A Computer-Based IEC 61850 Sampled Values Analyzer for Parallel Power Quality Analysis

This article introduces a system capable of characterizing on-site digital instrument transformers from the analysis of the IEC 61850/IEC 61869–9 frames injected by the Stand Alone Merging Unit (SAMU) located in digital substations. Besides, the second objective of this work is to implement a suitable computation architecture to monitor distributed power quality (PQ) nodes. For this aim, the capacity of calculating PQ from the information sent by the SAMU will be leveraged. In a first step, this approach relies on the implementation of an IEC 61000-4-30 class-A PQ library on an industrial-based computer. Concerning the first objective, several experimental tests were driven for a solid timestamping characterization of the received data. After that, different PQ tests were carried out to verify the suitability of the proposed solution by comparing the system against one traceable generator. The calculation of normalized error indexes ( $E_{n}$ ) revealed that the developed system is compatible with respect to the reference generator. In this regard, the system can be used to calibrate digital instrument transformers (via SAMUs) against one analog reference transformer. Later, the library is migrated to a more constrained hardware to identify the maximum number of parallel nodes that the analyzer can process. On this basis, several tests were conducted to stress the low-cost platform until reaching the thermal limit on CPU. In light of the results, the maximum number of nodes was 20. This fact indicates that the proposed low-cost analyzer meets the stringent class-A requirements of IEC 61000-4-30 for real-time parallel evaluations.