I>: Current level for the Stub protection, set in % of IBase. This parameter shouldbe set so that all faults on the stub can be detected. The setting should thus be basedon fault calculations.t: Time delay of the operation. Normally the function shall be instantaneous.9.10 Pole discordance protection CCPDSC IP14516-1 v59.10.1 IdentificationM14888-1 v4Function description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberPole discordance protection CCPDSCPDSYMBOL-S V1 EN-US52PD9.10.2 Application M13270-3 v6There is a risk that a circuit breaker will get discordance between the poles atcircuit breaker operation: closing or opening. One pole can be open and the othertwo closed, or two poles can be open and one closed. Pole discordance of a circuitbreaker will cause unsymmetrical currents in the power system. The consequenceof this can be:• Negative sequence currents that will give stress on rotating machines• Zero sequence currents that might give unwanted operation of sensitive earth-fault protections in the power system.It is therefore important to detect situations with pole discordance of circuitbreakers. When this is detected the breaker should be tripped directly.Pole discordance protection CCPDSC will detect situation with deviating positionsof the poles of the protected circuit breaker. The protection has two differentoptions to make this detection:• By connecting the auxiliary contacts in the circuit breaker so that logic iscreated, a signal can be sent to the protection, indicating pole discordance.This logic can also be realized within the protection itself, by using openedand close signals for each circuit breaker pole, connected to the protection.• Each phase current through the circuit breaker is measured. If the differencebetween the phase currents is larger than a CurrUnsymLevel this is anindication of pole discordance, and the protection will operate.1MRK 506 369-UEN B Section 9Current protectionLine distance protection REL670 2.2 IEC 513Application manual
