Electrical installations have to been checked electrically at commissioning but also increasingly during operation. In all countries the legislator ensures this by laws, standards and guidelines. In order to establish the electrical safety, grounding resistance, insulation resistance, loop resistance, tripping time and maybe also the harmonics between current and voltage have to be measured.
Furthermore the PV specialist measures the irradiation, voltage-current characteristic of the strings, off-load voltage, the performance and voltage in the maximum Power Point, the temperature of the modules and their ambient temperature, the infrared radiation of the modules, inverter and control cabinets during operation. As such extra equipment cannot be bought in a simple construction market, it is very expensive and therefore requires a professional operational planning.
ENcome is working in the error analysis according to a 3-step process, which guarantees that the right measuring tool will be used at the right time to avoid a waste time for the wrong measuring.
The analysis process starts with the inspection of the historical plant data. This includes, in particular, energy data and irradiation data. If irradiation data are not available, ENcome provides this data from a corresponding database, based on the plant location and the special orientation of the module. If deviations between the nominal and actual values are detected, the next step in the analysis is the string-Monitoring. In this process the error is usually largely restricted, so not all modules have to be considered by the following measurements.
In a next step, the affected strings are checked with the thermo-graphical camera and the voltage-current characteristic tool, in addition to the visual control (by means of the visual control you can already discover e.g. broken modules or cell breakage as well as soiled modules). With the thermo-graphic measurements you can detect invisible cell breakage, as well as Hotspots or PID. The characteristic line measurement allows, amongst other things, the identification of leak flow or diodes error.
To receive meaningful measurements you definitely need experience, which the operating manager gathered for years. Some simple measurements might be executed by any electrician, but an O&M provider like ENcome is required for the correct selection of measurements and the identification of defects.
The ENcome group is a pan-European leading and independent provider for the operation of photovoltaic power plants with focus on technical Operation and Maintenance (O&M), technical Asset Management (TAM) and the compilation of technical expertise. At present ENcome operates power plants with a nominal capacity of several hundred megawatts in different countries. Well skilled engineers ensure the best yield for every renewable energy park in any grid environment. Furthermore ENcome offers other services along the asset lifecycle of photovoltaic installations partnering amongst others with renown law firms, tax advisers and security centres.