| 摘要 |
PURPOSE:To enable monitoring of an input section based on input signals of two phases, by shifting the phase of one of two AC signals by a predetermined angle and performing vector addition or subtraction of the two AC signals to remove input signal of a power system and extracting error component produced at the input section. CONSTITUTION:A and B phase voltages of a power system are fed through input sections 1a, 1b a multiplexer circuit 2 and an A/D converter 3 to a CPU 4. The CPU 4 shifts the phase of one of the AC voltages by a predetermined angle in the overlapping direction, then a vector sum or difference of the voltage having the shifted phase and the other voltage is obtained and employed for removing input voltage from the power system and extracting error components produced at the input sections 1a, 1b. |
