Severe lightning environment has been the major cause of overhead transmission line outages. In order to minimise the impact of lightning overvoltage, it is necessary to further evaluate lightning performance of any line before implementing specific protection methods. Therefore, in this work, a thorough study on back flashover tripping patterns of a 275/132 kV quadruple steel monopole towers in Malaysia is presented. Several design parameters such as lightning current magnitude, tower footing resistance and power frequency voltage were varied to investigate their influences on the line performance associated with lightning events. The results show that each parameter gives a significant effect on the flashover patterns. For each case, no flashover was recorded on the higher voltage circuits (275 kV), even though the line consists of tall structures, which might be more susceptible to lightning strikes at the upper part. Regardless of the effect of tower height, flashovers occur mainly on 132 kV circuits due to difference in the line insulation level. The results obtained were then used in designing appropriate protection scheme to further improve the transmission line lightning performance, mainly in terms of reducing the double circuit line outages.

Surge arrester is widely used as a protective device to reduce possibility of flashover during transient overvoltage event. The device needs to withstand high energy discharged by the overvoltage which may increase the degradation rate of its characteristics. In this study, a set of transmission line surge arresters with different dimensions and ratings was simulated to investigate their discharge energy capabilities during fast‐front surge events using the finite element analysis method. To validate the accuracy of the method, the arrester models were also simulated by the use of PSCAD/EMTDC and EMTP‐RV software and compared with the specifications provided by the manufacturer. In spite of distinctive representations of the arrester models in COMSOL Multiphysics, EMTP‐RV and PSCAD, the comparison made between the simulation results indicates a satisfactory agreement. The manufacturers’ data were used to validate that the proposed simulation model is acceptable. It was found that the simulation results were comparable with the manufacturer's test data of the discharge voltages and energy withstand capability, thus proving that all studied cases were adequately modelled. Parametric analyses were also conducted using finite element method to study the effects of varying the design geometry of the ZnO blocks and the arrester's housing on the energy absorption, which cannot be evaluated using PSCAD and EMTP‐RV software.

This paper introduced a new swarm based optimization technique for tuning Power System Stabilizer (PSS) that attached to a synchronous generator in a single machine infinite bus (SMIB) system. PSS which is installed with Lead-Lag (LL) controller is introduced to elevate the damping capability of the generator in the low frequency mode. For tuning PSS-LL parameters, a new technique called Whale Optimization Algorithm (WOA) is proposed. This method mimics the social behavior of humpback whales which is characterized by their bubble-net hunting strategy in order to enhance the quality of the solution. Based on eigenvalues and damping ratio results, it is confirmed that the proposed technique is more efficient than Particle Swarm Optimization (PSO) and Evolutionary Programming (EP) in improving the angle stability of the system. Comparison between WOA, PSO and EP optimization techniques showed that the proposed computation approach give better solution and faster computation time.

This paper discussed the prediction of oscillatory stability condition of the power system using a particle swarm optimization(PSO) technique. Indicators namely synchronizing(K_s)and damping(K_d) torque coefficients is appointed to justify the angle stability condition in a multi-machine system. PSO is proposed and implemented to accelerate the determination of angle stability. The proposed algorithm has been confirmed to be more accurate with lower computation time compared with evolutionary programming(EP) technique. This result also supported with other indicators such as eigenvalues determination, damping ratio and least squares method. As a result, proposed technique is achievable to determine the oscillatory stability problems.