The Importance of Bandwidth, Noise Separation Method and Operating Conditions in On-line Partial Discharge (PD) Measurement on Large Turbo Generators

Diagnostic assessment of the insulation systems of large rotating machine is a concern of increasing priority to the electrical supply industries. Life extension and life assurance strategies for thermal stations have also increased the desire for determining the remaining life of machine insulation systems. For these purposes, on-line partial discharge measurement is one of the most important tests among all recommended on-line and offline tests. Since this test is performed in real operating conditions, many considerations should be taken into account to have reliable diagnosis and avoid false assessment. In This paper, a practical experience in online PD test for a 440 MW hydrogen-watercooled generator, including the results of some tests, analysis and some suggestions to do the test and analyze the data more effectively, are addressed. The paper also outlines the required specification for the PD detector particularly from sides of noise reduction, bandwidth and software. Index Terms—Condition Assessment, Partial Discharge, Stator Insulation, Turbo Generators.

Keywords:

Partial discharge , condition assessment , Turbo-Generators , Bandwidth , Noise Separation