Reactive Power Considerations in Reliability Analysis of Photovoltaic Systems

Reactive power is very essential in maintaining voltage stability of power systems. The voltage constraint at network nodes due to reactive power deficit or insufficiency of reactive power sources restricts active power delivery to the loads and could result in forced load curtailment. Limited attention has been given to reactive power aspect in reliability evaluation of power systems with penetration of renewable energy sources. The reactive power issues become more significant in distributed generation using renewable energy sources such as photovoltaic (PV) Cells, which operate mostly at unity power factor. This paper investigates the effect of reactive power shortage on reliability of power systems with significant penetration of PV cells. The IEEE 14-Bus system is utilized to perform this study. A measure of Expected Energy Not Supplied (EENS) on account of reactive power shortage and voltage violation in network is calculated. By using conventional Monte Carlo simulation, the results are compared with the case without taking into account reactive power and voltage violation constrains. This paper suggests that placement of the PV in the network can greatly reduce active and reactive power shortage during the contingencies. The reactive power is studied here from design and planning perspectives for reliable and stable power system operation when high penetrations of PV energy sources are present.