CTDim - Current and voltage transformer selection, dimensioning and simulation

Current and voltage transformer dimensioning
Current and voltage transformer dimensioning

Electrical power systems are continuously evolving – influencing changes to even the secondary control and protection applications. Due to these impacts, engineers require a tool that accurately enhances the process of selection and optimization of instrument transformers to fit the modern power system protection and control equipment.   With CTDim, engineers can optimize the selection and dimensioning of instrument transformers, while meeting technical requirements of modern digital relays and decreasing costs.

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CTDim software

Select and optimize your instrument transformers to best fit the protection and metering applications

CTDim is a software tool for current transformer (CT) and voltage or potential transformer (VT / PT) selection and dimensioning. By optimizing selection of CTs or VTs data with respect to technical requirements of power system protection and/or metering, the engineering and production costs can be substantially reduced while maintaining technical excellence. CTDim provides clear benefits to your customers and all involved parties.

CTDim standard features

  • Straightforward check whether selected CTs and VTs data fulfill requirements of connected devices
  • Powerful documentation: Short and long reports are prepared automatically (easily editable rich text format RTF)
  • Supports overcurrent protection, distance protection, line differential protection, transformer protection, generator protection, busbar protection as well as a wide range of high impedance protection schemes
  • Both protective CT cores as well as metering CT cores included. Dimensioning for VT protective and metering windings covered. CT cores as per international standards supported:
    - IEC protective CT classes: 5P, 10P, 5PR, 10PR, PX (former BS Class X), TPX, TPY, TPZ and TPS
    - ANSI protective CT C-Class, and X-Class as well as
    - IEC metering classes: 0.1, 0.2, 0.5, 1, 3, 0.2S and 0.5S
  • Transient simulation of CT behavior (e.g. time-to-saturation) for all the above mentioned protective CT classes and protection devices. COMTRADE export function allows further analysis and even hardware testing
  • Large relay and metering instrument database: Siemens SIPROTEC numerical relays supported (SIPROTEC 3, SIPROTEC 4, SIPROTEC 5 included!), as well as large number of non-Siemens devices

Save engineering and production costs by properly selecting and optimizing your instrument transformer data

Benefits of using CTDim

  • Highly efficient current and voltage transformer data selection and dimensioning
  • User-friendly help-file supports selecting and optimizing process
  • Easy check of CT and VT burden avoids extensive under-burdening of instrument transformers and helps when specifying instrument transformers
  • Savings in engineering and production costs by optimizing the CT and VT data
  • Consideration of latest international instrument transformer standards
  • Automated generation of reports supports high quality of project documentation for your customers
  • Customized data base for metering devices speeds up calculation time
  • Exportable simulation curves enable further analysis and even relay testing with regard to CT saturation and DC-component, especially within systems with high X/R-ratios
CTDim releases

What’s new in CTDim

  • Technical dimensioning and optimization of selected CTs according to new IEC 61869-2 Standard (former IEC 60044-1, IEC 44-6) and ANSI C57.13-2008
  • High impedance protection scheme calculations include MOV and stabilizing resistor dimensioning
  • Powerful reporting tool clearly documents the selection steps using flexible rich text format (RTF) that can be read by any word processing program
  • Rct (internal CT resistance) estimation
  • Flexible customization of metering instrument data base
  • Export of results of transient simulation into COMTRADE file format


We are happy to answer all your questions

Looking for a trusted software to optimize your instrument transformers? Contact us to learn how CTDim can help you to optimally configure your equipment.

Interested in implementing CTDim?

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