Realisation of AD hoc renewable rural power systems with decentralised active power dispatch techniques

Abstract

Ad hoc power systems offer a promising opportunity to provide affordable reliable renewable energy to rural areas. Classical grid solutions are impeded by low population densities and poor economic conditions that perpetuate energy poverty in large areas of rural Africa. Existing islanded renewable energy based solutions can not typically be expanded at will as the needs of its users increase. Scalable power systems, that can lower the engineering costs of commissioning and modifying the system represents a potential solution to energy poverty. Existing solutions rely on the ability to tightly model and control all elements a result of the stringent requirements imposed on these systems. Meaning scalable power systems are theoretically unrealisable. Thus, this is a system architecture and control issue, not a generation or storage issue. This thesis explores ways to realise low cost scalable power systems for low (> 1 kW) to medium (< 1 MW) power requirements. Allowing power system parameters to indefinitely deviate from nominal values, which discards a 140 year old assumption, is achievable in new electronic generation based power systems. This allows all system elements to contribute towards system operation without additional communication. Modelling is presented which simplifies complex power interactions in AC systems to passive circuit components. The desired characteristics of each element while utilising existing technologies can be identified from this modelling. These techniques, which are demonstrated and verified on a hardware based power system simulator, enable scalable economically feasible renewable power systems. This provides a novel, flexible and robust alternative to existing power systems that enables the affordable decentralised ownership and operation of renewable power systems at a household level.