Design and evaluation of metal oxide surge arrester parameters for lightning over voltages / Syahirah Abd. Halim

Surge arrester is widely used as a protective device to reduce possibility of flashover during transient overvoltage. It is important to understand the characteristics of surge arrester as over-specification of its rating will result in a reduction of the protective characteristics. Researches on reliability and stability of surge arrester normally involve detailed experimental works, which are usually not feasible due to high cost in conducting test using actual prototype. The usage of computer tools in carrying out virtual testing is important to verify the performance of the arresters in early stages before proceeding with actual prototype built-up. In this work, transmission line surge arresters with different dimensions and ratings were modeled to investigate their discharge energy during lightning discharge using the finite element analysis (FEA) method. The main advantage of FEA models in this work is real dimensions of the actual surge arrester can be modeled, which may increase the accuracy of the results obtained. 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/EMTDC, the comparison made between the results indicates a satisfactory agreement. Parametric analyses were also conducted using finite element method to study the effects of varying the design geometry of the arresters, which cannot be evaluated using PSCAD and EMTP-RV software. The surge arrester models that have been developed were then used in designing protection scheme for a 275/132 kV quadruple circuit transmission line in Malaysia. The best arrester configuration was selected by considering the effects of tower footing resistance, lightning current and power frequency angle on the line lightning performance. Improvement on the lightning performance could be achieved by installing surge arresters on all phases of a 132 kV circuit, where the double circuit outages were successfully eliminated. The results are useful for the utility company in determining the most effective installation position with the minimum number of installed surge arresters.