difference between droop and isochronous

Mr. esmaiel elnour,

Isochonous = constant frequency by automatically adjusting output power.

Droop = frequency is automatically adjusted, but when power increases, frequency decreases a bit. ( if 5% droop, power increases 0 to 100%, frequency drops 5%).

The difference between the two is that the genset keep the frequency or not.

Paralelling gensets, you can have only one Isochonous and all others must be in droop. If your genset will run with utility, your genset must be in droop.

If the load increases, isochronous genset will increase its power to maintain the freqeuncy. While droop gensets maintian their power.

If two gensets are in Isochronous, they must have load sharing function, otherwise two isochronous gensets will be unstabled.

All generator can be in droop, but load change will result frequency change.

Regards

Dear esmail elnour, I want to supplement to the reply by Mr. Akihito Shigeno who has nicely explained. You should carefully examine the Droop Character of the gen set while putting in to parallel operation. The higher the droop, lower will be the load shared and vise-versa and there is a possibility of one or two set will get over loaded. This droop character applies to the prime mover also, be it steam turbine or gas turbine or diesel engine. Dhayanandhan.S