Question

某發(fā)電站的輸出功率為10⁴ kW，輸出電壓為4 kV，通過理想變壓器升壓后向80 km遠(yuǎn)處用戶供電.已知輸電線的電阻率為ρ=2.4×10^-8 Ω·m，導(dǎo)線橫截面積為1.5×10^-4 m²，輸電線路損失的功率為輸出功率的4%，求：

（1）升壓變壓器的輸出電壓；

（2）輸電線路上的電壓損失.

Answer 1

思路解析：(1)輸電線的電阻為：R=ρ                                       ①

P_損=P₁×4%                                                                               ②

P_損=I₂²R                                                                                    ③

P₂=P₁                                                                                        ④

P₂=I₂U₂                                                                                     ⑤

由①②③④⑤得升壓變壓器的輸出電壓：

U₂=80 000 V.

(2)輸電線路上的電壓損失U=I₂R=3 200 V.

答案:(1)80 000 V  (2)3 200 V