GB/T 32288-2020 in English
VALIDElectrical steel core for power transformers
- Issued on:2020-06-02
- Implemented on:2020-12-01
- File Format:PDF
- Delivery:Within 1 day
Price(USD)：
$200.00
$194.00
$194.00
《GB/T 32288-2020电力变压器用电工钢铁心》由TC183（全国钢标准化技术委员会）归口，TC183SC6（全国钢标准化技术委员会钢板钢带分会）执行，主管部门为中国钢铁工业协会。
Introduction
Core changes in the standard revision
| Technical dimensions | Requirements of the 2015 version | Updates to the 2020 version |
|---|---|---|
| Scope of application | Grades above 35kV are not specified | Special requirements for voltage levels above 35kV are added |
| Insulation requirements | Dry type ≥5MΩ, oil immersed ≥1MΩ | Insulation between oil channels ≥0.5MΩ requirement is added |
| Test items | 6 geometric characteristics | Four new tests, including white edge and metal hairline, have been added. |
Analysis of key technical requirements
1. Core insulation system
The new standard divides insulation requirements into two voltage levels:
- 35kV and below: Dry-type transformer core insulation to ground ≥5MΩ, oil-immersed ≥1MΩ
- Above 35kV: Added the requirement of core oil channel insulation ≥0.5MΩ, and the test voltage is increased to 2500V
2. Geometric accuracy control
Taking the longitudinal shearing process as an example, the main control indicators are:
| Project | Below 35kV | Above 35kV |
|---|---|---|
| Width deviation | ±0.2mm | ±0.1mm |
| Burr height | ≤0.02mm | ≤0.015mm |
| White edge width | ≤0.1mm | ≤0.05mm |
Implementation Suggestions
Production process adjustment
- Upgrade the guide system of the slitting equipment to ensure the ±0.1mm width tolerance of products above 35kV
- Add an online burr detection station and use laser scanning instead of manual sampling
- Insulation treatment process, add oil channel withstand voltage test
Main points of quality control
Focus on the new items:
- Metal hairline defects require 100% visual inspection immediately after longitudinal shearing
- A special thickness gauge should be used to detect the lamination coefficient, and 9 points on the core diagonal should be measured
- For window height and width detection, it is recommended to use a laser rangefinder instead of a tape measure
Sample only — not a preview of GB/T 32288-2020
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