Solid-state tap-changer of transformers: Design, control and implementation

Review on voltage‐violation mitigation techniques of distribution networks with distributed rooftop PV systems

“…In a mechanical tap changer, at least 20 cycles are required for measuring the RMS value of the bus voltage due to the delay time of the low‐pass filter. At first glance, the OLTC can mitigate the temporary voltages’ sag or swell but the mechanical parts of OLTC do not provide that because it has a specific taps number before malfunction [20]. Therefore, the operation time of high/MV OLTC is 30 s and operation time of MV/LV OLTC is 60 s [21].…”

“…Therefore, it is necessary to detect the zero crossing frequently for measurement and tapping. The other drawbacks of solid‐state devices are high conduction loss, high cost, the need for snubber circuit, and a proper protection equipment [20].…”

Power Loss Minimization for Transformers Connected in Parallel with Taps Based on Power Chargeability Balance

“…This is carried out keeping all transformers in the same tap position. In [17], the authors proposed an OLTC with solid-state tap-changer using power electronics. Results showed reduction in frictional losses, size of components and operation cost; nevertheless, solid-state tap changer components are more expensive in comparison with mechanical OLTC currently used.…”

Analysis of Affected Phenomena on Electronic Oltc Design for Distribution Transformers

“…While electromechanical OLTCs perform toadjacent-tap change in 2-10 s [8], solid-state OLTCs can do a tap-change in a half period of the fundamental frequency [9].…”