Tutorials on Electrical Power Factor Correction

All About Power Factor Links

Power Factor Meter
A direct reading instrument for measuring power factor. It is provided with a scale graduated in power factor.

Power Factor Relay
Power system device function numbers. A relay that operates when the power factor in an alternating current circuit rises above or falls below a predetermined value.

Power Feeder
A feeder supplying principally a power or heating load.

Power Frequency
The value of frequency used in the Electrical power system, such as 50 hz or 60 Hz.

Power Inverter
A converter unit in which the direction of average power flow in from the DC circuit to the alternating circuit.

Power Monitor
A functional module that monitors the status of the primary power source to the system, and signals when that power has strayed outside the limits required for reliable system operation. Since most systems are powered by an alternating current source, the power monitor is typically designed to detect dropout or
brown out conditions on alternating current lines.

Power Factor Question and Answer

1. If a current of 10 amperes at a power factor of 0.8 lagging is taken from 250 Volt alternating current supply, the reactive power of the system will work out to be 1500 VAR.
2. Many industrial tariffs penalise consumers whose power factor falls below 0.8.
3. Power factor improvement may be achieved the use of synchronous motor.
4. One of the reasons for improving the power factor is to decrease the reactive power.
5. The power factor of incadescent bulb is unit.
6. The power facotor of an inductive circuit can be improved by connecting a capacitor to it in series.
7. The capacitor of power factor correction are rated in terms of KVAR.
8. In an alternating current circuit, a low value of with reactive volt ampere compared with watts indicates high power factor.
9. It is not easy to find the value of impedance for a parallel circuit but power factor can easily be obtained as a ratio of active current to line current.
10. In a series circuit consisting of resistance and reactance, power factor is a defined as the ratio of resistance to impedance.
11. In pure reactive circuit, the power factor is zero.
12. Power factor is defined as the ratio of watts to volt ampere.
13. For a parallel circuit consisting of resistance and reactance the value of power factor is the ratio of impedance to resistance.
14. The power factor of an alternating current circuit containing both a resistor and a conductor is between 0 - 1 leading.
15. In a given circuit when power factor is unity the reactive power is zero.
16. A poor power factor results in overloading of transformer as well as alternators.
17. For the same load, if the power factor of load is reduced, it will draw more current.
18. The power factor of the magnetizing component of a transformer is always leading.
19. Another reason for improving the power factor is to avoid poor voltage regulation.
20. The advantage of using static capacitors to improve the power factor is that they are almost loss free.

Causes of Low Power Factor
1. Arc lamps and industrial heating furnaces are typical of low power factor operating equipments.
2. During the night time when load is less the supply voltage increase which in turn, causes the magnetising current of transformers and motors to increase. Therefore, the power factor at which the system operates becomes low.
3. Mostly alternating current motors are of induction type. These operate on low lagging power factor.

The Adverse of Low Power Factor
1. With low p.f. cost of generation and transmission increases due to increase in current and use of thicker wires and bigger switches.
2. Low pf. makes the voltage regulation of generators, transformer and transmission line greater.
3. For a given p.f. to be supplied, the current is increased due to low p.f. in causes increase in copper losses, and decreases the efficiency of both apparatus and supply system.
4. With low pf generators, transformer, swithes transmission lines become over loaded.

All About Capacitors Electrostatics and Electric Lines of Force

Some Important Characteristics of Capacitors
1.The current through capacitor is zero, if the voltage across it is not changing with time.
2. A capacitor is sort of open circuit to direct current.
3. The capacitor never dissipates energy but only stores it.
4. A capacitor resits an abrupt change in voltage across it.
5. A finite amount of energy can be stored in a capacitor even if the current through capacitor is zero, such as when the voltage across it is constant.
6. It is impossible to change the voltage across a capacitor by a finite amount in zero time, for this requires infinite current through the capacitor.

Electrostatics Question and Answer
1. Relative permitivity of vacuum is unity.
2. In the electric field, the potential is the work done in joules to bring positive charge of one coulomb from infinity to that point.
3. The unit of field intensity is newtons/coulomb.
4. Coulomb's law for the force between electric charges most closely resemble with Newton's law of gravitation.
5. Mica medium has highest value of dielectric strength.
6. The maximum value of potential gradient in cable occurs in conductor.
7.A region around a stationary electric charge has electric field.
8. Inside a hollow spherical conductor electric field is zero.
9. The effect of the dielectric is to reduce the working voltage.
10. Electrolytic capacitor is the most commonly used type but it has two disadvantages, namely low insulation resistance and suitable for Direct current only has high capacitance and low insulation resistance.
11. In a radio a gang condenser is a type of air capacitor.
12. A sphere of one metre redius can attain a maximum potential of three kilo volt.
13.The power dissipated in a pure capacitor is zero.
14. In a capacitor the eletric charge is stored in dielectric.
15. One farad is one coulomb per volt.
16. If a dielectri is placed in an electric field, the field strength decreases.
17. If the medium of a parallel plate capacitor consists of mica and air, the capacitance is increased by increasing the area of plates.
18. A capacitor with capacitance is charged through a resistance. The time constant of the charging
circuit is given by RC.

Properties of Electric Lines of Forces
A line of force is supposed to start or emanate, from a unit with a positive charge. A line of force does not form closed loop unlike a magnetic line of force. The line of force is always normal to the surface of the body at the point from where they originate or terminate. No two lines of force can across each other. An electric line of force in the same direction repel each other and those in opposite direction attract each other. There will be neutral point in this case between the two sphere. An electric line of force has a tendecy to take an easy path.

Transmission and Distribution Lines Key Facts and Tutorials

Key Facts and Tutorials On Electrical and Distribution Lines

1. The economical section of a feeder can be obtain by applying Kelvin's law.
2. There should be be no break in the neutral, which is usually earthed at the supply end, of a two wire Alternating Current distribution system because excess current protection would be affected.
3. In actual practice the potential at the two feeding points is unequal. To calculate the voltage drop, the difference in potential is converted into ampere metres and the moments of the lower feeding point start from this initial value.
4. Uniformly loaded distribution fed at equal potential from both ends is treated like the distributor because the voltage drop is exactly halved.
5. Voltage drop in a uniformly loaded distributor fed at once end is calculated by assuming the whole of the load concentrated at middle point.
6. For Alternating current distribution the power factor of the load has to be taken into consideration and the calculations become cumbersome. The approximate method which gives results with in plus or minus five percent of the actual voltage drop involves calculating the centre of gravity of the load, resistance and reactance per double run and average power factor.
7. To determine the distribution of load at the point of minimum potential, the moments in ampere metres about of the feeding points must be equal to the moment in ampere metres about the other feeding point.
8.At the point of minimal potential in a distributor fed from both ends, the load at the point is supplied from right and left hand feeding points.
9. With point loads in a distributor fed at both ends, in order to determine the maximum voltages drop it is necessary to know the point of minimum voltage.
10. For a three wire Direct Current distributor fed at one end, if the total voltage drop in the neutral is positive it is added to the positive drop and deducted from the negative drop.

Limitation of high transmission voltage
a. Increased cost of line support
For high transmission voltage, the insulation required between the conductors and the earthed tower is more. This increases the cost of line supports.
b. High towers:
For high transmission voltage, the clearance between conductors and groundo should be more. Therefore, higher lower is required.
c. Longer cross arms:
FOr higher transmission voltage, distance between the conductors should be more. Therefore, longer arms are required.

The Flow Of Electricity On Transmission Lines Engineering

The Flow Of Electricity On Transmission Lines Engineering Tutorials
By: IIEE

Electricity is usually generated by a generator that converts mechanical energy into electrical energy. The electricity is then run through a transformer where voltage is increased to several hundred thousand volts and in some instance to a million or more volts. This high voltage is necessary in order to  increase the efficiency of power transmission over long distances.This high-transmission voltage is then stepped down reduced to normal 110 volt/220 volt household current by a transformer located near the point of use residence. The electricty is then transmitted to the house by a series of wires call a service drop. In areas where the electric wiring is underground, the wires leading to the building are burried in the ground. In order for electric current to flow, it must travel from a higher to a lower potential voltage. In an electrical system the hot wires black or red are at a  higher potential that the neutral or ground wire white or green. Therefore, current will flow between the hot wires and the neutral or ground wires. The voltage is a measure of the force at which electricity is delivered. It is similar to pressure in a water supply system. Current is the quantity of flow  of electricity. It is similar to measuring water in gallons per second. A watt is a measure of how much power is flowing. Electrity is sold in quantities of  watt-hour. The earth, by virtue of moisture contained within the soil, serves as a very effective conductor. Therefore, in power transmission, instead of having both  the hot and neutral wires carried by the transmission poles, one lead of the generator is connected to the ground, which serves as a conductor. Only hot wire  are carried by the transmission towers. At the house or point where the electricity is to be used the circuit is completed by another connection to ground.


Tracing The Flow Of Electricity
The mesh Structure of high voltage transmission networks provides a large number of possible routes by which electrical power can flow from the sources  generators to the sinks grid supply points.

Circuits and the Flow of Electricity
To understand current electricity, many vocabulary words must be introduced. The first
part of this lesson uses a hands-on, problem-solving activity that helps students define the
vocabulary terms and demonstrate the terms’ relationships. After gaining foundational
understanding, students create their own circuits.

Electrical Transmission lines Free PDF ebook download

 List of Electrical Engineering Ebooks

Electrical Characteristics Of Transmission lines
Transmission lines are generally characterized by the following properties: balance-to-ground characteristic impedance attenuation per unit length velocity factor electrical length, Skin effect is a phenomenon that occurs in conductors carrying an AC current. As the frequency increases, the current tends to be concentrated near the surface of the conductor. At RF, almost no current flows down the center of wire. It is all on the surface.


Electrical Power Transmission Lines
Properties Values, and Compensation, The effects of electric power transmission lines on property values is a controversial issue, and conventional procedure appear to be a major source of public dicontent over the sitting of transmission lines.


Review of Transmission-line Theory
The term transmission-line in electromagnetics is commonly reserved for those structures which are capable of guiding TEM waves. Transmission-lines are a special class of the more general electromagnetic waveguide. TEM waves can only exist in structures which contain two or more separate conductors. Coaxial lines, parallel plates, and two-wire lines are examples of practical transmission-lines.



Wireless Sensor Network for Electric-Transmission
Line Monitoring, Obtain electric power line (or grid) information in real time independent of owners/operators of grid assets. Provide source of information that Government can use to obtain situational awareness of the electrical grid.


Introduction To Transmission Lines and Waveguides
Is a device designed to guide electrical energy from one point to another. It is used, for example, to transfer the output rf energy of a transmitter to an antenna. This energy will not travel through normal electrical wire without great losses. Although the antenna can be connected directly to the transmitter, the antenna is usually located some distance away from the transmitter. On board ship, the transmitter is located inside a radio room, and its associated antenna is mounted on a mast.


Transmission Line Protection Principles
Factors like de-regulated market environment, economics, rightof- way clearance and environmental requirements have pushed utilities to operate transmission lines close to their operating limits. Any fault, if not detected and isolated quickly will cascade into a system wide disturbance causing widespread outages for a tightly interconnected system operating close to its limits.


Transmission Line Corona
Under certain conditions, the localized electric
field near energized components and conductors can produce a tiny electric discharge or corona, that
causes the surrounding air molecules to ionize, or undergo a slight localized change of electric charge.
Utility companies try to reduce the amount of corona because in addition to the low levels of noise that
result, corona is a power loss, and in extreme cases, it can damage system components over time.


The Nature of Electricity
The current transmission grid includes not only transmission lines that run from power plants to load
centers, but also from transmission line to transmission line, providing a redundant system that helps assure the smooth flow of power. If a transmission line is taken out of service in one part of the power grid, the power normally reroutes itself through other power lines to continue delivering power to the customer.

Free Electrical Capacitor Bank Tutorials PDF ebooks Dowload Diagram

Almost Electrical company are always improving the quality of the electrical supply. Those are
they use capacitor-banks speaking of this bank are : Shunt capacitor banks, Power Factor in ac machines, Delta Connected Capacitor banks, Undergrounded wye, grounded wye connected, power factor correction etc. You can download a free pdf file ebooks below.

Shunt Capacitor Bank Fundamentals
And protection, This paper reviews principles of shunt capacitorbank design for substation installation and basic protection techniques. The protection of shunt capacitor bank includes: a) protection against
internal bank faults and faults that occur inside the capacitorunit; and, b) protection of the bank
against system disturbances. Are mainly installed to provide capacitive reactive compensation/
power factor correction.

Shunt Capacitor Bank Swithing Transients
A Tutorial and case Study,power systems may damage key equipment, potentially having
a great impact on system reliability. These transients may be introduced during normal
switching operations, interruption of short circuits, lightning strikes, or due to equipment
failure. Phasor analysis or other simplified analysis methods are usually inadequate due
to system frequency dependencies and nonlinearities.

Analyzing Transmission Capacitor Bank
This paper will cover operations of banks that have
microprocessor relays utilizing the voltage differential protection scheme. Examples of several
unique events are included. While these events may be unusual, the same analysis can be applied
to most, if not all, capacitor bank operations.

Capacitor Banks Protection
Mov Protection of series capacitor banks, When capacitors are inserted in a transmission line, the series capacitance effectively compensates for the inherent inductance in the line to lower the total impedance. This in effect allows the circuit to transfer more energy with less heating of the lines. The series banks are generally located at either end of the section of the transmission line in one of the existing substations.

Fuseless Capacitor Banks
using Digital Relays, discuss the protection of shunt capacitors banks and present innovative techniques for fuseless shunt capacitor banks using digital relays to provide complete and economical
protection. These techniques eliminate the need for high voltage transducers for voltage differential
protection, provide more sensitive protection, and make the relay settings insensitive to system
voltage variations, as well as to capacitance variation caused by temperature.

Power Factor Correction Evaluation
Power factor correction needs are
calculated and the impact of the existing capacitors bank (provides about 600 kvar of compensation) is illustrated. The capacitor increases distortion levels at the 7th and 11th harmonics, resulting in overall voltage distortion levels exceeding 5% on the 480 volt system.

How Does Electrical Transmission Lines Capacitor Works?

A Million Dollars would you save when you truly know how does Capacitor works in electrical transmission lines. As modern transmission systems become more and more heavily loaded, the benefits of series
compensation for many of the grid’s transmission lines become more obvious. Clearly, adding series
compensation is one of the cheapest, simplest ways of increasing transmission line capacity and system stability, lowering losses, and improving voltage regulation. I have here a list of useful site and free pdf file for you to know more about this particular topics.


Power Factor Correction


How Does Your Capacitor Work?
We call this difference in potential as voltage of one point with respect to earth or just a voltage between to points. Electric current flows in three difference ways.


Transmission Line Capacitance Measurement
The capacitance of coplanar lines is measured with two new techniques, one utilizing the resistance.


Calculating the capacitance and Inductance
Multiconductor transmission lines in multilayered circuit are used to reduce dimensions and minimize pulse.


Articles of a Capacitors
Capacitors in generals the test and methology.

The Basics of Capacitance
The source of capacitance is a two conductors separated by an insulating materials, or dielectric, form.

Capacitive Loading and Ramp Input
Transmission line effects become increasingly significant
for on-chip high-speed interconnects.

Power Systems With Series-Compensated Transmission Lines
Abstract—A capacitor in series with a transmission line is protected
from overvoltage due to a large fault current by a nonlinear
metal–oxide varistor (MOV) connected in parallel.

SHUNT CAPACITOR BANK SWITCHING TRANSIENTS
A tutorial and case study.

Installation of MVAR Line Capacitors
Reactive power compensation is defined as the management of reactive power to
improve the performance of alternating-current (ac) power systems.

Capacitor Bank Switching Recovery Voltages
This paper is devoted to the evaluation of the transient
recovery voltages in a test power network.

Capacitor - Definition
Its Definition, Overview, it common types of fixed, properties and its application.