I found something, but additional informations are welcome...
The bushing is mounted on a turret which is in the power transformer. The turret is contained in the transformer tank and it, as well as the bottom part of the bushing, is immersed in oil. The bottom part of the turret contains a current transformer which measures the amount of current flowing in or out of the power transformer. The current transformer is directly connected to protection relays in the substation.
A turret is a raised structure on the top or flank of the transformer, usually round in section, to which the bushing flange is mounted. Turrets are usually used to mount large bushings where the bushing would otherwise intrude excessively into the tank, requiring the tank to be increased in size. Your quote is correct, the turret is often a location for mounting current transformers on the oil side of the bushing, although this is not its only purpose.
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Your body may be a temple. Mine is an amusement park...
