Relay protection distance setting value check method based on measured impedance

The invention discloses a relay protection distance setting value check method based on measured impedance, comprising the following steps: determining a line to be checked and setting fault points; obtaining the measured impedance of protection related to the line after a minimum short-circuit fault occurs to the fault points of the line, and comparing the measured impedance with the setting value of each section of protection to get the action result of each section of protection; testing the selectivity of protection according to the action result of each section of protection and the time setting value thereof; setting fault points at the head and tail ends of the line to be checked, and checking the sensitivity of protection according to the measured impedance of protection after the minimum short-circuit fault occurs to the fault points of the line; calculating the minimum load impedance under the current operation mode, and testing whether the setting value of section-III protection can avoid the minim