ONIS
Online Network Impedance Spectrometer
Discover the ONIS
ONIS (Online Network Impedance Spectrometer) is a state-of-the-art device designed for high-frequency power quality and network impedance measurements up to 500 kHz1. It detects dangerous resonances to avoid potential problems and ensures the reliable operation of high-power inverter systems under the most challenging conditions. With its precise control and local problem-solving capabilities, the ONIS is characterised by its special impedance measurements, advanced monitoring and analysis functions, making it essential for maintaining the stability and efficiency of electrical grids.
See what ONIS can do
Comprehensive impedance analysis
With our powerful ONIS system, you can carry out detailed impedance measurements up to a frequency of 500 kHz. The intuitive Measurement Center software provides you with precise results in a matter of seconds. The visualised data in the form of heat maps and root locus plots provide a comprehensive overview of the impedance behaviour of your network. Quickly identify bottlenecks and optimise your networks.
Diving deeper into the network with sub-cycle impedance measurement
With our sub-cycle function, you can customise your impedance measurements precisely to your individual requirements. The targeted excitation of frequency ranges gives you valuable insights into the behaviour of your components and systems. Whether you want to investigate the properties oaf new materials, optimise the performance of high-frequency circuits or ensure the quality of components – our solution offers you the flexibility you need.
Discover the full potential of ONIS with the Measurement Center
Fields of application
Photovoltaic power plants – preventive maintenance and troubleshooting
With the ONIS measuring device, currents, voltages and impedances of renewable generation systems and their grid connection points can be measured and analyzed at high frequency. This allows status information from relevant component groups and the grid connection to be determined. In addition, recommendations for action can be developed for the controller parameters and the filter design of the installed inverters in order to optimally adapt the systems to the local connection point and thus avoid failures due to inadequate control.
Electric drive of lift systems – Testing and troubleshooting
With our ONIS technology, we can determine whether the control system is stable or whether a component in the electric drive system is defective. We determine the causes of faults and can make recommendations based on our measurements to make the system stable and reliable.
Electric drive of rail vehicles – Testing of electric railroads
With our ONIS 36kV technology, we can determine whether the railway’s control system is stable or unstable. We determine the causes of instabilities and can therefore issue a recommendation after our measurements to make the system stable.
Fields of application
Power Line Communication
Power Line Communication (PLC) is used for smart metering systems and operates in the frequency range from 9 kHz to 487 kHz, in accordance with the CENELEC A, B, C, D, FCC and ARIB standards. This technology utilises existing electrical infrastructure for the transmission of data. However, transmission interference can occur due to the specific properties of network components and cables. Causes of this can include supraharmonic emissions, which amplify the background noise, as well as series resonances, for example due to LCL input filters of other devices, which create a low-impedance path for targeted emissions. In addition, the signal attenuation varies with the distance between the transmitter and receiver.
Power Quality
The increase in decentralised energy generation and advanced electronic devices based on active power electronics leads to significant fluctuations in grid impedance at higher frequencies. These changes, caused by additional inductances and capacitances (such as LCL filters and DC systems), result in a large number of parallel and series resonances. This causes problems such as increased harmonic currents and voltages, overheating of devices, noise generation, additional losses or malfunctions of devices and digital communication. Current grid codes (e.g. DACH-CZ, TOR, TAR) integrate resonance factors into the determination of emission limit values for harmonics individually for each harmonic.
Development of charging parks for e-mobility
Determination of dependencies and influences of different e-car models on each other.
Fingerprint of electrical system health
Focus on the health of the system from the outset and create the basis for a long and efficient service life.
Control of supraharmonic emissions
Supraharmonic emissions up to 500 kHz are becoming increasingly noticeable. These emissions are often caused by active power electronics, such as those used in photovoltaic systems, chargers for electric vehicles, wind turbines, heat pumps and similar technologies. Supraharmonic interference can affect the quality and stability of the power supply. It is therefore crucial to measure the grid impedance under different conditions in order to identify and resolve potential problems.
Example cases:
Within a customer installation:
Here, measuring the grid impedance helps to understand the effects of supraharmonic emissions on the internal power grids. Especially in complex systems where numerous devices with active power electronics are operated, mutual interference often occurs. Early detection through impedance measurements makes it possible to take appropriate measures to ensure power quality.
To the substation:
In this case, measuring the grid impedance makes it possible to analyse how supraharmonic emissions propagate over longer distances in the power grid and what effects they have on the infrastructure and other consumers. Transmission over long distances in particular can lead to significant changes in impedance that affect the efficiency and reliability of the energy supply.
Charging stations for electric vehicles:
Charging stations are typical sources of supraharmonic emissions, and even if they are not actively used, they can influence the local power grid. By measuring the grid impedance, potential disturbances can be recognised and corrective measures can be initiated if necessary.
In all cases, the measurement of grid impedance enables a precise diagnosis of the status of the power grid caused by supraharmonic emissions. This is a crucial step in ensuring high power quality and avoiding problems that can be caused by modern electronic devices and equipment.
What makes ONIS special?
Early detection of problems
Patented Online Network Impedance Spectrometer (ONIS) enables high-frequency power quality measurements and detects dangerous resonances up to 500 kHz in the power grid.
Reliable operation of inverter systems
Ensures the reliable operation of high-performance inverter systems even under the most difficult conditions.
Precise control
Precise management of loading speeds, lift movements and energy control.
Local identification and resolution of vulnerabilities
On-site analyses help to precisely identify weak points in the electricity grid and offer expert suggestions for solutions.
Specialised mains impedance measurement
This function sets ONIS apart from the competition by providing precise insights into the grid impedance.
Advanced monitoring and analysis
High-frequency measurement and analysis of currents, voltages and impedances in renewable energy systems for preventive maintenance and troubleshooting.
ONIS Models
Classic
Maximal frequency up to 20 kHz
Premium
Maximal frequency up to 150 kHz
Plus
Maximal frequency up to 500 kHz
Additional modules
Customise your ONIS with our optional modules.
Sub-Cycle Impedance
Determine the so-called sub-cycle impedance, i.e. the impedance of a specific period of the periodic sinusoidal oscillation of the mains voltage. The sub-cycle impedance is of interest because some power electronic systems are particularly active at the voltage maximum of the sinusoidal mains voltage.
Battery box
Enjoy maximum flexibility with our battery box. Measure independently of the mains and eliminate interfering mains influences on your impedance measurements.
Network nominal frequency extension
In its basic state, the ONIS can be used to measure impedance at grid connection points with a nominal grid frequency of 50 and 60 Hz. If the ONIS is to be used in networks with other nominal network frequencies, nominal network frequencies from DC to 800 Hz can be realised.
Current and power module
Record in-depth electrical parameters. This module allows you to analyse currents and power in detail, including high-frequency components. Calculate complex electrical outputs and gain valuable insights into your system.
Mesh simulation according to DIN IEC/TS 62578
Mains simulation in accordance with DIN IEC/TS 62578 is a three-phase measurement and reference tool that is used to evaluate interference emission values and harmonic distortions of inverters.
Digital Twin
The Digital Twin module makes it easy to analyse the network impedance measurements recorded with the ONIS in simulations or in the laboratory. The module is divided into two sub-modules: impedance synthesis and impedance replication.
PQ Pro module
The PQ Pro module gives you a complete picture of harmonics on the grid connection under investigation. The ONIS makes it easier to visualise not only the symptoms but also the causes of harmonics. All relevant characteristic values are calculated and continuously recorded in accordance with DIN EN 61000-4-7.
Experience Excellence – Request your personalised offer
- The maximal frequency depends on the purchased model. Only ONIS Plus model can measure up to 500kHz. See ONIS variants. ↩︎