Function
Range or value
Accuracy
Timers
(0.000-60.000) s
±
0.5%
±
10 ms
Operate time for
current detection
20 ms typically
-
Reset time for current
detection
10 ms maximum
-
8.7
Pole discordance protection CCRPLD
8.7.1
Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Pole discordance protection
CCRPLD
PD
SYMBOL-S V1 EN
52PD
8.7.2
Functionality
Circuit breakers and disconnectors can end up with the 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 own breaker is tripped to correct such a situation. If the situation persists
the surrounding breakers should be tripped to clear the unsymmetrical load situation.
The pole discordance function operates based on information from the circuit breaker
logic with additional criteria from phase selective current unsymmetry.
8.7.3
Function block
CCRPLD
I3P*
BLOCK
CLOSECMD
OPENCMD
EXTPDIND
TRIP
START
IEC08000041 V1 EN
Figure 83:
CCRPLD function block
1MRK 504 135-UEN A
Section 8
Current protection
185
Technical manual
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