Blackout

About: Blackout is a research topic. Over the lifetime, 2088 publications have been published within this topic receiving 30433 citations.

Cascading failure model of AC-DC system and blackout mechanism analysis

Abstract: Because more and more DC systems come into use, it is necessary to analyze the role of DC systems in cascading failures. In this paper, blackout model of AC-DC system is proposed. To save computation time, short-circuit voltage, instead of detail time domain simulation, is used to evaluate the impact of AC system fault on DC system. And an AC-DC OPF of multiple islands is proposed to analyze the controllability of DC system in the background of cascading failure. With this model, simulation is performed on a reconstructive IEEE 30 bus test system. The result shows that appropriate dispatching operation on DC interconnection system can decrease more risk of blackout, comparing to AC or AC/DC interconnection system.

Transformer overvoltage problems and countermeasures at black start

Abstract: A system of Kyushu Electric Power Company Inc. or KEPCO (about 19 GW) belongs to the western Japan system (110 GW) and has a 500-kV and 220-kV transmission line in a loop configuration. Japan's power system has high reliability and experienced no blackout for the past several decades. However, there is a possibility, though very slight, of a blackout in the event of a big earthquake or unforeseen accident. Considering the risk of blackout, KEPCO has been conducting studies on system restoration. This paper discusses a mechanism of an overvoltage phenomenon during a restoration period in which, about 0.2 seconds or more after a transformer is energized, a voltage becomes maximum in excess of 200% of the rated voltage. The paper also discusses countermeasures against this phenomenon.

Dynamic behaviors of Distributed Generators and Proposed Solutions to Avoid Loss of Critical Generators

Abstract: As the penetration level of the distributed generations on distribution network will increase, they must take their share of responsibility in the system security and provide flexibility and controllability necessary to support secure system operation. However, following the occurrence of large disturbances on the network (short-circuits, line outage, voltage dips...) the protective disconnection of large amount of DG (distributed generation) plants results in loss of generation and of support to the network that may lead to significant load shedding or in the worse case even a blackout. This paper presents an investigation about the transient stability and the capacity of DG to withstand disturbances of distributed synchronous generators and wind turbine generators on the distribution network. Two proposed control solutions to avoid the loss of generation are presented.

Load Shedding in Microgrids with Consideration of Voltage Quality Improvement

Abstract: Microgrids have become more and more popular their usefulness as a renewable energy resource has been recognized. The core ability and promise of microgrids is addressing the environmental concerns due to climate change that have been growing during recent years. The innovation of microgrids is that they are designed to operate either in island mode or interconnected with the main grid system. However, when the microgrid operates in islanded mode, faults may occur which can cause system collapse or even blackout. Load curtailment schemes can be utilized to decrease the quantity of associated load to a level that can be securely supported by accessible generation in isolated mode. The main goal of this research is to evaluate the optimal amount of shedding power considering sustainable power sources, with the help of primary and secondary adjustments of the generator to restore the frequency to the allowed range. Particle Swarm Optimization algorithm is applied in this paper to determine the distributed shedding power on each demand load bus which can improve the voltage quality of the isolated microgrid system. The effectiveness of the proposed method is demonstrated through the simulation of IEEE 16- bus microgrid.