A power supply and measuring device for an intelligent electronic device

Abstract

The present invention relates to a power supply and measuring device for an electronic device (e.g. an IED), which is configured to provide supervision, control, protection, communication and / or monitoring functionalities for LV or MV circuits or apparatuses. The power supply device comprises a current transformer, which is operatively associated to a main power line. An input section of the power supply device comprises a burden regulating stage that is configured to regulate the equivalent electric load at the secondary winding of said current transformer. An output section of the power supply device provides a supply voltage suitable to feed said electronic device.

Description

technical field [0001] The invention relates to the technical field of so-called Intelligent Electronic Devices (IEDs) for Low Voltage (LV) or Medium Voltage (MV) switchgear or installations. [0002] More specifically, the present invention relates to electronic power and measurement equipment for powering IEDs and providing accurate measurements of current flowing through power lines. Background technique [0003] As is well known, an IED is an electronic device configured to provide management, control, protection, communication and / or monitoring functions to LV or MV switchgear or devices, such as circuit breakers, disconnectors, contactors, etc. switchgear. [0004] In the framework of the present invention, the term "low voltage" or "LV" relates to voltages below 1 kV AC, while the term "medium voltage" or "MV" relates to voltages below 72 kV AC. [0005] As is known, IEDs are generally arranged so as to be fed by an electronic circuit which draws power from the main...

AI Technical Summary

Problems solved by technology

[0009] Currently available power and measurement equipment suffers from significant shortcomings

[0010] Due to the presence of multiple current transformers, they often have significant size and weight, which makes their installation / integration on distribution boards difficult

[0011] Furthermore, their implementation on an industrial scale is relatively expensive

[0012] Further, since the equivalent electrical load provided by the IED can change significantly during the operation of the latter (IED), the rated load of the main current transformer can be easily exceeded, causing said main current transformer to work in a saturated state

[0013] In this case, the main current transformer no longer operates linearly, and as a result deviates from its ideal characteristics, which can lead to harmonic generation and intermodulation distortion of the supply current (see Figure 4 )

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