This paper proposes a network splitting strategy following critical line outages based on N-1 contingency analysis. Network splitting is the best option for certain critical outages when the tendency of severe cascading failures is very high. Network splitting is executed by splitting the power system network into feasible set of islands. Thus, it is essential to identify the optimal splitting solution (in terms of minimal power flow disruption) that satisfies certain constraints. This paper determines the optimal splitting solution for each of the critical line outage using discrete evolutionary programming (DEP) optimization technique assisted by heuristic initialization approach. Heuristic initialization provides the best initial cutsets which will guide the optimization technique to find the optimal splitting solution. Generation-load balance and transmission line overloading analysis are carried out in each island to ensure the steady state stability is achieved. Load shedding scheme is initiated if the power balance criterion is violated in any island to sustain the generation-load balance. The proposed technique is validated on the IEEE 118 bus system. Results show that the proposed approach produces an optimal splitting solution with lower power flow disruption during network splitting execution.

Switches fault in power converter has become compelling issues over the years. To reduce cost and maintenance downtime, a good fault detection technique is an essential. In this paper, the performance of STFT and S transform techniques are analysed and compared for voltage source inverter (VSI) switches faults. The signal from phase current is represented in jointly time-frequency representation (TFR) to estimate signal parameters and characteristics. Then, the degree of accuracy for both STFT and S transform are determined by the lowest value of mean absolute percentage error (MAPE). The results demonstrate that S transform gives better accuracy compare to STFT and is suitable for VSI switches faults detection and identification system.

<p>Intentional islanding is the last defense mechanism executed to avoid cascading failures and total blackout in power system network during severe or critical contingency. It is performed when other mitigation techniques are unable to save the network from collapse. Intentional islanding is preferred compared to unintentional islanding, which produces unstable islands. The objective of intentional islanding is to split the network by disconnecting appropriate transmission lines to produce electrically stable and balanced islands. There are many methods suggested by previous researchers on intentional islanding. This paper presents a comprehensive review on various intentional islanding methods proposed based on the common objective function used which are minimal power imbalance and minimal power flow disruption. The paper focuses on five intentional islanding methods which are analytical, numerical, heuristic, meta-heuristic and hybrid approaches. This review paper will serve as guideline and reference for researchers to explore further in this topic of interest.</p>

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