In partial discharge detection, signal capture capability directly determines detection effectiveness. The PDM-9200 partial discharge detector collects three types of signals—electromagnetic waves, ultrasonic waves, and transient voltage—in a coordinated manner, providing a multi-dimensional basis for assessing insulation degradation trends. For procurement personnel, understanding the parameter boundaries and coordination logic of each sensing channel is the starting point for selection verification.
Parameter Matching of Transient Earth Voltage and Ultrasonic Sensing Channels
The TEV sensor response band typically covers 3–100 MHz, suitable for capturing electromagnetic wave signals excited by internal discharge in switchgear; the AE sensor operating band is mostly 20–300 kHz, sensitive to the ultrasonic components generated by discharge. The two frequency bands do not overlap, which determines their division of labor in different detection scenarios: TEV is used for rapid scanning of cabinet gaps and observing overall discharge levels, while AE is used for locating abnormal points and assisting pattern identification. During procurement, it should be verified whether the sensor frequency band matches the host sampling rate, to avoid amplitude distortion caused by undersampling of high-frequency signals.
The Role of Alloy Resistors in the Signal Conditioning Circuit
The alloy resistors in the front-end signal conditioning circuit of the detector have a low temperature drift coefficient, which can reduce measurement deviation introduced by resistance value drift during prolonged inspection or ambient temperature fluctuations. For applications requiring continuous recording of discharge trends, this parameter affects the longitudinal comparability of data. During procurement verification, attention can be paid to the temperature characteristics specifications of key components in the conditioning circuit, rather than only looking at overall instrument accuracy indicators.
Operational Coordination in 10kV Switchgear Inspection
In 10kV switchgear inspection, the conventional practice is to first use the TEV sensor to scan along cabinet gaps, and after abnormal readings are found, switch to the AE sensor for localization. This process relies on the switching response speed of the two sensors on the same host and the background noise suppression capability. Procurement personnel can refer to inspection work instructions to confirm whether the equipment supports rapid sensor switching and background noise recording functions, so as to match the on-site operational rhythm.
