Monitoring of partial discharges through fiberoptic sensors in medium voltage switchgear

Summary

Improvements in material science, designing and manufacturing processes made medium voltage switchgear much more reliable. In spite of this, insulation deteriorates due to voltage stresses, partial discharges (PD), vibrations and temperature, leading to eventual catastrophic equipment damage in the switchgear. To counter these harmful events, focusing on PDs and mechanical stresses, HTW Berlin is working on the development of new measurement techniques using fiber optic sensors in the switchgear. Events and locations will be detected via intelligent signal processing within a monitoring system. For the detection of PDs, different conventional offline techniques have already been introduced. However, the continuous electrical monitoring of the PDs may be challenged by electromagnetic interference from the environment. In such situation, electromagnetically immune fiber optic sensors are used to detect the PDs by their acoustic emissions. This paper presents investigations to detect PDs through acoustic sensors. To achieve this, a highly sensitive, electromagnetically immune fiber optic sensor is used. During experiments with such a fiber optic sensor which is specially designed and manufactured for detection of acoustic emission from PDs. The measurment results have been compared with those of conventional sensors like a piezoelectric acoustic emission sensor. To monitor the switchgear an FPGA based diagnostic hardware is going to be developed. Recorded data are analyzed in real time and quantified in terms of damaging potential. Classification of different PD events is in the focus of current research and is planned to be included in the hardware.

Additional informations

Authors

M. KÖLLING, T. GRÄF, M. MENGE

Keywords

Partial discharges, acoustic emission, switchgear, acoustic sensors, online monitoring system