The productivity of individual strings
The photovoltaic systems, both on the ground and on the roof, are normally controlled by monitoring systems, even sophisticated, which provide useful information on the proper functioning of the various components (inverters, parallel switchboards, string boxes, etc..), promptly reporting any faults. However, monitoring systems are not always able to immediately detect the correct functioning of each string of the system, periodically measuring the currents at the same time and comparing the results produced by all the strings subject to the same radiation. In the event that the monitoring system in use is not equipped with the instruments to simultaneously measure the individual string currents, a predictive check based on the data of one or more solarimeters and, above all, the frequent field measurement of the current produced by the individual strings is often used.
The importance of accurate monitoring of productivity
Photovoltaic plant owners, maintenance workers, O&M Managers and Asset Managers know very well how important it is, in order to maximize production, to frequently check the production levels of each string.
If, for example, in a 1MWp power plant composed of about 200 strings of modules, 4 or 5 strings are temporarily unproductive (fuses, blown connectors, broken modules, etc..), the situation can hardly be detected by the monitoring system with the simple evaluation of the expected production, but only with the measurement in the field, frequent and accurate.
However, the field measurement may not be sufficient to detect less serious problems related to strings that are producing, but below their potential (dirty modules, oxidized connectors, damaged cables): in fact, in the time required to manually perform the measurements, the radiation conditions change, making it virtually impossible to make a probative comparison between the different strings.
Measuring string currents with WiEgg
The WiEgg solution for string current measurement has been designed to integrate monitoring systems of any type and complexity, with this important functionality.
WiEgg is really innovative because it solves in an economic and effective way the problem of measuring at predetermined intervals and simultaneously, the individual currents of each string and immediately send the data collected to a remote cloud system for the timely management of alert messages and the processing of statistical reports.
WiEgg uses a new sensor technology and data transmission, which exceeds the limits and costs often highlighted by similar systems, long on the market.