Product Principle




We know that when the loop frequency f=1/2π√LC, the loop resonates, and at this time the voltage on the test object is Q times the output voltage at the high-voltage end of the excitation transformer. Q is the quality factor of the system, i.e., the voltage resonance multiple, generally ranging from tens to over a hundred. First, adjust the output frequency of the variable frequency power supply to make the loop resonate in series, then under the condition of loop resonance, adjust the output voltage of the variable frequency power supply to make the test voltage reach the test value. Due to the resonance of the loop, a relatively small output voltage of the variable frequency power supply can generate a high test voltage on the test object CX.

Shanghai Dafan Schematic Diagram

Main Technical Parameters of the Equipment

*Working Power Supply: 220V/380V, 50HZ *Test Capacity: 30-30000KVA

*(Test Voltage: 1000KV and below *Resonant Frequency Range: 20-300Hz

*Test Voltage Waveform: Sine wave, waveform distortion rate less than or equal to 0.3%

*Test Voltage Accuracy: Class 1

*Frequency Adjustment: 0.01Hz *Protection Response Time: less than 1 microsecond

*The system has overvoltage protection, overcurrent protection, discharge protection, breakdown trip protection, and overheat protection.

Common Models




Model Interpretation: 44/22, capacity is 44KVA, voltage is 22KV

I. Cable AC Withstand Voltage Test Series

































Model Satisfiable Test Items Equipment Reactor Configuration Remarks
DFVF3000-44/22 10kV (300mm) cable 1KM 22kV Ⅹ 1 unit Portable
DFVF3000-132/66 1. 10kV (300mm) cable 3KM

2. 35kV (300mm) cable 1KM		 22kV Ⅹ 3 units Portable
DFVF3000-264/52 1. 10kV (300mm) cable 5KM

2. 35kV (300mm) cable 2KM

3. 35kV transformers, switches,

4. 10kV motors, transformers

5. Generators of 600MW and below, etc.		 22kV Ⅹ 6 units Portable
DFVF3000-1560/66 110kV (300mm) cable 3KM 130kV Ⅹ 2 units Non-portable

II. Generator Power Frequency Withstand Voltage Test Series




























Model Satisfiable Test Items Equipment Reactor Configuration Remarks
DFVF3000-44/22 1. Generators of 100MW and below, phase capacitance 0.1-0.3uF

2. 10kV (300mm) cable 1KM		 22kV Ⅹ 1 unit Portable
DFVF3000-100/36 1. Generators of 600MW and below, phase capacitance 0.1-0.25uF

2. 10kV (300mm) cable 1.5KM		 18kV Ⅹ 2 units Portable
DFVF3000-176/44 1. Generators of 600MW and below, phase capacitance 0.1-0.3uF

2. 10kV (300mm) cable 3KM 3. Can also cover generator busbars, main transformers, etc.		 22kV Ⅹ 4 units Portable

III. GIS and SF6 Switch AC Withstand Voltage Test Series






















Model Satisfiable Test Items Reactor Configuration Remarks
DFVF3000-250/200 1. AC withstand voltage test for 110kV GIS

2. 35kV (300mm) cable 1KM

3. 10kV (300mm) cable 3KM

4. Power frequency withstand voltage for transformers below 220kV 5. AC withstand voltage for 110kV instrument transformers		 40kV Ⅹ 5 units Portable
DFVF3000-100/200 1. AC withstand voltage test for 110kV GIS 2. AC withstand voltage for 110kV instrument transformers 50kV Ⅹ 4 units Portable

IV. Power Frequency AC Withstand Voltage Test Series for Transformers, Motors, and Other Equipment






















Model Satisfiable Test Items Reactor Configuration Remarks
DFVF3000-105/84 1. Power frequency withstand voltage test for 110kV transformers

2. Power frequency withstand voltage test for 10kV motors 3. AC withstand voltage test for 35kV switches

4. 10kV (300mm) cable 1KM		 28kV Ⅹ 3 units Portable
DFVF3000-100/80 1. Power frequency withstand voltage test for 110kV transformers

2. Power frequency withstand voltage test for 10kV motors 3. AC withstand voltage test for 35kV switches

4. 10kV (300mm) cable 1KM		 40kV Ⅹ 2 units Portable