Influence of DC Electric Fields on Pollution of HVDC Composite Insulator Short Samples with Different Environmental Parameters

Xinhan Qiao,Tian Liang,Zhijin Zhang,Xingliang Jiang

doi:10.3390/en12122304

Abstract

Pollution-induced flashover is a serious threat to the safe operation of power systems. With the development of High Voltage Direct Current (HVDC), it is necessary to study insulator contamination in DC electric fields. In this paper, the energized wind tunnel contamination test was conducted in order to systematically study the pollution ratio, k (ratio of non-soluble deposit density (NSDD) of a DC-energized condition to a non-energized condition), under different environmental parameters. Later, a two-dimensional contamination model of short samples of an HVDC composite insulator was established. The particle motion characteristics under different environmental parameters were then analyzed by the finite element method (FEM). The research results showed that—the DC electric field had an influence on particle motion but in different environments, the degree of influence was different. In addition, k was found to largely vary, with a variation in the environmental parameters. When the electrical stress (Es) increased from 0 to 70 kV/m, k increased gradually. However, when the wind speed (ws) increased, k experienced a decreasing trend. Finally, as the particle diameter (dp) decreased, k increased at first, followed by a decrease, and then again showed an increase. The results of the pollution ratio, k, for different environmental parameters are of great importance for guiding anti-pollution work in power systems.

Highlights

China has suffered increased levels of air pollution in the last three decades, due to a rapidly increasing economy, industry-dominated urbanization, and a lack of environmental protection [1].Pollution affects people’s health and harms the power system, thereby affecting social production safety
A wind tunnel contamination test was conducted, in order to carry out a systematic study on the pollution ratio k, under different environmental parameters
As the diameter increased, vt did not always decrease. vt increased by 325% (5 μm), 63% (10 μm), 127% (20 μm), 185% (30 μm), 78% (40 μm), and 48% (50 μm), respectively, compared to that without an electric field

Summary

Introduction

China has suffered increased levels of air pollution in the last three decades, due to a rapidly increasing economy, industry-dominated urbanization, and a lack of environmental protection [1].Pollution affects people’s health and harms the power system, thereby affecting social production safety. Insulator surfaces get wet under heavy pollution, fog, and rain, causing a continuous water film to form on the pollution layer, which increases the insulator surface’s conductivity. Under such conditions, the pollution flashover of insulator in transmission lines and transformer substations could occur [2,3,4]. Insulator pollution flashover is still a threat to the stable operation of power systems. It might cause power failure and negatively affect the social economic production [5,6,7,8]

Methods

Discussion

Conclusion