Skip to main content

POWER FACTOR


What is the use of power factor in power system?

Power Factor is defined in the fundamentals of electrical engineering as the cosine of the phase angle between the voltage and the current. An inductive circuit is said to have a lagging power factor, and a capacitive circuit is said to have a leading power factor indicate, respectively, whether the current is lagging or leading the applied voltage. (Stevenson Jr.)

Alternatively, power factor can also be determined to the ratio of power. Power factor is the ratio of useful power to the apparent power. Power factor can be likened to the efficiency formula where it is the ratio of the output over the input. The reason why the useful power is usually lesser to that of the apparent power is simply because apparent power (expressed in kVA) has the useful power (kw) and reactive power (kVAR) as its components. If kW and kVAR is sum vectorially, the result would be kVA.


POWER FACTOR = (KILOWATT) / (KILO VOLT-AMPERE)


Because the kVAR is drawn by the consumer's loads, line and transformers must carry more current than they would if only kW were required by the loads. Since losses equal (I)squared(R), the need to provide kVAR to load increases the losses on the distributor's system.(TVPPA nov.1994)

Regarding Power Factor, the common misconception is that by increasing the power factor would result to lowering the kVAR requirement of the system when it should be the other way around. Power factor is said to be dependent to the value of kW and kVAR which exist in the system.


Labels:

Comments

Post a Comment

Popular posts from this blog

PARTS OF A POWER TRANSFORMER

What are the name of the basic parts of a Power Transformer? We can not deny the fact that only a handful of electrical engineering students are presently familiar with power transformers especially on what it looks like. Unlike a transformer we found in our homes, a power transformer’s appearance and construction is somewhat more complicated. It is not just a simple winding with a primary and secondary terminal although basically any transformer has one. The function that a power transformer plays in an electrical system is very important that an electric utility can not afford to loss it during its operation. Our discussion here will focus more on the basic parts and functions of a power transformer that are usually tangible whenever you go to a substation . Although not all power transformers are identical, nonetheless they all have the following listed parts in which the way of construction may differ.
50 comments
click here to continue

ELECTRIC MOTOR FRAME SIZE STANDARD SPECIFICATIONS

ELECTRIC MOTOR FRAME SIZE STANDARD SPECIFICATIONS How is electric motor frame size being specified? Motor frame dimensions have been standardized with a uniform frame size numbering system. This system was developed by NEMA and specific frame sizes have been assigned to standard motor ratings based on enclosure, horsepower and speed. The current standardized frames for integral horsepower induction motors ranges from 143T to 445T. These standards cover most motors in the range of one through two hundred horsepower. Typical example of where you can locate the frame is shown in Fig 1.2.D – Frame No. The numbers used to designate frame sizes have specific meanings based on the physical size of the motor. Some digits are related to the motor shaft height and the remaining digit or digits relate to the length of the motor. The rerate, or frame size reduction programs were brought about by advancements in motor technology relating mainly to higher temperature ratings of insulating mate...
5 comments
click here to continue

ELECTRIC MOTOR NAMEPLATE SPECIFICATIONS

How do we interpret an electric motor nameplate? Motor standards are established on a country by country basis.Fortunately though, the standards can be grouped into two major categories: NEMA and IEC (and its derivatives). In North America, the National Electric Manufacturers Association (NEMA) sets motor standards, including what should go on the nameplate (NEMA Standard MG 1-10.40 "Nameplate Marking for Medium Single-Phase and Polyphase Induction Motors").
44 comments
click here to continue