Comprehensive Analysis of GB/T 4207-2022 Standard: Determination Method for Tracking Resistance Index and Comparative Tracking Index of Solid Insulation Materials

1、 Overview and Scope of Application of Standards

GB/T 4207-2022 "Determination Method for Tracking Resistance Index and Comparative Tracking Index of Solid Insulation Materials" is a Chinese national standard, equivalent to the international standard IEC 60112:2020, and was released and implemented on July 11, 2022. This standard mainly specifies the testing method for the formation of conductive channels (traces) on the surface of solid insulation materials under the combined action of electrical stress and electrolytic impurities.

Scope of application:

Equipment components and disc-shaped materials suitable for use under AC voltage

Used to evaluate the electrical trace resistance performance of solid insulation materials

The test results can serve as material acceptance criteria or quality control methods

Compared to the electrical trace index, it is mainly used for characterizing the basic characteristics of materials and comparing their performance

The standard test results cannot be directly used to evaluate the safe creepage distance of electrical equipment, but can identify the resistance to electrical traces of materials on electrical equipment working in humid environments.

2、 Technical parameters and testing methods

1. Main technical parameters

2. Testing methods

The standard specifies two main testing methods:

Constant voltage method:

Apply a constant voltage(2.5/3.5/4.5 kV) for 6 hours

Judgment condition: Current>60mA or perforation may occur

Suitable for routine quality control

Step by Step Boosting Method:

withStep up voltage to failure at a rate of 250V/hour

Only using current as a criterion

Suitable for material research and development evaluation

Standard testing process:

Sample preparation: Clean with isopropanol and rinse with distilled water if necessaryP800 sandpaper wet grinding

Sample installation: Install the sample onOn a bracket with a 45 ° inclined surface

Application of contaminated liquid: Drop the specified contaminated liquid onto the surface of the sample through a dropper tube

Voltage application: Close the switch and increase the voltage to the selected value

Data recording: The system automatically monitors leakage current, immediately cuts off voltage and records data when breakdown occurs

3、 Correspondence between international standards

GB/T 4207-2022 corresponds to the following international standards:

IEC 60112:2020: Determination method for resistance to electrical trace index and comparative electrical trace index of solid insulation materials

IEC 60664-1: Insulation coordination for low voltage electrical equipment

IEC 60587: Test Method for Electrical Traceability and Corrosion Resistance of Insulation Materials Used in Harsh Environments (Slant Plate Test)

Standard test results andThe inclined plate test results of IEC 60587 may differ due to the different material arrangement order of the two test methods (titration test and inclined plate method).

4、 Testing Equipment and Selection Guide

1. Main testing equipment

The leakage trace tester is the core equipment for implementing this standard and must meet the following technical requirements:

Voltage range:0-6000V ± 5% adjustable

Current threshold:Can move at 60mA for 2 seconds

Power frequency:45Hz-65Hz

Flow rate error of contaminated liquid:±10%

Equipped with automatic monitoring and recording functions

Select AC or AC/DC dual-use models according to testing requirements

Consider the degree of automation(Batch testing requirements)

Confirm if the equipment meets the requirementsGB/T 4207-2022 standard requirements

Check if the equipment has the necessary safety protection functions

5、 Application Fields and Implementation Precautions

1. Main application areas

The GB/T 4207-2022 standard is widely used in the following industries:

Electrical equipment industry: insulation layer for wires and cables(PVC, PE material), insulation base for switch sockets, insulation shell for low-voltage electrical appliances (relays, contactors)

New energy industry: insulation components for charging piles, insulation materials for lithium battery casings, insulation partitions for photovoltaic inverters

Power equipment manufacturing: outdoor insulation materials(Thermosetting, thermoplastic molding materials, laminated boards, etc.)

Rail transit: harsh environmental adaptability assessment of insulation materials for locomotive electrical systems

2. Implementation precautions

Sample preparation:

Ensure that the surface of the sample is free of scratches and dirt

Strictly follow the standard requirements for cleaning and pretreatment

Test environment control:

The temperature is strictly controlled within23±2℃

Humidity control within50±5%RH

Avoid testing in flammable gases, high temperatures, humidity, or corrosive environments

Equipment maintenance:

Regularly followJJG series metrological verification regulations calibration equipment

Check whether the fixture and clamping surface are worn, cracked, or deformed

Annual comprehensive inspection and maintenance by professional engineers

Safety regulations:

Operators need to wear insulated gloves

Ensure good grounding before testing

After testing, the high-voltage output terminal needs to be discharged for treatment

The equipment should be equipped with overcurrent protection devices(Cut off power within 0.05s upon breakdown)

6、 Significance of standard implementation

The implementation of GB/T 4207-2022 standard has the following important significance:

Provided a unified and scientific method for evaluating the electrical trace resistance performance of solid insulation materials

Helps electrical equipment manufacturers make scientific judgments during the material selection stage

Ensure the safe operation of products and extend the service life of equipment

Provide effective basis for quality control and improvement of material suppliers

Promote the alignment of Chinese standards with international standards and enhance international competitiveness