I. Core Functions and Detection Significance of the Equipment
The dielectric loss tester is the core instrument for the preventive test of insulation of electrical equipment. It is mainly used for accurately measuring the dielectric loss factor (tanδ) and capacitance (Cx) of insulating materials. These two parameters can directly reflect the energy loss and polarization state of the insulation system under AC voltage, and are important sensitive indicators for judging insulation moisture, aging deterioration, and local defects.
According to the different objects being tested and the on-site working conditions, the dielectric loss tester has developed multiple specialized technical branches. The usage scenarios, functional characteristics, and test standards of various equipment are all different, and can adapt to the detection needs of different power equipment and insulating materials.
II. Field Application Characteristics of High Voltage Dielectric Loss Tester
2.1 Applicable Scenarios and Anti-interference Technology
In the on-site testing of high-voltage power equipment, the high-voltage dielectric loss tester is the most widely used. It mainly serves substations and maintenance workshops, and conducts detection work on the main insulation of core power equipment such as transformers, current/voltage transformers, bushings, power cables, and capacitors.
In response to the complex electromagnetic field interference environment on-site, modern high-voltage dielectric loss testers generally adopt frequency conversion and non-frequency anti-interference technologies. By switching to non-fundamental frequency test frequencies such as 45Hz and 55Hz, combined with professional digital filtering algorithms, they can effectively isolate industrial frequency and harmonic interference, significantly improving the repeatability and detection accuracy of measurement data.
2.2 Wiring Method and Special Detection Functions
The equipment is equipped with two core wiring modes, suitable for different on-site conditions: the positive connection method is applicable for the detection of ungrounded test samples, and the reverse connection method is specifically adapted for power equipment with the shell directly grounded, covering most on-site detection scenarios.
High-end model equipment integrates self-excitation measurement function, which can be specifically applied to the detection of capacitive voltage transformers (CVT). Without disassembling the high-voltage leads, it can complete the insulation status assessment of the dividing voltage capacitor and intermediate transformer, simplifying the on-site operation process and significantly improving the maintenance and detection efficiency.
III. Characteristics of Special Insulating Oil Dielectric Loss Testing Equipment
For the detection of liquid insulating media, the special insulating oil dielectric loss tester can accurately monitor the quality status of insulating oil such as transformer oil and switch oil, and is the core equipment for power oil supervision work.
The dielectric loss values of oil products are highly sensitive to temperature. Therefore, this type of equipment is equipped with a high-precision temperature control system, which can strictly maintain the standard detection temperature of 90℃ according to industry standards. The constant temperature detection mode can effectively avoid data errors caused by temperature deviations, ensuring the uniformity and comparability of detection data from different batches of oil samples, and providing precise basis for oil quality judgment and aging assessment.
IV. Application Areas of High-Frequency Dielectric Performance Testing Equipment
In the research fields of insulation material development and performance failure analysis, high-frequency dielectric performance testing equipment plays a key role. This type of equipment can test frequencies up to megahertz levels, relying on the resonant method and Q-meter core working principle, to accurately collect dielectric spectral characteristic data of solid insulating media such as insulating paperboard, epoxy resin, and composite insulating materials.
Through precise dielectric performance testing, it can systematically assess the insulation performance and aging resistance of new insulating materials, providing solid data support for new material iteration research and the optimization design of power equipment insulation structure.
V. Industry Execution Standards and Technical Specifications
5.1 Update of Core Industry Standards
The core general technical basis of the dielectric loss tester at present is DL/T 846.17—2025 “High Voltage Testing Equipment General Technical Conditions Part 17: High Voltage Dielectric Loss Tester”. This standard was officially implemented on December 30, 2025, and completely replaces the old version DL/T 962-2005 standard, unifying the technical requirements and inspection specifications of high-voltage dielectric loss testers.
5.2 Scope of Application and Execution Requirements of Standards
This new standard is applicable to high-voltage dielectric loss testers with a rated output voltage of 10kV or less and a working frequency ranging from 45Hz to 55Hz. It provides comprehensive and clear specification requirements for the core performance of the equipment, such as measurement accuracy, environmental adaptability, and operational safety. It serves as the authoritative technical basis for equipment selection and procurement, factory acceptance, and periodic verification.
For specific testing items, such as insulation oil dielectric loss testing, special operations must be carried out in accordance with national standards like GB/T 5654, ensuring the standardization of all testing processes and the authority of the test results.
Post time: Sep-10-2026