SynchroTeq Plus - reducing voltage dip and inrush current

Posted by: Tim Rastall MEng MIET
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SynchroTeq Plus - reducing voltage dip and inrush current

The commissioning and installation of a SynchroTeq Plus controlled switching unit at a wind farm has exhibited excellent performance and resulted in a maximum inrush current of 0.3pu for energisation of a 90MVA transformer. The unit successfully mitigated inrush current and fully satisfied the requirements specified for Grid connection.

The device addressed a voltage dip non-compliance issue identified in a P28 site study that highlighted a maximum voltage dip of 17.88% for transformer energisation. This exceeded the 12% as specified in Grid Code Section CC.6.1.7, and an inrush current mitigation solution was needed. A SynchroTeq Plus was installed to control transformer energisations.

On-site commissioning helped to characterise and tune circuit breaker operation times ensuring that the SynchroTeq Plus can target a 2ms window on the wave and reduce energisation inrush current.

Final commissioning results were excellent with a max. inrush current of 0.3pu obtained. This lead to a 0.63% voltage dip at the POC. A marked improvement over the 17.88% voltage dip previously predicted, and the 6.46% measured on-site without the SynchroTeq Plus.

The SynchroTeq Plus successfully mitigated inrush current and achieved a POC voltage dip that complies with Grid Code.

The image shows Post-tuning Voltage Dip