Risks, Load Shedding and System Separation during Emergency Situations

Changes in operating conditions of power system depend on many random and uncertain factors. Moreover, power systems are stressed by new challenges of the power market. Therefore, there is risk that any originated operating condition can lead to emergency situation in the power system resulting in economic, social and ecological losses sometimes of tremendous degree. In this situation one of the first-rate important issues, is the estimation of originated risks as degree of possible losses. Widely used deterministic methods cannot solve this task in full. Probabilistic methods constitute powerful tools for use in many kinds of decision-making problems and there is great interest in applying them today. The paper deals with description of methodology for risk estimation. A practical example of risk evaluation is presented, simulating behavior of the power system under emergency situation with different control actions. Synthesis of losses function and estimation of penalty coefficient using experience of selection of high voltage urban substation electrical schemes are presented as well