The power loss of the conductor is 20% of the transmission power when the voltage of 220 V is used in a substation. If the power loss of the conductor is to be reduced to 5% of the transmission power, what is the transmission voltage?

The power loss of the conductor is 20% of the transmission power when the voltage of 220 V is used in a substation. If the power loss of the conductor is to be reduced to 5% of the transmission power, what is the transmission voltage?

Suppose that the transmitted power is p, the transmitted voltage is u, the current in the conductor is I, the resistance of the conductor is r, and the power lost by the conductor is △ P. then △ P = I2R and P = UI are obtained simultaneously: △ P = p2u2r. It is known that if the power lost by the conductor is to be reduced to 5% of the transmitted power, that is, 14% of the original power lost, the U strain is to be twice of the original power lost, so the transmitted voltage should be U ′ = 2U = 2 × 220V = 440V answer: the transmission voltage should be 440V