Enabling technologies for increasing renewable energy penetration in isolated power systems

Isolated Power Systems supply electric energy to customers living in remote areas across the world. Traditionally, electric energy in IPSs is produced using diesel generators, which are convenient, but produce several problems for the isolated communities such as high cost of electric energy, high amount of GHG emissions, and they force isolated communities into an energy dependence from other communities or nations. Renewable energy technologies offer some of the solutions to the problems isolated communities face as they often produce energy at a lower cost than diesel generators, they provide energy independence as local energy resources are used and produce very small amount or no polluting emissions at all. Renewable energy generation also brings challenges to the isolated communities, such as lowered power system stability. Renewable energy generation in IPSs is therefore often paired with enabling technologies, which allow it to generate reliable emissions-free power. Defining appropriate enabling technologies which facilitate cost-effective high renewable energy generation in IPSs is the primary goal of this Thesis. Three enabling technologies were outlined, and some real-world measurements presented in this thesis. First proposed enabling technology supports IPS stability during high renewable penetration by enabling standby diesel generators to rapidly synchronise during periods of high renewable energy generation intermittency. The technology is dubbed predictive synchroniser as it uses neural networks to predict future IPS frequency and rapidly place frequency and phase of incoming diesel generators in synch with the power system. By doing so, it decreases the chance of generation deficiency and increases IPS reliability of supply. Second proposed enabling technology is fast-acting aggregated demand response which helps IPSs to have longer periods of diesel-off operation. By actively monitoring the controlled loads and controlling them in sub-second time periods, this enabling technology can rapidly reduce power system load during short-time lulls in renewable energy generation production and by doing so, maintain IPS stability and reduce cost of generation by prolonging diesel-off operation. Measurements taken in a real-world IPS support the proposed effectiveness of this enabling technology. Finally, third proposed enabling technology is a synergy between synchronous condenser and a fast-acting battery energy storage. The proposed enabling technology supports IPS operating in diesel-off regime by providing power system inertia, sufficient levels of fault currents and rapid emissions-free real power support. Measurements taken in a real-world IPS support the proposed effectiveness of this enabling technology. Overall, the work contained in this thesis has proposed and demonstrated three enabling technologies which further advance the integration of renewable energies in isolated power systems. Taken altogether, this thesis provides novel information, and represents a significant advancement to the operation on isolated power systems under high renewable energy penetration levels