35KV zinc oxide arrester 51/134
Product Overview
The arrester is connected between the cable and the earth, usually in parallel with the protected equipment. The arrester can effectively protect communication equipment. Once an abnormal voltage appears, the arrester will be activated to play a protective role. When the communication cable or equipment is running under normal operating voltage, the arrester will not work and it will be regarded as a circuit breaker to the ground. Once a high voltage appears and endangers the insulation of the protected equipment, the arrester will immediately act to guide the high voltage impact current to the earth, thereby limiting the voltage amplitude and protecting the insulation of the communication cable and equipment. When the overvoltage disappears, the arrester quickly returns to its original state, allowing the communication line to work normally.
Features
◆Flow capacity
This is mainly reflected in the fact that the lightning arrester has the ability to absorb various lightning overvoltages, power frequency transient overvoltages, and operating overvoltages.
◆Protection features
Zinc oxide lightning arresters are electrical products used to protect various electrical equipment in power systems from overvoltage damage, and have good protection performance. Because the nonlinear volt-ampere characteristics of the zinc oxide valve plate are very good, only a few hundred microamperes of current pass through under normal working voltage, which is easy to design into a gapless structure, making it have the characteristics of good protection performance, light weight and small size. When overvoltage invades, the current flowing through the valve plate increases rapidly, while limiting the amplitude of the overvoltage and releasing the energy of the overvoltage. After that, the zinc oxide valve plate returns to a high-resistance state, allowing the power system to work normally.
◆Sealing performance
The arrester components use high-quality composite jackets with good aging performance and good air tightness. Measures such as controlling the compression of the sealing ring and adding sealant are adopted. The ceramic jacket is used as the sealing material to ensure reliable sealing and stable performance of the arrester.
◆Mechanical properties
The following three factors are mainly considered: the seismic force it bears; the maximum wind pressure acting on the lightning arrester; and the maximum allowable tension of the conductor on the top of the lightning arrester.
◆Decontamination performance
Gapless zinc oxide arresters have high pollution resistance.
The creepage distance levels specified in the national standard are: Level II moderately polluted areas: creepage distance 20mm/kv; Level III heavily polluted areas: creepage distance 25mm/kv; Level IV extremely heavily polluted areas: creepage distance 31mm/kv.
◆High operational reliability
The reliability of long-term operation depends on the quality of the product and whether the product selection is reasonable. The following three aspects affect its product quality: the rationality of the overall structure of the arrester; the volt-ampere characteristics and aging resistance of the zinc oxide valve plate; the sealing performance of the arrester.
◆Power frequency withstand capability
Due to various reasons in the power system, such as single-phase grounding, long-line capacitance effect, and load shedding, the power frequency voltage may increase or a transient overvoltage with a high amplitude may be generated. The lightning arrester has the ability to withstand a certain power frequency voltage increase within a certain period of time.