How current-sensing power supplies differ from conventional power supplies

Isolation transformation of power supply mainly relies on the principle of electromagnetic induction for both voltage conversion and current conversion; at present, various types of power conversion are mainly voltage conversion, current induction power supply and people's common power supply is different, its theoretical basis stems from the electromagnetic induction principle of power conversion, the premise of its energy conversion is that the primary side (often the transmission conductor) has sufficient AC current transmission, and regardless of the Conductor current fluctuations, the power output should remain stable.

　　Therefore, the current-sensing power supply can not use conventional CT, plus a simple rectifier, voltage regulator circuit to obtain power. Use: Mainly used in power cable accessories, no DC power supply work site; energy harvesting CT starting current is small, energy harvesting CT with overcurrent protection device, can be used to install in the current range of larger cables, the output of a stable standard DC power supply.

　　General current transformer power take-off of the power supply is used in the way of capacitance (such as capacitors) energy storage, energy storage is relatively small (can be instantaneous high-power power supply to meet the current requirements of many high-voltage online monitoring systems and instrumentation power supply; a certain amount of power storage, line short-term blackout continue to be able to power supply), the current-sensing power supply (energy harvesting CT ) is the cable-type fault indicator communication terminals power supply is the ideal choice. Cost-effective and easy to install, taking into account the service life and the need for small maintenance workload, we recommend the use of super capacitors for energy storage components.

　　Current transformer taking power combined with battery storage power supply storage device is the battery, energy storage capacity is larger, a complete charging time is longer, for a few hours to a dozen hours ranging. After the charging is completed, it can protect the distribution automation terminal equipment for more than ten hours of power supply (the distribution automation terminal equipment can obtain normal working power through DC-DC converter). Intelligent ring network cabinet, ring network cabinet wireless temperature measurement system, high voltage overhead transmission line detection system is recommended to use capacitor or storage battery (lithium battery) as the energy storage element.

　　Current transformer power taking combined with battery energy storage power supply as shown in the figure, the circuit mainly includes power taking transformer, relay switch, rectifier bridge, energy storage battery and DC-DC converter part.

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