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Page 275

| Figure 14-8 Pilot wire schemes: (A) Circulating-current scheme with load currents and through fault currents circulating over pilot wires; (B) balanced-voltage scheme with load currents and through fault currents producing equal opposing voltages at line terminals; |

| come faulted, that is, the system fails safe. One of the disadvantages of pilot wires is that they may be adversely affected by the extraneous voltages and currents induced in them, especially when they are on the same right-of-way as the power circuit. To avoid this situation, pilot circuits sometimes make use of leased telephone lines and extend over routes far removed from the trans- |

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