Solid-State Point-on-Wave Fault Branch With Fault Clearing Capability

A Point-on-Wave Fault Branch (PWFB) can be used to create various balanced and unbalanced electrical faults in an experimental testbed. Utilizing fully controllable semiconductor switches, the PWFB offers unique advantages of precise fault creation and clearance at user-defined angles relative to the input reference voltage. In contrast to the traditional fault branches utilizing Four-Quadrant Switches (FQSes), which necessitate one or two capacitors or surge arresters for over-voltage protection per FQS, this paper proposes a PWFB design that incorporates a single capacitor to protect all FQSes from over-voltage conditions during various fault scenarios. The proposed method significantly reduces the overall size and cost of the PWFB. Furthermore, the paper introduces a novel FQS configuration, leveraging commercially available half-bridge Insulated Gate Bipolar Transistor (IGBT) and power diode modules. A PWFB prototype is developed and rigorously tested on two distinct systems: (i) a 5 kVA grid-connected transformer with an inductive load and (ii) a Single-Machine Infinite Bus (SMIB) system. These experiments demonstrate the single capacitor's efficacy in clamping peak voltages and validate the PWFB's ability to generate consistent and reproducible faults while protecting all associated FQSes.