also be realized within the protection itself, by using opened and close signals for
each circuit breaker pole, connected to the protection.
• Each phase current through the circuit breaker is measured. If the difference
between the phase currents is lar
ger than a CurrUnsymPU this is an indication of
pole discrepancy, and the protection will operate.
9.11.3 Setting guidelines
M13274-3 v8
The parameters for the Pole discordance protection CCPDSC (52PD) are set via the
local HMI or PCM600.
The following settings can be done for the pole discrepancy protection.
GlobalBaseSel: Selects the global base value group used by the function to define
IBase, VBase and SBase as applicable.
Operation: Disabled or Enabled
tTrip: Time delay of the operation.
ContactSel: Operation of the contact based pole discrepancy protection. Can be set:
Disabled/PD signal from CB. If PD signal from CB is chosen the logic to detect pole
discrepancy is made in the vicinity to the breaker auxiliary contacts and only one signal
is connected to the pole discrepancy function. If the Pole pos aux cont. alternative is
chosen each open close signal is connected to the IED and the logic to detect pole
discrepancy is realized within the function itself.
CurrentSel: Operation of the current based pole discrepancy protection. Can be set:
Disabled/CB oper monitor/Continuous monitor. In the alternative CB oper monitor the
function is activated only directly in connection to breaker open or close command
(during 200 ms). In the alternative Continuous monitor function is continuously
activated.
CurrUnsymPU: Unsymmetrical magnitude of lowest phase current compared to the
highest, set in % of the highest phase current. Natural difference between phase
currents in breaker-and-a-half installations must be considered. For circuit breakers in
breaker-and-a-half configured switch yards there might be natural unbalance currents
through the breaker. This is due to the existence of low impedance current paths in the
switch yard. This phenomenon must be considered in the setting of the parameter.
CurrRelPU: Current magnitude for release of the function in % of IBase.
Section 9 1MRK 504 163-UUS A
Current protection
578 Transformer protection RET670 2.2 ANSI
Application manual
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