GB/T 29311-2020 in English
VALIDElectrical insulating materials and systems—AC voltage endurance evaluation
- Issued on:2020-06-02
- Implemented on:2020-12-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
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《GB/T 29311-2020电气绝缘材料和系统 交流电压耐久性评定》由TC301（全国电气绝缘材料与绝缘系统评定标准化技术委员会）归口，主管部门为中国电器工业协会。
Introduction
Analysis of the core content of the standard
| Technical elements | 2012 version | Main changes in the 2020 version |
|---|---|---|
| Scope of application | Insulating materials only | Extended to insulation systems |
| Definition of terms | Including "electrical life" | Delete this term and add α symbol |
| Test methods | Description of routine tests | Increase diagnostic test and threshold detection requirements |
Key technologies for voltage durability
VE curve construction must meet the following requirements: ①3 or more different voltage tests ② single voltage group failure time> 1000h ③ at least 3 valid tests. The curve shape can be divided into the initial low slope area, the mid-term steep area and the late threshold approaching area.
Test method comparison
High frequency accelerated test Note: When the frequency exceeds 10 times the power frequency, the dielectric loss heat generation needs to control the temperature rise ≤3K. The applicability of the formula Lf=Lh(fh/f) needs to be verified.
In the incremental stress test, the size effect follows the Weibull distribution: E1/E2=R1/γ, where γ is the shape parameter.
Implementation recommendations
- The pre-test phase should include a short-time electrical strength test to record the breakdown path morphology
- Four voltage gradients are recommended for constant stress testing, with a sample size of ≥10 per group
- The β value is required to remain constant across voltage groups during Weibull analysis
Statistical processing specifications
Data validity verification must meet the following requirements: ① Random sampling ② Thickness deviation <5% ③ Ambient temperature fluctuation ±2℃. Weibull fitting requires a correlation coefficient R²≥0.90, and low probability points (<1%) require special marking of confidence intervals.
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