| 摘要 |
PROBLEM TO BE SOLVED: To ensure safety by interrupting output from an inverter means when power interruption is detected at a power interruption detecting section, thereby eliminating the possibility of electric shock, even at the occurrence of power interruption. SOLUTION: When a switch 5 is opened, a system power supply 3 is interrupted or the line between a system interconnection inverter 11, and the system power supply 3 is disconnected, for example, the voltage waveform detected by a voltage detecting means 12 is varied from a normal waveform. Consequently, the interval of a zero-volt signal generated by a ZVP generating means 13 is lengthened or shortened. A power interruption detecting section 16 monitors a zero-volt pulse signal generated by the ZVP generating means 13. When the time interval is varied due to an abnormality caused by the interruption of the system power supply 3, a relay 17 is driven to produce a signal for opening the circuit. According to the arrangement, an electric worker can be protected against electric shocks, even if the worker touches a line in order to recover from power interruption. |
