2013年7月31日星期三

Voltage transformer works


It works the same transformer, the basic structure is the core and the primary and secondary windings. Characterized by a constant and relatively small capacity, when normal operation is close to empty state.
Impedance voltage transformer itself is small, once the secondary side short circuit, the current will increase dramatically and burned coils. To this end, the voltage transformer primary side is connected with fuses, the secondary grounded, so the primary and secondary side insulation is damaged, the secondary appeared on the ground caused by the high potential

Personal and equipment accidents.
Measuring voltage electric transformer are generally made of a single-phase double-coil structure, and its primary side voltage is measured voltage (such as the power system line voltage), you can use single-phase can also be used as a two-phase connected into VV-shaped be used. Laboratory voltage transformer primary side is often more pumping

Head to suit the needs of different voltages measured. For protective grounding voltage transformer also comes with a third coil, said three coil voltage transformers. The third phase coils connected in open delta, the opening of the triangle two terminals and the ground voltage protection relay

Coil connection.
Normal operation, the symmetrical three-phase voltage power system, the third coil of the three-phase induced electromotive force is zero. In the event of single-phase, the neutral point displacement occurs, open triangle will appear between the terminals so that the zero-sequence voltage relay to the power system

Statistics play a protective role.
The zero-sequence voltage coil corresponding iron hearts will be zero-sequence flux. To this end, this three-phase voltage transformer yoke iron core using the next (10KV and below) or using three single-phase voltage transformer. For this transformer, the accuracy requirements of the third coil is not

High, but requires a certain degree of over-excitation characteristics (ie, when the primary voltage is increased, the iron core is also a corresponding increase in the magnetic flux density in multiples without damage).
Voltage power transformers are power plants, substations and other transmission and distribution system is indispensable to a electrical appliances.
Precision voltage transformer is used to electrically test laboratories to expand the range, the measured voltage, power and energy of an instrument.
Voltage transformer and the transformer is very similar, are used to transform the voltage on the line.
Why do we need convert line voltage it? This is because under the generation, transmission and consumption of different circumstances, the voltage on the line sizes, and disparities, some low-voltage 220V and 380V, some tens of thousands of volts or even hundreds of thousands of high-voltage volts . To directly measure this

These low and high voltages, it is necessary according to the size of the line voltage, low-voltage and high-voltage production of the corresponding voltage tables and other instruments.

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