DF6000 Cable Very Low Frequency Withstand Voltage and Dielectric Loss Tester
Darui Electric recommends:
I. Product Overview:
Power cables are one of the important assets of power supply departments. With the continuous improvement of power supply reliability requirements, maintenance based on accidents can no longer meet the requirements. Condition-based maintenance, i.e., "condition-based maintenance," is increasingly valued.
Cable aging, moisture ingress, water trees, partial discharge, and poor joints can all cause cable failures, resulting in large-scale power outages, severe economic losses, and social impacts. How to effectively detect cable conditions and identify hidden dangers has always been an important topic.
Under ideal conditions, a cable is a good insulator, equivalent to a pure capacitor with very low dielectric loss to the external sheath grounding body. The aforementioned defects will all lead to an increase in the cable's dielectric loss, so accurate measurement of dielectric loss can detect these problems. However, due to the large capacitance of cables, AC voltage application requires a large test capacity (hundreds of kVA), and conventional dielectric loss testers cannot meet the requirements. Using external power frequency voltage would result in bulky and heavy equipment, high costs, and inconvenience in field use. Therefore, for a long time, there has been a lack of cable dielectric loss testing technology suitable for field use.
Very low frequency (VLF) dielectric loss testing is currently an advanced technology widely used internationally that can effectively detect cable dielectric loss without causing damage to the cable itself. It applies a 0.1Hz VLF sine wave to test the cable's dielectric loss, reducing the test current and making the equipment lightweight and portable. Currently, standards recommending VLF dielectric loss testing for cables include IEEE 400 & IEEE 400.2 (North America and International), IEC 60060-3 (International), CENELEC HD 620 & 621 (Europe and International), and VDE 0276 Part 620 (Germany).
The main technical difficulty in using 0.1Hz VLF for dielectric loss measurement is that the dielectric loss angle of general cables is very small, about 0.01° or less. The 0.1Hz waveform is very flat, making it difficult to accurately determine the zero-crossing position of the waveform, so accurately measuring its phase is very difficult. At the same time, there are strong power frequency interference and high-frequency interference signals at the test site. It is technically very challenging to accurately measure such a small value under such strong interference.
The DF6000 Cable VLF Withstand Voltage and Dielectric Loss Tester (DF6000) is specifically designed for accurate dielectric loss and partial discharge testing of distribution cables (6kV, 10kV, 20kV, 35kV). It outputs a 0.1Hz VLF sine wave, reducing output current, making the equipment compact and lightweight, convenient for field use, and accurate in measurement. The main functions of the system include: withstand voltage and dielectric loss testing of distribution cables.
II. Technical Features:
*Multifunctional: VLF withstand voltage and dielectric loss.
*Lightweight: Small size, light weight, convenient and portable for field use.
*High precision: Dielectric loss testing accuracy better than 1×10-4.
*Simple and intelligent: Automatic analysis and judgment of results.
*No electric shock risk: Test data is transmitted wirelessly to a laptop, no need to contact high-voltage equipment.
*Advanced control method: The central control unit (laptop) communicates wirelessly with each component, making it simple and convenient to use.
*Safe and reliable: The control system uses a DC power supply of ≤36V.
*The system internally uses the Linux industrial operating system.
*The system integrates an insulation resistance measurement device: it can measure cable capacitance and resistance, operated and displayed on the laptop.
*Meets smart grid regulations: Complies with the State Grid's "Q/GDW1168—2013 Regulations for Condition-Based Maintenance and Test of Power Transmission and Transformation Equipment"
*Has a high-voltage side measurement resolution of up to one hundred thousandth (0.001%).
*Automatically generates dielectric loss-voltage curves at the test site.
*Fully automatic: Software controls hardware, wireless LAN networking.
*Intelligent shielding ring: Completely solves the influence of external insulation contamination on terminal heads that have been in operation for many years.
*Fully complies with the national standard GB50150-2016 for cross-linked cable withstand voltage test regulations.
*Built-in power supply: Comes with a built-in lithium battery, can be used continuously for more than two hours on site.
