Analog-to-digital AD check method and system for measuring and controlling protection device

The invention discloses an analog-to-digital AD check method and system for a measuring and controlling protection device and belongs to the technical field of power system relay protection. Detectionof an analog quantity acquisition loop is carried out by comparing the protection number of the measuring and controlling protection device with corresponding measuring and controlling number data and with data of an external zero sequence. The analog-to-digital AD check method for a measuring and controlling protection device is characterized by at least comprising the following steps: step 1: calculating an effective value; step 2: calculating a mutation amount, wherein the mutation amount is an absolute value of the difference between the current effective value of the analog quantity andan effective value before two cycles; step 3: judging analog quantity mutation, wherein the analog quantity mutation is the corresponding mutation quantity greater than a mutation quantity threshold value set therefor; step 4: