PID – PV OFFSET BOXES
PID phenomenon (Potential Induced Degradation) affects the performance of photovoltaic frames and leads to its gradual decrease up to 30%. The phenomenon may start by a single photovoltaic panel and gradually expand to more, even to all the panels of a station, if not dealt with promptly.
At a photovoltaic panel, PID appears more intensely at the cells found near the aluminum frame, whereas at the cells found at the center of the photovoltaic panel it appears less frequently.
In a string of photovoltaic panels, PID appears more intensely at the panels closer to the negative side of the string, in terms of dynamics.
This phenomenon mainly appears to photovoltaic frames presenting high dynamics (positive or negative) towards Earth and mainly to frames with negative dynamics. Factors leading to the appearance of this phenomenon feature the high current of the photovoltaic strings, humidity, high temperature and constructive characteristics of the photovoltaic frames.
Phenomenon diagnosis takes place in two ways.
First way of diagnosing PID phenomenon is through measurement using special devices and the second, which is particularly difficult, happens through the remote monitoring system of the photovoltaic station. The disadvantage with the second way is that the phenomenon becomes evident only after having spread substantially to the photovoltaic station strings.
Way of Dealing with PID Phenomenon
The way to deal with PID is to install PV Offset Boxes. These devices reverse the polarizing effect, which occurred during the installation function. According to several studies, the time duration of invigorating the photovoltaic frames lasts for about half the duration of affecting them.
PV Offset Boxes by Apolloteck come with embedded power supply, they can be connected with up to three different photovoltaic strings and are easily installed.