SNTPEE 2025 - Artigo: Testes de Injeção Secundária em Merging Units com LPITs

During the National Seminar on Electric Power Production and Transmission (SNTPEE 2025), the Director of Conprove, Paulo Sérgio Pereira Júnior, presented the technical paper “Secondary Injection Tests in Merging Units Considering the Use of Low Power Instrument Transformers (LPITs)”. The work highlighted the importance of interoperability and synchronization tests in digital substations, demonstrating how the use of LPITs and Merging Units can increase the levels of accuracy, safety, and reliability of electrical measurements. Right at the beginning, the need to ensure that digitized data correctly represent the analog world was emphasized, reinforcing the importance of transduction and analog-to-digital conversion tests. The digitization of measurements opens up space for the use of artificial intelligence and advanced real-time data analysis, but it depends directly on the accuracy of the samples collected by LPITs and Merging Units. Low Power Instrument Transformers (LPITs) were presented as a modern and safe alternative to conventional transformers, eliminating saturation risks, reducing infrastructure costs, and increasing the sustainability of systems. These devices also provide high precision and reduced dimensions, making them ideal for new substations. In practical terms, the study explored different closed-loop test setups, employing Conprove test sets capable of injecting low-power signals and comparing the results in real time with the Sampled Values ​​(SV) messages from the Merging Units. Primary and secondary tests were performed, with measurements via fiber optics and synchronization through the Precision Time Protocol (PTP), in which the test equipment itself acted as the Grandmaster Clock. Among the main results observed: • Average error less than 0.005%, proving the high precision of the measurements; • Stable linearity in voltage and current responses; • Average processing time of 1.28 ms, ensuring deterministic communication; • Reliable PTP synchronization without packet loss; • Similar behavior between setups with and without adapters, validating both test methods. Statistical analysis of Sampled Values ​​frames showed zero packet loss, absence of corrupted frames, and constant message-to-message time, with an average variation of only 250 microseconds — a high-level performance for applications in digital protection systems. The study concluded that LPITs offer a significant operational advantage for the future of digital substations, highlighting: ✅ Greater security and immunity to saturation; ✅ Reduction of civil and structural costs; ✅ High precision and excellent linearity; ✅ Sustainability and lower environmental impact; ✅ Full compliance with the principles of the IEC 61850 standard. With these results, Conprove reinforces its role as a national reference in testing and diagnostics for automation and protection systems, contributing to the technological advancement and reliability of the digital substations of the future. 🔗 Learn more about Conprove's products and solutions at: https://conprove.com/todos-produtos/ https://conprove.com/produto/02-0-ce-... https://conprove.com/produto/03-0-ce-... -61850/ https://conprove.com/produto/05-ce-70... https://conprove.com/produto/07-ctc-c... https://conprove.com/produto/07-netwo...