Thyristor Circuit Breaker Research Articles

A New Reclosing and Re-breaking DC Thyristor Circuit Breaker for DC Distribution Applications

The DC circuit breaker is essential for supplying stable DC power with the advent of DC transmission/distribution and sensitive loads. Compared with mechanical circuit breakers, which must interrupt a very large fault current due to their slow breaking capability, a solid-state circuit breaker (SSCB) can quickly break a fault current almost within 1 [ms]. Thus, it can reduce the damage of an accident a lot more than mechanical circuit breakers. However, previous DC SSCBs cannot perform the operating duty, and are not economical because many SCR are required. Therefore, this paper proposes a new DC SSCB suitable for DC grids. It has a low semiconductor conduction loss, quick reclosing and rebreaking capabilities. As a result, it can perform the operating duties of reclosing and rebreaking. The proposed DC SSCB is designed and implemented so that it is suitable for home dc distribution at a rated power of 5 [kW] and a voltage of 380 [V]. The operating characteristics are confirmed by simulation and experimental results. In addition, this paper suggests design guidelines so that it can be applied to other DC grids. It is anticipated that the proposed DC SSCB may be utilized to design and realize many DC grid systems.

A two-stage DC thyristor circuit breaker

High-current DC thyristor circuit breaker (TCB) devices, based on the parallel capacitor-current commutation-forced turn-off principle, require very large capacitors to effect correct operation as fault-current interrupters in electrical circuits. The commutation capacitors of TCB devices that interrupt current in a single switching operation absorb virtually all the electromagnetic energy stored in circuits, where they operate during the single switching process. These device types interrupt current extremely fast, but because of the scale of the energy transfer to the commutation capacitor, they are especially prone to producing short-duration switching overvoltages of excessive magnitude. A novel TCB device involving two switching operations or stages is presented and analyzed. With this device type, the circuit-stored energy is transferred to the commutation capacitor in two stages, which, in so doing, produces significantly lower switching overvoltages than the conventional single-stage TCB device. Results of a range of tests on a low-voltage two-stage TCB device and a high-power-prototype version are given together with the basis for determining their optimum design criteria. Comparative simulation studies are also provided. Finally, the limitations of TCB devices are examined and discussed in conjunction with cost comparisons and their merits and limitations for typical applications.

Application of thyristor circuit breaker to ohmic heating coil power supply systems.

New ohmic heating coil power supply systems which can generate high voltage are studied to insure their effective and economical use in nuclear fusion devices. Several systems are conceived by using normal, module, and multi-stage repetition types of thyristor circuit breakers. The operation of these systems are analyzed by digital simulation. It is seen that these thyristor circuit breakers are practical and applicable in ohmic heating coil power supply systems.

直流しゃ断用酸化亜鉛素子の熱応力解析

直流しゃ断用酸化亜鉛素子の熱応力解析

Development of Zinc Oxide Ceramic Energy Absorbers for DC Thyristor Circuit Breakers

The performance and the overall bulk of low-voltage DC thyristor power circuit breakers explained in this article tend to be determined by the media in which circuit interruption is performed. The zinc oxide ceramic energy absorber is an extinguishing medium with capabilities beyond the counterparts used in the conventional high-speed circuit breakers. The withstand-voltage, the interrupting time and the surge energy to be extinguished during interrupting are considered, together with parameter values specified in JEC Standard. Each energy absorber for the prototype DC 1500V-3000A thyristor circuit breaker consists of twenty four 115 mmo 15 mm thick zinc oxide ceramic elements and is capable of absorbing 400 kJ. The performance of these assembled devices in an energy absorber and incorporated with a thyristor circuit breaker as well as in the discrete form have been verified.

Development of Zinc Oxide Ceramic Energy Absorbers for DC Thyristor Circuit Breakers

Development of Zinc Oxide Ceramic Energy Absorbers for DC Thyristor Circuit Breakers

Circuit configurations and interrupting performances of Bi‐directional DC thyristor circuit breakers

Circuit configurations and interrupting performances of Bi‐directional DC thyristor circuit breakers

Ohmic heating coil power supply using thyristor circuit breaker in a thermonuclear fusion device

Ohmic heating coil power supply using thyristor circuit breaker in a thermonuclear fusion device

Thyristor circuit breaker for overcurrent protection of industrial d.c. power installations

The paper describes a d.c. thyristor circuit breaker (t.c.b.) used for high-speed overcurrent protection in low-voltage industrial power installations. The forced-commutation t.c.b. principle of operation, and an industrial model (rated at 600 V d.c., 800 A continuous current) that was subjected to tests under various duty conditions, are discussed. In conclusion, the presented contactless c.b. gives lower peak let-through currents, lower let-through I2t values, and clears faults at least ten times faster than its electromechanical equivalent. It may be advantageously used in networks with a fault-current rise rate up to 107 A/s. Therefore the t.c.b. may be considered an effective overcurrent protector for solid-state power devices in industrial applications.