1. A method of converting elements of a file that is based on a first standard to elements of a file that is based on a second standard, the standards being IEC 61970 and IEC 61850, a file in IEC 61970 being coded according to CIMXML (RDF Schema) and a file in IEC 61850 being coded according to SCL (XML Schema), the data in each file being modelled by using a UML model for the corresponding standard, and the conversion being performed by using mapping rules generated based on the UML models of the two standards and a UML model of mappings between the two standards; comprising: selecting at least one element of the file that is based on the first standard; identifying and selecting all the elements referenced by the at least one selected element; recursively identifying and selecting all the elements referenced by the previously selected elements until none of the selected elements reference any element that is not selected, and converting the selected elements, the conversion being performed by using the mapping rules.