Analysis of generator ratings on inertia and frequency respone in power systems

The increasing share of renewable generation integrated in the traditional power systems network has brought new challenges to the utility. More specifically, the high penetration of solar energy in the network will reduce the total system inertia which could jeopardize the system 's stability during contingency. The lack of inertia in the power system will increase the rate of change of frequency (ROCOF). Moreover, the primary frequency response (PFR) should react fast after the contingency event and if it happens the PFR should response to prevent system blackout. In this dissertation the effects of generator ratings on inertia and frequency response in power systems have been analysed and discussed. Moreover, the impact of increasing solar photovoltaic (PV) penetration level on the frequency stability and response has been illustrated. The IEEE 9 bus test system and IEEE 39 bus New England system have been utilized in this dissertation to model the system's inertia response under various contingency scenarios. The results show that the small rating of generators can achieve higher inertia response as compared to the case with larger generator rating. This implies that system with small rating generator can better recover the system frequency than the large-scale generators of similar total rating. Furthermore, the results suggest that the increasing share of solar generation in the generation mix will result in the reduction of total system inertia. Hence the system becomes more susceptible to disturbance and contingency events. The presented study also shows that the system will collapse during the worst case contingency situation when the solar PV penetrations are over 40% of the system's generating capacity