Modular multilevel converter station current signal acquisition system and method

Abstract

The present invention proposes a modularized multi-level converter station current signal acquisition system and method, wherein: the power supply module is a multi-port high-redundancy power supply with low insulation withstand voltage, and the three-phase MMC sub-module with the closest electrical distance The internal DC capacitors are interconnected; the current sensor is a Hall-type current sensor with a low insulation withstand voltage of the kilovolt level, which is connected in series in the MMC converter station line, and collects the current of the three-phase upper and lower bridge arms and / or the total current of the DC port on the spot. The quantity output is connected with the digital-to-analog conversion collector; the digital-to-analog conversion collector accepts the current signal collected by the current sensor, converts it into a digital signal, and transmits the digital signal to the controller of the MMC converter station through an optical fiber communication link. The invention can reduce the withstand voltage requirement of the acquisition system, reduce the difficulty of system design, realize the application of the Hall type current sensor in the flexible direct current transmission project, and improve the reliability of the system.

Description

technical field [0001] The invention relates to the fields of flexible direct current transmission technology, power electronics technology and the like in power systems, in particular to a novel modular multilevel (Modular Multilevel Converter, MMC) converter station current signal acquisition system and method. Background technique [0002] Voltage source high-voltage direct current transmission technology (VSC-HVDC), due to its control flexibility, is especially suitable for renewable energy grid connection, passive network power supply, urban power grid power supply and asynchronous AC grid interconnection and other occasions. Therefore, the research on VSC-HVDC has received extensive attention from academia and engineering circles in recent years. [0003] Traditional VSC-HVDC adopts two-level or three-level topology, and uses direct series connection of multiple switching devices to meet the requirements of voltage levels. However, this method has high requirements fo...

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Problems solved by technology

[0005] In view of the current MMC flexible direct current transmission project, the commonly used Hall-type current sensor cannot be applied due to the problem of insulation withstand voltage, and the photoelectric current sensor is expensive. The purpose of this invention is to propose a new MMC converter station current signal The acquisition system and method can reduce the withstand voltage requirements of the acquisition system, reduce the difficulty of system design, realize the application of Hall-type current sensors in flexible direct current transmission projects, and improve the reliability of the system

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