1. What is KVA?
KVA is called kilovolt-amperes is the unit of measurement of power, generally to describe the apparent power of the equipment only in the efficiency of 100% when the kVA is equal to the power, including the power and reactive power, the kVA is calculated as follows
KVA = 1000 × U (V) × I (A)
Although the calculation of kVA is basically the same as the power, but in practice they are not exactly the same!
2. What is the power factor?
The difference between kVA and power is the most important power factor represents the ratio of effective power and apparent power in the electrical system, is a measure of the efficiency of the electrical system in the most direct description of the power factor: PF, is the efficiency of the electrical system itself, if the equipment is not damaged in the case of no change of course, in the use of the will be lowered, the power factor is 0 ~ 1, the most desirable electrical systems in the power factor of 1, but most of the Power factor is 0 to 1, the ideal electrical system power factor of 1, but most of the power factor in 0.9 or so, the specific power factor needs to be in the professional test to get the power factor of different circuit systems.
The principle of finding the power factor is to calculate the current and voltage (VA) respectively for a period of time and then take the average when the current size and voltage size is the same compared with the calculated power, the current and voltage will not be the same all the time so the power factor is between 0 and 1 for heavy loads in high power motors the power factor is below 0.35, and some people propose to plan for the power to be 0.6 which is a conservative power factor.
3. What is a watt?
Watt is the unit of power to describe the current in a specified period of time in the current to release the size of the energy, that is, the current in the circuit to do work at the rate of use W said watt is the longest used in electrical equipment is the simplest unit to assess the size of the power consumption of each piece of electrical equipment, usually watt is used to describe the consumption of electricity on the smaller equipment, for large power station consumption is generally used in the kilowatts, 1,000w = 1kw
4. Conversion between watts and kilovolt-amperes
The conversion between kilovolt-amperes (KVA) and watts is often used on electrical systems, if the calculation of kilovolt-amperes (KVA) and watts (W) first you need to convert kilovolt-amperes (KVA) to volt-amperes (VA)
1KVA = 1000VA
For volt-amperes (VA)
VA = I (A) x U (V)
Power is calculated as
P(w) = I(A) x U(V) x PF
So we can simply get the relationship between volt-amperes and watts
P (W) = VA x PF, since 1kw = 1000w so
kw=KVA×PF
To summarize the calculation of kilovolt-amperes and watts as follows
P (W) = KVA x 1000 x PF
For example, 6KVA, power factor of 0.8 electrical equipment converted to watts as
P (W) = 6KVA x 0.8 x 1000 = 4800W
5. Why do kVA and power factor exist?
In AC circuits the size and direction of the current and voltage are constantly changing so the direction of the current and voltage are not always the same, they change independently of each other when the voltage is at its highest peak when the current is at its lowest, the current can not catch up with the voltage Calculation of the power of AC circuits you need to calculate the power of each moment separately: P (W) = U (V) × I (A)
Then take the average of the time, for the power calculation of periodic circuits in the effective voltage and current (VA) and the ratio of watts for the power factor (PF)
Conclusion
In the AC circuit due to the existence of varying current volt-amperes (VA) and watts (w) is not the same, there is a power factor (PF) for the relationship between the three can be expressed as P (w) = VA × PF, understanding the relationship between kilovolts per ampere and watts of the alternating current solar system is a good help.
