Table 339:SMAIHPAC Output signalsName Type DescriptionAI3P GROUP SIGNAL Analog input 3-phase groupAI1 GROUP SIGNAL Analog input 1AI2 GROUP SIGNAL Analog input 2AI3 GROUP SIGNAL Analog input 3AI4 GROUP SIGNAL Analog input 412.1.5 SettingsTable 340:SMAIHPAC Non group settings (basic)Name Values (Range) Unit Step Default DescriptionConnectionType Ph - PhPh - N- - Ph - N Analogue input connection typeSetFrequency 2.0 - 500.0 Hz 0.1 50.0 Desired frequency to be extracted by thefilterFreqBandWidth 0.0 - 60.0 Hz 0.1 0.0 Extra added frequency band around theset frequencyFilterLength 0.1 s0.2 s0.5 s1.0 s2.0 s4.0 s- - 1.0 s Approximate length of the filtering windowin secondsOverLap 0 - 95 % 5 20 Filtering window overlap between twocalculations in percent12.1.6 Operation principleFor all four analogue input signals into this filter (i.e. three phases and the residualquantity) the input samples from the TRM module which are coming at rate of 20samples per fundamental system cycle are first stored. When enough samples areavailable in the internal memory, the phasor values at set frequency defined by thesetting parameter SetFrequency are calculated. The following values are internallyavailable for each of the calculated phasors:• Magnitude• Phase angle• Exact frequency of the extracted signalNote that the special filtering algorithm is used to extract these phasors. Thisalgorithm is different from the standard one-cycle Digital Fourier Filter typically usedby the numerical IEDs. This filter provides extremely good accuracy of measurementand excellent noise rejection, but at the same time it has much slower response time.It is capable to extract phasor (i.e. magnitude, phase angle and actual frequency) ofSection 12 1MRK502052-UEN BSystem protection and control596Technical manual
