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The electric power system is facing greater threats each year due to malicious attacks. In the recent decade, multiple attacks on both physical and cyber layers of the power system resulted in significant economic loss. In particular, a cyber-physical coordinated attack is deemed to be a destructive behavior that is likely to cause cascading failures. Therefore, this paper focuses on hedging against a coordinated cyber-physical attack from the standpoint of allocating defending resources. The coordinated attack involves physical short-circuiting of transmission lines after intruding the communication network of protection relays. The paper proposes a tri-level optimization model to formulate the coordinated attack scenario and identify the optimal defending strategy, which is a first of its kind study of defending resource allocation to hedge against the coordinated attack. Upper-level problem represents the actions of the planner and determines the optimal defending resource allocation on transmission lines and communication network of protection relays. Defending strategy achieves the lowest expected unserved energy with coordinated attacks considering multiple representative operating conditions. Middle-level problem formulates the behaviors of the attacker, who identifies the targets and attack time to maximize unserved energy. Lower-level problem simulates the actions of operator for system redispatch aimed at minimizing unserved energy. Sensitivity analyses are conducted on IEEE 14-bus system and IEEE 57-bus system to investigate the effects of attack budget, defend budget and restoration duration on unserved energy. The results indicate greater unserved energy with higher attack budget, lower defend budget, and longer restoration duration. Moreover, significant unserved energy reduction was observed when the proposed optimization model is applied to allocate defending resource.

The shipboard power system of an all-electric ship can be characterized as an isolated microgrid system. To achieve resilient, cost-effective and privacy-preserved operation of the shipboard power system, a novel energy management strategy is proposed in this paper. Currently, a master controller is required for energy management. However, such a centralized energy management strategy suffers from numerous disadvantages. Therefore, a modified nested energy management method is proposed to preserve privacy and run the microgrid system in a distributed manner for plug-and-play operation. Furthermore, the system resilience is enhanced against energy deficiency by reserving more in the energy storage system. This is achieved by a distributed algorithm, known as alternating direction method of multipliers (ADMM), to obtain the solution of an optimization problem with contradicting objectives. Simulation results are presented to demonstrate the benefits of proposed energy management system.

The future all-electric ship (AES) requires a resilient shipboard power system (SPS) that can withstand extreme events without substantial damage and maintaining critical capabilities. For superior capability to sustain disruptions, numerical measures of resilience provide assistance to engineers in making planning and operational decisions. This paper presents a novel method for analyzing the resilience characteristics of an SPS using correlation-based feature selection (CFS) to identify the system attributes that are the best predictors of performance during contingencies. Such attributes are typically chosen in the design stage and are not subject to modification during operation. The selected features are adjusted and their ramifications on the SPS performance are evaluated under the same contingencies. Results show quantitatively how a change of relevant attributes can improve or degrade the system performance in terms of unserved load and minimum recovery time.

In this paper, a microgrid consisting of four fuel cell-battery hybrid Distributed Energy Resources (DERs) is devised for an industrial crusher–conveyor load. Each fuel cell was accompanied by a Li-ion battery to provide energy storage support under islanded condition of the microgrid since the fuel cells typically have poor transient response characteristics. After carrying out extensive modeling and analysis in MATLAB®, the battery utilization was found to vary significantly based on the DER's ‘electrical’ placement within the microgrid. This paper presents, under such conditions, a variety of battery life balancing solutions through the use of the new framework of Flexible Distribution of EneRgy and Storage Resources (FDERS). It is based on an in-situ reconfiguration approach through ‘virtual’ reactances that help in changing the ‘electrical’ position of each DER without physically displacing any component in the system. Several possible approaches toward balancing the battery utilization are compared in this paper taking advantage of the flexibility that FDERS offers. It was observed that the estimated battery life is dependent on factors such as cycling sequence, pattern, and occurrence.

Malfunctioning of distance relay third zone has been identified as one of the leading factors of power system blackouts in several nations. This inconsistency in operation happens when heavy loads start encroaching the zone 3 settings. In this paper, a novel multi-agent system based methodology for power system protection coordination is proposed. Various system agents are designed to collaborate and adaptively modify the setting of distance relay zone 3 via communication with neighboring substations. The proposed coordination scheme aids in preventing fault misjudgment and possible network breakdown because of load encroachment. Furthermore, it enhances the relay selectivity and loadability. It has been tested using MATLAB ® /Simulink™ with the agent programming in Java Agent DEvelopment Framework (JADE) platform. Analysis and test results demonstrate that the proposed method effectively mitigates distance relay malfunction under load encroachment.