Does anybody know of a useful communication framework, which provides basic services to build a telecontrol application on top of it (e.g. a protocol converter)?
Look into the Utility Communications Architecture (UCA) and the Generic Object Models for Substation and Feeder Equipment (GOMSFE). These EPRI standards are being developed into IEC61850 and provide an excellent framework for telecontrol applications in the energy utility industry by providing flexible standardized models for many types of utility objects. The models would enable a framework for the interchange of data between many different protocols, including the majority of which provide no modelling features. See ftp://ftp.sisconet.com/epri/uca2.0/intro.zip for a brief intro.