Common Diesel Generator Protection of power systems in DP classified vessels. By Shuang Li in partial fulfilment of the requirements for the degree of Master of Science in Electrical Sustainable Energy at the Delft University of Technology, to be defended publicly on Thursday July 14, 2016 at 9:00 AM. Supervisor: Dr.ir. Marjan Popov TU Delft Mr. Remmert Dekker Bakker Sliedrecht Thesis committee: Prof.dr. Peter Palensky TU Delft Dr.ir. Marjan Popov TU Delft Dr. Armando Rodrigo Mor TU Delft Mr. Remmert Dekker Bakker Sliedrecht Abstract For commercial and environmental reasons, DP vessel owners intend to operate with a reduced number of diesel generator sets, which often operate at very low power levels, to minimize the costs of fuel and maintenance. The solution for these phenomena is that vessel’s power systems are operated under one or more coupled bus-bars (closed Bus-Ties mode). The classification societies are now providing special rules which make it possible for suppliers of electrical systems to follow the above mentioned trend. The consequence, however, for the suppliers of electrical systems is that the electrical systems require much more complex and expensive control and protection systems than before to obtain the same proven levels of safety and reliability of power systems with separated bus-bars. (open Bus-Ties). The protection circuits currently used are based on functional requirements of the classification societies, where insufficient account has been taken of errors caused by the diesel engine governor and generator AVR faults in closed bus tie mode. They occupy 15%~20% of all faults, according to the International Marine Contractors Association [1]. And they are easy to cause a blackout in the vessel. For example, when 2 paralleled generators are running online under low loading condition. Then a diesel engine is over fueling. The faulty generator takes more load and the healthy generator takes less load. The healthy generator takes reverse power, and will be tripped by protection. After tripping the healthy generator, the faulty generator will be over frequency. At last, the faulty generator will trip, and a blackout occurs. The purpose of this "Common Diesel Generator Protection" is to detect the early stage failures of diesel engine and generator in a power plant to avoid power interruption caused by a so-called snowball effect (resulting in a blackout). The other purpose of this master thesis is building a generator model with full excitation system and diesel engine. Then, with the help of the test measurement from manufacturer and vessel, tune parameters in diesel generator model and validate it. The validated diesel generator model can be used for the further research in the company. Preface This report is the result of my master thesis as a master student in Electrical Sustainable Energy master program. The work of the thesis is done at Bakker Sliedrecht, a marine power system integrator, from November 2015 to July 2016. Many thanks are expressed to the persons who helped and encouraged me during my thesis. Firstly, I would like to thank Prof. Marjan Popov, who is my supervisor at the TU Delft, for his guidance and many excellent suggestions to my thesis. Thank you for your patience and encouragement. Next, I would like to thank Remmert Dekker, who is the R&D manager at Bakker Sliedrecht and also is my daily supervisor in the company. Thank you for giving me the opportunity to have this thesis. Thanks for your encouragement when I met difficulties. Thanks for helping me to arrange all affairs, which are related to my thesis, in the company. At last, I want to thank the PHD candidate Lian Liu and Master student Meng Zhang for the fruitful discussion about power system modeling. Shuang Li Sliedrecht, June 2016 Abbreviations AGP Advanced Generator Protection AVR Automatic Voltage Regulator CDG Common Diesel Generator protection system DGMS Diesel Generator & Monitoring System DG Diesel Generator DP Dynamic Positioning IEC International Electro technical Commission IEEE Institute of Electrical and Electronics Engineers IMCA International Marine Contractor Association OEL Over Excitation Limiter PF Power Factor PID controller Proportional Integral Derivative controller PLC Programmable Logic Controller UEL Under Excitation Limiter Content 1. INTRODUCTION ................................................................................................ 1 1.1 Background ......................................................................................................... 1 1.2 Problem statement .............................................................................................. 2 1.3 Organization of the thesis ................................................................................... 3 1.4 Previous work ..................................................................................................... 4 2. MODELING OF MARINE POWER SYSTEM ..................................................... 6 2.1 Single diesel generator model ............................................................................ 6 2.1.1 Generator model ................................................................................................. 6 2.1.2 AVR and exciter ................................................................................................ 10 2.2 Diesel engine model ......................................................................................... 11 2.2.1 Engine model .................................................................................................... 12 2.2.2 Governor ........................................................................................................... 13 2.2.3 Emission control................................................................................................ 14 2.3 Consumer load.................................................................................................. 14 2.3.1 Constant impedance load ................................................................................. 14 2.3.2 Constant power load ......................................................................................... 15 2.4 Validation .......................................................................................................... 16 3. THREE PARALLEL DIESEL GENERATORS MODEL .................................... 20 3.1 Active and reactive power droop ...................................................................... 21 3.2 Load step test ................................................................................................... 22 3.3 Excitation system and prime mover faults simulation results ........................... 23 3.3.1 Excitation system faults simulation results ....................................................... 23 3.3.2 Prime mover faults simulation results ............................................................... 27 4. COMMON DIESEL GENERATOR PROTECTION DESIGN ............................ 29 4.2 Excitation system detection .............................................................................. 29 4.2.1 Mechanism ........................................................................................................ 29 4.2.2 Expected value calculation ............................................................................... 31 4.3 Prime mover detection ...................................................................................... 35 4.3.1 Mechanism ........................................................................................................ 35 4.3.2 Expected value calculation ............................................................................... 37 4.4 Voting system ................................................................................................... 37 4.5 Operation window ............................................................................................. 38 4.6 Deviation detection simulation results .............................................................. 39 4.7 CDG structure in simulation .............................................................................. 42 5. CDG VALIDATION ........................................................................................... 45 5.1 Test setup ......................................................................................................... 45 5.2 Test setup generator validation ........................................................................ 51 5.3 CDG test result ................................................................................................. 57 6. FUTURE WORK AND CONCLUSION ............................................................. 69 6.1 Future work ....................................................................................................... 69 6.2 Conclusion ........................................................................................................ 69 7. BIBLIOGRAPHY ............................................................................................... 71 APPENDIX A ........................................................................................................................... 73 APPENDIX B ........................................................................................................................... 74 APPENDIX C ........................................................................................................................... 82 APPENDIX D ..........................................................................................................................