Method for evaluating risk state of insulating layer of dry-type distribution transformer in alternate cooling and heating environment

The invention discloses a method for evaluating the risk state of an insulating layer of a dry-type distribution transformer in an alternate cooling and heating environment, and the method comprises the following steps: firstly, building an experimental platform for evaluating the risk state of the insulating layer of the dry-type distribution transformer, and obtaining the working voltage, temperature and humidity of the insulating layer of a transformer winding under rated operation according to the experimental platform; obtaining risk-resistant factors of the insulating layer of the transformer winding according to the dielectric loss tangent value, the dielectric constant, the partial discharge capacity, the partial discharge times, the temperature of the insulating layer of the winding and the current flowing through the winding during operation of the dry-type distribution transformer winding, which are measured by a simulation experiment; and calculating the risk assessment coefficient of the dry-type