Harmonic voltage monitoring based on coaxial capacitor and the analysis of influencing factors

Abstract

Harmonic content is a key indicator of power quality， and the level of harmonic voltage monitoring in high-voltage power grids still cannot fully meet the production needs of electric power enterprises. By establishing a harmonic voltage testing system based on the end screen grounding current of coaxial capacitor， the influence of capacitance on the test results of harmonic voltage content at different frequencies is analyzed. The actual measurement shows that the influence of capacitance change on the harmonic voltage content is no more than 2%. The correlation between insulation performance and the error of harmonic voltage content is analyzed： when tanδ is less than 0.2， the test error of harmonic voltage content is no more than 2%； the range of variation of tanδ（f） under different insulation states is measured， and the analysis shows that the influence of insulation state on harmonic voltage content rate is not significant.

Keywords

• coaxial capacitor
• current transformer
• harmonic voltage
• monitor