The kilowatt-hour meter measures the amount of electrical power consumed by the load over a certain period of time, typically used by utility companies to bill customers.

Generation

Electricity is generated in power stations, which convert energy from sources such as fossil fuels, natural gas, nuclear energy, and water into electrical energy. The turbines drive generators that produce AC electricity.

Transmission

The generated electricity is stepped up to a high voltage for transmission over long distances. This reduces energy losses due to resistance in the wires. Once at the destination, it is fed into a national grid.

Distribution

From the national grid, electricity is distributed to various substations and then stepped down to lower voltages required for commercial, residential, and other types of consumers.

The voltage phasor diagram consists of three vectors representing the line voltages $V_{L1}$, $V_{L2}$, and $V_{L3}$, which are $120^ ext{o}$ apart in phase. All vectors are drawn to scale with equal length, indicating equal voltage magnitude in each phase with the overall representation showing the direction of rotation.

A low power factor indicates that the system is drawing excessive reactive power, resulting in higher losses in the form of heat. This can lead to reduced system efficiency and may require larger capacity equipment to handle the increased current, ultimately raising operational costs.

To find the current in each phase, we use the formula:

$I_{ph} = \frac{V_L}{R} = \frac{380}{470} = 0.81 A$

So, the current in each phase is approximately 0.81 A.

The line current can be calculated using:

$I_L = \sqrt{3} \times I_{ph} = \sqrt{3} \times 0.81 \approx 1.40 A$

To find the total power consumed by the load, we sum the power of each meter:

$P_{T} = P_1 + P_2 = 500.65 + 421 = 921.65 W$

One advantage of a single-phase system is that it is generally cheaper and simpler to install than a three-phase system. Additionally, single-phase voltage is less than three-phase voltage, which makes it safer in many residential applications.