Power High-Voltage Test Transformer
Darui Electric recommends:
Power high-voltage test transformer has the characteristics of small size, light weight, compact structure, complete functions, strong universality, and convenient use. It is an indispensable important equipment in high-voltage testing.
Overview
Power high-voltage test transformer is particularly suitable for insulation strength testing under power frequency or DC high voltage for various high-voltage electrical equipment, electrical components, and insulating materials in power systems, industrial and mining enterprises, and scientific research departments.
Features
Adopts a unique structure of axisymmetric unequal-side octagonal shell; can output dual high voltage. The oil level in the oil tank is lower than the tank edge, avoiding oil leakage.
The wiring terminals are on the tank cover, avoiding collision and improving mechanical and electrical performance.
Selected materials are excellent, reliable quality, and good annual stability;
Large voltage margin, low noise, and low partial discharge;
Uses new insulating materials, small size, and light weight.
Parameters
◆ Input voltage: AC (0～200) V or (0～400) V.
◆ Output voltage: AC (0～200) kV or DC (0～280) kV.
◆ Rated capacitance: 1~400kVA;
Capacity Selection
The formula for determining the nominal test transformer capacity Pn: Pn=KVn2ωCt×10-9
Where: Pn----nominal test transformer capacity (kVA)
Vn-----effective value of the rated output high voltage of the test transformer (kV)
K------safety factor. K≥1, when the nominal voltage Vn≥1MV, K=2, when the nominal voltage is lower, the K value can be taken higher.
Ct-----capacitance of the test object (PF)
ω----angular frequency, ω=2πf, f----frequency of the test power supply
The capacitance Ct of the equipment under test can be measured by an AC bridge. Ct varies greatly and can be determined by the type of equipment. Typical data are as follows:
Simple bridge or suspension insulators: tens of microfarads
Simple graded bushings: 100 – 1000PF
Voltage transformers: 200 – 500PF
Power transformers: < 1000kVA - 1000PF
> 1000kVA 1000 – 10000PF
High-voltage power cables and oil-impregnated paper insulation: 250 – 300PF/m
Gas insulation: - 60PF/m
Enclosed substations, SF6 gas insulation: 100 – 10000PF
For different test voltages Vn, select different (appropriate) safety factors K. The K values selected for different Vn are listed above for reference
Vn = 50–100kV K=4
Vn = 150–300kV K=3
Vn > 300kV K=2
Note: The above information and technical parameters are compiled and published by Yangzhou Darui Electric Co., Ltd.
