Worth it to Install Harmonics?

If i am not wrong, you install harmonics filters in order to complyto regulatory requirement. The harms caused by harmonics is to the system cables and transformers (heating) , which mean more cost for the power supply company. The harmonics are generated by your equipment, these harmonics will not cause problem to IT equipment, but mostly to machines or motors that has magnetic cores.

so you're saying it should be "you have to" (regulatory requirement like IEEE 519?) and shouldn't be an cost-saving option in the first place?

I do not know how it will save cost for IT equipment, unless someone prove otherwise

When providing a power connection the UTILITY should sign an agreement with consumer that power will be disconnected if they find harmonics generated in equipments used in that premise is injected into the distribution network which can affect other consumers as well as the utility's equipment.

Whether or not its a rquirement or cost effective, can only be decided by yourself or somebody with knowledge of your installation.

There are a number of sites you can look at for some assistance example:

http://www.mtecorp.com/Cost_of_Harmonics.pdf

belongs which harmonics you have to decrease. 5th, 7th, 11, 13......

as much you have to more expensive it will be. the best is to measure when your datacenter is working.

This is a double-folded question.

Harmonics coming from the grid might disturb your equipments. On the other hand harmonics generated by you devices can result additional loss on the power line and sometimes can trip the protection system. Depending on the size (power consumption) of your system it can be a significant effect. Electricity suppliers often specify the acceptable level of generated harmonics. If your system is above the limit you have to pay a sort of fine. In this case you really can save money with a harmonic filter.

My opinion is that first you should check the present harmonic level, the supplier's contract and the influence of the present level on your system, then you can make the right decision.

If the secondary of the transformer in your premises has closed delta or zig-zag winding will the harmonics have any adverse effect by inducing from primary to secondary or vice versa?.

The harmonic filters are required in many places, so the cost ssavings is zero since it is mandatory.

But as indicated before the overheating caused and extra energy consumed for powering the systems and coolers do have cost saving associated, but it will depend on the size of the data center and the volumes of information being handled. And that only you will be able to analyze and define.

For single phase loads like you probably have, the third harmonic group is the main problem. It adds up onto the neutral wire and can overload it. You should have an electrician measure the current in the neutral wires coming back to the electrical box to see if it exceed the wires capacity. Leave some margin as the higher frequency can produce up to 25% more heating.

If your neutrals are overloaded, you could end-up producing a fire / failures at worst or simply have voltage regulation and EMI problems. CTR screens are particularly sensitive to these magnetic fields that cause various distortions.

Large amount of harmonics in a building can also cause problems with light fixtures.

Can you elaborate on problems caused to light fittings by harmonics?. What damages will occur in each of the following fittings:incandescent,fluorescent with electromagnetic/ electronic ballast,LED,CFL with integral/external ballast,MH,SON,HPSV,Induction etc

You can do a search for harmonics on single phase distribution to get more details.

In general, the potential failures depend on the specifics of the design.

Typical weak points are the protections (RC networks, varistors, fuses) that may be overloaded when a large amount of harmonics are present.

Other affected devices are the diodes and capacitors in a AC/DC supply that may see a higher peak current than with a nice sinusoidal voltage (it depends on the harmonics present and their phase). Some magnetic ballasts don't start/resonate properly with large voltage distortion and some overheat.

The effect on the above depends on how much voltage distortion is present on the line and the specifics of the light fixture technology.

In the data center, by choosing UPS to control Harmonics

for example,in UPS, rectifier circuit is composed of 2 groups of 6 pulses rectifier composition, one being a group 6 pulse, another group of 6 pulse with 30 degrees offset, which filters 5 and 7 harmonics, then add the 11 harmonic powerless filter for filtering the 11 and the 13 harmonic component

You may also consider replacing the the NON PFC rack mount power supplies with PFC supplies. This is a distributed solution and can be performed one rack at a time.