Improved Methodology for Testing the Compliance of Residual Current Detection of Non-Isolated Grid-Connected Photovoltaic Inverters

Henrique Bizzi Morari; Ricardo Jochann F. Bortolini; Lucas Vizzotto Bellinaso; Leandro Michels

doi:10.18618/REP.2023.3.0008

Authors

Henrique Bizzi Morari Claro S.A., São Paulo – SP, Brazil
Ricardo Jochann F. Bortolini Universidade Federal de Santa Maria (UFSM), Santa Maria – RS, Brazil
Lucas Vizzotto Bellinaso Universidade Federal de Santa Maria (UFSM), Santa Maria – RS, Brazil
Leandro Michels Universidade Federal de Santa Maria (UFSM), Santa Maria – RS, Brazil

DOI:

https://doi.org/10.18618/REP.2023.3.0008

Keywords:

Leakage Current, Photovoltaic Inverter, Residual Current, Safety Standards, Test Methodology

Abstract

Ensuring user safety in transformerless photovoltaic (PV) inverters is crucial due to the high leakage current caused mainly by the PV modules’ capacitance. Compliance with safety standards IEC 62109-2:2011 and IEC 63112:2021 demands leakage current tests utilizing a variable resistive-capacitive (RC) load. However, limited research has been conducted to assess the impact of test parameters on result conclusiveness. To address this gap, this paper investigates the influence of AC mains voltage phase angle on trip time results in the continuous leakage current test as per these standards. Our experiments, performed with five commercial transformerless PV inverters, reveal significant sensitivity of the results to this specific parameter. Supported by RMANOVA analysis, our findings substantiate this observation. Subsequently, we discuss potential strategies to enhance the accuracy of test outcomes and propose a well-defined methodology to ensure repeatability and reliability of results.

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Author Biographies

Henrique Bizzi Morari, Claro S.A., São Paulo – SP, Brazil

received his B.S. degree in Control and Automation Engineering from the Federal University of Santa Maria (UFSM), Santa Maria, Brazil, in 2019. He has worked in the PV Systems industry and is currently working in data engineering at Claro S.A. His research interests include computer science, power electronics, and control systems.

Ricardo Jochann F. Bortolini, Universidade Federal de Santa Maria (UFSM), Santa Maria – RS, Brazil

was born in Rodeio Bonito, Brazil, in 1992. He received the B.S degree in Automatic Control and Systems Engineering, M.Sc. and Dr. degree in Electrical Engineering from the Federal University of Santa Maria (UFSM), Brazil in 2015, 2018 and 2023, respectively. He is currently post-doc in UFSM in the PV Inverters tests laboratory and is member of working groups that develops Brazilian’s PV standards. His research interests include PV systems, Hardware-in-the-loop, power electronics and safety of PV systems. Additionally, he is currently a Brazilian expert in the IEC TC 82 – Solar photovoltaic energy systems.

Lucas Vizzotto Bellinaso, Universidade Federal de Santa Maria (UFSM), Santa Maria – RS, Brazil

received his B.S. and M.S. degrees in electrical engineering in 2012, followed by his M.Sc. and Ph.D. degrees in electrical engineering from the Federal University of Santa Maria (UFSM), Santa Maria, Brazil, in 2014 and 2017, respectively. Since 2015, he has been with the Power Electronics and Control Group (GEPOC) at the same university, where he is currently Professor. His research interests include PV systems, power electronics and control applied to renewable energy systems, and safety of PV systems. Additionally, he is currently National Secretary of ABNT/CB-003/CE 003 082, the Brazilian mirror committee of IEC TC 82.

Leandro Michels, Universidade Federal de Santa Maria (UFSM), Santa Maria – RS, Brazil

was born in Não-Me-Toque, Brazil, in 1979. He received the B.S and Ph.D. degrees from the Federal University of Santa Maria, Santa Maria, Brazil, in 2002 and 2006, respectively, both in electrical engineering. Since 2009, he has been with the Power Electronics and Control Research Group (GEPOC) at the Federal University of Santa Maria, where he currently is Associate Professor and the director of the Smart Grid Institute (INRI/UFSM). He is also coordinator of the INRI laboratory for testing photovoltaic inverters, accredited by INMETRO, and the coordinator of the Unit of the Brazilian Company of Research and Industrial Innovation (EMBRAPII) focused on Distributed Energy Resources. Additionally, he is the National Coordinator of ABNT/CB003/CE 003 082

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