Voltage Transformer A voltage transformer (abbreviated as PT), similar to a transformer, is an instrument used to transform voltage. The primary purpose of a voltage transformer's voltage transformation is to supply power to measuring instruments and relay protection devices. It is used to measure line voltage, power, and energy, or to protect personnel safety and valuable equipment, motors, and transformers on the line in the event of a fault.

Voltage Transformers Voltage transformers (abbreviated as PT) are similar to transformers and are instruments used to transform voltage. Classification of Voltage Transformers 
1. By purpose: measuring voltage transformers, protective voltage transformers. 
2. By installation type: indoor voltage transformers, outdoor voltage transformers. 
3. By insulation medium: dry-type voltage transformers, oil-immersed voltage transformers, cast resin voltage transformers, gas-insulated voltage transformers. 
4. By structural type: Single-stage voltage transformers, where primary and secondary windings are on the same core column with non-graded insulation. Cascade-type voltage transformers: Primary windings with equal turns and identical geometric dimensions are connected in series. Ground insulation for each winding decreases progressively from the line end to the grounding end. 
5. By transformation principle: Electromagnetic voltage transformers, capacitive voltage transformers. Electromagnetic voltage transformers: Based on their application in the system, they can be classified as ungrounded or grounded voltage transformers. In ungrounded voltage transformers, all parts of the primary winding, including the lead terminals, are insulated to ground according to their rated insulation level. When in use, the two lead terminals of the primary winding are connected to different phases in the system. In a grounded voltage transformer, one terminal of the primary winding is insulated from ground, while the other terminal is directly grounded. Capacitive voltage transformer: This type of voltage transformer consists of a capacitive divider and an electromagnetic unit. Its design and interconnection ensure that the secondary voltage of the electromagnetic unit is essentially proportional to the primary voltage applied to the capacitive divider, with a phase angle difference approaching zero.