The dielectric strength tester is classified into multiple dimensions based on different technical characteristics and application scenarios. It can be mainly divided according to voltage type, voltage level, application object, and technical implementation method.
I. Classification by Voltage Type
AC Dielectric Strength Tester
This type is a common device that outputs sinusoidal alternating current voltage (50Hz or 60Hz), which can simulate the actual operating voltage of the power grid. AC testing can simultaneously evaluate the polarization and leakage effects of materials, and the results are close to the actual working conditions, meeting the requirements of most material testing standards, such as GB/T 1408 and IEC 60243 series standards.
DC Dielectric Strength Tester
It outputs stable direct current high voltage and is mainly used for insulation assessment of high-voltage direct current transmission equipment and some special materials that are sensitive to AC testing. DC testing has no interference from capacitive current, and the results are more stable, and the power demand for testing with large capacitance loads is lower.
II. Classification by Voltage Level
Low Voltage Type Tester
The output voltage range is usually 10kV to 50kV, suitable for testing conventional insulating materials such as plastics, rubber, insulating varnish, and insulating paper, and is the most widely used type in production and research laboratories.
High Voltage Type Tester
The output voltage can reach 100kV or even above 150kV, used for insulation strength assessment of thick insulation layer materials, composite insulation structures, and high-voltage electrical equipment. This type of equipment is larger in size and has stricter requirements for safety protection and operating environment.
Special Insulating Oil Tester
It belongs to a special type of equipment, with an output voltage of typically 0-100kV, a fixed rise rate of 3kV/s, and is equipped with automatic stirring and standing functions, which can meet the special process requirements of insulating oil testing.
III. Classification by Application Object
General Solid Material Tester
It is equipped with a standard flat electrode system and is suitable for testing samples such as solid insulating materials, films, and laminated boards. The electrode size and spacing can be adjusted according to standard requirements.
Insulating Oil Dielectric Strength Tester
It is specifically designed for liquid insulating media and has functions such as automatic multiple tests, breakdown voltage recording, and average value calculation. It is usually equipped with an oil cup, stirring device, and temperature control system.
Electrical Equipment Withstand Voltage Tester
It is used for overall withstand voltage tests of finished electrical equipment such as transformers, switch cabinets, and cables, featuring high output voltage and large capacity, and also has overcurrent protection and breakdown indication functions.
IV. Classification by Technical Implementation Method
Traditional AC Testers
They use an AC transformer for voltage boosting, with mature and reliable technology, small waveform distortion, but have the characteristics of large volume and heavy weight.
Programmable Intelligent Testers
Based on microprocessor control and power electronic technology, they can achieve functions such as automatic voltage boosting, constant voltage maintenance, rapid disconnection, and data storage, significantly improving test accuracy and operational convenience. They are the mainstream development direction of modern testers.
V. Core Application Areas
Dielectric strength testers run through the entire life cycle of electrical insulating materials and power equipment, and are important testing equipment in the research and design, production and manufacturing, and operation and maintenance stages.
Power Industry
As a key detection device for ensuring the safe operation of power grids, it can conduct regular dielectric strength tests on oil-filled equipment such as transformers, circuit breakers, and current transformers, promptly detecting problems such as oil deterioration, water intrusion, and impurity contamination; for solid insulating equipment such as cables, bushings, and insulators, it conducts withstand voltage tests to verify whether their insulation performance meets the operation standards. Relevant power preventive test regulations clearly stipulate the test cycle and qualification standards for various electrical equipment. In the production and manufacturing process, products such as automotive wiring harnesses, motor windings, connectors, and PCB boards all need to pass a withstand voltage test before they can be shipped; in the aerospace field, the insulation performance of composite materials is extremely demanding, and dielectric strength testing is a necessary item for aviation material certification.
Electronic and electrical industry
Products such as household appliances, consumer electronics, and industrial control equipment need to pass safety certification before they are launched on the market. Withstand voltage testing is a core item in safety certification, which can verify whether the design of the electrical clearance and creepage distance of the product meets the standards, and avoid the risk of electric shock under abnormal high voltage; products such as LED lighting, switching power supplies, and inverters have high insulation performance requirements, and withstand voltage testing is an important part of their quality control.
Standardization laboratory
Third-party testing institutions and enterprise certification laboratories are important users, conducting testing services based on national standards or international standards, and the test reports they issue have legal effect and industry credibility. The equipment used in the laboratory has higher requirements for precision and traceability, and needs to be calibrated regularly.
Six. Standard System
Dielectric strength testing covers three types of norms: product testing methods, instrument technical conditions, and equipment safety requirements. It forms a complete standard system.
Product testing method standards
The series of standards GB/T 1408 “Electrical Strength Test Methods for Insulating Materials” are the core basis for testing solid insulating materials, corresponding to the international standard IEC 60243 series. They specify detailed regulations for all testing phases such as sample preparation, electrode system, voltage rise method, breakdown determination, and data processing. Among them, GB/T 1408.1 is applicable to power frequency testing, GB/T 1408.2 is applicable to DC testing, and GB/T 1408.3 is applicable to pulse testing.
GB/T 507 “Determination of Dielectric Strength of Insulating Oil” (corresponding to IEC 60156) is the standard for insulating oil testing, clearly stipulating requirements for sample processing, electrode structure, voltage rise rate, and test times, and requiring that the same oil sample complete at least six tests and take the average value as the final result.
Instrument technical condition standards
DL/T 846.7 “General Technical Conditions for Insulation Oil Dielectric Strength Testers” is a technical specification specific to the power industry, stipulating contents such as instrument classification, technical requirements, test methods, inspection rules, and marking and packaging. It is the technical basis for the design, production, and inspection of insulation oil dielectric strength testers.
There is no unified national standard for general dielectric strength testers. Usually, relevant industry standards or enterprise standards are referred to for implementation. Core technical indicators include output voltage accuracy, voltage rise rate control accuracy, breakdown cutting time, and measurement repeatability.
Post time: Apr-23-2026