OSI Model for Smart Meters
The OSI model (Basic Reference Model) itself (as a set of services and protocols) is defined in the ITU-T X.200 series of publications (they are aligned with the corresponding ISO/IEC standards) which are publicly available (search www.itu.int).

As for smart meters, there are several methods based on the ISO modeling approach.  I know DLMS/COSEM (IEC 62056 series), so called "Digital Substation" (IEC 61850 series), TASE/TASE.2 telecontrol (IEC 60870 parts).  May be other exist.

If that is your research interest, i recommend you to take a look on ANSI C19.xx series protocols.  They are not ISO based, but technically they are much more perfect than any ISO based attempt.

In practice, proprietary protocols rules now...