Ricerc@Sapienza

Due to the growing use of additional and regenerative energy systems such as solar, wind and biomass energy plants, the observance of strict grid feeding specifications is becoming more and more important for the manufacturers. With the help of the Grid Emulator, the various required power conditions as well as failures and interferences in the power system can be exactly generated.
The multi-level inverter technology allows a wide base frequency range from DC up to 1000Hz and an exceptionally high modulation bandwidth of 5 kHz. Therefore, harmonic distortion up to the 100th harmonic @ 50 Hz can be exactly reproduced. The system can easily and comprehensively be adapted to the various tasks to be carried out within the fields of R+D, laboratory, end-of-line testing and education. By means of the application software, the user is enabled to program the following parameters:
- variation of basic system voltages and frequency
- settings of phase relationship
- voltage drops in the whole network or individual drops per phase
- micro ruptures and flickers
- over- and under voltages
- voltage asymmetries
- superimposed harmonic and interharmonic voltage waveforms
- variation of phase angles
- special conditions for EMC testing
- transition from feeding to refeeding operation and vice versa
- analyses of energy flow

The Grid Emulator can also be used as a comprehensive 4 quadrant AC voltage amplifier with three independent phase inputs. Thus, the system can be integrated into a HIL “Hardware-in-the-loop”-circuitry by using an external Real-Time processor, permitting the user to run complex, high dynamic system analyses.
A third interesting way to operate the Grid Emulator is the “RL load mode”. In this mode, the operator can use the system as a programmable three-phase electronic load with programmable complex load RL impedance. This operation mode as well provides for an efficient feeding back of active energy into the public grid.