Patent attributes
Capacitors (5a, 5b) are provided in the insulators of bushings (4a, 4b), respectively. One ends of the capacitors (5a, 5b) are connected to central conductors (3a, 3b) side, and the other ends are connected to a tank (1) side at the ground potential. When a discharge signal from the outside of the tank (1) reaches the capacitors (5a, 5b) through the central conductors (3a, 3b), the capacitors (5a, 5b) work as a filter to attenuate and prevent the signal in the frequency band of the discharge waveform from propagating to the inside of the tank (1). When an antenna (7) placed in the tank (1) receives a signal in the frequency band of the discharge waveform, a discharge detection unit (20) determines that a discharge inside the tank has been detected.