Direct-current power transmission system for load lines

The invention discloses a direct-current power transmission system for load lines. A current-limiting reactor shows high impedance to higher harmonic waves, so that the higher harmonic waves in alternating current are filtered, and the distortion of the waveform of the alternating current is reduced; a silicon diode group or a three-phase full-wave bridge type pulsating rectifying device is used, so that the rectification effect is good, the harmonic component is less, and the investment is saved; a smoothing reactor filters the alternating current in current after rectification to ensure that the waveform of direct current after rectification is smooth; a direct-current capacitor shows a conducting state to the alternating current and a disconnecting state to the direct current, so that the alternating current can be further filtered; a current changer consists of a high-power insulated gate bipolar transistor (IGBT) with breaking capacity and a diode; a high-pass filter filters out higher harmonic current after current change, so that waveform distortion is reduced; and a current change reactor cancels out the capacitive current generated by an earth capacitor of a cable circuit. By the direct-current power transmission system, direct-current power transmission of the load lines is realized, the transmission capacity of electric energy is improved, and a conducting wire material is saved.