## 2 Faults in a PV System
### PV Inverter Faults (PVI)
#### 2.2.2 Open-Circuit Fault  
An open-circuit fault can occur in a photovoltaic system due to a disconnection of the jumper wire, overheating, or a device driver fault, resulting in a broken connection. Unlike a short-circuit fault, an open-circuit fault may not immediately affect the inverter, but if left unaddressed, it can lead to serious accidents with other components [71]. This is because an open-circuit fault distorts the output current of the inverter, causing an increase in the total-harmonic ratio, which does not meet the grid connection requirements. Table 1 provides a list of main faults that can occur in a photovoltaic system, and Figure 6 illustrates an overview of the open-circuit fault that can occur in the IGBT transistor of a PV inverter.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Type of Defects** & **Causes** & **Effects** & **Consequences** \\ \hline \multirow{4}{*}{Internal} & Short circuit & Manufacturing defect & Low impedance, blocked path between internal power rails & Reduction of power produced \\ \cline{2-5}  & Cell microcracks & Manufacturing defect & Difference in module characteristics & Unable to deliver power to the load \\ \cline{2-5}  & Broken modules & Shock during transport & & \\ \cline{2-5}  & Degraded modules & Aging & Drop in power delivered & Low production \\ \cline{2-5}  & Bypass diode & Manufacturing defect, wiring defect & Can’t drive & Unable to prevent the appearance of hot spots, electric arc, fire risk \\ \cline{2-5}  & Open circuit & Manufacturing defect, wiring defect & Lack of access path for the power produced & No power produced \\ \hline \multirow{2}{*}{External} & \multirow{2}{*}{Mismatch fault} & Temporary & Temporary shading & Cloud & Drop in production, risk of fires \\ \cline{2-5}  & Permanent & Equipment damage & Blackout & No production \\ \hline \multirow{4}{*}{Shading} & \multirow{2}{*}{Temporary} & Passage of clouds, weather conditions & Uneven distribution of irradiation on the surface of the modules & Drop in power produced \\ \cline{3-5}  & & Natural disaster & Module reverse bias & Hot spot/fire hazard \\ \cline{2-5}  & Permanent & Partial shading & & \\ \hline \multirow{4}{*}{PV field} & Short circuit & Bad wiring between inverter and PV field, chewing of cables by animals, water infiltration into modules & Drop in network voltage and increase in current & Drop in production \\ \cline{2-5}  & Open circuit & Accidental breakage of connecting cables & Drastic drop in short-circuit current & Drop in production \\ \cline{2-5}  & Line to line & Faulty connection link between the different rail circuits & Power loss & Reduction of open circuit voltage, modification of characteristic IV \\ \cline{2-5}  & Arc fault & Accidental passage of current in a dielectric & Strong noise in currents and voltages & Fire hazard \\ \cline{2-5}  & Line to ground & Ground wiring fault, corrosion & Drop in network voltage and increase in current & Risk of electrovection, variable voltage \\ \hline \multirow{4}{*}{PV inverter open circuit} & \multirow{2}{*}{Inverter open circuit} & Absence of gate control, connection wire breakage due to high short-circuit current, external disconnection due to vibrations & Deterioration of phase current and torque & External radiation \\ \cline{2-5}  & & High gate voltage, delamination and cracking in the solder layer, static locking and high temperature & Excessive leakage current, affected phase current close to zero & Temperature variation \\ \cline{2-5}  & & \multirow{2}{*}{Insulation fault} & Humidity, high heat, poor connection in the solar panel junction box, aging of solar panels & No power \\ \hline Grid & Grid anomalies & Electrical overload, deterioration of conductive insulators & Network disruption, voltage dips and peaks, harmonics & Interruption of current flow, short circuit \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summarizes the various faults, their causes, and the resulting consequences.