This paper presents an expert system composed of two knowledge-based programs designed to help power system planners and to assist system operators. The first is designed to guide to the solution of system voltage violations. The second knowledge-base is developed to perform power rerouting to alleviate line overloads . Both systems use the sensitivity factor concept to converge to a decision. Voltage sensitivities to various control tools such as shunt compensation, transformer tap changes and generator voltage controls are used. Power rerouting is achieved through distributions-factors directives for generation re-scheduling. The production rules are applied to two power system models to demonstrate of the effectiveness of the developed engines. The obtained results are consistent with the load flow run.