Our head end server received data from meters and data is shared with other team using oracle views.
How I can connect to geo event server and start displaying the real changes on the maps
my favorite option would be to develop a custom transporter to create your own input connector that is able to connect to an oracle database. In this case you will receive the data very performant.
For none developer I would try to use a query layer (pointing to the oracle view) and publish it as map service. GeoEvent is able to send a query to this map service containing the query layer. I am not sure how performant this solution is, but it should work.