Section 12 System protection and control12.1 Multipurpose filter SMAIHPAC GUID-6B541154-D56B-452F-B143-4C2A1B2D3A1F v112.1.1 Identification GUID-8224B870-3DAA-44BF-B790-6600F2AD7C5D v1Function description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberMultipurpose filter SMAIHPAC - -12.1.2 Application GUID-A1F20DD8-571E-42C3-84F3-C557EC352ED0 v1The multi-purpose filter, function block with name SMAI HPAC, is arranged as a three-phase filter.It has very much the same user interface (e.g. function block outputs) as the standard pre-processing function block SMAI. However the main difference is that it can be used to extract anyfrequency component from the input signal. For all four analogue input signals into this filter (i.e.three phases and the residual quantity) the input samples from the TRM module, which are comingat rate of 20 samples per fundamental system cycle, are first stored. When enough samples areavailable in the internal memory, the phasor values at set frequency defined by the settingparameterSetFrequency are calculated. The following values are internally available for each of thecalculated phasors:• Magnitude• Phase angle• Exact frequency of the extracted signalThe SMAI HPAC filter is always used in conjunction with some other protection function (e.g. multi-purpose protection function or overcurrent function or over-voltage function or over-powerfunction). In this way many different protection applications can be arranged. For example thefollowing protection, monitoring or measurement features can be realized:• Sub-synchronous resonance protection for turbo generators• Sub-synchronous protection for wind turbines/wind farms• Detection of sub-synchronous oscillation between HVDC links and synchronous generators• Super-synchronous protection• Detection of presence of the geo-magnetic induced currents• Overcurrent or overvoltage protection at specific frequency harmonic, sub-harmonic, inter-harmonic etc.• Presence of special railway frequencies (e.g. 16.7Hz or 25Hz) in the three-phase power system• Sensitive reverse power protection• Stator or rotor earth fault protection for special injection frequencies (e.g. 25Hz)• etc.The filter output can also be connected to the measurement function blocks such as CVMMXN(Measurements), CMMXU (Phase current measurement), VMMXU (Phase-phase voltage1MRK 511 364-UUS A Section 12System protection and control179Application manual
