Thinking outside the box

At Softstart UK we were recently challenged to think outside the box, to come up with a unique Soft Starter to create a multiple voltage solution.

The challenge was to create a 300A Soft Starter that would take an interlocked feed from multiple supply voltages via transformers with tappings of 11, 10, 6.6, 5 and 3.3kV with a required starting range and test measurement range of 10-219A at 3.3kV and 10-66A at 11kV.

This meant we needed to provide a unique solution as we also had to use ISO 9906:2012 to provide the standards for the measurement accuracies, using a standard medium voltage soft starter, this is an issue as the EPT electronic potential transformer is scaled for use with our own MCU for the control algorithm.

On this unit we needed to use the data for our own starting control and also for providing measured data accurate enough to comply with test certificates, so we had to redesign and create a measurement cabinet using separate CT and VT’s with calibration certificates.

We delivered the complete unit to our customer in the UK after many weeks of design and review on August 21st 2014 and the new pump test station will be commissioned shortly, the starting data can be monitored by Profibus via the SCADA to help the pump manufacturer produce their calibration certificates.

Now we have been asked to look at building a 600A version for 5MW at 11kV and 3MW at 3.3kV for the same customer.