| 摘要 |
A self-powered current monitor for monitoring current in electric power systems. Various data relating to input currents may be displayed, such as current magnitude, current demand, and harmonics levels. Operating power is derived from one or more of the input currents. Ordinary current transformers may be utilized as input current sources. The power supply configuration may include a burden-reducing means to reduce the burden on input current sources during sampling of the input currents. The self-powered current monitor (1) includes a power supply circuit (3), current-sensing resistors (R1 and R3), an analog-to-digital converter circuit (5), a microprocessor circuit (6), and a memory circuit (9). Optional features include a display circuit (7), a burdenreducing circuit (2), input circuit protective elements (D1, D2, D3, D4, R2, and R4), an amplifier circuit (4), a user interface circuit (10), and an interface circuit (8) for communication to other equipment.
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