4 
3.4.2.2.2 Direct current transmission 22 
3.4.3 Environmental influences 22 
3.4.3.1 Electrical fields 22 
3.4.3.2 Magnetic fields 23 
3.4.3.2.1 Alternating current 23 
3.4.3.2.2 Direct current 23 
3.4.3.3 Heat loss from power cables 23 
3.4.4 Cable laying and construction site safety 23 
3.4.5 Cable protection 24 
3.5 Additional components of the offshore wind farm 24 
4 Configuration, operation and decommissioning 24 
4.1 General 24 
4.2 Technical codes of practice 25 
4.3 Approvals from the responsible authorities 25 
4.4 Required certificates for the implementation phase 25 
4.5 Operation 28 
4.6 Decommissioning 28 
5 Other approval requirements 28 
6 Inspection services 29 
6.1 Preliminary remarks 29 
6.2 Production inspection 29 
6.3 Transport- and installation inspection 30 
6.4 Commissioning inspection 30 
6.5 Periodical inspections 31 
6.5.1 General 31 
6.5.2 Evaluation criteria for the periodical inspections 31 
6.5.3 Documents of the offshore wind turbines to be tested 31 
6.5.4 Scope of the periodical inspections 31 
Teil C: Time sequence 
1 General 33 
2 Development phase 33 
3 Design phase 34 
4 Implementation phase 34 
5 Operating phase 34 
6 Decommissioning phase 35 
Appendix 1 : Hull-retaining configuration of the substructure 39 
Appendix 2: Technical codes of practice and literature 42 
Appendix 3: Use of the observation method according to EC 7 and DIN 1054 46 
Appendix 4: Numerical models for geotechnical certificates 47 
Glossary 48 
List of abbreviations 50