摘要：高压真空断路器在我国供电系统中的应用始于1978年，其重量轻，结构简单，使用寿命长等优点很快被电力部门运行、检修和技术人员认可。早期国内生产的高压真空断路器质量不够稳定，操作过程中载流过电压偏高，个别真空灭弧室还存在有漏气现象。
1 我国高压真空断路器的现状
高压真空断路器在我国供电系统中的应用始于1978年，其重量轻，结构简单，使用寿命长等优点很快被电力部门运行、检修和技术人员认可。早期国内生产的高压真空断路器质量不够稳定，操作过程中载流过电压偏高，个别真空灭弧室还存在有漏气现象。至1992年天津真空开关应用推广会议时，我国真空断路器的制造技术已经进入了国际同行业同类型产品的前列，成为我国高压真空断路器应用，制造技术新的历史转折点。
2 真空灭弧室的漏气问题
新一代高压真空断路器普遍使用纵向磁场灭弧原理和铜铬触头材料，其目的是减少触头烧损，提高电气使用寿命。导电杆同心度调整不当，将使纵向气线、陶瓷、可伐—金属封接强度不够稳定，致使真空灭弧室漏气。
真空灭弧室的波纹管绝大多数都是采用0．15mm厚度的不锈钢油压成型的。高压真空断路器应用环境的污秽等级、湿度、盐雾等选择不够合适，有害气体、凝露造成波纹管点状腐蚀，导致波纹管和盖板及封接面的漏气。
保证高压真空断路器同心度的调整，合理的选择使用和储存环境，是解决真空灭弧室漏气问题的重要措施。
3 合理选择高压真空断路器电气寿命
高压真空断路器的电气寿命是指设备技术条件中规定的和型式试验中实际进行的满容量开断次数。应用中高压真空断路器触头是不能维修和更换的，要求高压真空断路器有足够高的电气寿命是很有必要的。
新一代真空灭弧室采用了纵向磁场电极和铜铬触头材料。纵向磁场电极成倍的降低了短路开断电流作用下的电弧电压(电弧能量)，并使电弧在触头表面均匀分布；铜铬触头材料降低了单位电弧能量所造成的触头烧损量。这两者的有机结合，使得高压真空断路器的电气寿命有了突破性的提高。当前，我国高压真空断路器再开断、关合能力等方面的性能是比较高的，也是比较稳定的。
我国早期高压真空断路器电气寿命只有30次，运行*长的已有20余年，在电力系统至今还没有发现高压真空断路器因为短路开断电流的电气寿命问题而退役，也没有发现因为短路开断电流的电气寿命短导致事故发生，这就充分说明这些高压真空断路器基本上能够满足电力系统对于短路开断电流电气寿命的要求。所以，高压真空断路器的短路开断电流电气寿命并不是越高越好。
4 重视高压真空断路器机械参数调整
高压真空断路器有许多的机械参数，如合闸速度、分闸速度、触头行程、触头合闸弹跳时间、触头分闸反弹幅值等。这些机械参数都是用以保证高压真空断路器技术性能而设定的。
我国高压真空断路器的机械寿命一般为10000～20000次，正在开展将机械寿命提高到30000～40000次的研究工作，电磁操动机构结构简单、性能可靠、调整维修方便、运行人员习惯使用和维修而被广泛使用；有些地方也有习惯使用电动弹簧操动机构的。操动机构在高压真空断路器机械结构中是*为复杂、精度要求*高的部分，多数制造厂生产条件是难以满足加工精度要求的。
为了保证高压真空断路器的可靠性，我国对高压真空断路器采取了分装式结构，即将操动机构与断路器主体二者分开，由生产条件比较好的工厂集中生产操动机构，然后再将机构的输出轴与断路器合而为一，所以机械参数的合理配置，直接关系到高压真空断路器的技术性能和机械寿命。理想的机械参数调整，对于高压真空断路器的机械性能十分要害。满足的缓冲特性应该是运动部件接触缓冲瞬间，缓冲器提供较小的反力，随着缓冲距离的增加，缓冲特性迅速变陡，较大可能地吸收分离能量，达到限制分闸反弹和分闸行程的目的。
5 提高高压真空断路器动作的可靠性
我国高压真空断路器由于国产材料、元件和标准件的质量问题以及传统的产品设计观念，致使其机械可靠性和机械寿命还不够十分理想。
(1)把握真空断路器的基本结构，熟悉其技术性能指标，合理选择使用条件，密切与制造的信息联系，准确地应用高压真空断路器先进技术功能；
(2)认真做好高压真空断路器机械参数调试工作，严格机械参数指标要求，才能保证其基本功能；
(3)规范备品备件治理和储存，保证备品备件的技术性能指标和质量的一致性、通用性和可靠性；
(4)做好高压真空断路器的运行记录和事故分析，总结经验，和制造部门通力合作，不断提高真空断路器的先进性，可靠性和经济性。
6 高压真空断路器的温升
高压真空断路器的回路电阻是影响温升的主要热源，而灭弧室的回路电阻通常要占高压真空断路器回路电阻的50以上。触头间隙接触电阻是真空灭弧室回路电阻的主要组成部分，因为触头系统密封于真空灭弧室内，而产生的热量只能通过动、静导电杆向外部散热。
真空灭弧室静端直接与静支架相连，动端则通过导电夹、软连接与动支架相连。虽然动端向上运动有利于动端散热，但因动端连接环节较多，导热路径较长，所以高压真空断路器温升的*高点多集中于动导电杆与导电夹搭接部位。在实际应用中，有效的利用静端有利于散热的元件，迫使触头间隙热量比较多的从静端导出，分流动端的热量，是解决高压真空断路器温升偏高的有效措施。
高压真空断路器优越的技术应用特性，得到了广大电力部门普遍认可，上述所涉及的有关问题，供实际工作中借鉴，以期充分利用，更好发挥高压真空断路器的技术优势，对提高我国农村电网整体装备水平是非常有益的。
Abstract
The application of high-voltage vacuum circuit breakers (HVVCBs) in China's power supply system began in 1978. Their advantages—light weight, simple structure, and long service life—were quickly recognized by operation, maintenance, and technical personnel in the power sector. Early domestic HVVCBs had unstable quality, with relatively high switching overvoltage during operation and air leakage in individual vacuum interrupters.
1. Current Status of HVVCBs in China
The application of HVVCBs in China's power supply system started in 1978, and their advantages quickly won recognition from power sector staff. Early products had quality issues, including high switching overvoltage and air leakage in vacuum interrupters. By the 1992 Tianjin Vacuum Switch Application Promotion Conference, China's HVVCB manufacturing technology had reached the forefront of international peers, marking a new historical turning point for HVVCB application and manufacturing technology.
2. Air Leakage Issues in Vacuum Interrupters
New-generation HVVCBs commonly use the longitudinal magnetic field arc extinguishing principle and copper-chromium contact materials to reduce contact wear and extend electrical life. Improper adjustment of the conductor rod concentricity can destabilize the sealing strength of longitudinal gas lines, ceramics, and Kovar-metal joints, leading to air leakage in vacuum interrupters.
Most bellows in vacuum interrupters are formed from 0.15mm-thick stainless steel by oil pressure. Inappropriate selection of pollution grade, humidity, salt spray, etc., in the application environment of HVVCBs can cause pitting corrosion of bellows due to harmful gases and condensation, leading to air leakage at bellows, covers, and sealing surfaces.
Ensuring concentricity adjustment of HVVCBs and rationally selecting use and storage environments are key measures to solve air leakage in vacuum interrupters.
3. Rational Selection of Electrical Life of HVVCBs
The electrical life of an HVVCB refers to the number of full-capacity breaking operations specified in technical conditions and actually conducted in type tests. Since HVVCB contacts cannot be repaired or replaced in application, it is necessary to ensure sufficiently high electrical life.
New-generation vacuum interrupters adopt longitudinal magnetic field electrodes and copper-chromium contact materials. Longitudinal magnetic field electrodes exponentially reduce arc voltage (arc energy) under short-circuit breaking current and evenly distribute arcs on the contact surface; copper-chromium contacts reduce contact wear caused by unit arc energy. Their combination has drastically improved the electrical life of HVVCBs. Currently, China's HVVCBs show high and stable performance in breaking and closing capabilities.
Early HVVCBs in China had an electrical life of only 30 operations, and the longest-running ones have been in service for over 20 years. No HVVCB has retired due to electrical life issues of short-circuit breaking current, nor have accidents occurred from short electrical life, proving that these HVVCBs generally meet the power system's requirements. Thus, the electrical life of short-circuit breaking current for HVVCBs is not "the higher, the better."
4. Attention to Mechanical Parameter Adjustment of HVVCBs
HVVCBs have numerous mechanical parameters, such as closing speed, opening speed, contact travel, contact closing bounce time, and contact opening rebound amplitude—all set to ensure technical performance.
The mechanical life of HVVCBs in China is generally 10,000–20,000 operations, with research ongoing to increase it to 30,000–40,000 operations. Electromagnetic operating mechanisms are widely used for their simple structure, reliable performance, convenient adjustment/maintenance, and familiarity among operators; some regions prefer electric spring operating mechanisms. Operating mechanisms are the most complex and precision-demanding part of HVVCB mechanical structures, and most manufacturers struggle to meet machining accuracy requirements.
To ensure HVVCB reliability, China adopts a split structure—separating the operating mechanism from the circuit breaker body, with well-equipped factories mass-producing mechanisms, then integrating the output shaft with the circuit breaker. Thus, rational configuration of mechanical parameters directly affects technical performance and mechanical life. Ideal mechanical parameter adjustment is crucial for HVVCB mechanical performance. The optimal buffer characteristic should provide a small reaction force when the moving part contacts the buffer, then rapidly increase with buffer distance to absorb separation energy and limit opening rebound and travel.
5. Improving Operational Reliability of HVVCBs
Due to quality issues with domestic materials, components, and standard parts, as well as traditional design concepts, the mechanical reliability and life of Chinese HVVCBs are not yet ideal.
(1) Grasp the basic structure and technical performance indicators of vacuum circuit breakers, rationally select operating conditions, maintain close information exchange with manufacturers, and accurately apply advanced technical functions of HVVCBs.
(2) Carefully debug mechanical parameters and strictly adhere to indicators to ensure basic functions.
(3) Standardize spare parts management and storage to ensure consistency, versatility, and reliability of technical performance and quality.
(4) Maintain operation records and analyze accidents, summarize experience, and collaborate with manufacturers to continuously improve the advancement, reliability, and economy of vacuum circuit breakers.
6. Temperature Rise of HVVCBs
The loop resistance of an HVVCB is the main heat source affecting temperature rise, with the vacuum interrupter's loop resistance typically accounting for over 50% of the total. The contact gap contact resistance is the primary component of the vacuum interrupter's loop resistance. Since the contact system is sealed in the vacuum interrupter, heat can only dissipate externally through the moving and static conductor rods.
The static end of the vacuum interrupter connects directly to the static support, while the moving end connects to the moving support via a conductive clamp and flexible connection. Although upward movement of the moving end aids heat dissipation, the moving end has more connection links and a longer thermal conduction path, so the highest temperature rise in HVVCBs often occurs at the overlap between the moving conductor rod and conductive clamp. In practice, effectively utilizing heat-dissipating components at the static end to force more heat from the contact gap to dissipate through the static end and Branch off (divert) heat from the moving end is an effective measure to address excessive temperature rise in HVVCBs.
The superior technical characteristics of HVVCBs have been widely recognized by power sectors. The issues discussed above aim to provide references for practical work, promoting full utilization of HVVCB technical advantages and contributing to improving the overall equipment level of China's rural power grid.
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温州孰高电气有限公司
