Dear sir,
sorry now i attached our distribution single line diagram. its useful for you.
i got you all informetion now im following that. sorry to mention before. in the distribution board we are using RCCBO (residual current circuit breaker with overload) all burned its around 500 Nos and its happened three times.

We are using 11Kv/440 v distribution system.
We are mostly using our loads all Electronics system for example (AC Digital controllers, Plasma TV, Digital Light Dimming system and exact……). So due to this our Loads getting burn..
We have problem Y phase and B phase only..
Our Voltage analyzer meter showing Neutral to Earth has 220Volt. This voltage Only getting few second not always example some time taking two or three days.
We don't have any problem in R phase lodes.
Now we are checking the cablings and panels. We can't found any things still now? For time being we can not shutdown the transformer.
Do you have any information about problem?