2　Terms

2.0.1　Power transformer

A static piece of apparatus with two or more windings which，by electromagnetic induction，transforms a system of alternating voltage and current into another system of voltage and current usually of different values and at the same frequency for the purpose of transmitting electric power.

2.0.2　Oil-immersed type transformer

A transformer of which the magnetic circuit and windings are immerged in oil.

2.0.3　Dry-type transformer

A transformer of which the magnetic circuit and windings are not immerged in an insulating liquid.

2.0.4　Winding

The assembly of turns forming an electrical circuit associated with one of the voltage assigned to the transformer.

2.0.5　Sealing

Isolating coil and iron core inside a transformer from atmospheric air.

2.0.6　Vacuumize

Extracting the air inside the transformer with a vacuum pump to make the transformer at vacuum state.

2.0.7　Hot oil circulation

A transformer filled with insulating oil，heating and circulating the insulating oil by the lower-inlet and upper-outlet method.

2.0.8　Resting

Without any works involved in oil duct of a transformer filled with insulating oil，making the air rising to the top of the oil naturally.

2.0.9　Sealing test

After the transformer installed completely，inspecting（testing）the leakage of the transformer by the method of boosting the pressure inside the transformer.

2.0.10　Reactor

Electric appliance used in a circuit or electrical power system making use of its inductance.

2.0.11　Shunt reactor

Reactors connected phase-to-earth，phase-to neutral or between phases in a power system to compensate for capacitance current.

2.0.12　Instrument transformer

A transformer intended to transmit an information signal to measuring instruments，meters and protective or control devices.

2.0.13　Current transformer

An instrument transformer in which the secondary current，in normal condition of use，is substantially proportional to the primary current and differs in phase from it by an angle which is approximately zero for an appropriate direction of the connection.

2.0.14　Capacitor voltage transformer

A voltage transformer comprising a capacitor divider and an electromagnetic unit so designed and interconnected that the secondary voltage of the electromagnetic unit is substantially proportional to the primary voltage and differs in phase from it by an angle which is approximately zero for an appropriate direction of the connection.