POWER CONVERSION DEVICE, DIRECT CURRENT POWER TRANSMISSION SYSTEM, AND POWER CONVERSION DEVICE CONTROL METHOD

PROBLEM TO BE SOLVED: To stop a plurality of unit converters in a short time when it was detected that overcurrent flowed through a group of the unit converters.SOLUTION: A power conversion device 102a comprises a plurality of groups of unit converters 106 in each of which groups a plurality of unit converters 108 each comprising a switching element allowing the voltage of a capacitor to output are connected in series, and converts system current, which is alternate current, into direct current or direct current into alternate current. The power conversion device comprises: an arm voltage command value generating unit 311 for generating and outputting a command value to the unit converters 108; an overcurrent detection unit 117 for detecting overcurrent flowing through the group of unit converters 106; and a communication interface unit 118 that transmits an operation command frame to each unit converter 108 at a prescribed cycle on the basis of the command value generated by the arm voltage command value generating unit 311, and that transmits a stop command frame for emergency stop to each unit converter 108 not depending on the prescribed cycle if the overcurrent detection unit 117 detected overcurrent. 【課題】単位変換器群に過電流が流れたことを検知した際に、複数の単位変換器を短時間で停止させる。【解決手段】電力変換装置１０２ａは、コンデンサの電圧を出力可能とするスイッチング素子を備える単位変換器１０８が複数直列に接続された単位変換器群１０６を複数備えて、交流である系統電流を直流に、または、直流を交流に電力変換するものであり、単位変換器１０８に対する指令値を生成して出力するアーム電圧指令値生成部３１１と、単位変換器群１０６に流れる過電流を検出する過電流検出部１１７と、アーム電圧指令値生成部３１１が生成した指令値に基づき、所定周期で各単位変換器１０８に運転指令フレームを送信すると共に、過電流検出部１１７が過電流を検出したならば、所定周期に依らず各単位変換器１０８に非常停止用の停止指令フレームを送信する通信インタフェース部１１８とを備えている。【選択図】図１