Puffer Type Gas Research Articles

Analysis of Nozzle Ablation Characteristics of Gas Circuit Breaker

Thermal puffer type gas circuit breakers have become a mainstream of high voltage circuit breaker, because they are compact in size and interrupt high current with low driving energy. In this type, ablation gas of nozzle material flows back to a puffer chamber during nozzle clogging, and it increases gas temperature and pressure in the puffer chamber. Namely, ablation gas plays an important role for puffer pressure build-up. However, the nozzle ablation characteristics are not yet well known. In this paper, we developed calculation program of nozzle ablation and using this program, we analyzed the amount of nozzle ablation and throat diameter after current interruption. The results found that the amount of nozzle ablation increases in proportion to the 2.2 power of interrupting current, and this calculation results agree fairly well with experimental results. It was also found that the dc component included in interrupting current greatly influences the amount of nozzle ablation. However, the phase of major current loop does not influence the amount of nozzle ablation.

Relation between Gas Blast Characteristics and Gas Passage Structure of the Thermal Puffer Type Gas Circuit Breaker

In order to evaluate thermal interruption capability of gas circuit breaker, we consider that mass flow rate in nozzle throat at around current zero points is the most effective parameter, because it is closely related to the cooling capability of arc. In thermal puffer type gas circuit breaker, the mass flow rates depend not only on puffer pressure but also on gas passage structure. So using a calculation program of gas blast characteristics taking both arc energy and ablation gas into consideration, the relations between the mass flow rate at current zero points and gas passage structure were investigated. As the results, we found that shorter gas passage length greatly increases the mass flow rate at current zero points, although it does not influence puffer pressure formation so much. We also found that optimum cross sectional area of gas passage is a bit smaller than that of nozzle throat. If thermal interruption limit were determined by mass flow rate at current zero points, the shorter gas passage length and optimized cross section area will increase the SLF interruption capability of thermal puffer type gas circuit breaker.This paper describes the detail of the results of simulations and discussions.

パッファ式ガス遮断器の電流遮断直後の極間過渡絶縁回復特性

パッファ式ガス遮断器の電流遮断直後の極間過渡絶縁回復特性

パッファ式ガスしゃ断器のノズル閉そく現象とそのしゃ断性能に及ぼす影響

パッファ式ガスしゃ断器のノズル閉そく現象とそのしゃ断性能に及ぼす影響

パッファ式ガスしゃ断器適用自励振動方式１２５ｋＶ ４ｋＡユニット直流しゃ断器のしゃ断特性

パッファ式ガスしゃ断器適用自励振動方式１２５ｋＶ ４ｋＡユニット直流しゃ断器のしゃ断特性

混合ガスを用いたパッファ式ガス遮断器の遮断特性

混合ガスを用いたパッファ式ガス遮断器の遮断特性

Investigation of Interrupting Performance of Puffer Type Gas Blast Circuit Breaker Under Various Nozzle Clogging Conditions

The interrupting ability of a puffer type Gas Blast Circuit Breaker (GCB) was investigated under various nozzle clogging conditions. A model puffer type GCB was used in the interrupting experiments, in which nozzle diameter, nozzle geometry and current wave form were varied. The following results were obtained from the experiments, 1 At a nozzle current density of 2.5-5.5kA/cm2, the low puffer pressure makes it possible to interrupt a current with a large dI/dt. 2 An increase of base gas pressure effectively contributes to improving interrupting ability. 3 The puffer chamber pressure rise which is caused by excess nozzle clogging does not improve interrupting ability.

A Method and Applications of a Theoretical Calculation for on-load Pressure Rises in Puffer Type Gas Circuit Breakers

An on load pressure rise in a puffer chamber of puffer type gas circuit breakers (GCB) is higher than a no-load pressure rise. A method of calculation of the on-load pressure rise has been developed. The calculation results show good agreement with the on-load pressure rises measured with an experimental puffer type GCB.