he PDM system is an online partial discharge monitoring system for transformers, Adopting industry recognized UHF technology. The PDM system is used to continuously evaluate the insulation performance of power transformers to ensure corrective measures are taken before faults occur. State based maintenance decisions can be made based on the information collected by the system to reduce maintenance expenses ·PDM is a complete PD monitoring package that includes sensors, cables, data acquisition units, central processing units (CPUs), and software Ultra high UHF measurement sensitivity and accuracy (-75 dBm) ● Wide range bandwidth from 300MHz to 1500MHz ·Higher sampling rate (256 samples per cycle) to improve PD event detection accuracy ● Amplitude comparison can help approximate the location of PD faults ·Easy to use alarm settings that can be set separately for each channel ·Multiple communication methods (Ethemet, RS-485, RS-232, etc.) ● Built in Modbus, DNP3.0, and IEC 61850 protocol support The components of a typical PDM system: ·UHF sensors/couplers (internal, external, or drain valve sensors) · Single OCU supporting 1 to 6 sensors ·PDM main panel, including central processing unit (PD monitor) ·PD analysis and reporting software Optional: ·External OCU supporting 1 to 6 sensors ● An independent system cabinet that accommodates the PDM basic unit and one OCU Each external OCU is equipped with 1 Ethernet switch (fiber or copper)