds is acceptable.
rd
harmonic voltage measurement at normal
rd
harmonic stator earth fault protection. The
Section 10
Voltage protection
435