Different Types of Electrical Loads | Resistive, Inductive and Capacitive Load

What is an Electrical Load?

Any electrical device or appliance that consumes electrical power is called an Electrical load. In other words, We can define Electrical load as Any electrical device that consumes electrical energy in the form of current and voltage and converts them into some other form of energy like heat, light, work, etc is known as Electrical load. Electrical lamps, motors, Fans, Heaters, air conditioners, and all electrical and electronic devices that consume electricity are examples of electrical load.

Types of Electrical Load

Electrical loads can be classified according to various different factors. There are mainly two aspects of the classification of electrical load.

According to the Nature of load, Electrical load can be classified into three types:

• Resistive load
• Inductive load
• Capacitive load

Apart from this, there are two more types of loads in electrical systems named as:

• Balanced load
• Unbalanced load

Whereas in a power system, Electrical load can be categorized as:

• Industrial load
• Domestic load
• Commercial load
• Agriculture load

Let’s discuss all these loads in detail.

Resistive Load

Resistive load is defined as An electrical load that consumes electrical energy and converts it into thermal or heat and light energy form is known as Resistive load. As the name suggests Resistive load resists the flow of current through it due to its large resistance and hence converts that Electrical energy into heat or light energy.

Since in Resistive load the current and voltage becomes in-phase with each other, Hence the power factor of Resistive load become unity (1).

Examples of Resistive Load

Examples of Resistive load includes: Incandescent bulb, Electric heater, Electric iron, and any electrical load that consists of only heating elements, etc. are examples of Resistive load.

Properties of Resistive Load

These are some important properties of Resistive load:

• It consumes only Active power.
• In pure Resistive load, current and voltage waveform becomes exactly in phase with each other. So the phase difference between voltage and current will be zero.
• Hence power factor of pure resistive load becomes unity (1).
• In the case of a Resistive load, Power always flows from source to load.

Inductive Load

Inductive loads are such electrical loads that consume only Reactive power. Any Electrical load that consists of coils or inductors comes in the category of Inductive load.Inductive loads are more complex than Resistive loads. If you observe the voltage and current waveforms of Inductive loads then you will find that current and voltage waveforms are 90 degrees out of phase ( Current lags behind Voltage by 90 degrees). So there is a phase difference of 90 degrees. Hence the power factor of Inductive loads becomes Lagging nature (not unity).

Since in Inductive load the current and voltage becomes 90 degree out of phase with each other, Hence the power factor of Inductive load become lagging nature, whereas power factor of pure Inductive load becomes zero lagging.

In the case of Inductive loads, Switching is more difficult than Resistive loads. As we know the circuit breaker opens at current zero condition. But in Inductive load when the current becomes zero then at the same instant Voltage becomes maximum due to the 90-degree phase difference. So when the circuit breaker opens at zero current then maximum voltage appears across the terminals of CB. Hence Switching of Inductive loads are very critical and tricky job.

Examples of Inductive Load

Examples of Inductive load include an electric motor, Fans, Induction heater, washing machine, and any other electrical load that has coils and a motor inside it, etc. are the examples of Inductive load.

Properties of Inductive Loads

These are some important properties of Inductive load:

• It consumes only Reactive power.
• In pure Inductive load, current and voltage waveform become 90 degrees out of phase with each other. Current lags behind Voltage by 90 degrees. So the phase difference between voltage and current will be 90 degrees.
• Hence power factor of the Inductive load becomes Lagging in nature. Whereas the power factor of pure Inductive load becomes zero lagging.
• In the case of Inductive load, Power flows from source to load and load to source.

Capacitive Load

Capacitive load is similar to Inductive load. In capacitive load current and voltage waveform becomes 90 degrees out of phase with each other. So there is a phase difference of 90 degrees. But the only difference between capacitive load and Inductive load is that, In capacitive load current leads voltage by 90 degrees, Whereas in Inductive load current lags behind Voltage by 90 degrees. Hence the power factor of capacitive load becomes the leading nature.

Examples of Capacitive Load

Examples of capacitive load include: A battery in charging condition, Buried cables, a motor starter circuit, a TV picture tube, and an AC long transmission line connected only to lighting load are the best examples of Capacitive load.

Whereas Synchronous condenser and capacitor bank are not considered as capacitive load. Most people have misconceptions about it and they consider a capacitor bank as a Capacitive load.

Capacitor banks are installed at power stations to improve the power factor of the load or system. Their job is to supply reactive power to the system. They don’t absorb any power. So we can’t call a capacitor bank a Capacitive load. Because Electrical load is something that consumes power. Therefore capacitor bank and synchronous condenser can not be considered as Capacitive load.

Let’s understand it more clearly with an example: Consider a 230V AC generator and a capacitor bank of 23 ohms connected across it. So the current drawn by the capacitor bank is 10 Amp.

Now, If you connect a VAR meter to read reactive power across the generator and capacitor bank then It will show -2300 VAR or -2.3kVAR. Here negative reading of the VAR meter indicates that Reactive power is flowing from the capacitor bank to the generator. Hence here capacitor bank is the source of reactive power, not the Capacitive load.

Properties of Capacitive Load

These are important properties of Capacitive loads.

• Capacitive load consumes both active and reactive power.
• A pure capacitive load has zero resistance although practically it’s not possible. Every capacitive load has some internal resistance.
• In capacitive load, Current leads voltage by 90 degrees. Hence it has a leading power factor.
• Since the capacitor blocks DC current and allows AC to pass through it, the capacitive load shows very high resistance for DC supply and low resistance for AC.
• Capacitive load can also store Electrical energy in the form of electric charge and return back to the source.
• Capacitive load consumes less power as compared to Resistive and Inductive load.

Balanced Load

These are loads that are evenly distributed between the three phases of a power system. They don’t create any unbalanced current or voltage in the system.

Unbalanced Load

These are loads that are not evenly distributed between the three phases of a power system. They can create an unbalanced current or voltage in the system, which can lead to power quality issues.

Now moving towards the next part of the article that is According to our power system network there are four types of Electrical loads named below.

• Industrial load
• Domestic load
• Commercial load
• Agriculture load

Let’s discuss all these loads in detail.

Industrial Load

Industrial load mainly consists of loads of all types of industries such as large-scale industries, medium and small-scale industries, and heavy and cottage industries. Industrial loads are also considered as Composite loads. The composite load becomes a function of the voltage and frequency of the supply. Since in all industries, Induction motors are heavily used, Induction motors take a high proportion of the total composite load or Industrial load. It consumes a very large amount of power among all types of Electrical loads. The electricity tariff rate becomes high for Industrial loads.

Domestic Load

Domestic load is defined as the total electrical energy consumed by all electrical appliances in household work. It is also called Residential load. It depends on the living standard and also on the weather. It consists mainly of Resistive and Inductive loads like lighting loads, Fans and coolers, air-conditioners, TVs, refrigerators, mixer grinders, heaters, water-pumping motors, Induction stoves, etc. Domestic load consumes less power than other types of load and is also independent of frequency. The electricity tariff rate of domestic load becomes lower than all types of power system load.

Commercial Load

Commercial loads are Electrical loads that are used for commercial purposes. It consists of a light load of large shops, shopping malls, restaurants, large commercial buildings and apartments, offices, etc. Generally, Fans and coolers, air-conditioners, heaters, lights, and other electrical appliances are used in commercial loads. Commercial load consumes more power than Domestic load. For commercial load, the electricity tariff plan becomes higher than the Domestic load.

Agriculture Load

Agricultural load is mainly the load of motor pump sets used for irrigation purposes. Generally, the agriculture load is ON during off-peak or night hours. The load factor of this load becomes small nearly 0.15-0.25. It depends on weather conditions. The electricity tariff rate for the Agriculture load becomes approximately the same as the tariff for the domestic load.

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