| 摘要 |
PURPOSE:To simplify the circuit constitution and cheapen the price and elevate the accuracy and detect the inferiority of the analog input circuit of a digital protective circuit without stopping the protective relay function. CONSTITUTION:This device is equipped with a superimposing circuit 24, which superimposes the signal Eref for monitoring outputted in optional cycles from a monitoring signal circuit 23 on the system input different in frequency, an A/D converter 12, which coverts the analog signal outputted from this superimposing circuit 24 into a digital signal, a digital filter, which abstracts only the data relevant to the monitoring signal Eref from the output of this A/D converter 12, and a monitor, which monitors the magnitude of the output of this digital filter. |
