Continuous and periodic DC grid impedance measurement with MoMe and ONIS
The morEnergy DC MoMe is the first power quality and grid impedance measurement device for onboard, live DC grid monitoring.
Electrical behaviour of DC-grids
The electrical behaviour of ships with DC-grids are relatively unstudied and therefore unknown. DC grids of ships behave very differently to AC grids because of the high number of power converters, the more capacitive behaviour, and the lack of zero crossing in load currents.
Power quality and health monitoring
DC ships with a high number of switching converters and constantly changing load conditions should be monitored in real-time at the switchboard and the cabins to ensure safe operations and unnecessary tripping of protective devices.
Time- and frequency dependent grid impedance
Modern AC/DC and DC/DC converters could switch at a grid resonance frequency. The knowledge of resonance points can avoid such switching and prolong lifetime of electrical components like filters.
Technical specifications DC MoMe
- DC voltage measurements up to 1.000 V peak between phase and neutral or phase-to-phase conductors
- Precise current measurements up to 1.000 Apeak
- Current and voltage ripple detection up to 30 kHz
- Grid impedance measurement from 0 Hz to 30 kHz
- Power quality analysis according to IEC 60092-101 and IEC CDTR 63282
▪ Voltage tolerance
▪ Voltage cyclic variation deviation
▪ Voltage ripple
▪ Fast transients - Additionally, to today’s norms:
▪ Current ripple
▪ Power factor
▪ Voltage unbalance in bipolar systems
▪ Resonance detection
▪ Under- and over-voltage ride through - Health monitoring & power management
- Analysis of abnormal grid states
- Communications interface: WLAN, LTE, Ethernet, USB and CAN
- Time synchronisation via NTP or GPS
- Real-time monitoring of the PQ parameters via web interface
- Operating environment IP 20, 0 – °C
Increase System Performance
Reduce System Energy Loss
Avoid Resonance Effects
Periodic monitoring of DC grids
ONIS Online Network Impedance Spectrometer
With the ONIS, high frequency power quality measurements can be performed. MorEnergy specializes in network impedance measurement for the detection of dangerous resonances in the frequency range up to 500 kHz in the power network. This allows us to detect problems before they cause system or component failure.
Technical specifications ONIS
- Voltage range at the load and sense terminals (outer conductor-outer conductor voltage) ± 70 to max. 1000 Vpeak
- 50 Vrms to 690Vrms
- Measurement category of load and sensor connections CAT IV 600 V to 1000 V
- 50/60Hz Power frequency
- Maximum current of load connections 6 Apeak
- Frequency range of impedance measurement DC up to a maximum of 500 kHz
- ±5% measurement tolerance of impedance measurements
- Representation of the net impedance as magnitude & phase and Nyquist curve
- Automated three-phase impedance measurement
- Class A measurement accuracy for voltage measurements
- Sampling rate up to 1 Mhz for voltage measurements
- Three-phase measurement inputs for voltage measurement
- Supply voltage of the ONIS 12 Vdc ± 1.2 Vdc, max. 5A 60W
- Connection via 5.5/2.1 hollow plug
- Supply voltage of the supplied 12V power supply for the ONIS 100-240Vac 50/60 Hz
- Operating environment IP 20, 0-40°C, 75% RH
- Maximum operating altitude < 2000 m above sea level
- Dimensions (LxWxH) 54 cm x 45 cm x 14,5 cm
- Weight 13 kg
ONIS Types
ONIS 600: For networks with voltages up to 600 Vpeak (400 Vrms)
ONIS 1000: For networks with voltages up to 1000 Vpeak (690 Vrms)
Frequency ranges
- ONIS Classic: Frequency range from DC to 20 kHz
- ONIS Premium: Frequency range from DC to 150 kHz
- ONIS Plus: Frequency range from DC to 500 kHz
Introducing the Digital Twin Solution by morEnergy and Astrolkwx
ONIS 1000 for spectral grid impedance measurement
In modern power grids, the growing share of power electronics like inverters and switching-mode power supplies creates highly dynamic and complex topologies. Accurately determining spectral grid impedance through simulations alone can be unreliable due to many unknown or hard-to-estimate parameters. morEnergy and Astrolkwx, with over 15 years of experience, offer precise solutions for the design, testing, and grid interaction of renewable energy systems.
The morEnergy Digital Twin solution provides a cost-effective and efficient way to conduct detailed investigations within simulations, making it more employee-friendly. The challenge lies in converting real network data into a suitable network model for conclusive simulations.
Our Solution
Online Network Impedance Spectrometer (ONIS) and Power Quality (PQ) with 19” Rack Design
Measurement
Real spectral impedance data is recorded using the ONIS 1000 in the actual power grid. The ONIS 1000 (Online Network Impedance Spectrometer) offers spectral impedance measurement up to 690 VAC RMS on 50 Hz/60 Hz mains, with long-term spectral impedance measurement and monitoring up to 500 kHz total bandwidth. It also features simple operation and results visualization in the morEnergy Measurement Center.
Digital Twin
Simulations for investigation
When investigating real grid problems, it is more cost-effective and more employee-friendly to carry out detailed investigations within simulations. The difficulty lies in converting the real network data into a suitable network model for carrying out conclusive simulations.
Key steps in the Digital Twin process
Modelling
morEnergy’s impedance synthesis engine creates physically accurate, passive RLC models from the measured data.
Export
The resulting circuit is exported as a SPICE netlist or Matlab/Simulink model for use in simulations.
Simulation
The real measured, frequency-dependent behavior of a grid connection point is integrated into simulations using the generated model.
Application
A grid Digital Twin can be connected to PV inverter Digital Twins to simulate and assess stability as more inverters are added.
