Improving the quality of the electrical power improves reliability and reduces electrical costs. Additionally, it will improve their own electrical distribution system and reduce the likelihood of the utility company penalizing them for a low “power factor”. The key to improving electrical power is understanding the importance of the power factor.
What is the Power Factor?
Real power (also known as kW) is what powers electrical equipment and performs useful work
The power factor is defined as the ratio of real power versus the apparent power. To ensure an optimal electrical system, aim for a high “power factor”. To understand the concept of the power factor, let’s review the components of real power, reactive power, and apparent power.
Real power (also known as kW) is what actually powers electrical equipment and performs useful work. Reactive power (also known as kVAR) is what powers the magnetic flux of inductive loads such as transformers and motors. Apparent power (also known as kVA) is the vectorial summation of kW and kVAR.
How does a low Power Factor affect Them?
Only real power (kW) is required to perform useful work on an electrical distribution system. In an ideal world, reactive power (kVAR) would be negligible. However, this is often not the case, particularly in complex industrial facilities where large motor and transformer loads are prevalent. Consequentially, the need for reactive power will result in an increase in the apparent power required.
This increase in apparent power would translate to high current flows, inefficient power distribution, greater voltage drops, and increased line losses. The resulting increased consumption will increase electrical charges plus any penalties assessed by the utility company for maintaining a poor power factor.
Power Factor Correction Solutions
Adding shunt capacitor banks to an electrical distribution is the most viable solution
To achieve the most efficient power distribution system, the power factor should be as close as possible to unity (value of 1.0). Adding shunt capacitor banks to an electrical distribution system is the most commercially viable solution.
These capacitors act as kVAR generators to offset the kVAR usage of inductive loads, such as transformers and motors, to increase the overall power factor. Two types of capacitor banks are available (passive and active), where active correction is the most cost-effective solution:
- Passive Capacitor Banks. Installing a passive capacitor bank will provide a fixed kVAR compensation. To prevent the detrimental effects of ferroresonance, its operation is triggered only when the reactive power consumption exceeds the kVAR rating of the capacitor bank. With this approach, the capacitor bank provides a fixed compensation when above its kVAR setpoint. This approach has a limited range and does not provide the best power factor correction for instances of low and high reactive power usage.
- Active Capacitor Banks. Installing an active capacitor bank will provide dynamic kVAR compensation. This device is always operational and actively providing dynamic, electronically-regulated, kVAR compensation to effectively match the real-time measured reactive power usage. With this approach, optimal power factor correction is provided at all levels of reactive power usage.
Establishing a high power factor will improve efficiency, reliability, and functionality, and save money on electrical costs. A properly designed and implemented power factor correction solution can virtually pay for itself in as little as 12 months.
