1. Frequently occurring problems are resonances.

When the measurement shows, that a resonance occurs in a particular frequency range, the causes are often hard to figure out. By using the simulation as a tool, the resonance point and its effects on the supply voltage can be calculated and the sources can be found. Filter solutions can be planned based on the simulation model.

2. The connection of new loads to an existing network may cause unknown distortions.

Fixing such problems during or after commissioning, leads to high and unnecessary costs. By means of simulation, it is possible to create safety for the planned investment in advance. The distortions and other effects on the grid can be calculated during planning and mitigation solutions can be planned.

• High- and Low-Voltage grids
• Interactions between the grids
• Load Flow Analysis
• Short Circuit Analysis
• Harmonics (with load flow)
• Interharmonics
• Grid Impedance (i.e. resonances)
• Switching
• Transients
• Switching Ripple

With the help of a professional grid simulation, the effects of new consumers on a grid can be determined before installation. Appropriate measures and solutions for optimizing the power quality can already be considered during the planning phase. The risks during commissioning are minimized. This saves costs and ensures a scheduled start.

Power Quality problems can also be analyzed by means of simulation, when a measurement analysis only shows the effect, but can't localize the cause. The calculations are performed by our network simulation specialists. For our simulation studies, we use the well known software PowerFactory, which is developped by DIgSILENT.

The electrical supply grid, specified by the customer, will be transferred to a complex model for the simulation. After a suitable reduction of the elements of the grid, to be evaluated, the grid elements required for the simulation (eg short-circuit power, transformer data, cable data, etc.) will be placed in the model. If necessary, replacement circuit diagrams are developed for components or parts of the grid, which represent the original elements in a suitable manner.

On the basis of the digitized replacement grid, load and operating conditions are simulated in the next step. The evaluation includes, bar graphs for harmonics, line diagrams for impedance and time sequences, eg U (t) and I (t), as well as single line diagrams. Optionally, results of the simulation can also be incorporated into other formats for further processing, e.g. MS Excel.

The documentation of the simulation results is presented in a detailed report.

Info: If the customer can not select load or switch states for the graphical display of the simulation results, the contractor will make an appropriate selection of calculations and case studies, based on the problem description of the client.

The following technical data and informations are required for development of the model:

• Actual state of the test object by means of photographic documentation and descriptions
• Problem description
• Single line diagram
• Cable data, transformer data and, if applicable, generator data
• Harmonic distortion of the feeding grid
  If there are no data for the harmonic load, these can be determined by means of a harmonic measurement. Alternatively, appropriate data of the client can be used for the simulation.
• Technical data of electrical consumers and equipment
• Harmonic currents (possibly with angular reference), characteristic curves, circuit diagrams, data sheets, etc.
• Operating conditions / load conditions

• Project discussion and consultation
• Preparation and coordination of a short project description
• Verification of the provided basic data (data collection by third parties is not included and is billed according to expenses if necessary)
• Creation of the simulation model with DIgSILENT PowerFactory
• Documentation of the simulation (diagrams of the study cases showing impedance curves, current and voltage harmonics, grid diagram, descriptions and comments)
• Sending of the complete report by e-mail (pdf)

• Determination of the filter requirements by taking the targets into account
• Study of suitable and technologically feasible filter solutions
• Selection of the most economically and technically appropriate solution
• Adaptation of the simulation model of the previously performed grid simulation
• Creation of the documentation of the modified simulation (diagrams of the study cases showing impedance curves, current and voltage harmonics, single line diagram, descriptions and comments)
• Send the complete report by e-mail (pdf)
• If required, discussing the filter solution with the client and preparing requests for quotation at suitable suppliers

• The basic data should be provided by the client as completely as possible and should show representative load conditions in order to achieve a practical simulation result.
• Services beyond the scope described above will be billed according to our hourly rates applicable at the time of the service according to our price list.