No abstract

This paper presents the effect of lightning waveform to the voltage at the pole top and back flashover rate (BFOR). The result found that short front time of lightning current waveform or high slope will cause high voltage and back flashover rate at the top pole. However the tail time of lightning current waveform will not effect to the top pole voltage and backflash over rate because the impulse resistance will only affect to the long front time of lightning current waveform. In case of short front time, impulse resistance will not affect to voltage at the pole top and backflash over rate. Moreover BFOR will vary with the event of thunder storms per year. ATP-EMTP is used to simulate cases in this paper to receive pole top voltage, critical current and backflash over rate. The 69 kV subtransmission line system of Metropolitan Electricity Authority (MEA) is demonstrated as the case study to improve its grounding standard of subtransmission and distribution line system in MEA's power system

No abstract

No abstract

This paper presents the optimal and sizing of distributed generation (DG) placement in a radial distribution system for loss reduction. The main emphasis of this paper is to identify proper locations for installing DGs in a distribution system to reduce active power loss and improve bus voltages. Nevertheless, proper placement and sizing of DG units are not straightforward to be identified as a number of their positions and capacities need to be determined. It is therefore proposed in this paper to solve a DG placement problem based on a Tabu search algorithm. The objective function of the problem is to minimize the system loss subject to power flow constraints, bus voltage limits, pre specified number of DGs, and their allowable total installed capacity, and only one distributed generator for one installation position. The effectiveness of the methodology is demonstrated by a practical sized distribution system consisting of 69 bus and 48 load points. The results show that the optimal DG placement and sizing can be identified to give the minimum power loss while respecting all the constraints.