The emphasis of controlling the system frequency and the tie line power change between interconnected power systems leads to develop and implement load frequency controller (LFC). Oman Electricity Transmission System Company which is the system operator of Main interconnected power system in Oman has a lack of such controller and the difficulty of manual control increases with system expansions and interconnection with Abu Dhabi power system and PDO network. The ultimate objective of this study is to design load frequency controller using classical control approach with PID controller and a new controller with direct adaptive fuzzy logic controller. Time delay may exist in the system when using open communication channels and it may degrade the performance of the proposed LFC. As a result, the proposed LFC-PID controller is incorporated with a fixed time delay and hence system performance is investigated. In addition to this, the need of introducing a new adaptive controller in this study is to overcome the disadvantage of conventional controllers in adapting the variation of every operating condition of the system and to handle the problem of uncertainty.