Grade 10 electricity – Generation, Transmission and Distribution of Electricity Quiz

Olkaria in the Rift Valley is the largest geothermal power-producing area in Kenya and supplies a significant portion of the country's electricity from geothermal energy.

Step-up transformers raise voltage so current is lower for the same power, reducing losses during long-distance transmission.

Kenya Power is the utility that distributes electricity to homes and businesses across Kenya; KenGen is mainly a generator.

Hydroelectric plants convert the energy of flowing or falling water into mechanical energy and then electricity using turbines and generators.

Kenya, like most countries in Africa and Europe, uses a mains frequency of 50 hertz for its electrical supply.

400 kV is used for high-capacity long-distance transmission in Kenya; lower voltages like 11 kV are for local distribution.

For a given power, higher voltage means lower current; lower current reduces I^2R losses in transmission lines, making long-distance transmission more efficient.

Geothermal is renewable because it uses Earth's natural heat; diesel, coal and petrol are fossil fuels and not renewable.

Circuit breakers detect faults and automatically open to isolate the faulty section, protecting the rest of the power system.

Load shedding is a controlled measure where supply is temporarily cut to some areas when generation is insufficient to meet total demand, avoiding wider outages.

Distribution substations contain step-down transformers that lower transmission voltages (e.g., 132 kV) to distribution voltages (e.g., 11 kV) for local supply.

Tall towers provide clearance to prevent accidental contact with live conductors and to reduce the risk of arcing to the ground or nearby structures.

I^2R losses are resistive heating losses in conductors and increase with the square of the current flowing through the line.

Lake Turkana Wind Power is a major wind farm in Kenya that generates electricity from wind resources; Olkaria is geothermal and Masinga is hydro.

Distribution transformers step down medium distribution voltages (e.g., 11 kV) to low voltages like 240 V (single-phase) and 415 V (three-phase) for consumer use.

Higher voltages allow the same power to be transmitted with lower current, which reduces I^2R losses over long distances.

Substations contain transformers and switchgear to step voltages up or down and to route and protect power flows within the network.

Diesel and heavy fuel oil are used in thermal plants to provide flexible generation when hydro or other sources are insufficient, though they are costly and polluting.

Earthing directs fault currents safely into the ground, reducing the risk of electric shock and helping protective devices operate correctly.

Grid interconnection allows different regions or countries to exchange power, improving reliability and enabling sharing of generation resources.

Kilowatt-hour is a unit of energy representing power (kilowatts) used over time (hours) and is commonly shown on electricity bills.

At high voltages, the electric field can ionize surrounding air causing a corona discharge, which results in power loss and audible noise.

Underground cables are less exposed to weather and lightning but are more expensive to install and are harder and costlier to repair than overhead lines.

Protection relays monitor electrical quantities and, when they detect abnormal conditions, send signals to breakers to open and protect equipment and people.

Wind and solar vary with weather and time, so the grid needs additional measures (storage, demand management, flexible plants) to keep supply and demand balanced.

Geothermal generation uses heat from beneath the Earth's surface to produce steam that drives turbines. Kenya's Rift Valley, including Olkaria, is known for geothermal power plants.

Raising voltage reduces the current for the same power transfer; lower current reduces I²R losses in the conductors, making long-distance transmission more efficient.

A transformer changes alternating voltage levels. Step-up transformers raise voltage for transmission; step-down transformers lower voltage for distribution to consumers.

Most homes in Kenya receive single-phase supply at about 230 V (50 Hz), which is the common household voltage standard in many countries.

Hydroelectric stations use the kinetic energy of flowing or falling water, often from a dammed reservoir, to spin turbines that drive generators.

A fuse contains a metal link that melts when current exceeds its rating, interrupting the circuit to protect wiring and equipment from damage.

Substations contain transformers, switches and protection gear; they step voltages up or down and connect or route power between parts of the grid.

I²R losses are proportional to the square of current. Increasing voltage reduces current for the same power transfer, thereby reducing resistive (I²R) losses.

Earthing provides a low-resistance path to ground so that fault currents go safely into the earth, reducing the risk of electric shock and equipment damage.

A radial system feeds consumers one after another from a single source; it is simple but a fault can cut supply to downstream customers.

Tall towers provide safe ground clearance and spacing between conductors to prevent dangerous arcing and to allow safe passage under lines.

A circuit breaker trips when current exceeds safe limits; unlike a fuse it can be reset after the fault is cleared, restoring the circuit.

Solar PV panels convert sunlight into electricity and their output varies with solar irradiance, making them suitable for rooftop installations.

A step-up transformer raises generator voltage to higher levels to reduce current and transmission losses over long distances.

An isolator provides a visible open gap and is used to ensure a section of line is de-energized for safe maintenance; it is operated under no-load conditions.

Load shedding is deliberate disconnection of supply to parts of the network when available generation cannot meet total demand, protecting the grid from collapse.

Three-phase supplies deliver constant power transfer and are more efficient for driving motors and heavy industrial loads compared with single-phase.

Poor power factor means more apparent power for the same real power, causing higher currents, increased I²R losses, and utilities may charge penalties for low power factor.

An energy (electricity) meter records the amount of electrical energy consumed by a household so the utility can bill the customer.

Underground cables are protected from wind and storms and are visually unobtrusive, but installation and fault repairs tend to be costlier than overhead lines.

An RCD detects difference between live and neutral currents (indicating leakage to earth) and quickly disconnects the supply to reduce shock risk.

Pole-mounted distribution transformers reduce the high distribution voltage down to the standard household voltage (e.g., ~230 V) for safe use in homes.

Thermal power plants burn fossil fuels to produce steam which drives turbines connected to generators that produce electricity.

Fuses and circuit breakers are designed to detect overcurrent conditions like a short circuit and open the circuit to isolate the fault and protect the system.

Wind and solar output depends on weather and time of day; to ensure a reliable supply they often require storage (batteries) or backup generation.

Placing step-down transformers near consumers lowers the distance that low-voltage (high-current) supply must travel, reducing losses and delivering usable voltages locally.