The main functions of instrument voltage transformers include the following aspects:
Voltage conversion: Instrument voltage transformers can convert high voltage of the system to low voltage, which is convenient for connecting measuring instruments and relays. This conversion function enables measuring instruments and relays to work safely, avoiding the risks of directly measuring high voltage.
Electrical isolation: Instrument voltage transformers insulate secondary devices such as measuring instruments and relays from the main circuit, thereby preventing high voltage from main circuit going directly into these devices, and also preventing the failure of secondary devices from affecting the main circuit, thereby improving the safety of equipment and operators.
Expanding the scope of application: By using voltage transformers with different ratios, any high voltage can be measured, so that a single measuring instrument and relay can be applied to multiple voltage levels, simplifying the specifications of the equipment, and facilitating standardization and mass production.
Protection function: In conjunction with relay devices, the power system and equipment are protected with overvoltage-protecting, single-phase grounding, etc., to ensure the safe operation of the power system.
Wiring method
The wiring of the instrument voltage transformer must be correct. The primary winding should be connected in parallel with the circuit to be measured, and the secondary winding should be connected in parallel with the voltage coil of the connected measuring instrument, relay protection device or automatic device. At the same time, attention should be paid to the correctness of the polarity.
Voltage transformers play an important role in power transmission and power supply systems such as power plants and substations, and are an indispensable electrical appliance in power systems. With the development of technology, precision voltage transformers are also widely used in electrical test laboratories to expand the measurement limit, measure voltage, power and electric energy, etc.