On-line measuring device and method for electrical parameters of power transmission and distribution line

The invention discloses an on-line measuring device and an on-line measuring method for electrical parameters of a power transmission and distribution line. The on-line measuring device for the electrical parameters of the power transmission and distribution line comprises a plurality of measuring unit; each measuring unit communicates with a main station system through a data concentrator. Time synchronization is performed among the measuring units through a clock synchronization unit. The measuring units collect synchronous phasor data of corresponding measurement points under the same time point by each given time interval through one CT (i.e., current transformer) and one PT (i.e., potential transformer). The measuring units are also connected with a measuring current sensor and a protective current sensor through a measuring range switching circuit. When the power transmission and distribution line is in fault, a corresponding waveform can still be recorded by utilizing the measuring range switching circuit. The measuring units send the collected data to the main station system through the data concentrator. The on-line measuring device for the electrical parameters of the power transmission and distribution line utilizes the synchronous phasor measuring terminal DPMU that is specified to the power distribution system for improving the real-time performance and the accuracy of the power distribution network data acquisition.