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IEC 61850‑9‑2 Sampled Values applies to all the 20+ T-group sensors (T Group - analogue samples (22)) - of which only two relate to CT and VT sensors (Logical Nodes TCTR and TVTR).
IEC 61850‑9‑2LE and now IEC 61869-9 "simply" provide the parameters associated with configuring the Merging Unit's generic Multicast Sampled Value Control Blocks "MSVCBxx" to suit CT and VT applications (you could for instance use TCTR to provide sampled values of the battery d/c/ current once every hour but those parameters would not suit CT and VT applications).
However have you ever wondered what the difference in sampling rates really means in accuracy?
Well, "accuracy" is probably not the right word as that has many aspects, but rather correlation or discrepancy between the known samples (which as a number may be highly accurate at that instant) to the continuous waveform itself between the samples.
When an IED is sampling, it only knows the value of the waveform at the last sample. There is a step-change in "known value" every time a new sample is taken. Obvious really.
that means the IED must take samples sufficiently frequently to satisfy the performance requirements and accuracy requirements of the function itself.
Of course using faster sampling is no problem for the function as it can "pick and choose" which ones it uses - it can even "re-sample" a derived waveform at a different sampling rate.
However using unnecessarily faster sampling increases the bandwidth requirements which puts additional performance requirements on the IED port itself as well as the LAN bandwidth capabilities to distribute all messages with the required latency.
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