Oil type transformer: internally filled with insulating oil
Dry type transformer: filled with epoxy resin internally
Voltage transformer can be divided into electromagnetic induction type and capacitive voltage divider type according to the principle.
According to the purpose, Voltage transformer can be divided into two categories: measurement and protection.
Electromagnetic induction Voltage transformer. The working principle is the same as that of a transformer. The basic structure is also an iron core and primary and secondary windings. The characteristic is that the capacity is very small and relatively constant, and it is close to the no-load state during normal operation. The impedance of Voltage transformer is very small. Once the secondary side is short circuited, the current will increase sharply and the coil will be burned. For this reason, the primary side of the Voltage transformer is connected with a fuse, and the secondary side is grounded to avoid accidents caused by high potential to the ground at the secondary side when the insulation of the primary and secondary sides is damaged. The equivalent circuit of electromagnetic induction Voltage transformer is the same as that of transformer.
Capacitive voltage divider Voltage transformer. Made on the basis of capacitive voltage divider. The capacitive Voltage transformer is mostly used with the coupling capacitor of power system carrier communication to simplify the system and reduce the cost. At this point, it also needs to meet the requirements for communication operation. According to the structure, Voltage transformer can be classified into oil filled, dry, three core five column and single phase, as well as fully insulated and semi insulated.
Current transformers, oil type current transformers, dry type current transformers, specialized transformers, High voltage transformer
