Improvement of frequency response in remote area power supply systems using ultracapacitor with enhanced inertia support controller

Remote area power supply systems (RAPS) are increasingly equipped to provide support from renewable power generators. This necessitates the requirement of inertial support from the energy storage systems (ESSs) to attain frequency and voltage regulation. One such ESS with low energy and high power density is ultracapacitor (UC). The effective utilisation of state of charge (SOC) of UC and rate of change of frequency (ROCOF) help to provide dynamic virtual inertia support. This work initially involves utilising the virtual inertia and primary frequency response provided by UC to provide frequency regulation for RAPS system. The case study is set in a remote area devoid of grid support and a scenario with negligible support from renewable sources due to its intermittent nature is studied. The limitations of the traditional UC controller are identified and evaluated. The UC and its controller are designed in such a way that the response time during frequency variation events should be below 1 s. The novelty involves designing the UC controller with an algorithm that enables the UC to provide an additional dynamic virtual inertia, thereby enhancing the frequency response in addition to controlling the charge and discharge rates. The virtual inertia powers provided by the UC in both traditional and modified controllers are compared, and analysis is presented with comprehensive simulation results to prove the advantages of the proposed modified controller over the traditional one.