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#power transmission

3 public questions tagged with this topic.

AC Fundamentals - RMS, Average and Peak Values

What is the primary reason AC voltage is preferred over DC voltage for long-distance power transmission?

**Peak current** I_peak = V_peak/R for resistor, I_rms = V_rms/R, V_peak = √2 V_rms, for 200 V rms, V_peak=282.8 V, I_peak=282.8/80=3.535 A, rms I=200/80=2.5 A, average over complete cycle zero because positive and negative halves cancel. AC voltage is preferred for long-distance power transmission because it can be easily stepped up or down using transformers. This allows for high-voltage transmission to reduce energy losses due to resistance, followed by stepping down to safer levels for distribution. Applying X_L = ωL, X_C = 1/ωC, Z = √(R² + (X_L - X_C)²), I_rms = V_rms/Z, P = V_rms I_rms c

Ref: NCERT > Physics Book > Alternating Currents > AC Fundamentals - RMS, Average and Peak Values

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Electrical Power, Energy and Heating Effect

Why is high voltage used in power transmission lines to reduce energy loss?

**Power dissipation** in resistor converts electrical energy to heat, P = V²/R inversely proportional to R for fixed V, directly proportional for fixed I. For battery with internal r, power wasted internally = I² r, useful power = I² R, efficiency η = R/(R+r). Power loss in lines is Plₒₛₛ = I² R . For a given power ( P = V I ), increasing V reduces I ( I = P / V ), significantly lowering I² R losses. Applying I = n e A v_d, R = ρ l/A, R_t = R₀[1+αΔT], Kirchhoff's ΣI=0, ΣV=0, R_eq series/parallel, V = ε - I r

Ref: NCERT > Physics Book > Current Electricity > Electrical Power, Energy and Heating Effect

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PHYSICS

Why is high voltage used in power transmission lines to reduce energy loss?

Power loss in lines is P_{loss = I² R . For a given power ( P = V I ), increasing V reduces I ( I = P / V ), significantly lowering I² R losses. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Laws of Motion, Work Energy Power, Gravitation and System of Particles, Topic: Newton's laws, work-energy theorem and rotational dynamics.

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