The establishment of idealized model is the practical application of scientific method. Particle, point charge, light spring, ideal voltmeter, ammeter and ideal transformer are all idealized models.

A, particle as an idealized model ignores the size and shape of the object, so A is wrong;

B, as an idealized model, point charge ignores the size and shape of the object; So, B is wrong;

C, the ideal voltmeter thinks that the voltmeter internal resistance is infinite, and the ideal ammeter ignores the ammeter internal resistance. So, c is wrong;

D, the ideal transformer ignores the magnetic loss of the core and the copper loss in the coil, and thinks that there is no energy loss. Therefore, d is correct.

Therefore, choose: d.