HT Instruments MPP300 Adapter for PV Testing on Multistring Installation
The innovative accessory MPP300, used together with SOLAR300N or SOLAR I-V, allows measuring and recording the main parameters which characterize single-phase and three-phase, single-string and multi-string (up to three strings) photovoltaic systems. MPP300 is perfect for use in systems with three-MPPT three-phase inverter and in three-phase systems provided with three single-phase inverters. MPP300 is provided with a practical anti-shock “field” case, lightweight and small in size.
The front panel carries the LEDs for operating information and the DC and AC inputs for upstream and downstream connection of the inverter(s). MPP300 interfaces with SOLAR300N via USB connection and SOLAR I-V via wireless connection. SOLAR300N and SOLAR I-V are used for MPP300 settings, to start/stop recording electrical and environmental parameters and to enable the download of the recorded values.
The distance between the photovoltaic modules and the inverter is often considerable, and this forces the operator to carry out measurements in different places at the same time. Therefore, it would be necessary to lay long connection cables between the environmental probes and the instrument. These cables could hamper the operator’s movements, be a hindrance, etc. This kind of connection is therefore not acceptable. In case of photovoltaic installations on buildings, the so-called photovoltaic roofs, in addition to the problem of the distance between modules and inverter, the presence of floors, of reinforced concrete or metal structures, etc. must be taken into consideration.
These structures would make a possible (wireless) radio connection between the environmental probes and the instrument impossible, because of signal attenuation. In order to avoid the above-mentioned problems and to carry out measurements with the necessary contemporaneity, MPP300 is synchronized with the remote unit SOLAR-02 (provided as standard accessory of master instrument SOLAR300N or SOLAR I-V). The remote unit SOLAR-02 is positioned next to the photovoltaic modules and it is connected to the probes for measuring environmental parameters (irradiation and temperature).
MPP300 is connected upstream and downstream of the inverter in order to acquire the electric parameters (continuous power and alternating power). The synchronization between the two units guarantees the necessary contemporaneity of measurements, the two separate and independent units make measurements comfortable and safe
The master instrument SOLAR300N or SOLAR I-V is only used in the initial and final phase of recording, and it does not play any active role while recording electrical and environmental parameters. Therefore, while MPP300 and SOLAR-02 respectively record the electrical and environmental parameters of the system being measured, it is possible to use the master instrument SOLAR300N or SOLAR I-V for carrying out other measurements. For example, with SOLAR I-V it is possible to measure the I-V characteristics of strings and modules.