A Two-Dimensional Cloud Model for Condition Assessment of HVDC Converter Transformers

Jian Li,Youyuan Wang,Zhiman He,Linjie Zhao,Jinzhuang Lv

doi:10.3390/en5010157

Jian Li, Youyuan Wang + Show 3 more

Open Access

https://doi.org/10.3390/en5010157

Copy DOI

Journal: Energies	Publication Date: Jan 23, 2012
Citations: 19	License type: CC BY 3.0

Affiliation: Chongqing University, China Southern Power Grid (China)

Abstract

Converter transformers are the key and the most important components in high voltage direct current (HVDC) power transmission systems. Statistics show that the failure rate of HVDC converter transformers is approximately twice of that of transformers in AC power systems. This paper presents an approach integrated with a two-dimensional cloud model and an entropy-based weight model to evaluate the condition of HVDC converter transformers. The integrated approach can describe the complexity of HVDC converter transformers and achieve an effective assessment of their condition. Data from electrical testing, DGA, oil testing, and visual inspection were chosen to form the double-level assessment index system. Analysis results show that the integrated approach is capable of providing a relevant and effective assessment which in turn, provides valuable information for the maintenance of HVDC converter transformers.

Highlights

In China commercial high voltage direct current (HVDC) power transmission systems have grown up to become ultra-high voltage (UHV) levels since some two years ago
two-dimensional cloud model (TDCM) is appropriate in the analysis of the operation condition of the HVDC converter transformers
The present study employed the preventive test data from a 500 kV HVDC converter transformer pole II Y/Δ connection 022B transformer belonging to the Southern Power Grid Company in China

Summary

Introduction

In China commercial high voltage direct current (HVDC) power transmission systems have grown up to become ultra-high voltage (UHV) levels since some two years ago. Fault diagnosis and condition assessment of electric power systems and equipment have attracted the attention of researchers and engineers [4,5,6,7]. The standards and judgment criteria for conventional AC power transformers are still used for condition monitoring and for fault diagnosis of HVDC converter transformers. The present paper presents an integrated approach for assessing the operation conditions of HVDC converter transformers. The analysis of the final example shows that the integrated approach is capable of providing a significant and effective assessment. These conclusions provide valuable information for maintenance planning and execution

Framework for HVDC Converter Transformer Condition Assessment

Weight of Factors and Indices

Overall Assessment Based on TDCM

Experimental Results

Results

Conclusions