**2. PV system and data acquisition**

The chapter presents the authors activity and results regarding the operation of a PV system and aspects on monitoring the electric energy supplied by a PV system built in University "Valahia" of Targoviste, Romania.

a) North view b) South view

Fig. 1. PV system

Part of the ICOP DEMO 4080-90 European research program, this PV system has been realized by the staff of the Electrical Engineering Faculty, Targoviste, Romania (Andrei et al., 2007).

The PV system integrated into the roof of the building has been designed using 66 Optisol SFM 72Bx glass roof integrated multi crystalline Si modules produced by Pilkington Solar and 24 ST40 thin film modules produced by Siemens which generates a total amount of 10 kWp. Position of panels on the southern front is shown in Figure 2. These modules can be serial or parallel connected. The dc voltage produced by the PV system is converted by the Sunny Boy inverters (SWR 700, SWR 1100, SWR 2000 and SWR 2500) and supplied directly into the public electricity system – Figure 3.

The use of a controller to monitor the operating parameters ensures the sine-wave form of the voltage and current, with a low amount of harmonics. The control of operations serves to totally automated functioning and to adjustement of the MPP (maximum power point).

inputs of multiple channels and drives a single ADC can substantially reduce the cost of a

Specialized data acquisition systems for PV installations require a study of sample rates and an optimal configuration of the measuring chain. This chapter brings informations regarding the structure of data acquisition systems used in the monitoring of photovoltaic installations. It shows the operating principles of building blocks and the operation is performed by simulations using LabVIEW™ - Laboratory Virtual Instrumentation

An important part of the presentation is dedicated to current measurement and data acquisition systems dedicated for monitoring PV systems. Applied solutions and experimental results are discussed in terms of accuracy and optimization needs of the

The chapter presents the authors activity and results regarding the operation of a PV system and aspects on monitoring the electric energy supplied by a PV system built in University

a) North view b) South view

Part of the ICOP DEMO 4080-90 European research program, this PV system has been realized by the staff of the Electrical Engineering Faculty, Targoviste, Romania (Andrei et

The PV system integrated into the roof of the building has been designed using 66 Optisol SFM 72Bx glass roof integrated multi crystalline Si modules produced by Pilkington Solar and 24 ST40 thin film modules produced by Siemens which generates a total amount of 10 kWp. Position of panels on the southern front is shown in Figure 2. These modules can be serial or parallel connected. The dc voltage produced by the PV system is converted by the Sunny Boy inverters (SWR 700, SWR 1100, SWR 2000 and SWR 2500) and supplied directly

The use of a controller to monitor the operating parameters ensures the sine-wave form of the voltage and current, with a low amount of harmonics. The control of operations serves to totally automated functioning and to adjustement of the MPP (maximum power point).

system (Szekely, 1997).

Engineering Workbench.

**2. PV system and data acquisition** 

into the public electricity system – Figure 3.

"Valahia" of Targoviste, Romania.

operation.

Fig. 1. PV system

al., 2007).

The connection diagram of the PV system has been designed after a series of shading effects analyse and buiding placement restrictions (Dogaru Ulieru et al., 2009).

Fig. 2. Panel position

Fig. 3. Electric energy producing system using photovoltaic panels (phase A)

PV system monitoring was done by two methods:


To ensure the accuracy of the measurement, the operating parameters of the PV system and the configuration of the acquisition system are taken into account and have imposed the signal conditioning and the setting of the signal source, of the field and of the channels. Analog inputs can be differently configured, with a voltage level of ±2.5V, ±5V, ±10V (bipolar/single polar) which can be selected through the configuration program of the acquisition board. The block diagram of the acquisition system is presented in Figure 5. Figure 6 shows the LabVIEW™ block diagram of the virtual instrument attached to the data acquisition system (Cepisca et al., 2004).

Fig. 4. Monitoring system Sunny



PV system monitoring was done by two methods:

acquisition system (Cepisca et al., 2004).

Fig. 4. Monitoring system Sunny

has been preset to 10 minutes (day and night).

Fig. 5. DAQ Block diagram

Fig. 6. LabVIEW™ block diagram
