The storage battery generally used in electric power station is

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Examoogle · Accepted Answer

lead-acid battery

Explanation: The lead-acid battery is the industry standard for electric power stations due to its high reliability, capability to provide high discharge currents, and cost-effectiveness. It is primarily used for control room operations, emergency lighting, switchgear operation, and protective relaying circuits.

Working Principle: The lead-acid cell operates through the chemical reaction between lead dioxide ($PbO_2$) at the positive plate and sponge lead ($Pb$) at the negative plate, immersed in a dilute sulfuric acid ($H_2SO_4$) electrolyte. During discharge, both plates react with the electrolyte to form lead sulfate ($PbSO_4$), releasing electrons and consuming acid. This reversible electrochemical process allows for efficient charging cycles necessary for stationary industrial backup applications.

Key Formulas: $PbO_2 + Pb + 2H_2SO_4 \leftrightarrow 2PbSO_4 + 2H_2O$ — The global reversible chemical reaction during charging/discharging; $E = E_0 - I(r_i)$ — Simplified terminal voltage equation where $E_0$ is EMF and $r_i$ is internal resistance

Key Points: Used for backup power in substations and generating stations.; Known for low internal resistance enabling high current delivery.; The state of charge is monitored by measuring the specific gravity of the electrolyte.; Requires regular maintenance, including topping up distilled water.

Advantages: Low cost per watt-hour; High cell voltage (approx. 2V per cell); Excellent high-discharge performance

Disadvantages: Heavy weight and bulky construction; Requires periodic maintenance (sulfation risk); Toxic lead content

Applications: Switchgear tripping and closing mechanisms; Emergency DC lighting and signaling; Uninterruptible Power Supplies (UPS) in power grids

Additional Info: Nominal voltage per cell is roughly 2.0 to 2.1 volts.. Zinc-carbon batteries (Option B) are primary cells unsuitable for high-capacity stationary power stations as they are non-rechargeable.. Nickel-cadmium batteries (Option A) are used in specific applications but are significantly more expensive than lead-acid.

Answer: C is correct — Lead-acid battery is the preferred storage battery for power stations due to its economic viability and high discharge capability.

Exam Tip: Always remember that stationary batteries in power stations are classified as 'Secondary' because they are rechargeable, unlike 'Primary' cells used in portable devices.

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