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10 Electrical power systems ± an overview
9 m
6.9 m
0.46 m
0.46 m
2.65 m
guy guy
27.5 m
Fig. 1.7 Single circuit transmission line.
Fig. 1.8 (a) Three-conductor,shielded, compact sector; and (b) one-conductor,shielded.
applications. Figure 1.8 shows shielded, three-phase and single-phase cables; both
have a metallic screen to help confine the electromagnetic fields.
Belted cables are generally used for three-phase, low-voltage operation up to
approximately 5 kV, whilst three-conductor, shielded, compact sector cables are most
commonly used in three-phase applications at the 5±46 kV voltage range. At higher
voltages either gas or oil filled cables are used.
Power transformers are used in many different ways. Some of the most obvious
applications are:
