Electricity is generated at lower voltages & subsequently increased for transmission for wide range of technical and economic reasons.
Here’s the breakdown:
Why is electricity produced at lower voltages (Ex:11kV, 33kV)?
Generator Design & Insulation Limits
High-voltage generators are huge, complex, and expensive due to the need for extensive insulation and wider clearances.
Limiting the generator output to the lower voltage optimizes generator design, cost, and dependability.
Safety
Operating a generator at a lower voltage lowers the risk of electrical arcing, making maintenance safer and easier for plant personnel.
Efficiency of Power Plants
The power plant transmits energy across short distances (generator to a transformer), resulting in negligible I²R losses at low voltage.
As a result, there is no advantage to generating directly at extremely high voltages.
Why is the Voltage Stepped Up for Transmission?
To Reduce Power Losses (I²R Losses)
Power Loss = I² x R
For the same power (P = V × I), if you raise voltage (V), the current (I) falls.
Lower current means lesser resistive losses in the transmission lines.
Improved Transmission Efficiency
Stepping up the voltage (Ex: to 132kV, 220kV, 400kV, or 765kV) enables long-distance power delivery with minimal losses & voltage drops.
Reduced Conductor Size & Cost
Lower current allows the utilization of smaller conductors, saving material & structural cost in the transmission towers & lines.
Voltage Regulation & System Stability
High-voltage transmission assists in maintaining stable voltage over a long distances & decreases line reactance, enhancing system performance.
How does Voltage Stepped Up?
Power transformers are utilized at the generating station (GSS).
Ex: 11kV generator output can be stepped up to 132kV (or) 400kV, then transmitted and stepped down near the load centers.
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