Development of current independent line-line/Line-ground fault detection technique for grid-connected photovoltaic (PV) arrays part II

• Main Author: Koh, Alika Savira Ching Oon
• Other Authors: Amer M. Y. M. Ghias
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/149439
• Institution: Nanyang Technological University

In Singapore, the growth in the deployment of Solar Photovoltaic (PV) systems has been rapidly increasing in the first quarter of 2018 and the installation of the solar PV system is set to further increase to the installed capacity of 1.5 Gigawatt-peak by 2025 as part of the Singapore Green Plan 2030 that was announced jointly by the Singaporean government.With this impetus in the adoption of solar PV systems, it is foreseeable that protection of the PV installation becomes imperative, especially against PV faults. This is to protect and prevent potential hazards and as well as protecting assets for a longer operation during its system lifetime. PV faults pose a serious issue to most PV systems as most faults can go undetected due to its magnitude and the pre-existing faults level threshold. As per the Singapore Standard(SS) 638 section 712L[3], when designing for the fault protection of the PV system, the provision to be made is to ensure that the current-carrying capacity of the PV string cables to be designed at equal to or greater than 1.25 times of the Isc of the solar module[3]. The two major faults that can happen in a PV system are mainly Line-to-Line (LL), Line-to-Ground(LG) faults and faults arising to partial shading conditions. LL fault occurs when the strings (series connections) of the PV modules are shorted together, causing the fault across the lines. Whereas for the LG fault, this fault occurs when the strings of the PV modules are shorted to the ground. In addition, the fault can also occur from the partial shading as it gives rise to the undesirable Maximum Multiple Points, inducing a power loss from the generation. In view of long-standing operation of the PV system, these faults can go undetected as it falls below the protection threshold, causing the loss in the power generation and a potential hazard over the course of its lifetime.