Main Types Of Voltage Transformers
1. According to the installation location, it can be divided into indoor type and outdoor type
35kV and below are mostly made into indoor type; 35kV and above are made into outdoor type.
2. According to the number of phases
Can be divided into single-phase and three-phase type 35kV and above can not be made into three-phase type.
3. According to the number of windings
It can be divided into two-winding and three-winding voltage transformers. In addition to the primary side and the basic secondary side, the three-winding voltage transformer also has a set of auxiliary secondary sides for grounding protection.
4. According to the insulation method
It can be divided into dry type, pouring type, oil immersion type and inflatable type.
Dry-type voltage transformers have simple structure, no fire and explosion hazards, but low dielectric strength, and are only suitable for indoor installations below 6kV; cast-type voltage transformers are compact in structure and easy to maintain, suitable for 3kV ~ 35kV indoor installations Power distribution devices; oil-immersed voltage transformers have good insulation performance and can be used in outdoor power distribution devices above 10kV; gas-filled voltage transformers are used in SF6 fully enclosed electrical appliances.
5. According to the working principle
Electromagnetic voltage transformer: It is a device that uses the principle of electromagnetic induction to convert voltage or current proportionally.
Capacitive voltage transformer: Capacitive voltage transformer (CVT) is divided by series capacitor, and then step-down and isolated by electromagnetic transformer, as a voltage transformer for meter, relay protection, etc., capacitive voltage Transformers can also couple carrier frequencies to power lines for long-distance communications, remote measurements, selective line high-frequency protection, remote control, teletyping, and more.
Electronic voltage transformer: A device consisting of one or more voltage or current sensors connected to a transmission system and a secondary converter to transmit a quantity proportional to the measured quantity for measuring instruments, meters and relay protection or control device.
