Global environmental variations in the past two decades have contributed to a significant deviation of classic ecological patterns, leading to severe electricity outages triggered by extreme weather-driven phenomena. This has highlighted an urgent need for enhancing the resilience and robustness of the interconnected electricity grid against such High Impact Low Probability (HILP) incidents. From the electrical safety point of view, it is essential to increase the operators' awareness on a better understanding of such hazards and grid vulnerabilities, and enhance their preparedness on how to respond or mitigate the probable outages. This paper proposes a temporary, yet agile, restoration strategy in response to the forecasted HILP events, founded based on efficient utilization of the grid existing infrastructure, and aimed at improving its resilience against such extreme emergencies. The applied concept of reconfiguration is proactively planned to recover the electricity outages in a timely manner. In the meantime, two sets of metrics are proposed to quantify both the grid operational and infrastructure resilience. The presented framework aids the system operator to evaluate the outage recovery plans considering their impacts on system resilience and decide on the final implementation. The proposed approach is applied to the IEEE 118-bus test system facing an HILP event, where results reveal its applicability and efficiency.

Electricity grid complexity with its diverse critical infrastructures has been continuously evolved into a more complicated network that is vulnerable to unpredictable hazards of internal and external origins. Resiliency assessment of the large-scale smart electricity grids has recently attracted many attentions in electric industry for more efficient daily operations in face of emergencies. This paper aims to quantify the power system resiliency in dealing with grid severe vulnerabilities and extreme emergencies. The suggested approach for resiliency improvement is to harness the existing system infrastructure, with minimum additional cost, through transmission network reconfiguration. The applied concept of reconfiguration is predictively planned and used as a temporary operation mechanism for the main sake of electricity outage recovery. The system resiliency features, e.g., flexibility, capacity recovery and the imposed cost indices, are quantified for each optimal reconfiguration option, helping the system operators evaluate the recovery options and decide on the final plan for implementation considering its impacts on system resiliency requirements. The suggested approach is tested on the IEEE 118-Bus test system under a critical contingency and the results reveal its applicability and efficiency.

Energy management plays a pivotal role in enhancing the economic efficiency of power systems. However, it is noteworthy that a substantial number of microgrids (MGs) exhibit inherent unbalances that impose a range of critical issues, including voltage instability, elevated losses, power quality violations, safety concerns, and inefficiencies in energy management. Fast-acting power electronic converters present a relevant and efficacious solution for balancing such complex networks. This paper investigates the application of such converters within the realm of 3-phase unbalanced networks, wherein the proposed algorithm not only ameliorates network imbalances but also yields substantial reductions in operational costs, power losses, voltage deviations, and emissions. Demand response (DR) program has been applied to the model to enhance the system efficiency. The uncertainty about electric demand and renewable energy sources is considered in the simulation model for precise results. By implementing DR programs and penetrating distributed generators (DGs), the proposed model has been shown to reduce network losses and operation costs by 23% and 80%, respectively. Also, the total up-to-down voltage deviation of the voltage profile has been significantly reduced by 400%.

Due to the non-linearity and complexity of power systems, reduced model of these systems is used for dynamic and transient analysis. In this regard, a power system is partitioned into areas based on the similarity of dynamic responses of generators to the disturbances, which is called coherency. In this paper, a new method is presented for determining the degree of coherency between generators or non-generating buses using the data measured by wide area measurement system (WAMS). This method uses the amplitude as well as phase angles of frequency components that exist in the angular velocity signals after the disturbance has occurred. Those frequencies that are in the range of inter-area oscillation modes are selected to determine the coherency between each pair of generators using a correlation index. By expanding this index to the non-generating buses of the power system and using the tight coherency concept, the power system is partitioned into highly coherent areas. The effectiveness of this method for area detection is investigated on the 16-machine, 68-bus test system. It is observed that accurate coherent areas can be identified using both the phase angle and amplitude of frequencies in the range of inter-area oscillation modes.

Sever weather condition together with other natural catastrophes can danger lives, disable communities, and disrupt electric utilities' generation, transmission and distribution systems. An incident at a high-voltage transmission line may results in more significant cascading failure if appropriate safety measured contingency schemes are not well developed or not achievable by system operators, in the case of these unpredictable events the loss of multiple substations and lines would result in the loss of electricity to millions of customers. Many strategic utilities which their functionality heavily depend on the continual existence of electricity might fall in the major hassle. Since, restoration or repair of the failed components may take days to weeks, depending on the ability to bypass damaged substations or disrupted lines using the built-in resilience of the interconnected grid, having a proper resilience-based strategy in face of extreme weather is of great importance.