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Why CTDim?

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

A man in the foreground looks at a chart in the CTDim tool on his computer.

Compliance with standards

A CT and VT burden check avoids extensive under-burdening of instrument transformers and helps when specifying instrument transformers. The latest international instrument transformer standards are taken into consideration.

Cost savings

Enjoy savings in engineering and production costs by optimizing the CT and VT data.

Detailed reporting

Powerful reporting tool clearly documents the selection steps using flexible rich text format (RTF) that can be read by any word processing program.

Details of CTDim

CTDim Input window for the relevant current transformer data

CTDim standard features

Do you want the details of what you get with CTDim? Here they are:

  • Straightforward check of whether selected CTs and VTs data fulfill requirements of connected devices.
  • Both protective as well as metering CT cores are included.
  • Dimensioning of VT protective and metering windings.
  • 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, motor protection, and busbar protection, as well as a wide range of high impedance protection schemes.
  • Supports both non-gapped and gapped (non-remanence) CT cores:
    - IEC protective CT classes: 5P/10P, 5PR/10PR, PX (former BS cClass X), TPX, TPY, TPZ
    - ANSI protective C, T, and X classes
    - 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 for further analysis and even hardware testing.
  • Rct (internal CT resistance) estimation
  • Long list of supported meters and relays: Siemens SIPROTEC numerical relays (SIPROTEC 3, SIPROTEC 4, SIPROTEC 5), as well as a large number of non-Siemens devices

Additional information

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Visual CTDim Online Workshops

CTDim online workshops

Are you a new user of CDim and would like to get to know the main features? Have you recently updated your license to version 3.7 and would like to explore the latest enhancements? In a customized, practical online workshop, learn how CDim can assist you in optimizing your CT and VT settings. At the same time, you will expand your knowledge and capabilities around instrument transformers, nameplates, and related standards.

Choose from a variety of different workshop formats in the SiePortal.

Download CTDim workshops data sheet

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