DL/T 368-2024 in English

VALID

High-altitude correction for insulator external insulation in pollution-prone overhead power lines

Issued on:2024-12-25
Implemented on:2025-06-25
File Format:PDF
Delivery:Via email within 1~3 business days

Price(USD)： $189.00
$184.00

Standard No:	DL/T 368-2024
Document status:	VALID
Title in English:	High-altitude correction for insulator external insulation in pollution-prone overhead power lines
Title in Chinese:	输电线路用绝缘子污秽外绝缘的高海拔修正
Language:	English
File Format:	Electronic (PDF)
Delivery:	Via email within 1~3 business days
Issued on:	2024-12-25
Implemented on:	2025-06-25
ICS Classification:	29.080.10-Insulators
Chinese Classification:	K48-Insulator
Professional Classification:	DL-Electricity
Related Keywords:	altitude correction system high-altitude correction correction basis altitude edition altitude correction formula χ=1/ [ altitude correction factor χ

Introduction

Analysis of the core content of the standard

The new version of DL/T368-2024 establishes an altitude correction system based on the unified creepage distance (USCD) to address the problem of contaminated external insulation of insulators in high-altitude areas. Compared with the 2010 edition, the main technical innovations are reflected in:

Technical elements	2010 edition	2024 edition
Altitude correction formula	χ=1/[1-0.12n(H-1)]	Optimize the symbol system, clarify the χ_H/χ_sl relationship
n value selection	Fixed value (AC 0.55/DC 0.40)	Range value (AC 0.50-0.60/DC 0.35-0.45)
Correction basis	Altitude only	Dual track system (altitude or air pressure data)

Key technical parameter description

The calculation of the altitude correction factor χ adopts the dual track method:

Based on altitude: χ=1/[1-0.12n(H-1)] (H unit: km)
Based on air pressure data: χ=(P_H/P₁)^-n (P₁=89.8kPa)

Engineering Application Example

A ±800kV DC line passes through an area with an altitude of 3500m. When composite insulators are selected:

Take n=0.40 (DC recommended value)
Calculated χ=1/[1-0.12×0.40×(3.5-1)]=1.14
That is, USCD needs to be increased by 14%

Standard Implementation Recommendations

Design Phase

Pressure data correction method is preferred (higher accuracy)
For new projects, the n value is strictly selected according to the range in Table 1

Operation and Maintenance Phase

Regions below 1000m above sea level should directly refer to GB/T26218 series standards
Regularly check the deviation between the actual air pressure on site and the standard value