ABB REG650 Technical Manual page 141

1MRK 502 048-UEN A
Phasors IL1N, IL2N,IL3N
Phasors IL1T, IL2T,IL3T
Samples IL1N, IL2N,IL3N
Samples IAT, IBT,ICT
The sensitive protection is deactivated
above bias current > 150 % rated
Phasor IL1N (neg.seq.)
Phasor IL1T (neg.seq.)
IEC06000434 V3 EN
Figure 56: Principle design of the generator differential protection
Technical manual
Magnitude
Idiff and Ibias
Calculation
Idiff and Ibias
Calculation
Samples Idiff
instantaneous
Idiff
current.
Calculation
negative
sequence
Idiff
Simplified logic diagrams of the function is shown in figures below.
Differential protection
Start
phase
Diff.prot. selective
characteristic
Harm.
Hamonic
Block
analysis: DC,
2nd and 5th
Intern/
Internal/
extern
External Fault
Fault
Discriminator
and Sensitive
differential
protection
Section 6
TRIP
Signals
START
Signals
BLOCK
Signals
INTFAULT
Start and
EXTFAULT
trip logic
OPENCT
OPENCTAL
Analog
Outputs
en06000434-2.vsd
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