System Strength Improvement Using Reactive Compensation for Enhanced PV Hosting Capacity

The installation of dispersed generation in on the rise in modern power systems, while the investments on conventional large generators are declining. The majority of distributed generators (DG) are non-synchronous type such as photovoltaic generators (PV), which are operated at near unity power factor. These non-synchronous generators lack the capability of reactive power support and hence the strength of the system to withstand disturbances is deteriorating. Therefore, capacity of network to host more PV units is posing a major challenge. Deterioration of system strength is revealed by decreasing fault levels and short circuit ratio (SCR) across the nodes of a network as a result of increasing penetration of PV units. Therefore, utilities have prescribed minimum values of short circuit ratio as an important minimum requirement for the connection of new solar PV generators. This paper investigates the impact of solar PV units’ connection on SCR of an electricity network. Appropriate size of reactive compensation is calculated for the improvement of SCR. The effectiveness of capacitive compensation on the improvement of SCR across the network is also demonstrated.