Supercomponentes Contingency Modeling for Security Assessment in Power Systems

Abstract

The utilization of the power systems to its maximum capacity is a condition that produces economic benefits to all agents involved in the chain of energy supply and thus to society. However, under these conditions, operators can take risks that could cause the loss of system stability and, in the worst case, blackouts. Thus, operators require analysis tools that give them information in order to take preventive and corrective actions, to operate the system in a reliable way and to check the behaviour of the same. Generally, in this type of analysis, simple component's contingencies are used. However, the practice has shown that more than one component (generation unit, circuit line, single transformer, among others) of the system can fail, either by simultaneous outages; events in cascade or by a major outage that means a complete installation with several components gets out of service. So, a super component refers to complex electrical facilities as: substations, generation plants and multiple circuit transmission lines. An outage of the super component implies the multiple and simultaneous outages of many elements. These kinds of events are not, generally, considered in the mentioned analyses; however, it would be very important to keep them in mind in the security evaluation of power systems. This paper presents a methodology to evaluate the severity of this kind of contingencies in the operative planning scenario. The super components that are taken into account are the multiple circuit lines (in the same structure), generation plants and substations. The impact of contingency on power system security is evaluated in a 24-hour ?day ahead? planning horizon through the computation of the energy not supplied, the number of overloaded lines and the percentage of load loss The Energy not supplied is computed as function of a load shedding based on operator's rules.