Drive circuits for ultra-fast and reliable actuation of Thomson coil actuators used in hybrid AC and DC circuit breakers

Abstract

Thomson coil actuators (also known as repulsion coil actuators) are well suited for vacuum circuit breakers when fast operation is desired such as for hybrid AC and DC circuit breaker applications. This paper presents investigations on how the actuator drive circuit configurations as well as their discharging pulse patterns affect the magnetic force and therefore the acceleration, as well as the mechanical robustness of these actuators.Comprehensive multi-physics finite-element simulations of the Thomson coil actuated fast mechanical switch are carried out to study the operation transients and how to maximize the actuation speed. Different drive circuits are compared: three single switch circuits are evaluated; the pulse pattern of a typical pulse forming network circuit is studied, concerning both actuation speed and maximum stress; a two stage drive circuit is also investigated. A 630 A, 15 kV / 1 ms prototype employing a vacuum interrupter with 6 mm maximum open gap was developed and tested. The total moving mass accelerated by the actuator is about 1.2 kg. The measured results match well with simulated results in the FEA study.

Metal Oxide Varistor Design Optimization and Main Breaker Branch Switch Control of a Progressively Switched Hybrid DC Circuit Breaker

“…HYBRID CIRCUIT BREAKER COMPONENT OPTIMIZATION The key objective of this component optimization process is to increase uniformity in thermal stress on the MOVs in a hybrid DCCB even when the progressive switching scheme is employed so that no particular MOV performance is degraded differently over time. The FMS described in [22], [23] is chosen to use in a nominal 10kV /250A operation as it is rated for 15kV /630A. Initially, a number of combination for MOV clamping voltage is generated that satisfies the following constraint…”

“…V min and V max are chosen to be 5% and 85% of n * V s respectively to have a wide range of voltage combinations. Dielectric strength information of the FMS is extracted from its displacement curve [22]. It is used to calculate the switch turn-off time of each stage for all different combinations of the MOV blocking voltage so that the FMS contact separation can withstand the voltage differential induced by the MOVs as solid-state switches across them shut down progressively.…”

Thomson-Coil Actuator System for Enhanced Active Resonant DC Circuit Breakers

“…TCAs require a system including TC drivers, a DC power supply, a charging circuit, and a control unit. Various TC driver topologies were studied in [13] showing that the choice of the TC driver depends on the TCA requirements and design. Exciting the acceleration TC twice subsequently was studied in [14].…”

Modeling of Electrodynamic Phenomena in an Ultra-Rapid Inductive–Dynamic Actuator as Applied to Hybrid Short-Circuit Breakers—A Review Study

“…Concerning processes occurring in electrodynamic drives, previous papers on both using an analytical approach [1,2] and numerical-analytical approach [3,4] assumed several additional simplifications, the most important of which were: assumption of cylindrical symmetry of the system, simplification of the analysis to the skin layer only, omitting the influence of disc motion on IDD parameters, and, finally, assuming a priori knowledge of the excitation coil current (Thomson) or the distribution of the current radial density in the disc. Concerning these assumptions, the last important reports using the numerical approach [5][6][7][8][9][10][11][12][13][14][15][16][17] did not analyze all magneto-thermo-elastic phenomena or also assumed current extortion or quasi-steady state voltage.…”