The transformers can be buried underground in pits, and can meet the needs of single ring high-voltage power supply, applies to long distances but small loading system, such as roads，bridges, airports, tunnels, etc.

●Product standards
GB16927-1997 High-voltage test techniques
GB1094.1-1996 Power transformers
GB7328-1987 Determination of sound levels of transformers acrd reactors
GB/T6451-2008 Three-phase oil-immersed power transformer specifications and requirements
GB4208-2008 Casing protection levels
JB/T501-2006 Test of power transformer measurement
JB/T10544-2006 Buried distribution transformers

Main functions and characters

●Regular service conditions
·In outdoor pits,in the wall hole of tunnels.
·Altitude not exceed 1000m.
·Maximum ambient temperature +40℃
·Minimum ambient temperature -25℃
·Operating conditions in pit:The transformer can run up to 120 days while top covers are immersed under more than 1 meter by flood.
Note:If it' s necessary, for the ring-geographical-type transformer,four positions load switch could be provided, meanwhile two positions load switch could be also provided for the terminal-buried transformers comply with the user's requirement.

●Product Properties
A. The HV inlet wires adapt two (in/out) sets of three-phase integration plug-in HV cable connector.
B. The LV outlet wires adopt three-phase four-wire integration plug-in LV cable connector.
C. HV side is equipped with current-limiting fuse for protection.
D. The tank is made of A3 steel and processed by special protection treatment.
E. The protection class is IP68. It can operate up to 120 days under the water.
F. The temperature rise limit meets the GB1094.4-1996 requirements.

S11-M.D SERIES BURIED DISTRIBUTION TRANSFORMERS