Short description of when to use Normal or Heavy Duty KNK3053 capacitors

 

When to use Normal duty and when Heavy Duty type of capacitor?

In fact, there is no one general rule to define this strictly. Normal Duty capacitors can be used in major cases where are presented low levels of high harmonics.

Where high harmonics are in the network and power factor equipment is without detuning filter reactors it is better to use heavy-duty capacitors due to possible overloads.

For PFC equipment with detuning reactors use Heavy Duty capacitors.

 

Here is one recommendation which is not a strict rule but only as orientation:

-       If the power of loads generating harmonics is less than 15% of total power, standard capacitors and automatic banks can be used

-       If the power of loads generating harmonics is more than 15% and less than 25% of total power, reinforced capacitors (Heavy Duty) should be used. Even in this case sometimes detuning filter reactors should be used in case there exists a possibility of resonance after assembling a standard capacitor bank.

-       If the power of loads generating harmonics is more than 25% of total power, filter capacitor banks should be used. Capacitors should be heavy-duty.

 

Some specialists recommend different solutions based on different voltage total harmonics distortions:

-       If THDU ≤ 2%, standard capacitors and the automatic banks can be used

-       If THDU ≤ 3%, reinforced capacitors (Heavy Duty) should be used. Even in this case, sometimes detuning filter reactors should be used.

-       If THDU > 3%, filter capacitor banks should be used. Capacitors should be heavy-duty.

 

In the previous definition, current harmonics are not defined, but they have to be considered because of possible current overloads.


 Capacitor Brand : ISKRA , Slovenia