Dual Canopy Mechanic Electrical Engineering Co., Ltd. is one of the leading manufacturers and suppliers of 30kV Ultra-Low Frequency Tester in China. Please feel free to wholesale discount products for sale here and get quotation from our factory. Customized orders are welcome.
What is a 30kV Ultra-Low Frequency Tester?
The 30kV Ultra-Low Frequency Tester is a compact, portable high-voltage test system specifically designed for withstand testing (Hipot testing) of medium voltage (MV) power cables and rotating machinery. Operating at a very low frequency of 0.1Hz, this tester is the industry-standard solution for field testing of polymeric insulated cables (such as XLPE and EPR) rated up to 10kV or 20kV.
Unlike traditional power frequency (50/60Hz) test equipment which is bulky and heavy, the 30kV VLF tester utilizes advanced solid-state technology to generate a high-voltage, low-frequency sinusoidal or cosine-rectangular waveform. This drastically reduces the size and weight of the unit, making it possible for a single technician to transport and operate the equipment in confined spaces or remote field locations.
The tester complies with international standards such as IEEE 400.2 and IEC 60502, providing a non-destructive method to verify cable integrity after installation or during routine maintenance. It effectively identifies insulation defects, poor workmanship, and water treeing without causing the damaging space charge effects associated with DC testing.
| Output frequency | 0.1Hz, 0.05Hz, 0.02Hz |
| Load capacity | 0.1Hz - Maximum 0.5µF; 0.05Hz - Maximum 1.1µF; 0.02Hz - Maximum 2.2µF; |
| Measurement accuracy | 3% |
| Voltage positive and negative peak error | ≤3% ±3kV |
| Voltage waveform distortion rate | ≤5% |
In which scenarios is a 30kV Ultra-Low Frequency Tester typically used?
Application Industries | Specific Equipment/Scenarios | Test Objectives
Power Distribution Network | 10kV/20kV XLPE Power Cables | New line handover acceptance, operation and maintenance preventive testing
Industry and Mining | Internal power distribution cables and motor windings in factories and mines | Equipment maintenance and post-fault verification
New Energy Power Stations | Wind power/photovoltaic power station 35kV and below collector lines | Pre-grid withstand voltage test
Rail Transit | Subway and light rail power supply cables | Cable inspection and testing in tunnels
Building and Infrastructure | Urban underground utility tunnel cables | Precision testing in dense environments
How to troubleshoot common faults?
No output voltage
1. Grounding wire not properly connected. 1) Check grounding connection
2. Emergency stop switch not reset. 2) Rotate the emergency stop button to reset
3. Test sample short circuit. 3) Check test sample and wiring insulation
Unstable voltage
1. Large power supply voltage fluctuations. 1) Use a regulated power supply or generator
2. Overload. 2) Check if the test sample capacitance exceeds the limit
Frequent protection trips
1. High ambient humidity. 1) Improve the environment or shorten the test interval
2. Test sample insulation is damp. 2) Dry the test sample
3. Protection value set too low. 3) Verify protection setting value
No display on screen Power module fault or blown fuse Check power socket, replace with fuse of the same specification, contact manufacturer for repair
Dual Canopy Mechanical Electrical Engineering Co., Ltd. stands as a preeminent high-tech enterprise at the forefront of electrical system automation and precision testing.
We focus on innovative R&D, developing cutting-edge intelligent control systems and automated monitoring solutions. These meticulously designed systems significantly enhance the stability, efficiency, and overall performance of modern power systems. Our high-precision testers and sophisticated fault diagnosis instruments, with their superior data acquisition accuracy and efficient, in-depth analysis capabilities, have earned us the trust of power companies worldwide.
FAQ
Q1: Can the 30kV VLF Tester be used for testing 20kV cables?
A: The suitability depends on the specific test requirements and cable length. For a 20kV cable system (U0 = 20kV/√3 ≈ 11.5kV), the required withstand test voltage (3U0) is approximately 34.5kV peak. Since this tester's maximum output is 30kV peak, it is generally not recommended for acceptance testing of 20kV cables according to strict standards. However, it may be used for maintenance testing at reduced voltage levels or for shorter cable lengths where the voltage stress is lower. For standard 20kV cable acceptance testing, a 45kV or 50kV VLF tester is recommended.
Q2: How long of a 10kV cable can this tester handle?
A: The maximum cable length depends on the cable's capacitance per meter. A typical 10kV XLPE cable has a capacitance of approx. 0.2μF/km. With a load capacity of approx. 1.0μF - 1.5μF (at 0.1Hz, 30kV), this tester can typically test 5km to 7km of 10kV cable. For longer cables, you may need to test in sections or use a higher power unit (e.g., 50kV model with larger current capacity). Please provide your cable specifications for an exact calculation.
Q3:Is this tester suitable for testing PILC (Paper Insulated Lead Covered) cables?
A: VLF testing can be used for PILC cables, but it requires careful voltage selection. Unlike XLPE, old PILC cables may have reduced insulation strength. It is recommended to use a lower test voltage (e.g., 2U0 instead of 3U0) and consult the cable manufacturer or relevant standards (like IEEE 400.2) for specific guidance on aged PILC cables. The 30kV tester is capable of performing this test with adjustable voltage settings.
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