Metering & protection

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Inductive position sensorIND POS · Schematic Instantaneous ground overcurrent50G · SLD / Schematic Instantaneous negative-sequence overcurrent50Q · SLD / Schematic Instantaneous neutral overcurrent50N · SLD / Schematic Instantaneous overcurrent50 · SLD / Schematic Instantaneous phase overcurrent50P · SLD / Schematic Insulation monitoring relayIMD · Schematic / SLD Insulation resistance meterMΩ · Schematic Insulation-failure indicationQ021702 · Schematic Integrating instrument general symbol* · SLD / Schematic Interposing CT ratio-matching interfaceICRI · Schematic Interposing current transformerICT · Schematic / SLD Inverse-time characteristic qualifierIDMT · Schematic / SLD Ionising-radiation qualifierQ020903 · Schematic IRIG-B time-distribution interfaceITI · Schematic Isolated analogue-to-digital converterISO ADC · Schematic Isolating contactor29 · SLD / Schematic Level switch or relay71 · SLD / Schematic Line current differential protection87L · SLD / Schematic Line differential communication interfaceLDCI · Schematic Line distance zone-selection interfaceLDZI · Schematic Line-voltage synchronising input interfaceLSII · Schematic Load-resistor contactor73 · SLD / Schematic Lockout86 · SLD / Schematic Loss-of-voltage monitoring relayU LOSS · SLD / Schematic Low-power current sensor relay interfaceLCSRI · Schematic Low-power current transformerLPCT · SLD / Schematic Low-voltage ride-through supervision27T · SLD / Schematic Magnetic position sensorMAG POS · Schematic Magnetic-field-effect qualifierQ020804 · Schematic Main-input overvoltage59M · SLD / Schematic Main-input undervoltage protection27M · SLD / Schematic Manual transfer or selector device43 · SLD / Schematic Master contactor4 · SLD / Schematic Master element1 · SLD / Schematic Master sequence device34 · SLD / Schematic Maximum-current monitoring relayI HIGH · SLD / Schematic Maximum-demand indicatorMD · SLD / Schematic Maximum-voltage measuring relayK · Schematic / SLD Measured ground directional overcurrent67X · SLD / Schematic Measured ground instantaneous overcurrent50X · SLD / Schematic Measured ground time-overcurrent51X · SLD / Schematic Mechanical condition monitor39 · SLD / Schematic Merging-unit analogue channel mappingMACM · Schematic Merging-unit binary status publisherMBSP · Schematic Merging-unit time-quality interfaceMTI · Schematic Metering-core CT secondary circuitMCSC · Schematic Metering-winding VT secondary circuitMVSC · Schematic Minimum active-power relayP LOW · SLD / Schematic Minimum-current monitoring relayI LOW · SLD / Schematic Minimum-impedance measuring relayK · Schematic / SLD Minimum-voltage measuring relayK · Schematic / SLD Motor differential protection87M · SLD / Schematic Motor jam or stall protection50J · SLD / Schematic Motor thermal-model protection49M · SLD / Schematic Multi-core current transformerCT · SLD / Schematic Multi-rate energy meterkWh · SLD / Schematic Multifrequency admittance earth-fault protection67YN · SLD / Schematic Multifunction device11 · SLD / Schematic Multifunction power meterPM · SLD / Schematic Negative-sequence differential protection87Q · SLD / Schematic Negative-sequence overvoltage59Q · SLD / Schematic Neutral CT directional-reference interfaceNCDI · Schematic Neutral differential protection87N · SLD / Schematic Neutral-current measuring relayK · Schematic / SLD Neutral-unbalance relay between two polyphase systemsK · Schematic / SLD Notching or jogging device66 · SLD / Schematic NTP station time-service interfaceNSTI · Schematic Numerical protection relay (IED)IED · SLD / Schematic OhmmeterΩ · Schematic One-pulse-per-second timing interfaceOTI · Schematic Open-delta voltage transformer connectionVT · SLD / Schematic Operating mechanism84 · SLD / Schematic Optical current measurement processing interfaceOCMPI · Schematic Optical current sensorOCT · SLD Optical tachometric transducerHIN1B13 · Schematic OscilloscopeOSC · Schematic Overexcitation protection24 · SLD / Schematic Overfrequency protection81O · SLD / Schematic Overspeed device12 · SLD / Schematic Overvoltage59 · SLD / Schematic Panel power meterGA · GA / Schematic Parallel-transformer tap-control coordinatorPTC · Schematic Partial discharge sensorPD · SLD / Schematic Percentage-biased differential current relayK · Schematic / SLD Permissive control device69 · SLD / Schematic Permissive overreach transfer-trip interfacePOTI · Schematic Permissive underreach transfer-trip interfacePUTI · Schematic Phase distance protection21P · SLD / Schematic Phase-angle meterPHASE · SLD / Schematic Phase-angle or out-of-step protection78 · SLD / Schematic Phase-discontinuity protection46PD · SLD / Schematic Phase-loss monitoring relayPH LOSS · SLD / Schematic Phase-sequence indicatorPSI · Schematic Phase-sequence or voltage-balance protection47 · SLD / Schematic Phase-to-neutral voltmeter selectorHSW1S91 · Schematic Phase-to-phase voltmeter selectorHSW1S90 · Schematic Phasor measurement unitPMU · SLD / Schematic Photovoltaic arc-fault detectionPV AFD · Schematic Pilot or carrier receiver relay85 · SLD / Schematic