Published by Jonny Carlsson, Unipower AB, Case Study: Container Harbour in Gothenburg, Date: November 8th, 2010. http://www.unipower.se
The most important problem was the sags that were caused by the container cranes. The cranes created a lot of high reactive power during the start of the lift procedure. The high currents caused high demand on the transformer and also on the net supplying the harbour. The transformer protection had to be adjusted to cope with higher currents then what it was originally designed for. This put extra stress and heating on the transformers. The solution was to put in a fast 6 level capacitor compensation that could compensate for the high inductive reactive power during the start of the lift procedure. The installation was also verified and was proven to comply with the specification made by the Harbour personal thanks to the measurements.
Another problem that was discovered was the amount of current harmonics. Current harmonics cause heating of transformers. The lifetime of a transformer is significantly reduced if the transformer is over heated.
The K-factor measured show that the transformer has to be designed so that it can handle high current harmonics. A standard transformer is designed for K-factor 1.0.
The powerful report tool can also be used for statistical study of disturbances. Sag and swell disturbances can be caused by fault, switching or lightning in the electrical network. It is very important to be aware of the nature of the disturbances. Any disturbance below the green curve in the report below can cause malfunction and production losses.
About Unipower: Unipower AB offers a wide range of products for Power Quality measurements and Smart Grid systems.
Originating from a Swedish ABB company in the mid 80’s, Unipower has developed a competitive edge within the field of Power Quality and Smart-Grid solutions. We focus on norm compliance equipment, with a special focus on the requirements for power generation, transmission and distribution.
Our product lines reach from traditional portable PQ analysers to fully integrated and automated Power Quality Management systems for continuous supervision of the energy supply.
Website: unipower.se
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