DL/T 266-2023 in English
VALIDGuide for measurement of impulse grounding grid parameters
- Issued on:2023-05-26
- Implemented on:2023-11-26
- File Format:PDF
- Delivery:Via email within 5 business days
$291.00
Introduction
Background of Standard Revision and Technological Evolution
As a key standard for grounding device testing in the power industry, DL/T 266-2023 has been comprehensively upgraded for grounding performance evaluation under transient conditions such as lightning overvoltage. Compared with the 2012 version, the main additions are:
| Technical dimension | 2012 version | New in the 2023 version |
|---|---|---|
| Test object | Foundation grounding device | Added special tests for vertical grounding body and large horizontal grounding network |
| Safety assessment | Basic electrical parameters | Added step voltage and secondary equipment counter-voltage measurement |
| Measurement method | Conventional impedance test | Clearly define zero potential point positioning technology and interference suppression measures |
Analysis of core test items
5.1 Electrical integrity test
It is required to use a continuity tester (resolution ≤1mΩ) to detect the connectivity of the grounding grid. Key points to note:
- The test range should cover all connection points between the main grounding grid and the independent grounding body
- The reference point selection should avoid the severely corroded area, and the grounding electrode lead-out terminal should be used preferentially
5.2 Impact grounding impedance test
The 8/20μs standard impulse wave is used to simulate the lightning current. Key parameter requirements:
| Grounding body type | Current amplitude (kA) | Measurement accuracy |
|---|---|---|
| Horizontal grounding grid | ≥10 | ±5% |
| Vertical grounding electrode | ≥5 | ±7% |
Implementation suggestions and risk prevention and control
Typical application scenarios
A test case of a 500kV substation shows that after adopting the new version of the standard:
- The impulse impedance value is reduced by 15-20% compared with the power frequency test result
- The local potential gradient exceeds the standard area through zero potential point measurement
Safety Tips: When the test voltage exceeds 10kV, the GB 26861-2011 safety specification must be implemented and a double isolation area must be set.
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