DF6000 Cable Ultra-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 is far from meeting 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 faults, leading to large-scale power outages, resulting in severe economic losses and social impacts. How to effectively detect the condition of cables and identify hidden dangers has always been an important topic.
Under ideal conditions, a cable is a good insulator, and the grounding body of the outer sheath is equivalent to a pure capacitor with very low dielectric loss. The above defects will lead to an increase in the dielectric loss of the cable, 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. If an external power frequency voltage is applied, the equipment is bulky and heavy, costly, and inconvenient for on-site use. Therefore, for a long time, there has been a lack of cable dielectric loss testing technology suitable for on-site use.
Ultra-low frequency dielectric loss testing is 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 ultra-low frequency sine wave to perform dielectric loss testing on cables, reducing the test current and making the equipment lightweight and portable. Currently, standards recommending ultra-low frequency 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 ultra-low frequency 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 very difficult to accurately measure such a small value under such strong interference background.
The DF6000 Cable Ultra-Low Frequency Withstand Voltage and Dielectric Loss Tester (DF6000) is specially designed for accurate dielectric loss and partial discharge testing of distribution cables (6kV, 10kV, 20kV, 35kV). It outputs a 0.1Hz ultra-low frequency sine wave, reducing the output current, making the equipment small and lightweight, convenient for on-site use, and accurate in measurement. The main functions of the system: withstand voltage and dielectric loss testing of distribution cables.
II. Technical Features:
*Multi-functional: ultra-low frequency withstand voltage and dielectric loss.
*Lightweight: small size, light weight, convenient and portable for on-site 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 wirelessly transmitted to a laptop, no need to contact high-voltage equipment.
*Advanced control method: the central control unit (laptop) is connected to each component via wireless communication, making it simple and convenient to use.
*Safe and reliable: the control system uses a DC power supply of less than or equal to 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, and can be operated and displayed on a laptop.
*Meets smart grid regulations: meets 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 meets the national standard GB50150-2016 for cross-linked cable withstand voltage test regulations.
*Built-in power supply: built-in lithium battery power supply, can be used continuously for more than two hours on site.
