Function Range or value Accuracy
Phase current pickup for
blocking of contact
function
(5-200)% of
lBase
± 1.0% of I
n
at I £ I
n
± 1.0% of I at I > I
n
Reset ratio > 95% -
Timers (0.000-60.000) s ± 0.5% ±10 ms
Operate time for current
detection
35 ms typically -
Reset time for current
detection
10 ms maximum -
7.5 Pole discrepancy protection CCRPLD (52PD)
7.5.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Pole discrepancy protection CCRPLD
SYMBOL-S V1 EN
52PD
7.5.2 Functionality
Circuit breakers and disconnectors can end up with their phases in different positions
(close-open), due to electrical or mechanical failures. An open phase can cause
negative and zero sequence currents which cause thermal stress on rotating machines
and can cause unwanted operation of zero sequence or negative sequence current
functions.
Normally the affected breaker is tripped to correct such a situation. If the situation
warrants the surrounding breakers should be tripped to clear the unsymmetrical load
situation.
The pole discrepancy function operates based on information from the circuit breaker
logic with additional criteria from unsymmetrical phase currents when required.
Section 7 1MRK 505 277-UUS C
Current protection
112
Technical Manual
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