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This paper proposes a method for identifying event sequences leading to blackouts in power systems. To identify the cascades, grid is modeled like an event tree where each branch represents a contingency and each node represents state of the system. Due to huge number of possible paths in the event tree, computational burden is the key issue in searching the cascades. In this paper, computational...
This paper describes a stochastic “Random Chemistry” (RC) algorithm to identify large collections of multiple contingencies that initiate large cascading failures in a simulated power system. The method requires only simulations per contingency identified, which is orders of magnitude faster than random search of this combinatorial space. We applied the method to a model of cascading...
In order to prevent cascading events caused by hidden failures in zone 3 relays, agent based relay architectures have been suggested in the recent past. In such architectures each zone 3 relay contains agents that require communication with other agents at various relevant relays in order to distinguish a real zone 3 event from a temporary overload. In the presence of hidden failures such temporary...
During a power swing, currents and voltages behave such as a fault. Therefore, power swing blocking function in distance relays is necessary to discriminate between a power swing and a fault. Otherwise power swings can be considered as a fault and causes relay trip. The main problem happens when during power sings a fault occurs. In this case, distance relays should be unblocked. In this paper, a...
Protective relay operations during wide area disturbances have often contributed to the spread of the disturbance instead of preventing the disturbance propagation. The paper highlights various points discussed in an IEEE working group report on the performance of protective relays during wide area stressed power systems conditions.
The electric power system maintains a dynamic and delicate balance between generation and load in normal operation condition. A disturbance, such as a sudden change of load, a power system fault, or a trip of a large generation unit, may break the balance, cause the oscillations among the generator rotor angles and force the generators to adjust to a new operating condition. The adjustment will not...
This is a summary for presentation in the panel session, ldquoUnderstanding, Prediction, Mitigation and Restoration of Cascading Failuresrdquo at IEEE PES PSCE 2009. Recent major blackouts in North America, Europe, and other countries highlight the importance of reliability of our electric energy infrastructure and the economic impact of blackouts. These blackouts were caused by a cascading sequence...
Distribution power system islanding will involve significant grid reconfiguration, especially if maximum flexibility of operation is to be achieved. Protection selectivity will be a challenge because of the associated changes in fault conditions, and is further complicated by distributed generator fault characteristics. This paper proposes a three-stage communication assisted protection selectivity...
Electric power systems are complex systems with Self-Organized Criticality (SOC) that are commonly run near their operational limits. In these systems, blackout is unavoidable. One of the main causes for some of the recent blackouts around the world was distance relay hidden failure. In this paper a novel approach is proposed to prevent the undesirable contribution of distance relay on cascading failures...
This is a summary of the presentation in the panel session on blackouts for the 2008 IEEE PES General Meeting. This presentation will discuss the state of the art methodologies for the prevention of cascaded events in blackouts. A new topic concerning the identification of basic patterns of cascaded events following a contingency will be included.
The paper presents the application of software tools to simulate system dynamic behaviour together with the possibility to select critical contingencies of an electrical energy system. The protection system with relay functions, characteristics, settings and communication schemes will be considered. Possible visualization methods are presented which can support the operators to select critical system...
The increasing amount of distributed generation (DG) located on distribution level is affecting the usage of the power system in different ways. The traditional planning and control schemes may become inoperative due to the contribution of DG. As the impacts of DG are significant and they are increasing rapidly, they should be better included in the planning systems and methods applied. Instead of...
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