what is the solution Line Voltage drops

[mannumss]

i am working in middle east one of the steel company, we have Electric Arc furnace of danieli,we are supplying the 33 KV Line voltage to Furnace side,we have all compensation equipments SVC everything is running smoothly, only the problem is when the Furnace arcing time ( power ON )the Line voltage Drops and becomes 30~31 KV, while furnace stop time its OK, Furnace area side they have Furnace transformer from 33kv/400V ETC. WE Have another Furnace same type but there is no any problem like this.
i appreciate evrything response from Forum guys

 

[PHovnanian]

What are the differences between the installation experiencing the problems and the one that is not. Differences in equipment , regulator settings, furnace operation, etc.

 

[Marmite]

Please post a single line diagram.
Regards
Marmite

 

[mannumss]

actually i am not from the Furnace side that is another section, i am from Main S/S and we are supplying the Voltage to furnace side, phovnanian sir actually same type means just We have Electric furnace but it is different that one from siemens and this is by Danieli, i will post the single line diagram within soon as much possible. i just want to know that what can be the possible reason of this?

 

[jghrist]

1. High source impedance causing voltage drop. What is the available fault at the new furnace compared to other locations where there is no problem? A lower available fault would indicate higher source impedance.
2. High distortion in the arc furnace current, causing high distortion in the voltage. Maybe made worse by resonant conditions at some harmonic frequencies.

 

[PHovnanian]

OK, so there are two possible sources of differences between the behavior of the systems. The furnace design differences (between Siemens and Danieli) could easily change their interaction with the supply. And then there's the supply systems themselves (which appear to be your area of responsibility).

First, rule out differences in the supply systems, like impedances (fault current available at the point of delivery) or regulator settings.

If that doesn't explain it, you'll have to look at the characteristics of each load (each furnace system). There could be differences in the current/voltage waveform distortion caused by the loads. Its possible that two identical supply and regulation systems will behave differently serving loads with seemingly the same MW and MVA but different THD.