VLF Cable Tester

Hipot Cable Testing and Analysis

Precisely detect hidden faults in cables and high-voltage equipment, extend equipment lifespan, and ensure safe and stable operation of your power system

With the rapid development of the power industry, power cables play a crucial role in the stability and safety of running power systems. The demand for cable testing equipment is steadily increasing. VLF(Very Low Frequency) cable tester is a specialized instrument designed to assess the insulation performance of power cables, motor windings, and high-voltage equipment. By operating at low frequencies, it can effectively detect defects that may not be easily identified with high-frequency signals, making it essential for the maintenance and fault detection of power systems.

Hipot Cable Tester

Hipot Cable Tester is used to verify the integrity of the insulation in medium and high voltage (MV and HV) cables. This technique is particularly advantageous for field testing due to the portability of VLF equipment, which is typically smaller and lighter compared to traditional high-frequency test equipment. The inherent capacitance of power cables requires charging when energized, and since VLF systems operate at frequencies below 1 Hz, they consume significantly less power than systems using higher frequencies. This makes VLF testing an efficient and cost-effective approach, especially for testing modern polymer-insulated cables such as XLPE and EPR.

VLF Tester

Portable Hipot Test for Cable

VLF Hipot Tester

High Voltage Cable Tester

Cable Tan Delta Test

During long-term operation, power cables may experience insulation aging, damage, and other issues due to various factors. These problems can lead to dielectric loss, which affects the normal functioning of the cable. The dielectric loss testing in power cables is essential.

VLF cable tan delta tester is an effective and reliable test equipment for measuring the dielectric loss factor, or Tan Delta, of high-voltage cables. It operates by applying a low-frequency AC voltage to the cable and measuring the phase angle difference between the induced current and the voltage, which is then used to calculate the dielectric loss factor.

VLF Tan Delta Tester

VLF Hipot Tester

Advanced VLF tester by application

VLF testers are widely used in power transmission and distribution networks for testing medium- and high-voltage cables, ensuring grid reliability and safe operation. They play a crucial role in renewable energy systems, industrial plants, electrical system and transportation networks like railways and subways by verifying the insulation integrity of critical infrastructure. Additionally, they are essential in factory testing for cable manufacturers and maintaining underground cables in airports, mining, and utilities

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Product Details

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What is the standard of vlf tester ?

IEEE 400.2-2013 standard provides a guide for field testing of shielded power cable systems using VLF and is particularly useful for diagnosing various cable insulation problems. It suggests that VLF testing should last between 15 and 60 minutes, with a recommended minimum duration of 30 minutes, and that the tested cable must withstand the AC voltage for the specified time without flashover. VLF testing can use different wave shapes, such as sine and square, and it is important to note that RMS and peak voltages have different relationships depending on the wave shape. IEEE 400.2 uses the peak voltage level to equate the wave shapes. The standard also embraces VLF testing as a viable alternative to DC testing, as it exposes serious cable defects without harming healthy insulation or aggravating minor defects. IEC 60502-2:2014 specifies the construction, dimensions, and test requirements for power cables with extruded solid insulation from 6 kV up to 30 kV for fixed installations. It includes a new subclause for a routine electrical test on the oversheath and the inclusion of a 0.1 Hz test after installation, which is relevant for VLF testing.

Why do people use VLF Hipot Tester?

VLF hipot testers use a sine wave voltage output that typically ranges from 0.1 Hz to 0.01 Hz. The frequency of the VLF output is important because it affects the test voltage level that can be applied to the insulation without causing damage. At lower frequencies, higher voltages can be applied without damaging the insulation. This is because the low frequency allows the voltage to penetrate the insulation and charge the capacitance of the system, rather than simply causing surface breakdown.

What is the principle of vlf hipot tester

VLF testing adopts generate AC voltage with the accuracy very low frequency signal and high output power . The output voltage of a VLF generator is passed through an insulation load connected to the cable to be tested. The insulation load is a highly capacitive load which simulates the properties of the cable insulation material. Measure the current and voltage of cable conduct and insulation material and analyze the abnormal voltage and current waveform to check the cable insulation and potential faults.

How does work for 33kV cable by VLF tester

For a 33kV cable, the test voltage is typically set to 2.5–3 times the system voltage, i.e., between 57 kV and 76 kV (peak values) for the withstand test. This voltage is applied for the specified duration, usually between 15 to 60 minutes

what safe guarantee for hipot cable tester ?

VLF hipot cable tester ensures safety with built-in overvoltage and overcurrent protection features that promptly disconnect power in abnormal conditions by urgent stop button. It is designed with clear operational guidelines and safety warnings to prevent accidents due to incorrect use. Additionally, the equipment maintains stability during operation to avoid safety issues caused by malfunctions or unstable performance