Highly efficient and effective test and diagnostic solution for photovoltaic systems in accordance with international standards*
Numerous photovoltaic systems, especially in the private sector, are becoming outdated and not effective anymore. But how will you know, if a PV system is still safe and yields the anticipated returns? To be on the safe side, an expert solar engineer should be called in. By performing tests in accordance with DIN EN 62446 (VDE 0126-23) and DIN EN 61829 (VDE 0126-24), customers are given both a safety inspection and report regarding the quality and efficiency of the existing PV system.
The construction of low-voltage systems has been determined by particular specifications and guidelines for many decades now. Introduced approximately ten years ago, the EN 62446 standard defines the minimum requirements for documentation, commissioning and periodic tests of the grid-connected PV systems. However, similar standards and regular monitoring were given short shrift in the past, also due in part to the lack of awareness of private PV system operators. Older PV systems often deliver less power calculation promised. In order to detect a decrease of power in good time and to be able to initiate countermeasures, the proper method would be to have the PV characteristics measured by a corresponding specialist. In the event of quality and efficiency losses, the BENNING PV 2 combined with an irradiation and temperature sensor, can record the actual electrical values and document them using the BENNING SOLAR Manager PC software. The software is based on a comprehensive module database. It compares the measured values converted to STC (Standard Test Conditions) with the nominal manufacturer specifications.
In the heyday of PV systems, solar module manufacturers promised low power losses for a period of up to 20 years. If there is a deviation in the quality and efficiency assessment, a warranty claim can be proven, documented and requested.
Range of additional features
In 2011, BENNING launched BENNING PV 1-1, one of the first PV installation testers for standard-compliant, quick and easy testing of PV generators. Today, BENNING PV 2 is an all-in-one commissioning tester and supplements the PV check with an additional I-V curve tracer and power curve. In addition to the measurements of the noload voltage, the short-circuit current and the insulation resistance, the display shows the current and the voltage in the "Maximum Power Point" (the point of maximum power on the electrical curve) of the solar string. BENNING PV 2 calculates the filling factor as a measure of the solar cell quality based on the current and voltage values.
The ideal solar cell is a constant current source up to its maximum voltage and the filling factor is equal to one. The lower the filling factor, the lower the efficiency, since a part of the generated power is lost to the internal resistance of the solar cell. For crystalline solar cells, values between 0.75 and 0.85 are achieved; for amorphous cells the filling factor is between 0.5 and 0.7. The filling factor is thus a key indicator that provides a quality assessment at first glance. To ensure that a characteristic curve is recorded correctly and can be subsequently analysed, the ambient conditions should be taken into account.
A combination and wireless coupling of BENNING PV 2 with the irradiation and temperature measuring device BENNING SUN 2 is therefore necessary. Supplementary data on solar irradiation, module temperature and ambient temperature are essential because they directly impact the PV module performance. A new feature compared to its predecessor, BENNING PV 1-1, is the ability to provide separated and continuous insulation resistance measurement. BENNING PV 2 performs a “preliminary check” before each automatic test procedure in order to prevent damage (e.g. due to power surges) that could destroy the measuring device.
Software and accessories
The PC software BENNING SOLAR Manager can be used for generating complete test reports and documentation in accordance with DIN EN 62446 (VDE 0126-23) and DIN EN 61829 (VDE 0126-24). The I-V and power curves determined are converted to STC conditions and compared to the nominal manufacturer specifications via an integrated PV module database. If the solar energy specialist is using a smartphone or tablet with an Android operating system and NFC technology, he can download and use the free app "BENNING PV Link" from the Playstore.
With this "Android device" the expert can select data from the NFC chip integrated into the BENNING PV 2. The app can display and compare a characteristic curve with the STC data via the integrated module database. In addition, there are other accessories available that offer a practical range of additional features. This includes, for example, a shoulder bag for the PV measuring devices, which allows greater freedom of movement in thesolar field and in a PV plant.
The product range also includes a twochannel temperature sensor with suction cup, PV module retainer for the BENNING SUN 2, a 40 m measuring line reel (BENNING TA 5) and an AC/DC current clamp adapter (BENNING CC 3) suitable for DC and AC current measurement up to 40 A.
With its PV installation testers and curve measuring devices, BENNING is ideally placed for the needs of a solar energy specialist during the installation, maintenance and servicing of a photovoltaic system.
Please do not hesitate to contact us if you have any further queries about the testing and measuring equipment.
*BENNING PV 2 and BENNING SOLAR Manager are expected to be available in English from 06/2018.