1. Electrical Power & Machines “Electrical Engineering Dept” Prepared By: Dr. Sahar Abd El Moneim Moussa 1

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3.  Uses of UGC It is used to transmit electric power, when construction of OHTL is undesirable, for example, in crossing under seawater, highways or rail ways, or in approaches to the territories of high density populated areas. Dr. Sahar Abd El Moneim Moussa3

4.  Construction of UGC UGC consists of: 1) Core conductor 2) Core insulation Dr. Sahar Abd El Moneim Moussa4

5. 1) Core Conductor: a) Hard drawn Copper Conductors are used in low voltage networks, as it can withstand thermal stresses during overloading b) Hard drawn Aluminum Conductors are used in medium voltage and high voltage distribution network to decrease costs where 3-phase load are balanced and hence overloading problem is minimized Dr. Sahar Abd El Moneim Moussa5

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7. 1) Cable Insulation: a) Oil Impregnated-Paper Insulation (OIL): Advantages: Highest dielectric strength among all cable insulation material. Long life-time. Dr. Sahar Abd El Moneim Moussa7

8. 8 OIL FILLED CABLES

9. Dr. Sahar Abd El Moneim Moussa9 EHV DIRECT GAS PRESSURE CABLES

10. b) Polymeric Martials Insulated Cables: Thermoplastic materials:  Polyetheylene (PE)  Polyvinyl Chloride (PVC) Thermosetting materials:  Cross linked Polyethylene (XLPE)  Ethylene-Propylene Rubber (EPR) Dr. Sahar Abd El Moneim Moussa10

11. Advantages: Reduced weight Easier to repair faults Reduced risk of flammability and fire propagation. More economical in both initial costs and life time Dr. Sahar Abd El Moneim Moussa11

12. Dielectric field of High-voltage Power Cables: Dr. Sahar Abd El Moneim Moussa12

13. Dr. Sahar Abd El Moneim Moussa13 SHIELDED CABLES

14. Dr. Sahar Abd El Moneim Moussa14 CABLE CONSTRUCTION

15. CABLE PARAMETERS Dr. Sahar Abd El Moneim Moussa15

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19.  Dielectric Losses of Metallic Sheathed Power Cables Dr. Sahar Abd El Moneim Moussa19

20. Therefore, the dielectric stress will be: Dr. Sahar Abd El Moneim Moussa20

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