@article{GENERAL,
      recid = {11157},
      author = {Tsourakis, G and Prousalidis, J},
      title = {Stability and control of a ship electric grid emulator},
      journal = {Conference Proceedings of iSCSS},
      address = {2024-11-07},
      number = {GENERAL},
      abstract = {This paper presents an analysis of the frequency control  and stability of the ship electric power system emulator of  the School of Naval Architecture and Marine Engineering of  NTUA. The emulator is an AC three-phase microgrid,  comprising Generation, Distribution, Consumption,  Protection and Supervising Monitoring-Control sub-systems.  The generation system consists of (three) small AC  synchronous generators (5 to 6 kVA each), while its loads  are a passive RL load and a three-phase induction motor. As  the generators are of low power, they produce Low Voltage  (400 V), so no transformers are used in the system. The  system is an electric island as its frequency and voltage  are defined by its synchronous generators. 

Each generator  output voltage is regulated by its Automatic Voltage  Regulator. The generator rotors are driven by small  induction motors, which are in turn fed by the local  utility via power electronic converters. Therefore, each  induction motor emulates the prime mover for each generator  which results to a system with uncommon characteristics as  the system frequency is equal to the induction motor rotor  frequency, i.e. slightly lower than the frequency of the  voltage applied to the stator of each motor, assuming  normal operation (i.e. the generators supply the load, thus  the motors are loaded and their slip is non-zero).

In  order to analyze the frequency control of the system and  its stability, a MATLAB/Simulink model has been developed.  First, the primary frequency control is analyzed in this  paper and it is shown that the well-known speed-torque  characteristic of the induction motor defines the droop of  an emulated governor. Then, options for the secondary  frequency control are simulated and discussed. It is shown  that sharing of the load can be performed by modifying the  frequency of the voltage fed to each motor. Finally, the  system large-disturbance stability of the system is  analyzed with simulations of faults at the island system,  as well as at the motors. In the latter case, the voltage  stability of the induction motors affects the frequency  stability of the island system.},
      url = {http://library.imarest.org/record/11157},
      doi = {https://doi.org/10.24868/11157},
}