Safety Design Planning of Ground Grid for Outdoor Substations in MEA's Power Distribution System
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Abstract
This paper analyzes the performance of a grounding system made of copper conductors and significantly influenced by soil resistivity. The grounding performance is evaluated in terms of ground potential rise (GPR), touch voltage and step voltage caused by a short circuit that generates a flow of large currents in the aboveground structures and grounding system and dissipates in the soil. These currents may cause damage to substation equipment and may be dangerous to personnel working nearby. Safety design planning for step and touch voltages for the existing fault level and future fault levels are extensively investigated for utility applications where personnel hazards may exist. Modelling and simulation is carried out on the Current Distribution Electromagnetic interference Grounding and Soil structure (CDEGS) program. The safety design planning is illustrated by a practical case of ground grid design
for the 69/12-24 kV, outdoor-type Bangkrachao substation of Metropolitan Electricity Authority (MEA) with economic analysis. An e®ective solution to improve the performance of the substation grounding is also suggested.
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References
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