12.3.11.5 SignalsTable 261:POS_EVAL Input signalsName Type Default DescriptionPOSITION INTEGER 0 Position status including qualityTable 262:POS_EVAL Output signalsName Type DescriptionOPENPOS BOOLEAN Open positionCLOSEPOS BOOLEAN Close position12.3.11.6 SettingsThe function does not have any settings available in Local HMI or Protection andControl IED Manager (PCM600).12.3.12 Operation principleThe interlocking function consists of software modules located in each control IED.The function is distributed and not dependent on any central function.Communication between modules in different bays is performed via the station bus.The reservation function is used to ensure that HV apparatuses that might affect theinterlock are blocked during the time gap, which arises between position updates. Thiscan be done by means of the communication system, reserving all HV apparatuses thatmight influence the interlocking condition of the intended operation. The reservationis maintained until the operation is performed.After the selection and reservation of an apparatus, the function has complete data onthe status of all apparatuses in the switchyard that are affected by the selection. Otheroperators cannot interfere with the reserved apparatus or the status of switchingdevices that may affect it.The open or closed positions of the HV apparatuses are inputs to software modulesdistributed in the control IEDs. Each module contains the interlocking logic for a bay.The interlocking logic in a module is different, depending on the bay function and theswitchyard arrangements, that is, double-breaker or 1 1/2 breaker bays have differentmodules. Specific interlocking conditions and connections between standardinterlocking modules are performed with an engineering tool. Bay-level interlockingsignals can include the following kind of information:• Positions of HV apparatuses (sometimes per phase)• Valid positions (if evaluated in the control module)• External release (to add special conditions for release)• Line voltage (to block operation of line earthing switch)• Output signals to release the HV apparatus1MRK 502 048-UEN A Section 12Control411Technical manual
