In electrical systems, not all the power that flows through the wires is used to do practical work.
A part of it, known as reactive power, is needed to keep motors, transformers, and other AC equipment running properly.
But here is the twist — Reactive Power doesn’t light up a bulb or turn on a fan; it helps maintain the voltage levels required for these devices to work.
However, too much reactive power can make the system inefficient by increasing losses and reducing the overall power factor.
Which brings us to our topic of discussion — reactive power compensation.
By using special devices and techniques to control or reduce reactive power, engineers can improve system efficiency, reduce energy losses, and ensure a more stable power supply.
Take mental notes, as we share some interesting trivia about reactive power compensation in electrical devices that are quintessentially an electrical engineer’s forte.
For all the aspiring students and engineering enthusiasts reading this blog, we hope to bring some fundamental clarity in this chapter.
Enjoy the read!
Understanding Reactive Power in Alternating Current Operated Devices
Most electrical devices we use today, like fans, refrigerators or industrial motors, run on alternating current (AC).
In AC systems, the voltage and current continuously change direction, creating a need for both active and reactive power.
While active power does the actual work, reactive power is essential for building and maintaining the magnetic and electric fields in devices like motors and transformers.
This is not the case with direct current (DC) systems, where voltage and current flow steadily in one direction and no reactive power is involved.
As a result, reactive power compensation is essentially for AC systems, especially where inductive loads are present.
Without proper compensation in such systems, efficiency drops, energy losses increase, and the voltage quality suffers; making it a critical aspect of AC power system design.
Challenges of Poor Power Factor & the Need for Compensation
Power factor is a measure of how effectively electrical power is being used, and it ranges between 0 and 1.
A poor power factor, usually caused by inductive loads like motors and transformers, means a large portion of the electricity is being wasted as reactive power rather than being used for practical work.
This leads to several problems like increased energy losses in the system, overloaded transmission lines, and voltage drops at the consumer end.
Over time, it can also cause wear and inefficiency in the power infrastructure.
Utility companies often impose penalties on industrial users for maintaining a low power factor, making it both a technical and financial concern.
Reactive power compensation comes to the rescue.
Installing shunt capacitors, synchronous condensers, or advanced power electronic devices can supply the required reactive power locally, thereby reducing the burden on the power source.
Techniques of Reactive Power Compensation
Depending on the nature of the load and the system requirements, power compensation techniques are designed by electrical engineers.
The most common and cost-effective method is the use of shunt capacitors, which supply leading reactive power to counterbalance lagging reactive power from inductive loads.
In larger or more dynamic systems, synchronous condensers, essentially synchronous motors running without mechanical load, are used for smoother voltage control and dynamic compensation.
More advanced solutions include Static VAR Compensators (SVC) and STATCOM (Static Synchronous Compensator), both part of the FACTS (Flexible AC Transmission Systems) family.
These power electronic-based devices offer fast and precise control of reactive power, especially in high-voltage transmission networks.
How to Achieve Industrial-Level Compensation
At the industrial level, reactive power compensation becomes essential for maintaining power within acceptable limits, avoiding penalties and reducing energy bills.
In transmission and distribution grids, compensation is achieved through a mix of fixed and dynamic solutions like shunt capacitor banks, synchronous condensers and FACTS devices to regulate voltage levels and reduce transmission losses over long distances.
With the increasing penetration of renewable energy sources such as wind and solar, which can cause fluctuations in voltage and reactive power flow, dynamic compensators like STATCOMs are used to ensure grid stability and smooth integration.
In factories and large commercial setups, where inductive machinery like motors, welding equipment, and HVAC systems dominate, automatic power factor correction (APFC) panels are commonly installed.
Concepts like reactive power compensation are not just technical essentials—they’re gateways to smarter, more efficient energy management.
Omdayal Group of Institutions stands as a steady platform of breakthroughs in this dynamically evolving field, developing to meet the demands of modern power systems.
We remain committed to nurturing future-ready engineers who are equipped to lead these breakthroughs with knowledge, innovation, and purpose.
Sources:
- https://qualitypower.com/reactive-power-compensation-systems/#
- https://www.chintglobal.com/sg/en/about-us/news-center/blog/reactive-power-compensation-technology.html#
- https://www.irjet.net/archives/V4/i4/IRJET-V4I4113.pdf#
- https://www.inverterdrivesystems.com/the-effect-inverters-have-on-power-factor-correction#
