DDLO (Drop Down Lift On)

DDLO (drop down lift on )

DDLO is a devise that uses to protect Transformers , capacitor banmks or electrical devises from high curent surges and can consider it as a combination of fuse and a switch .
This can provide a wide range of protection for over head distribiution system rated from 10kV to 36kV .
Always DDLO conects in series with the transmition line.
For DDLO , standered voltage ratings are  maintained between
11/12 kV ,22/24 kV ,33/36 kV
Fuse cutouts are capable of carries a maximum curent of 100 A to 200 A.

Parts of the DDLO

Positioning Of The DDLO

In Sri Lnka CEB practice is to position the DDLO before the Arresrers along the high voltage circuit.(As shoen in figure A )
This concept ensure the safety of the workers who work on the
transformer during the maintainace .(As the arrester is isolated when DDLO switch is opened ) 



If the arrester can be  fixed and then the DDLO ,then there can be less DDLO failiers. (As shown in figure B )
Hence the relaibility is increased.
But this canot assure a good safety for the
workers as mentioned in above.









Technical Details