This industry-oriented paper proposes a novel sophisticated frequency control system for the Australian National Electricity Market (NEM) power system considering the special design of its current automatic generation control system, which does not involve interconnectors between different power regions, resulting in technical challenges for both stability and security of the system. The proposed new method converts the NEM centralised frequency control system to a fully decentralised one with virtually consideration of interconnectors’ power, thus the stability and security would be improved and the high fluctuations in interchanged power smoothed without extra costs of infrastructure and procurement of frequency control ancillary reserves (FCASs). The novel idea is to model the interconnectors’ power deviation as unknown input to operator in each power regions, like load disturbances and renewable power variations, using dynamic observation techniques, for enabling the proposed method capabilities. The method is theoretically verified that it can enhance stability and security and stabilise both local frequencies and power exchanges. The experiment results confirm the capability of the proposed method for the NEM system and its superiority over the existing adopted approaches in industries.
