Improvement of transient response in grid‐tied photovoltaic systems using virtual inertia

Abstract

Photovoltaic (PV) generation systems, unlike conventional generators, do not possess any inherent inertia. The problem is further amplified by the fact that they are non‐dispatchable and highly intermittent by nature. Furthermore, the rate at which PV power output changes is of a much shorter timescale than that of conventional generators. Thus, integrating them in large quantities to the power grid without appropriate measures will compromise the power grid stability. One of the feasible solutions is to implement the concept of virtual inertia to PV systems, by adding energy storage systems (ESS) such as batteries in parallel with PV systems. In this paper, the ESS will be controlled to regulate the ramp rate (RR) of the PV power output to the grid, which smoothens the overall generation power profile. By modelling the grid, PV, ESS and load individually in the s‐domain and using an equivalent overall two‐machine, two‐area model, the impact of implementing virtual inertia is demonstrated. The results highlight the effectiveness in using ESS to control the RR and improving the transient responses of the overall grid system. Moreover, the economic impact and feasibility of ESS are also analysed using a residential PV and load profile from Singapore.

Virtual Inertia Control for Power Electronics-Integrated Power Systems: Challenges and Prospects

“…The overall simulation is carried out on PSCAD/EMTDC software platforms. A two-area, two-machine power system is designed via HOMER, and the results are analysed in Python software in the work [63]. The overall control scheme based on VI provided an in-depth analysis of the techno-economic assessment of the ESS and proved that the control technique is robust for controlling RoCoF.…”

Optimization and Transient Analysis of Distributed Asynchronous Condenser

“…After a large number of new energy sources are connected to the system, the synchronous condenser, as the reactive power compensation equipment in the system, effectively adjusts the stability in the new energy system with its own advantages of high inertia and excellent voltage regulation ability. For example, two 300Mvar synchronous condensers put into use in Newfoundland, Canada, have an inertia time constant of up to 7.84s [14].At the same time, since the moment of inertia determines the initial frequency deviation and further determines the resistance of new energy power generation to disturbance in the system, the frequency support ability in the new power system can be effectively enhanced by optimizing the structure of the synchronous condenser to increase its inertia [15], [16]. However, with the increase of the proportion of new energy power generation, the advantages and disadvantages of centralized configuration and distributed configuration of condenser have attracted the attention of some scholars.…”