Power Factor Correction Devices such as Power Factor Correction Capacitors are used to correct the PF. To Understand how this impacts the electricity bills of the household read the article till the end.
Power Factor, also known as PF, is the Cosine Angle between Voltage and Current. It is one of the most important performance measurement parameters for AC devices. DC devices don’t have issues with power factor because of non-directional voltage & current supply. Only AC loads affect PF. Resistive loads are unity power factor devices, capacitive loads are leading power factor devices and inductive loads are lagging power factor devices. PF actually means that when voltage is appearing across the load, still the current is not flowing through it (in case of inductive load). Or the current has started flowing through the load but voltage has not appeared yet (in case of capacitive load).
Most practical AC loads/devices, even generators/power supplies, show lagging power factors due to the inductive nature. Because motors, generators, transformers are built using coils around iron cores, these have inherent inductance.
Power factor in terms of AC Power.
AC power is expressed by Power equals to Voltage multiplies by Current with respect to angle of apparent power cos? Where is the value of cos? represents PF, if the value of cos? is close to 1 (for example 0.90) then that system is maintaining a better power factor. Low PF systems are lossy, because it draws more reactive power from the generating side and may cause instability.
As lower PF is not recommended, so it is necessary to maintain the value of PF close to unity. Power factor correction devices (PFCD) are used to increase PF for systems suffering lower PF. The basic principle of power factor correction is to place the power factor correction capacitors load in parallel with the actual/inductive load. So the capacitive load tends to lead the PF while the real load lags in PF. This effect nullifies the lagging tendency of the PF and keeps it close to unity.
Power factor correcting methods are mainly 2 types. One is Active Power Factor Correction, which is used where PF varies widely over time due to different loading conditions. Another is Passive Power Factor Correction, which is used where loading conditions are static.
Active PF Control
Active PF control is required for industrial loads where load varies. In case of commercial or residential load where load may vary. One of the most common methods for correcting PF in industrial loads is to use a Synchronous Motor. If parallel with other heavy inductive loads. The amazing thing is this synchronous motor will draw Real power form the line to run itself. But it will feed Reactive power to the line. This reactive power is generated by Over Exciting the DC field of the synchronous motor. When over excited synchronous motors run in leading PF mode. That overcomes the lagging PF of other loads like Induction motors, Transformers etc.
Another way to achieve dynamic PF correction is performed using PF Control IC. Where Power electronics are used with a feedback control system to vary the Capacitance of a Variable AC Capacitor to achieve desired PF level.
Other methods for PF correction are placing Capacitor Banks in distribution lines. Long distance HV transmission lines, Underground AC lines also supply leading PF to correct PF due to inherent capacitance.
Correcting PF and sustaining close to unity is essential for healthy systems. Lower PF may cause higher current draw from the generating side, that increases thermal losses. Thick conductor requirement and tendency to instability. So, it is essential to design a proper PF correction system for better performance.
To understand the impact and effect of some household appliances on energy costs. You need to know the basics of how electricity is delivered to a home. What is an electrical load and how to use it?
Introduction to Electricity Load
Basically, there are two types of electrical loads: resistive and inductive. Resistive loads come from sources that provide light and heat and do not consume much energy. The inductive load comes from a source running on a motor that does not have built-in capacitors. If you can estimate the types of inductive loads you need to use on a daily basis through various household chores. Then understand the energy factors that need to be accessed and factored into the actual energy consumption they affect or bring in. To make a big difference in your energy costs.
Devices with inductive loads typically do not use the supplied power efficiently, resulting in wasted energy and increased costs. Fluctuations in the power supply also degrade these devices and reduce their durability. Therefore, low power factor figures. This result from the use of many inductive loads without capacitors. It is not a good sign from an efficiency point of view. Not only does it cause waste, but it has little effect on the health of the device.
Of course, many device manufacturers add power factor correction capacitors to make their devices more efficient. If you own a large number of Energy Star rated appliances. The power factor correction device you install will save you money. There may not be much. Power Factor Correction Capacitors have the ability to store excess current that the device does not need at that time. It is released as needed, making better use of the energy it provides.
However, given the power factors that different appliances provide in the home. It is useful to consider installing appropriate power factor correction devices to improve the efficiency and durability of these appliances. However, it is important not to be fooled by the exaggerated claims of companies offering these devices. And to have realistic expectations for the savings that will occur. Weather conditions and other factors affect the monthly use of electricity in the house. So it is difficult to immediately estimate the positive effect in terms of the savings they bring. However, over time, you will get a fair idea of its effectiveness.
Another way to monitor your electricity usage is to use a good energy monitor. This is a cheaper device and informs you of the consumption of different devices. So that you can take the necessary corrective actions. Raising awareness of what drives your energy costs can reduce some of the wasted consumption of these devices. And provide the savings you’ve always wanted.