Capacitive voltage transformer
Capacitive voltage transformers can be used for voltage and power measurement, relay protection, automatic control, and other aspects in high-voltage and ultra-high voltage power systems, and can also serve as coupling capacitors for power line carrier communication systems. If required, internal accessories and external wiring terminals for harmonic voltage measurement can be provided.
Environmental requirements for use
Installation and operation site: outdoor type
Altitude: Generally not exceeding 2000 meters, plateau products up to 4000 meters can also be provided according to order requirements.
Environmental temperature: divided into -25~+45 ℃ and -40~+40 ℃, selected by the user when ordering.
Wind speed: not exceeding 42m/s.
Pollution level:
Level III pollution (external insulation creepage distance ≥ 25mm/kV);
Level IV pollution (external insulation creepage distance ≥ 31mm/kV). The pollution level is chosen by the customer at the time of ordering.
Re icing thickness: not exceeding 10mm.
Earthquake intensity: not exceeding 8 degrees. According to user requirements, products with higher seismic resistance can also be provided.
System rated frequency: 50Hz or 60Hz. To be determined by the user at the time of ordering.
System grounding conditions: The neutral point is effectively grounded or the neutral point is not effectively grounded, which is determined by the user at the time of ordering.
Main technical performance
★ Allow long-term operation at any voltage below 1.2 times the rated voltage. The CVT for the neutral point effective earthing system can operate for 30s at 1.5 times the rated voltage, and the CVT for the neutral point ineffective earthing system (with tail note F in the model) can operate for 8h at 1.9 times the rated voltage.
The allowable deviation of the capacitance of the capacitive voltage divider is+10%~-5% of the rated value.
★ The dielectric loss angle tangent value (20 ℃) of the capacitive voltage divider shall not be greater than 0.001, and the partial discharge amount shall not be greater than 10pc.
★ Creepage distance: The minimum creepage distance is 25mm/kV~31mm/kV, which is selected by the user when ordering.
The phase relationship between the primary and secondary voltages of CVT is polarity reduction, and the connection method of each winding of the medium voltage transformer is as follows:
Secondary two winding 1/1/1-12-12
Secondary three winding 1/1/1/1-12-12-12
Secondary four winding 1/1/1/1/1-12-12-12
Radio interference level (RIV) of 330~500kVCVT ≤ 500 υ V。 The RIV of products below 200kV is less than 350 υ V。