On-line Monitoring System for Dielectric Loss of Capacitive Bushing Considering Harmonic Effects

Abstract

The existence of harmonic waves may cause some errors during measurement of dielectric loss, thus hindering accurate evaluation of insulation. By taking the influence caused by harmonic waves into consideration, this article introduces an approach which may achieve higher accuracy in the calculation of dielectric loss. Calculation results show that harmonic components and orders of harmonic waves may have big impact on dielectric loss. This article also develops a dielectric loss on-line monitoring system based on bus, which can fulfill tasks including signal conditioning, data acquisition and conversion, upper computer communication and data transmission. This system uses A/D conversion controlled by industrial computer to implement remote communication and synchronous sampling of harmonic waves and is able to able to improve accuracy of dielectric loss under the influence of high order harmonics, therefore, make accurate on-line evaluation of equipment’s insulative conditions.