High Voltage Equipment Diagnostics Inc. uses several methods of acoustic detection when surveying your substation equipment. On external connections, airborne corona can be source located and lead to findings such as cracked insulators and loose electrical connections. Air leaks in pneumatic systems and inert gas leaks on gas blanketed equipment can also be found using this process.
HVED Incorporated also uses sonic and ultrasonic listening devices to analyze problems inside oil filled equipment. This process involves the application of a portable battery powered acoustic monitor to the external tank of an energized power transformer. The device is calibrated to identify internally generated sonic and ultrasonic noise caused by electrical or mechanical anomalies inside the equipment. If an anomaly is detected, then other diagnostic methods are applied to confirm or dismiss this anomaly. With the aid of a portable oscilloscope, the magnitude and frequency of the internally generated noise can be further analyzed. This device can also be used on load tap changers to identify contact wear problems. This method has been used successfully on many occasions to source locate internal partial electrical discharges resulting from insulation degradation. The noises generated inside of equipment are very directional and problems have certain signatures that can be verified. Quite often this allows for source locating of the problem.
