Frequency of supply is an important aspect of electrical power system. Active power balance and frequency control are important tasks in the daily management of a power system. Due to variation in power demand as a result of load changes based on consumer usage, resultant change in frequency impacts on power system operation. The phenomena i.e. load fluctuation creates a burden on the generator prime mover. When the load demand is greater than the generation, generator speed drops, thus initiating a drop-in frequency. An unstable power system condition could lead to generator falling out of synchronism or overheating machines or malfunction of equipment. Should the frequency drop below certain limits automatic load shedding will occur. Minimization of frequency error will enable the matching of frequency system generation to load frequency to nullify sudden blackouts and system imbalance. Increasing economic pressures for power system efficiency and reliability have led to a requirement for maintaining system frequency and power flows closer to specified values as much as possible. Therefore, in a modern power system, load frequency control plays a fundamental role, as a help service, in supporting and providing better conditions for the electricity trading. This paper presents a case study of PID controllers that can withstand load variations and produce improved functionality outputs (results) in a power system. The PID controller is incorporated with a trignometric function of a fourier series to mimimise the change in frequency. To ascertain the proficiency of the proposed technique, different versions of the PID controller in operation was undertaken. The proposed adaptive controller design provided the best results in terms of both frequency deviation and speed drop.