Scheduled Maintenance - President's Day Weekend
The U.S. Department of Labor will be conducting scheduled system maintenance beginning Friday, Feb. 15 at 5 p.m. ET through Tuesday, Feb. 19 at 8 a.m. ET. Some pages may be temporarily unavailable. To report an emergency, file a complaint with OSHA, or to ask a safety and health question, call 1-800-321-6742 (OSHA).
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Substation Equipment:
High-Voltage Underground Cables
High-Voltage Underground Cables |
High-Voltage
underground cables are constructed in many different ways, but are usually
shielded cables. They are made with a conductor, conductor-strand shielding,
insulation, semi-conducting insulation shielding, metallic insulation
shielding, and a sheath. The sheath can be metallic and may then serve as
the metallic insulation shielding and be covered with a nonmetallic jacket
to protect the sheath. This sheath helps to reduce or eliminate
inductive reactance. Such cables are commonly used in circuits operating
at 2400 volts or higher.
 Figure 1. High-voltage underground cables
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 Figure 2. High-voltage underground cables
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