On August 14, 2003, a cascading outage of transmission and generation facilities in the North American Eastern Interconnection resulted in a blackout of most of New York state as well as parts of Pennsylvania, Ohio, Michigan, and Ontario, Canada. On September 23, 2003, nearly four million customers lost power in eastern Denmark and southern Sweden following a cascading outage that struck Scandinavia. Days later, a cascading outage between Italy and the rest of central Europe left most of Italy in darkness on September 28. These major blackouts are among the worst power system failures in the last few decades. The Power System Stability and Power System Stability Controls Subcommittees of the IEEE PES Power System Dynamic Performance Committee sponsored an all day panel session with experts from around the world. The experts described their recent work on the investigation of grid blackouts. The session offered a unique forum for discussion of possible root causes and necessary steps to reduce the risk of blackouts. This white paper presents the major conclusions drawn from the presentations and ensuing discussions during the all day session, focusing on the root causes of grid blackouts. This paper presents general conclusions drawn by this Committee together with recommendations based on lessons learned.

Causes of the 2003 major grid blackouts in North America and Europe, and recommended means to improve system dynamic performance

This paper provides the analytical basis for an application of slow coherency theory to the design of an islanding scheme, which is employed as an important part of a corrective control strategy to deal with large disturbances. The analysis is conducted under varying networks conditions and loading conditions. The results indicate that the slow coherency based grouping is almost insensitive to locations and severity of the initial faults. However, because of the loosely coherent generators and physical constraints the islands formed change slightly based on location and severity of the disturbance, and loading conditions. A detailed description of the procedure to form the islands after having determined the grouping of generators using slow coherency is presented. The verification of the islanding scheme is proven with simulations on a 179-bus, 29-generator test system.

Slow coherency-based islanding

Large blackouts are typically caused by cascading failure propagating through a power system by means of a variety of processes. Because of the wide range of time scales, multiple interacting processes, and the huge number of possible interactions, the simulation and analysis of cascading blackouts is extremely complicated. This paper defines cascading failure for blackouts and gives an initial review of the current understanding, industrial tools, and the challenges and emerging methods of analysis and simulation.

Initial review of methods for cascading failure analysis in electric power transmission systems IEEE PES CAMS task force on understanding, prediction, mitigation and restoration of cascading failures

This paper provides a self-healing strategy to deal with catastrophic events when power system vulnerability analysis indicates that the system is approaching an extreme emergency state. In the authors' approach, the system is adaptively divided into smaller islands with consideration of quick restoration. Then, a load shedding scheme based on the rate of frequency decline is applied. The proposed scheme is tested on a 179-bus, 20-generator sample system and shows very good performance.

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=2138&context=rtd

Self-healing in power systems: an approach using islanding and rate of frequency decline-based load shedding

Summary form only given. In the paper a new approach to adaptive underfrequency load shedding, a procedure for protecting electric power systems from dynamic instability and frequency collapse is presented. It consists of two main stages. In the first stage, the frequency and the rate of frequency change are estimated by the nonrecursive Newton type algorithm. By using the simplest expression of the generator swing equation, in the second algorithm stage the magnitude of the disturbance is determined. The underfrequency load shedding plan is adapted to the magnitude estimated, obtaining in this way a more efficient system operation during emergency conditions. Results of procedure testing are demonstrated through the dynamic simulations by using: a) a simple 3-machines test system and b) a 10-machines New England system.

Adaptive Underfrequency Load Shedding Based on the Magnitude of the Disturbance Estimation

This paper provides a self-healing strategy to deal with catastrophic events when power system vulnerability analysis indicates that the system is approaching an extreme emergency state. The system is adaptively divided into smaller islands with consideration of quick restoration. Then an adaptive load shedding scheme based on the rate of frequency decline is applied. The proposed scheme is tested on a 179-bus, 20-generator sample system and shows very good performance.

Yang

Papers

Self-Healing in Power Systems: An Approach Using Islanding and Rate of Frequency Decline Based Load Shedding