| 摘要 |
PURPOSE:To protect the high sensitivity by an inexpensive protective device by connecting in series an overcurrent relay and a coil at the secondary side of a current transformer to generate a series resonance. CONSTITUTION:One end of a reactor 11 is connected to a power source. A star connection of one phase is formed by connecting capacitors 21a, 21b to the other end of the reactor 11. This star connections are prepared for 3 phases, the connecting point 6a for connecting in parallel one respective capacitors 21a, 22a, 23a of each phase and the connecting point 6b for connecting in parallel the other respective capacitors 21b, 22b, 23b are connected, and a harmonic filter 8 is formed as a neutral point 6. A current transformer 3 is inserted to the point 6, and a coil 5 and an overcurrent relay 4 are connected in series at the secondary side of the transformer 3. The inductance of the coil 5 is selected to perform series resonance in the substantially basic wave by the inductance of the coil 5, the capacitance and inductance of the filter 8 and the inductance of an overcurrent relay 4. |
