The localized distributed transformer protection adopts the sub-machine mode, and transmits information such as AC sampling, input and parameters through the ring network. The information abnormality of the ring network will directly affect the reliable operation of the protection devices. In order to solve the problem that the transformer protection device does not operate correctly under various abnormal conditions of the ring network, the 220 kV transformer protection sub-machine configuration mode is taken for an example to analyze various abnormal situations that may exist in the ring network and the processing principles and solution are proposed. Based on the solution, the test environment is built and the rationality and feasibility of the solution are verified. The ring network anomaly solution can effectively improve the stability and reliability of the operation of the localized distributed transformer protection devices. This work is supported by Science and Technology Project of State Grid Corporation of China (No. JBB17201600240).