Direct-current circuit breaker

A direct-current circuit breaker that interrupts a direct current at a current zero point formed by superimposing an oscillating current on the direct current flowing through a direct-current line, the direct-current circuit breaker comprising:

• a circuit breaker inserted in the direct-current line;
• and
• a circuit portion connected in parallel to the circuit breaker unit to generate the oscillating current, wherein
• the circuit portion includes:
• a capacitor and a reactor connected in series to each other to generate the oscillating current;
• a high-speed closer connected in series to the capacitor to perform closing for forming the current zero point;
• and
• a lightning arrester to reduce an overvoltage of the capacitor, the lightning arrester being connected in parallel to the capacitor and the high-speed closer,
• the circuit breaker and the high-speed closer are aligned in a first direction with a distance provided therebetween, the distance being equal to or longer than a spatial distance for insulation between sites having potentials different from each other,
• the capacitor and the lightning arrester are aligned in a second direction that is a direction intersecting the first direction with a distance provided therebetween, the distance being equal to or longer than the spatial distance for insulation between sites having potentials different from each other, and
• a combination of the circuit breaker with the high-speed closer and a combination of the capacitor with the lightning arrester are aligned in a third direction that is a direction intersecting the first direction and the second direction with a distance provided therebetween, the distance being equal to or longer than the spatial distance for insulation between sites having potentials different from each other.