In order to reduce air pollution caused by coal combustion in thermal power plants, hydroelectric po

(1) The turbine output power is the generator input power, which is P1=

75%×(mgh+m< table cellpacing="0" cellpadding="0"> 1 2 v 21< /td> ? 1 2 m< tr> v 22 )< /td>< /tr>

t

=7.8×105W,

The output power of the generator P0= P1×80% =6.24×105W.

(2) The schematic diagramThe power transmission mechanism is as shown in the figure. The output current by the generator I1=

P0

U1

=

6.24×105

240

A=2600A．< /p>< p>Heat loss P loss in transmission wires=P0×5%=3.12×104W,

Current I2 in transmission lines=

< tr>

Consummation P R

=

3.12×104 50< /td> 3

≈43.27 A,

So, the rotation ratio of the primary and secondary coils of step-up transformer T1

< td style="border-bottom:1px plain black;padding-bottom:1px;font-size:90%">n1

n2

=< tr>< td style="border-bottom:1px plain black;padding-bottom:1px;font-size:90%">I2

I1

=

43.27

2600

≈

1

60

;

The output power P of the step-down transformer T2=P0-P consumption=5.928×105W,

The output current I3 of T2=

P

U

=A≈ 2.7×103A．

So, the rotation ratio of the primary and secondary coils of the step-down transformer T2

5.928 ×105

220

< td style= "border-bottom:1px plain black;padding-bottom:1px;font-size:90%">n3

n4

=