| Abstract: | This paper presents a new system for detecting electromagnetic waves emitted from partial discharges (PD) due to material defects in high-voltage electric machinery and apparatus. PD is a symptom and/or a direct cause of the deterioration of insulation systems used in high-voltage stator coils. This system can detect PD by using the spatial phase information of the microwaves emitted from PD, which are voltage pulses of very short duration. We describe the properties of this system which is composed of two double-ridge-guide-horn antennas, two preamplifiers, a gigahertz interference receiver (GHz-2ch-down-converter) of original design, two A/D (analog to digital) converters, and a personal computer. We experimentally show that this system can be used for detection of the microwaves emitted by PD occurring in the stator coil. The result of this work is the development of a new noncontact PD detection system for generators, which can be operated by station personnel. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 121(2): 16–26, 1997 |
