Impact of Penetration of Photovoltaic on Rotor Angle Stability of Power System

Jitendra Thapa, Dr. Sanjeev Maharjan

The small signal and transient behaviour of large multi-machine system is minimal when the small- scale PV farm power is connected to it. But the oscillation on dynamics or states of the multi-machine system begins to increase as the large-scale PV farm power is connected. In this work investigations are carried out on small signal stability and transient of large multi-machine system with PV connected to it. Eigenvalue analysis is carried out for both cases with and without the PVs and are compared. Transient stability is analysed by time domain simulation by executing three phase short circuit fault at critical location. When PV are integrated without the replacement of conventional generators, small signal stability and transient stability both improves. Eigenvalue analysis shows that the damping of critical modes increases. And the magnitude of the peak of rotor angle of generator 2 decreases from 17.984o to 13.069o due to addition of PV which shows improvement in transient stability. In contrast, the stability of system in terms of small signal and large signal both degrades as the addition of PV is done by the replacement of the conventional generators. The trend of critical mode 3 towards the RHP (right half plane) of the complex plane indicates that the small signal stability is degrading. For the same case, the peak of the speed of generator 1 increases form 1.015 p.u to 1.0311 p.u from no PV to various level of PV which indicates the degradation of transient stable. The reduction in inertia due to replacement of synchronous generators reduces the damping of the critical modes which is also verified by the transient analysis.

https://dx.doi.org/10.31873/IJEAS/6.4.2019.31