Operational characteristics of a cluster of distributed photovoltaic systems

As PV systems are an intermittent resource; their behaviour will need to be appropriately characterised before they can be reliably integrated into the electrical grid on a large scale. Relevant issues at the network level include voltage regulation and more variable power flows through network equipment. At the system level, high penetrations may have significant supply-demand and reserve implications. A particular challenge is that PV can be implemented in a highly distributed manner with potentially large numbers of small residential systems. This paper attempts to characterise the behaviour of a distributed system of small scale PV installations using high frequency (10 second) monitoring data from a number of existing PV installations in the Hunter region of Australia. Results highlight the significant variability of PV generation under some weather conditions, the benefits of distributed PV implementation in reducing aggregate short-term variability and the particular characteristics of this variability including its dependence on cloud cover and the time of day. Results are presented in a form which is hoped to allow easy incorporation into distributed generation models and which assists designers of smart grid systems.