This book presents a new control performance standard and its control strategies especially for the isolated single-area power system. The new developed standard is used to assess system frequency performance in a long-term aspect. Based on the new standard, two operational concepts are proposed to achieve the objective of both unit maneuvering relaxation and control performance. With the aid of Sugeno fuzzy inference system, and multi-objective optimization using genetic algorithm, the proposed concepts are successfully confirmed and implemented in the simulation cases. Simulation results validate the effectiveness of the proposed strategies in the performance of the load frequency control.