The liberalisation in the electricity supply industry, many changes have emerged, and as a consequence, system operation complexity has increased radically. Changes also effect the operation in abnormal system states and thus impact the performance of the human operators in the control centres. The job of the operators in the control centres is to avoid disturbances and, where this can not be achieved, to restore the system as quickly and effectively as possible. The operators have to react to the fast changing system statuses respecting the technical possibilities and limits, and at the same time they have to be aware of commercial interpretation of their actions. As the complexity of the restoration process has increased, more demands have been placed on human operators. The best way to cope up with this demand is to provide adequate operating personnel training.