EN
- Description
- Specifications
- Applications
- Advantages
- FAQ
- Recommended Products
Description
The GDTF-200kVA/50kV is a professional, field-optimized inductance-tuned power frequency series resonant test system exclusively designed for pure power frequency (50Hz) AC withstand voltage tests of large capacitive electrical equipment. It fully complies with DL/T 849.6-2016 and GB 50150-2016 standards, adopting the series resonance principle to generate high voltage and large current with only a small input power, while maintaining a pure 50Hz sine wave output identical to the grid frequency.
The system consists of a digital intelligent control box, an excitation transformer, a 40H-102H continuously adjustable dry-type epoxy-cast reactor, and a 0.5-grade standard capacitor voltage divider. Equipped with an electric servo tuning system and advanced automatic resonance finding algorithm, it can automatically adjust the reactor inductance to match the test sample capacitance and achieve resonance at 50Hz within 60 seconds. With comprehensive safety protection including over-voltage, over-current, flashover, zero-start, and emergency stop, it ensures safe operation in both laboratory and field environments. Ideal for commissioning and preventive maintenance tests of 35kV XLPE power cables, GIS, power transformers, generator stator windings, and capacitor voltage transformers (CVT).
Specifications
|
Parameter |
Specification |
|
Input Power |
3-phase 380V±10%, 50Hz |
|
Rated Output Capacity |
200kVA |
|
Rated Output Voltage |
0–50kV AC (RMS) |
|
Rated Output Current |
4A |
|
Output Frequency |
Fixed 50Hz±0.5Hz (pure power frequency) |
|
Reactor Type |
Dry-type epoxy-cast adjustable reactor |
|
Inductance Adjustment Range |
40H–102H (continuous stepless) |
|
Adjustment Method |
Electric servo motor drive |
|
System Quality Factor (Q) |
≥30 (typical 30–50) |
|
Output Waveform Distortion |
≤0.5% |
|
Voltage Measurement Accuracy |
≤±1.5% F.S |
|
Current Measurement Accuracy |
≤±1.5% F.S |
|
Test Modes |
Automatic test, Manual test, Timed test |
|
Timing Range |
0–9999s adjustable |
|
Display |
7-inch color touch screen |
|
Data Storage |
1000 groups (with time stamp) |
|
Data Export |
USB flash drive |
|
Protection Functions |
Zero-start, Over-voltage, Over-current, Flashover, Emergency stop, Ground detection, Over-temperature |
|
Continuous Operation Time |
5 minutes at full load |
|
Operating Temperature |
-10℃ ~ +40℃ |
|
Operating Humidity |
≤85%RH (non-condensing) |
|
Compliance |
DL/T 849.6-2016, GB 50150-2016, GB/T 16927.1-2011, IEC 60060-1, IEC 61010-1 CAT III 1000V |
Applications
Core Test Objects (35kV System)
- XLPE power cables: 35kV/300mm² cables ≤1.5km, 10kV/300mm² cables ≤4km
- GIS & gas-insulated switchgear: 35kV GIS, circuit breakers, disconnectors, busbars
- Power transformers: 35kV power transformers and distribution transformers
- Generator stator windings: medium and large-sized synchronous generator stator insulation test
- Capacitor voltage transformers (CVT): 35kV and below CVT calibration and test
- Bushings & insulators: 35kV transformer bushings, post insulators, suspension insulators
Typical Usage Scenarios
- Substation commissioning: new equipment acceptance tests according to GB 50150-2016
- Preventive maintenance: periodic insulation strength tests
- Power plant testing: generator stator winding and auxiliary equipment tests
- Third-party inspection: compliance testing and certification
- Construction site testing: on-site test of newly installed equipment
Advantages
Pure 50Hz Power Frequency Output
Identical to grid frequency, no frequency conversion stress on insulation → meets strictest national standards for generator and transformer tests
97% Energy Saving vs Traditional Test Transformers
Series resonance principle reduces input power to only 1/Q of output power → small input power, light weight, easy to transport
Electric Automatic Tuning
One-click auto tuning finds resonance point within 60 seconds → eliminates manual tuning, improves test efficiency
Excellent Waveform Quality
Output waveform distortion ≤0.5% → ensures accurate and reliable test results
Safe Breakdown Protection
Short-circuit current after breakdown is only 1/Q of test current → prevents further damage to test samples
Wide Inductance Adjustment Range
40H–102H continuous adjustment → matches a wide range of test sample capacitances
FAQ
Q: What is the difference between inductance-tuned and variable frequency resonant test systems?
A:
- Inductance-tuned: Adjusts reactor inductance to achieve resonance at fixed 50Hz power frequency, pure sine wave output, ideal for frequency-sensitive equipment like generators and transformers
- Variable frequency: Adjusts power supply frequency to achieve resonance, wider frequency range (30–300Hz), lighter weight, ideal for long cable tests
Both use the series resonance principle and have similar energy-saving advantages.
Q: Why is pure 50Hz output important?
A: Many national standards (including GB 50150-2016) require power frequency withstand voltage tests for generators, transformers, and CVTs. Pure 50Hz output ensures the test conditions are identical to actual operating conditions, avoiding any insulation stress differences caused by frequency changes.
Q: How long does it take to find the resonance point?
A: The electric automatic tuning system can find the resonance point at 50Hz within 60 seconds for most test samples.
Q: What is the maximum length of 35kV XLPE cable that can be tested?
A: With 4A rated current at 50kV, it can test up to 1.5km of 35kV/300mm² XLPE power cable or 4km of 10kV/300mm² XLPE power cable.
Q: What happens if the test sample breaks down during the test?
A: When breakdown occurs, the system immediately loses resonance, and the short-circuit current is only 1/Q of the test current (typically <0.1A), which effectively prevents further damage to the test sample.
