تصميم نظام تأريض ( محطة بربر التحويلية 220/33 KV )
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Date
2021-01-01
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جامعة الشيخ عبد الله البدري
Abstract
Substation grounding is a critical part of the overall electric power system. It is designed not only to provide a path to dissipate electric currents into the earth without exceeding the operating limits of the equipment, but also to provide a safe environment for any people that are within the surrounding area. The aim of this study is to design and develop a proper grounding system for Barbar Substation 220/33 KV based on necessary calculation to ensure a safe design. An adequate grounding grid has been designed and developed using concepts outlined in IEEE Standard 80-200. The developed grounding mesh consisted of 46 earthing rods (copper) driven to a depth of 1 meter and spaced 8 meters a part on 900 m2 substation area. Simulations were carried out using ETAP Software for verification of the developed grounding grid design. The obtained results for tolerable touch and step voltage were 1666.6V and 5767.9V, respectively. The ground potential rise (GPR) was 4.652 kV. The grid resistance (Rg) was 0.749 Ω which is within the range of international standards (˂ 1 Ω ).The total mesh and touch voltage were 188.5V and 479V, respectively, all these values are within the limits . Using ETAP simulation the output results of tolerable touch and step voltage were 1621.4 V and 5586.9V, respectively. The GPR and Rg were 5040.3 V and 0.74 ohm, respectively while the total mesh and Step voltage were 786V and 304.4 V, respectively. Both the measured and simulated results values were within the limits. The minor differences between calculated and simulated results do not affect the main design objective. Since these values are within the safe range, it is concluded that the parameters measured for the developed design are with the safe range recommended by international bodies.