Smart Grid

What does it mean, technically and economically speaking, to switch from rotary to static frequency conversion?

shore connection

For naval ports and vessels, shore connection solutions have been around for decades. Depending on technical specifications and/or performance requirements, port managers have to make the right choices at engineering, installation and operation phases of their shore connection projects. To do so, they consider two relevant frequency conversion technologies used for shore power connection: static and rotary.

A challenge for port managers, especially in the naval industry, is to optimize the use of their shore power connection assets. Upgrading technologies such as traditional rotary systems to newer static alternatives helps to make the most of these assets. Traditional rotary frequency conversion while reliable, requires regular heavy maintenance, suffers fixed losses inherent to any electromechanical system having an efficiency of less than 85%. In addition, static technology has a higher efficiency, result from a purely electrical system. Static technology provides benefits in terms of reduced installation and maintenance costs and greater efficiency.

Comparison criteria

Feasibility studies on the decision to switch from rotary to static frequency conversion showed that the latter provided solid improvements for their operations based on several aspects, such as:

  • Implementation
  • Maintenance
  • Efficiency
  • Reliability
  • Further technical specifications: input power, short-circuit current, regenerative loads, downstream power quality, and sensibility to voltage dip and brownouts.

Both conversion technologies meet the basic requirements of shore connection projects if certain precautions are taken. However, based on shore power project key success factors like OpEx, CapEx, maintenance, and reliability, it is possible to compare the two and determine which overall system best aligns costs and performance objectives of any specific project.

More information in new technical papers

Daniel Radu and Seyba Cissoko,  part of Schneider Electric team of experts, have developed a document to provide maritime and naval -industry decision makers seeking to implement shore connection systems with guidance on how to select between rotary and static frequency conversion technologies. To download and find out more, please click:

Selecting the frequency conversion system for shore connection, 2015

Photo: By Service Depicted: Navy Camera Operator: PHC LARRY FOSTER [Public domain], via Wikimedia Commons


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