preparing a standard test block by cutting a basin insulator from a same batch and performing stress relief annealing repeatedly on the basin insulator, and obtaining an acoustoelastic coefficient of the standard test block;

wherein obtaining the acoustoelastic coefficient of the standard test block comprises:

applying different pressures to the standard test block, wherein each of the different pressures is greater than or equal to 0; and

sending an ultrasonic wave of a set frequency to the standard test block under the different pressures and obtaining propagation time, wherein the propagation time is propagation time of the ultrasonic wave in the standard test block under the different pressures, and obtaining the propagation time comprises: scanning, by an ultrasonic probe carried by a robotic arm, a surface of the standard test block to obtain a waveform, and after the waveform is processed into a text document, screening out peak values of a primary echo and a secondary echo in the waveform to obtain the propagation time;

obtaining a propagation velocity of the ultrasonic wave based on a propagation distance and the propagation time of the ultrasonic wave in the standard test block under the different pressures; and

obtaining the acoustoelastic coefficient based on the propagation velocity of the ultrasonic wave;

testing, based on the acoustoelastic coefficient, ultrasonic sound velocities of a spatial point of the basin insulator at different frequencies, and calculating and acquiring a stress distribution cloud map of the basin insulator,

wherein testing, based on the acoustoelastic coefficient, the ultrasonic sound velocities of the spatial point of the basin insulator at the different frequencies, and calculating and acquiring the stress distribution cloud map of the basin insulator comprise:

acquiring residual stress data of the basin insulator;

dividing a square calculation area along an outer diameter of the basin insulator;

calculating, based on the residual stress data of the basin insulator, an attribute value corresponding to coordinate data of a to-be-measured location in the square calculation area, wherein a calculation formula of the attribute value is as follows: Z_p=G_pW, where p denotes the to-be-measured location, Z_p is an attribute value of the point p, 72≥P≥1, G_p is a Green's function matrix of the point p, and W is a weight matrix; and

obtaining the stress distribution cloud map of the basin insulator based on the attribute value and the coordinate data of the to-be-measured location; and

performing reliability verification based on the residual stress data.