DL/T 653-2023 in English

VALID

Technical conditions for use of discharge coils for high-voltage parallel capacitors

Issued on:2023-10-11
Implemented on:2024-04-11
File Format:PDF
Delivery:Via email within 2~4 business days

Price(USD)： $459.00
$446.00

Standard No:	DL/T 653-2023
Document status:	VALID
Title in English:	Technical conditions for use of discharge coils for high-voltage parallel capacitors
Title in Chinese:	高压并联电容器用放电线圈使用技术条件
Language:	English
File Format:	Electronic (PDF)
Delivery:	Via email within 2~4 business days
Issued on:	2023-10-11
Implemented on:	2024-04-11
ICS Classification:	31.060.70-Power capacitors
Chinese Classification:	K42-Power capacitor
Professional Classification:	DL-Electricity
Related Keywords:	discharge coils dry-type discharge coils discharge coil high-voltage shunt capacitors abnormal discharge coil temperature

Introduction

Background of Standard Revision and Technological Evolution

As an upgraded version of DL/T 653, this standard mainly responds to the power industry's demand for improved reliability of components in high-voltage shunt capacitors. As the capacity of the power grid expands, the failure rate of discharge coils, as key protection components, accounts for 23.7% of the total failures of capacitor devices (Statistics of Power Equipment Failures in 2018).

Comparison of major technical changes

Technical parameters	Original standard	New standard	Reason for change
6kV system power frequency withstand voltage	25kV	25/32kV	Coordinate with DL/T 604
Dry coil test	No special requirements	Add 3 high and low temperature cycles	Solve the problem of outdoor cracking
Installation method	Unrestricted	Reverse suspension is prohibited	Prevent mechanical stress damage

Analysis of key technical points

1. Insulation level adjustment

The new standard adjusts the rated short-time power frequency withstand voltage of the 6kV system discharge coil to 25/32kV. The reason for this change is:

Synchronize with the insulation coordination requirements of DL/T 604-2020
Actual operation data shows that the breakdown rate of the discharge coil under the original 25kV standard is as high as 1.8 times/thousand units per year

2. New requirements for dry-type discharge coils

In response to the 47 cases of dry coil cracking recorded by Anhui Power Grid from 2017 to 2019, the standard adds:

Alternating high and low temperature test (-40℃~+85℃ cycle)
Epoxy resin shell thickness detection (≥5mm)
Mandatory requirement for positive vertical installation

Implementation suggestions

Equipment selection guidance

It is recommended to give priority to discharge coils that meet the following characteristics:

Pass the new version of type test certification
Secondary junction box protection level ≥IP54
Provide a 3-year or more cracking warranty

Operation and maintenance precautions

Focus on the implementation of the standard:

Renovation period of existing reverse-installed equipment (recommended to be completed within 2 years)
Check the sealing of secondary terminals before the rainy season every year
Establish an early warning mechanism for abnormal discharge coil temperature

More samples: JGJ 94-2008 YD/T 3934-2021 GB 18306-2015

Sample only — not a preview of DL/T 653-2023