| 摘要 |
PURPOSE: A DPR(Digital Protection Relay) is provided to accurately detect generation of arc by differently applying an amplification ratio to compensation loss of light with respect to an input signal according to length of an optical cable for a point sensor. CONSTITUTION: A DPR includes an optical signal input unit(10), a signal conversion unit(20), an amplification unit(30), a MICOM(40) and an output unit(50). The optical signal input unit receives an optical signal through a point channel and a loop channel. The signal conversion unit converts an optical signal into an electric signal, and outputs the electric signal. The signal conversion unit converts an analog signal into a digital signal, and outputs the digital signal to the MICOM. The amplification unit selectively applies an amplification ratio with respect to the electrical signal based on a control signal and outputs the electrical signal. The MICOM determines an amplification ratio proportional to the length of an optical cable and outputs the amplification ratio as a control signal. If an amplitude of the electric signal is greater than the reference value, the output unit displays 1. If the amplitude of the electric signal is smaller than the reference value, the output unit displays 0. [Reference numerals] (10) Optical signal input unit; (20) Signal conversion unit; (30) Amplification unit; (40) MICOM; (42) Amplification ratio determining unit; (45) Comparing and determining unit; (50) Output unit; (AA) X times; (BB) X' times; (CC) X" times; (DD) Trip |
