When we talk about power and the different ways that power is used in modern power system applications, we frequently refer to the electrical load. Electrical loads are one of the fundamental principles of electrical energy and transmission in any circuit.
Let’s take a brief look at electrical theory and discuss a few different fundamental electrical loads, before looking at the different roles of electrical loads in power systems as well. Whatever the load of the power system you’re designing, our experts can help make sure that you get the right equipment and a safe design to make your project a success.
What is an Electrical Load?
An electrical load is any electrical device or component that consumes electrical energy and converts that energy into another form. As part of any electrical circuit, the component transforms current into something useful, commonly motion, light, or heat. An electric lamp, resistor, or even a motor are simple examples.
Broadly speaking, the electrical load can refer to: the equipment that uses electrical energy; the power required from a given circuit; the current (or power) passing through the line.
The Different Types of Electrical Load
Any load that consists of a heating element is generally referred to as a resistive load. A resistive load obstructs the flow of energy in the circuit, converting it to thermal energy. See incandescent lamps and electric heaters.
Importantly, resistive loads draw electrical power in a way that keeps the current and voltage waves in phase. The power factor for a resistive load is unity.
An inductive load is quite different and will use a magnetic field to do all of the work. In this case, the load could be a transformer, generator, or, more commonly, a motor. An inductive load has a coil that stores magnetic energy when current passes through it.
This means that the current wave trail behind the voltage wave. Therefore, the power factor of an inductive load is lagging.
And, as you’ve already guessed, the current wave leads the voltage wave in a capacitive load. The current wave reaches a maximum before the voltage wave, and that means that the power factor is leading.
Interestingly, there are no standalone capacitive loads – no one load is capacitive, such as a lightbulb or a motor. Capacitors are used in large power circuits to control power usage.
In fact, the majority of modern power circuits will use a combination of resistive, inductive, and capacitive loads. For example, you’ll almost always find a capacitor (capacitive load) being used to help control a motor (inductive load) during start-up or while it’s running.
Electrical Loads in Power Systems
Now, we’re going to look at the more practical applications of these types of electrical loads. How are these loads used in power systems? It can be broken down into four main categories of loads in a power system.
Domestic (Residential) Load
A domestic load is the total energy that’s consumed by the electrical appliances in a domestic – or household – setting. Naturally, this varies between household, and varies significantly between different countries.
Lights, refrigerators, heaters, air conditioners, are just a few of the domestic appliances that will create a total domestic load. Many of these are only connected for a few hours of each day, and consume a modest amount of power.
Turn your attention to the high street. A commercial load consists of shop lighting, office appliances, restaurant appliances, or any other electrical loads that are used commercially. These appliances are typically connected for longer hours than domestic loads.
Industrial load is next, and is made up of the load demand across various different industries. This is a coverall load, all the way from small-scale industries to heavy industries. The load will generally consist of heavy machinery and other systems that involve induction motors. They’re likely to be connected at all times.
Municipal load is the final type of electrical load in power systems that we’ll look at. Drainage systems, sewer systems, and traffic lights will all create the municipal load. Some of these systems operate at night, like street lighting, or pumps that replenish overhead storage tanks.
Agriculture loads, irrigation loads, and traction loads are other less common types of load.
Power and Power Systems International
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