The Photovoltaic (PV) monitoring system collects and analyzes number of parameters being measured in a PV plant to monitor and/or evaluate its performance. In order to ensure the reliable and stable operation of any PV system, an effective monitoring system is essential. Moreover, the monitoring system keeps track on various electricity generation indices and fault occurrences. The cost and complexity of existing PV monitoring systems restricts their use to large scale PV plants. Over the past decade, different aspects of PV monitoring systems were reported in wide range of literature. In this paper, a comprehensive review of various PV monitoring systems is presented for the first time. This includes the detailed overview of all the major PV monitoring evaluation techniques in terms of their relative performances. Major aspects of PV monitoring systems which examines in this paper are: sensors and their working principles, controller used in data acquisition systems, data transmission methods, and data storage and analysis. The acquaintance of all these aspects are crucial for the development of effective, low cost, and viable PV monitoring systems for small and medium scale PV plants without compromising on the desired performance.
Monitoring and control of photovoltaic systems is essential for reliable functioning and maximum yield of any solar electric system. The simplest monitoring of an inverter can be performed by reading values on display – display (usually LCD) is part of almost each grid-connected inverter. Most important inverter and grid related parameters are available on LCD screen in such case. Values like PV array power, AC grid power, PV array current are usually available. For sophisticated monitoring and control purposes environmental data – like module temperature, ambient temperature, solar radiation, wind speed can also be data logged, stored and analysed later. Remote control and monitoring can be performed by various remote connections: analog modem, ISDN, GSM etc. The most common connection for local/remote control are USB (sometimes even RS232) for local monitoring, RS485 and powerline for inverter interconnection. For wireless connection Bluetooth and Wi-Fi are most common used.