Capacitive making of vacuum circuit breakers: Double-break vacuum circuit breaker is superior to single-break vacuum circuit breaker

2022 ◽  
Vol 204 ◽  
pp. 107692
Author(s):  
Yun Geng ◽  
Jun Zhang ◽  
Xiaofei Yao ◽  
Jun Fan ◽  
Qingbin Jin ◽  
...  
Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3217
Author(s):  
Yun Geng ◽  
Xiaofei Yao ◽  
Jinlong Dong ◽  
Xue Liu ◽  
Yingsan Geng ◽  
...  

The prestrike phenomenon in vacuum circuit breakers (VCBs) is interesting but complicated. Previous studies mainly focus on the prestrike phenomenon in single-break VCBs. However, experimental work on prestrike characteristics of double-break VCBs cannot be found in literature. This paper aims to experimentally determine the probabilistic characteristics of prestrike gaps in a double-break VCB consisting of two commercial vacuum interrupters (VIs) in series under direct current (DC) voltages. As a benchmark, single-break prestrike gaps were measured by short-circuiting one of the VIs in a double break. The experimental results show that the 50% prestrike gap d50 of each VI in a double break, which is calculated with the complementary Weibull distribution, was significantly reduced by 25% to 72.7% compared with that in a single break. Due to the voltage-sharing effect in the double-break VCB, scatters in prestrike gaps of each VI in a double break was smaller than that in a single break. However, without the sharing-voltage effect, d50 of the low-voltage side in the double break was 65% higher than that of the same VI in the single break, which could be caused by the asynchronous property of mechanical actuators, the difference of the inherent prestrike characteristics of each VI and the unequal voltage-sharing ratio of VIs.


2021 ◽  
Vol 4 (4) ◽  
pp. 58-64
Author(s):  
Valery A. LAVRINOVICH ◽  
◽  
Alexey A. PERTSEV ◽  
Lidiya A. Ryl’skaya ◽  
◽  
...  

Requirements for high-voltage vacuum circuit breakers for networks with a grounded neutral, which are stemming from the prospects of using vacuum circuit breakers in networks with the solidly grounded neutral are formulated. The arch chute design for a 110 kV single-break vacuum circuit breaker that takes into account the occurrence of repeated breakdowns is developed. The shielding system equalizes the voltage over the chute casing, decreases the electric field intensity at the “triple point”, protects the casing dielectric from becoming dusted with metallic contact parts erosion products, prevents the occurrence of cascade breakdown between the contact parts and central shield, and eliminates a possible decrease of the chute electric strength as it gradually works out its switching life. It is shown that the chute design includes measures to prevent the possibility of repeated breakdowns during disconnection up to class С1 according to GOST 52565-2006. It has been proven that for vacuum arc chutes for class С2 (for switching a capacitive load) it is necessary to develop a chute with two breaks between the contact parts or to connect two vacuum chutes in series. The shielding system adopted in the chute rules out the possibility of ceramic casing to become metallized, which decreases the chute electric strength as it gradually works out its switching life, and the vacuum arc transfer to beyond the inter-contact gap boundaries onto the central shield, the burnout of which results in that the vacuum arc chute loses its tightness and fully loses its functional properties.


2016 ◽  
Vol 63 (0) ◽  
pp. 43-60 ◽  
Author(s):  
Janusz BANDEL ◽  
Artur HEJDUK ◽  
Andrzej DZIERŻYŃSKI ◽  
Piotr KORYCKI ◽  
Henryk SIBILSKI

This paper deals with the surges generated in the network during switching operations and lightning surges. The level of both kinds of surge was compared with the required dielectric strength between the open contacts of 245 kV circuit breakers. Overvoltages greater than the electrical withstand voltage of the circuit breaker can cause arc ignition between the circuit breaker’s open contacts and power engineering service s have reported such cases. The results of such failures can be very serious. This is a problem especially for single-break circuit breakers, in which the stresses on the electrical insulation between the open contacts of the breaker are very high. A method for selecting lightning arresters to lower the overvoltages is proposed. The switching of short-circuit currents by a circuit breaker may cause a weakening of the circuit breaker chamber’s insulation and reduce its electrical withstand and durability.


2011 ◽  
Vol 383-390 ◽  
pp. 2287-2292
Author(s):  
Yong Yuan Wang ◽  
Sheng Hui Liu ◽  
Wen Ze Liu ◽  
Ke Ying Wang

The shunt power capacitors are used as a reactive compensator while vacuum circuit breakers are used to switch shunt capacitors in power grid. To research the high over-voltage during switching off the shunt capacitors and a vacuum circuit beaker restriked, the restriking model is built with three-phase vacuum circuit breakers, considering the capacitors’ energy storage characteristic and asynchronous operating. The over-voltage is harmful to the insulation and life-circle of the equipments and even threatens power system safe and stabile operation. The variation trends of both recovery voltage between the contacts and the capacitors voltage are theoretically deduced. The model based on a 220kV substation of Guangdong grid was built and the most serious case that breakers are restriked in two phases are numbered with EMTP. Compared with theoretical results, simulation results are valid and practical.


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