Reliability comparison between electrical and mechanical linkage of high voltage switch

In this paper, we analyze the reliability of high-voltage circuit breakers that use both electrical and mechanical linkage systems. By considering the failure probability distribution and the respective advantages and disadvantages of these two types of linkages, we aim to provide a comprehensive understanding of their performance in real-world applications. 1. Introduction High-voltage circuit breakers are essential components in power systems, serving both control and protection functions. Their reliability directly impacts the safe and stable operation of the entire grid. To prevent non-full phase closing, some installations require three-phase mechanical linkage. While some users believe that mechanical linkage is more reliable than electrical linkage, this assumption needs to be verified through detailed analysis. 2. Circuit Breaker Failure Probability Statistics According to CIGRE's reliability survey on 66kV and above single-pressure SF6 circuit breakers from 1978 to 1991, 64.8% of total failures were attributed to operating mechanism issues. Among these, 21% involved secondary electrical control and auxiliary circuits, while 43.8% were due to mechanical failures. From 1989 to 1997, data from the national power system showed that out of 458 recorded faults, 304 were related to operating mechanisms. These mechanisms consist of mechanical transmission parts and control circuits, including terminals, contactors, auxiliary switches, coils, and other secondary components. CIGRE report WGl3.06 further categorizes fault types by operating mechanism, showing that spring-operated mechanisms have significantly fewer failures compared to hydraulic or pneumatic ones. To avoid bias in the analysis, this study focuses on spring-operated SF6 circuit breakers. 3. Analysis of Failure Rates in Electrical and Mechanical Linkage 3.1 Electrical and Mechanical Linkage Three-phase electrical linkage circuit breakers typically use independent operating mechanisms connected via a communication control box, with each phase’s output shaft directly linked to its pole. In contrast, mechanical linkage uses a single operating mechanism connected to all three poles through an operating rod. According to SDJ5-85, the phase-to-phase distance for outdoor power distribution devices must meet specific standards, such as 1000mm for 110kV, 2000mm for 220kV, and so on. 3.2 Failure Probability Analysis Based on Table 3, the probability of failure in both electrical and mechanical linkages is similar, except for internal mechanical differences within the spring mechanism and between the mechanism and the body—represented as P3 and P50 in the table. 3.3 Failure Analysis 3.3.1 Possible Failure Between Mechanism and Body Mechanical linkage requires precise installation, which can be challenging due to site conditions and varying construction quality. As shown in Table 1, 23% of mechanical failures involve deformation damage. This difficulty increases the likelihood of post-installation faults. In contrast, electrical linkage connects directly to the pole, reducing failure chances. Moreover, mechanical linkage causes uneven force and vibration distribution, with the closest pole experiencing higher stress. Temperature changes also affect metal expansion and contraction, altering the circuit breaker’s position during operation, which can lead to serious consequences. Finally, the stress inside the mechanical linkage increases with phase distance, proportional to dA (where 1 ≤ A ≤ 2). When the interphase distance exceeds 2.5 meters, stress and deformation impact reliability. Since SF6 breakers have smaller opening distances, even minor mechanical variations greatly affect performance, making mechanical linkage less suitable for voltages above 300kV. 3.3.2 Failure Possibility of the Mechanism Itself Although spring mechanisms have fewer failures than hydraulic or pneumatic ones, three-phase mechanical linkage still involves more complex operations, leading to higher stress and damage. While manufacturers may vary in quality, generally, the failure rate of mechanical linkage (P4) is higher than that of electrical linkage (P3). 4. Conclusion The failure rate of three-phase mechanical linkage is higher than that of electrical linkage. Unless there are special requirements, electrical linkage should be preferred. For 110kV and below, where phase distances are typically under 2000mm, mechanical linkage is more suitable. However, for 220kV and above, where phase distances range from 3000 to 4000mm, electrical linkage is more appropriate.

Arm Muscle Training

Arm training can enhance the strength and stability of arm muscles, and reduce the risk of injury caused by weak muscles. Common methods for preventing arm injuries include regular arm muscle strengthening training, such as wrist flexion and extension, wrist support, etc.

When conducting arm training, attention should be paid to controlling weight and frequency to prevent excessive fatigue or injury. In addition, choosing the appropriate venue and equipment is also important to ensure safe and effective training.

Exercise arm muscle methods for biceps:

Arm Muscle Training,Biceps Curl Trainer,Triceps training,Pull up power assist machine,Horizontal and parallel bars

Xuzhou Hongxing Gym Equipment Co., Ltd , https://www.hxygym.com