⚡ Card 1 — Power System Structure & Voltage Hierarchy
🔖
1200 kV Bina-Nashik Trial
AC Transmission Hierarchy
$$ \text{Gen (11kV)} \rightarrow \text{Step-up} \rightarrow \text{Primary Tx} \rightarrow \text{Step-down} \rightarrow \text{Sec Tx} \rightarrow \text{Dist} $$
- Primary Transmission: 132-765 kV (3-ph, 3-wire)
- Secondary Transmission: 33-66 kV (3-ph, 3-wire)
- Primary Distribution: 3.3-11 kV (Industrial)
- Secondary Distribution: 230V/400V (Home Load)
Voltage Range Classification
LV: <250V | MV: <650V | HV: 11-33kV
EHV: 66-220kV | UHV: 400-765kV+
EHV: 66-220kV | UHV: 400-765kV+
Permissible Frequency & Voltage
$ \Delta f = \pm 3\% \quad (50 \pm 1.5\,\text{Hz}) $
$ \Delta V_{EHV} = \pm 12.5\% \quad \Delta V_{LV/MV} = \pm 6\% $
$ \Delta V_{EHV} = \pm 12.5\% \quad \Delta V_{LV/MV} = \pm 6\% $
Voltage Pyramid
Higher V → Lower I → Less Loss
🔌 Card 2 — Feeders, Distributors & Service Mains
🔖
1. Feeder
Substation to Serving Area. No Tapping. Current remains constant. Designed for Current Capacity.
2. Distributor
Contains Tappings for consumers. Current decreases along length. Designed for Voltage Drop.
Service Mains
Distributor to consumer terminals. Connects individual homes. Must provide 82% transient protection.
Voltage Drop Accumulation
$$ V_{drop, total} = \sum_{k=1}^n I_k \cdot R_k $$
$$ I_x = I_{start} - \sum I_{tapped} $$
Current Staircase Profile ($I$ vs Distance)
📉 Card 3 — Power Loss & Conductor Economics
🔖
The Efficiency Formula
$$ W = \frac{P^2 \cdot f}{V^2 \cos^2\phi \cdot A} [Watts] $$
$W \propto 1/V^2$
$W \propto 1/\cos^2\phi$
$W \propto P^2$
$W \propto 1/A$
Conductor Volume Requirement
$$ \text{Vol} = \frac{P^2 \cdot f}{V^2 \cos^2\phi \cdot W} $$
Higher Voltage → Smaller conductor volume needed (More economic transmission).
Transmission Loss Dashboard ($P=100\text{MW}$)
0 MW Loss
0 m³ Cond. Vol
Red glow represents $I^2R$ heat dissipation
📊 Card 4 — Transmission System Comparison (K-Factor)
🔖
| System | Volume factor ($K$) |
|---|---|
| DC 2-wire, 1-e | 1.0 |
| DC 2-wire, mid-e | 0.25 (Best DC) |
| 1-ph, 2-wire | $2/\cos^2\phi$ |
| 3-ph, 3-wire | $0.5/\cos^2\phi$ (Best AC) |
3D Neutral Wire Comparison
DC Return: $1/2 A_{main}$
AC Return: $\sqrt{2} A_{main}$
Conductor Volume Rel. to DC 2-wire
Delta 3-wire is standard for AC transmission.
📊 Card 5 — Module 1 Master Quiz & Quick Summary
🔖
Quick Reference
- Underground: Leading Power Factor (Capacitive)
- Overhead: Lagging Power Factor (Inductive)
- Economy Check: $K$ (mid-e DC) < $K$ (3ph AC) < $K$ (2-wire DC)
- Route: 1200kV line starts at Bina (MP).
$ W \propto 1/(V^2 \cos^2\phi) $
$ A_{neutral} = 0.5 \text{ (DC)} \text{ vs } 1.414 \text{ (AC)} $
$ A_{neutral} = 0.5 \text{ (DC)} \text{ vs } 1.414 \text{ (AC)} $
1/15
Loading...
(Tap to reveal answer)
Answer
Loading...