Reducing inrush current to reduce voltage dip when the transformer is energised

The problem in detail

Initial simulation studies of the transformer showed that there would be a significant voltage dip of up to 18% on the 132kV system when the transformer was energised which exceeded the limits stipulated by Scottish Power.

Finding the solution

Powersystems engaged Enspec to supply and commission a Vizimax SynchroTeq Plus to control the energisation of a 90 MVA 132/33 kV transformer at Aikengall II Wind Farm.

Making it all work

Enspec engineers reviewed primary plant layout to ensure the correct VT, CT, and circuit breaker positioning to allow the scheme to work and reviewed schematic drawings to ensure correctly integration of SynchroTeq Plus with the 132kV circuit breaker.

What that means for the project now:

Our engineers also identified and resolved a cross-phasing issue with the wiring installed.

The SynchroTeq Plus successfully reduced the transformer inrush current to 0.3pu and reduced the 132kV voltage dip to 0.6% to bring it in line with limits stipulated by Scottish Power.


The wind farm


Compact switching units


The wind farm

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