Reliability Evaluation of PhotoVoltaic and Energy Storage Integrated Systems with Frequency Security Constraint

The increasing integration of solar power into the grid impacts the system reliability and stability due to its generation intermittency and low inertia. One of the major problems with increasing photovoltaic power integration is the reduction in system frequency stability as low inertia photovoltaic systems become more competitive with conventional generators in economic and environmental sectors. In this paper, a frequency security constraint based dynamic integration limit assessment technique is presented for solar power integrated system. This assessment technique will limit the integration of photovoltaic power based on system inertia while considering system status changes. Based on the dynamic integration limit assessment, a coordinated strategy for the energy storage system is formulated in order to improve the system reliability. The energy storage system is designed to maximize the renewable energy utilization in the system, smooth the photovoltaic power output and minimize system outage while considering the system frequency stability. The effectiveness of the proposed method is demonstrated using the modified IEEE RTS-79 system.