Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
K-factor is a weighting of the harmonic load currents according to their effects on transformer heating,
as derived from ANSI/IEEE C57.110.
A K-factor of 1.0 indicates a linear load (no harmonics).
The higher the K-factor, the greater the harmonic heating effects.
When a non-linear load is supplied from a transformer, it is sometimes necessary to derate the transformer
capacity to avoid overheating and subsequent insulation failure.
The reason for this is that the increased eddy currents caused by the harmonics increase transformer losses
and thus generate additional heat. Also, the RMS load current could be much higher than the kVA rating of
the load would indicate. Hence, a transformer rated for the expected load will have insufficient capacity.
The K-Factor is used by transformer manufacturers and their customers to adjust the load rating as a function
of the harmonic currents caused by the load(s).
Generally, only substation transformer manufacturers specify K-factor load de-rating for their products. So,
for K-factors higher than 1, the maximum transformer load is de-rated.
K-Factor Calculation
The K-factor is a number derived from a numerical calculation based on the summation of harmonic
currents generated by the non-linear load. The higher the K-factor, the more significant the harmonic
current content.
The K-factor is not corrected with capacitor banks.
Power Factor in Sinusoidal Situations (displacement power factor pf disp)
The concept of power factor originated from the need to quantify how efficiently a load utilizes
the current that it draws from an AC power system.
Power Factor is commonly known as the displacement power factor, and where (Phi) is
known as the power factor angle. Therefore, in sinusoidal situations, there is only one power
factor because true power factor and displacement power factor are equal.
For sinusoidal situations, unity power factor corresponds to zero reactive power Q, and low
power factors correspond to high Q. ( Q = reactive power )
Power Factor in Nonsinusoidal Situations ( pf dist )
Now, consider nonsinusoidal situations, where network voltages and currents contain harmonics.
While some harmonics are caused by system nonlinearities such as transformer saturation, most
harmonics are produced by power electronic loads such as adjustable-speed drives and diodebridge
rectifiers. The significant harmonics (above the fundamental, i.e., the first harmonic) are
usually the 3rd, 5th, and 7th multiples of 50/60 Hz, so that the frequencies of interest in
harmonics studies are in the low-audible range.
When steady-state harmonics are present, voltages and currents may be represented by Fourier
series
The K-factor is a number derived from a numerical calculation based on the summation of harmonic
currents generated by the non-linear load.
When you say 900kW , that means real power and tells nothing about power factor or reactive power.
For power factor with linear loads (displacement power factor) we must know value of reactive power too.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
