Power factor improvement is an indispensable piece of optimizing electrical systems for expanding effectiveness and diminished energy utilization. In the space of electrical designing, power factor is the extent of how effectively electrical power is changed over into important work output. The power factor has a worth somewhere in the range of 0 and 1, with a worth of 1 addressing ideal effectiveness. In numerous modern and business settings, power factors will in general go amiss from solidarity as a result of the presence of responsive power parts, prompting diminished system productivity.
This article aims to uncover knowledge of the significance of force factor improvement and the various methodologies used to overhaul power-enhanced electrical systems. As ventures have a go at energy productivity and supportability, understanding and having a tendency to drive factor issues become foremost. Businesses can not only reduce their energy consumption to a minimum while also contributing to a more environmentally friendly and cost-effective operation by learning the fundamentals of power factor improvement.
Table of Content
What is the Power Factor?
In electrical engineering, the power factor (PF) of an AC electrical power System is defined as the proportion of working power (measured in kilowatts, kW) consumed by the load to the obvious power (measured in kilovolt amperes, kVA) flowing through the circuit. The power factor is a dimensionless number in the closed interval from -1 to 1. One is the “ideal” power factor (also known as “unity”). When there is no reactive power through the circuit, hence apparent power – kVA is equal to real power – kW. A load with a power variable of 1 is the most proficient stacking of the stock That said this isn’t sensible, and the power factor will in practice be less than 1. Different power factor correction techniques are used to assist with increasing the power factor to this ideal state.
Derivation of Power Factor Improvement
Power is the ability to do work. In the electrical space, electrical power is how much electrical energy that can be moved to another form (heat, light, etc ) per unit of time.
Numerically power factor is the result of voltage drop across the component and current flowing through it.
Considering first the DC circuits, having just DC voltage sources, the inductors and capacitors act as short-circuits and open circuits separately in steady state.
Subsequently the whole circuit acts as a resistive circuit and the whole electrical power is dissipated as in the form of heat. Here the voltage and current are in a same phase and the complete electrical power is given by:
Electrical power = Voltage x Current
Presently coming to the AC circuit, here both inductor and capacitor offer a specific measure of impedance given by:
XL = 2 π f L and XC = 1 / 2 π f C
The inductor stores electrical energy as magnetic energy and the capacitor stores electrical energy as electrostatic energy. Neither of them disseminates it. Further, there is a phase shift among voltage and current. Therefore, there is a phase difference between the source voltage and current when we take into account the entire resistor, inductor, and capacitor circuit.
The cosine of this phase difference is known as the electrical power factor. The portion of the total power that is utilized for performing the useful work is represented by this factor (-1 cos 1). The other part of electrical power is stored away as magnetic energy or electrostatic energy in the inductor and capacitor separately.
This is called apparent power and its unit is VA (Volt-Amp) and meant by ‘S’. A negligible part of this all out electrical power that takes care of our helpful responsibilities is called active power. We denote it as ‘P’.
P = Active power = Total electrical power.cosφ and it unit is watt.
The other part of power is called reactive power. Reactive power accomplishes no useful work, however it is expected for the active work to be finished. We denote it with ‘Q’ and numerically is given by:
Q = Reactive power = Total electrical power.sinφ and it unit is VAR. This reactive power fluctuates between the load and the source. To help with understanding this better every one of these power are represented as a triangle.
This is mathematically, S2 = P2 + Q2
Power Factor Improvement
The term power factor comes into the picture in AC circuits as it were. Mathematically represents the cosine of the phase difference between the source voltage and current. It refers to the negligible part of total power (Apparent power) which is used to accomplish the helpful work called active power.
Cos Φ = Active power / Apparent power
Need for Power Factor Improvement
Real power is given by P = VIcosφ. The electrical current is inversely proportional to cosφ for moving a given measure of power at a specific voltage. Consequently higher the pf lower will the current flowing. A small current flow requires a less cross-sectional area of conductors, and in this manner it saves conductors.
From the above relation, we see having an unfortunate power factor expands the current flowing in a conductor, and in this way copper losses increases. The alternator, electrical transformer, transmission, and distribution lines experience a significant voltage drop, which results in very poor voltage regulation.
The KVA rating of machines is likewise decreased by having a more powerful element, according to the formula:
KVA = KW / cos Φ
Thus, the size and cost of the machine are likewise decreased.
To this end the electrical power factor should to be kept up with near unity – it is essentially less expensive.
Cause of Low Power Factor Improvement
- The vast majority of the AC apparatuses have induction motors 1−ϕ and 3−ϕ which have low lagging power factors.
- The heating furnace ( arc or induction) in industries has an extremely low lagging power factor.
- Arc lamps and electric release lamps worked at low factor.
- The load on the power factor isn’t consistent, however shifting varying to time. During times of low load (lunch, night, etc.), the supply voltage increases, which causes an expansion in magnetizing currents. Consequently, the power factor of the system come down.
Power Factor Improvement Methods
There are some list of Power Factor Improvement Methods given below :
- Static Capacitor
- Synchronous Condenser
- Phase Advancer
Static Capacitor
We are aware that the majority of power system loads and industries are inductive, which results in a lower system power factor due to lagging current. Static capacitors are connected in parallel to these low-power factor devices to raise the power factor. These static capacitors supply driving current, which adjust the lagging inductive part of the load current. This successfully wipes out or kills the lagging part of the load current and corrects the power component of the load circuit to improve the overall efficiency.
To enhance system or device efficiency, these capacitors are introduced close to enormous inductive loads, similar to inductance motors and transformers, to further develop the load circuit power factor.
For instance, we should consider a single phase inductive load shown in below, which is drawing lagging current (I), and the load power factor is Cosθ.
In below figure shows the load with a capacitor (C) associated in equal. Subsequently, a current (IC) courses through the capacitor and leads 90° from the supply voltage. The capacitor gives driving current, and in a simply capacitive circuit, the current leads the supply voltage by 90°, and that implies the voltage falls 90° behind the current. The load current remaining parts (I), and the vector amount of (I) and (IC) is (I’) which lingers behind the voltage at θ2, as shown in figure.
Static Capacitor
In below figure shows that the point of θ2 < θ1, implying that Cosθ2 is less than Cosθ1 (Cosθ2 > Cosθ1). Thusly, the capacitor further develops the heap power factor.
Phasor Diagram
It is vital to take note of that after power factor improvement, the circuit current is lower than the low power factor circuit current. Because the capacitor only removes the reactive component of the current, the active component of the current remains the same before and after power factor improvement. Finally, both before and after power factor correction, the Active power in Watts remains the same.
Advantages
- Low losses in static capacitors
- No moving parts, subsequently requiring low maintenance
- Capacity to work in ordinary atmospheric conditions
- No requirement for an foundation for installation
- Lightweight, making them simple to install
Disadvantages
- Less lifespan for static capacitor banks (around 8-10 years)
- The need to turn the capacitor bank ON or OFF when there is an adjustment of burden, which can cause switching surges in the system.
- Hazard of harm on the off chance that the appraised voltage expands past its cutoff
- When it was damaged it’s repairing cost is high.
Synchronous Condenser
At the point when a synchronous motor works at no-load and is over-excited, it is known as a synchronous condenser. At the point when a synchronous motor is over-excited, it gives driving current and works like a capacitor.
In a synchronous motor, a separate DC source is utilized to excite the field winding. Thusly, the input supply just gives current to energize the stator, i.e., the current gave is in-phase the supply voltage. So the power factor remains unity.
Synchronous Condenser
The power factor can be changed by shifting the DC excitation. By expanding the DC excitation, the power factor fluctuates from lagging to unity and driving power factor. At the point when the DC excitation builds, the field windings are over-magnetization. The input supply gives an current part to the stator to make up for this over-magnetization. This current leads the supply voltage, causing a main power factor or creating reactive power.
A capacitive load generates reactive power, whereas an inductive load consumes reactive power, resulting in a leading power factor. A synchronous motor can be utilized to further develop the general power variable of an electrical system by changing the DC excitation. The synchronous motor utilized explicitly for power factor improvement with practically no mechanical load is known as a synchronous condenser.
Phasor Diagram
The synchronous condenser is utilized in parallel up with the load to further develop the power factor. Further developing the power factor lessens the additional current drawn from the source that is squandered in the electrical cables. Subsequently, it helps in the decrease of power bills and saves energy.
A synchronous condenser draws leading current and partially eliminates the reactive component when connected across the supply voltage (in parallel). Along these lines, the power factor is gotten to the next level. In most large industries, synchronous condensers are used to raise the power factor.
Advantages
- Long life span
- High reliability
- Doesn’t produce harmonics or require maintenance for them
- When Faults occurs it can be easily to reduce
- Isn’t affected by harmonics
- Requires low maintenance
Disadvantages
- High cost, because it is mostly used by large power users
- Auxiliary device is required for operation as synchronous motors have no self-starting torque
- Produces noise.
Phase Advancer
The Phase Advancer is a simple AC exciter that connects with the primary shaft of an motor and works with the motor’s rotor circuit to further improve power factor. It is usually utilized in industries to further develop the power factor of induction motors.
Since the stator windings of an induction motor remove lagging current 90° from phase with voltage, the power element of the motor is low. The induction motor’s power factor rises as a result of the external AC source providing exciting ampere-turns. The Phase Advancer is responsible for this procedure.
Advantages
- Adequately reduces the lagging kVAR (reactive part of power or reactive power) drawn by the motor in light of the fact that the exciting ampere turns are provided at slip frequency (fs).
- The Stage Advancer can be easily used where the utilization of synchronous motors is unacceptable.
Disadvantage
- Utilizing a Stage Advancer isn’t economical for motors under 200 H.P. (around 150kW).
Advantages and Disadvantages of Power Factor Improvement
There are some list of Advantages and Disadvantages of Power Factor Improvement given below :
Advantages
- Efficiency of the energy: The essential advantage of further developing the power factor is expanded energy effectiveness. By diminishing responsive influence, less current is supposed to convey comparable proportion of certifiable influence, provoking lower energy mishaps in the structure.
- Diminished Energy Costs: Further created power ascertain results reduced energy use, inciting lower power bills for associations and ventures. Various assistance associations support power factor revision by offering lower obligations to purchasers with higher power factors.
- Updated System Cutoff: Power factor improvement can possibly support electrical frameworks’ successful limit. A similar electrical foundation can handle a larger amount of real power with a more powerful variable, reducing the need for additional equipment and framework redesigns.
Disadvantages
- Capital consumption: Doing control factor improvement measures regularly requires a capital interest in gear like capacitors or synchronous condensers. This hidden cost can be a limit for specific associations, particularly more unassuming endeavors.
- Support Requirements: Once introduced, power factor remedy gadgets might require routine upkeep to guarantee ideal activity. This adds a nonstop useful cost for the power factor improvement system.
- Hazard of Overcorrection: Overcorrection of power factor, provoking what’s going on where it ends up being irrationally capacitive, can obstruct. It could cause voltage weakness, equipment hurt, and extended mishaps, discrediting the arranged benefits.
Solved Problem on Power Factor Improvement
Let us consider a factory has a power factor of 0.95 and it charged at a rate of RS 9.60 per KWh. Connected load is 500 Kw. Determine the cost of electricity for a month if the power factor is improved to 0.85.
Solution:
Given That,
- Power Factor ( PF 1)= 0.95
- Power Factor ( PF 2) = 0.85
- Price of electricity = 9.60 rupees per kwh
- Load ( P ) = 500kw
- Time period ( t ) = 1 month
Apparent power ( S ) = P / PF
For power factor ( PF 1 )
S1 = 500kw / 0.85 = 588.24 kva
For power factor ( PF 2 )
S2 = 500kw / 0.95 = 526.32 kva
Now, Energy consumption ( E )
E = Apparent power ( S ) x Time period ( t )
For power factor ( PF 1 )
E1 = 526.32 x 1 month
For power factor ( PF 2 )
E2 = 588.24 x 1 month
Calculation of cost of electricity
Cost = E X Rate
For power factor ( PF 1 )
Cost 1 = E1 x 9.60 per kwh
= 526.32 x 9.60 = 5052.672
For power factor ( PF 2 )
Cost 2 = E2 x 9.60 per kwh
= 588.24 x 9.60 = 5647.104
Cost savings can be determined by subtracting Cost 2 from cost 1
therefore, = 5647.104 – 5052.672
= 594.328 rupees
Conclusion
All things considered, power factor improvement stays as an essential piece of electrical structure smoothing out, offering different advantages for organizations hoping to redesign energy capability and diminishing useful costs. The benefits consolidate lessened energy use, lower power charges, and further grew by and large system limit. In any case, it is principal to check these advantages against potential hindrances like starting capital endeavor and advancing upkeep necessities.
Power factor improvement and associated costs must be balanced for businesses to achieve optimal electrical system performance. With an extensive understanding of the advantages and burdens, affiliations can make informed decisions to execute power factor improvement techniques that line up with their energy viability goals and financial examinations.
FAQs on Power Factor Improvement
For what reason in all actuality does control factor matter?
Power factor is important because it affects how well electrical systems work, how much energy they use, how much they cost to use, and how far they can go.
How could power factor be moved along?
Power factor adjustment devices that offset receptive power, such as capacitors or simultaneous condensers, can improve the power component.
What are the generally anticipated risks of overcorrection in power factor improvement?
Overcorrection can result in excessively capacitive systems, which can outweigh the anticipated benefits of influence factor improvement and result in voltage insecurity, equipment damage, and expanded problems.