How to choose a lightning arrester suitable for different voltage levels?
Publish Time: 2025-03-24
As a key device for overvoltage protection of power systems, the selection of lightning arresters is directly related to the safe and stable operation of power grids. With the diversification of voltage levels in power systems, how to select matching lightning arresters for different voltage levels has become an important issue in power design. The selection of lightning arresters needs to consider many factors such as system voltage, insulation coordination, protection characteristics, and operating environment, and is a task that requires professional technical support.
Voltage level is the primary consideration for selecting a lightning arrester. Systems of different voltage levels have strict requirements on parameters such as the rated voltage and continuous operating voltage of the lightning arrester. For distribution systems of 10kV and below, distribution-type lightning arresters with a rated voltage of 17kV or 12kV are usually selected; for 35kV systems, lightning arresters with a rated voltage of 51kV are required; and for 110kV systems, the rated voltage of the lightning arrester is generally between 96kV and 108kV. The higher the voltage level, the higher the structural size and insulation requirements of the lightning arrester. It is particularly important to note that when selecting a lightning arrester, not only the nominal voltage of the system should be considered, but also the highest possible operating voltage of the system.
The protection characteristics of the lightning arrester must match the insulation level of the system. An ideal lightning arrester should act quickly when a dangerous overvoltage occurs in the system, limiting the overvoltage to a range that the insulation of the equipment can withstand. The main indicators for measuring the protection characteristics include the residual voltage value and the protection ratio under the nominal discharge current. For systems of different voltage levels, the residual voltage requirements of the lightning arrester need to be determined according to the insulation level of the equipment. For example, the residual voltage requirements of the lightning arrester for a 500kV ultra-high voltage system are much stricter than those for a 10kV distribution system. When selecting, it should be ensured that the protection level of the lightning arrester is lower than the insulation tolerance level of the protected equipment, and sufficient safety margin is left.
The type of lightning arrester also varies with the voltage level. At present, the power system mainly uses zinc oxide lightning arresters, but their structural designs vary at different voltage levels. Medium and low voltage systems often use gapless zinc oxide lightning arresters, which are simple and reliable in structure; while ultra-high voltage systems often use lightning arresters with grading rings to improve potential distribution. For particularly important systems of 500kV and above, it may be necessary to select high-performance lightning arresters with multiple protection units. The composite jacket lightning arresters developed in recent years are particularly suitable for use in high-voltage transmission lines due to their light weight and good explosion-proof performance.
Environmental conditions are also important for the selection of lightning arresters. High-altitude areas need to use lightning arresters with higher rated voltages to compensate for the decrease in insulation strength caused by thin air; areas with severe pollution should choose lightning arresters with good anti-pollution flashover performance; earthquake-prone areas need to consider the seismic performance of lightning arresters. For special environments such as offshore wind power, corrosion-resistant lightning arresters should also be selected. Projects of different voltage levels have different sensitivities to environmental factors, and high-voltage projects usually require more stringent environmental adaptability assessments.
Economic efficiency is also a factor that needs to be considered when selecting. High voltage lightning arresters are expensive, and it is necessary to balance the protection effect and investment cost. For important substations, lightning arresters with better performance should be selected; for general distribution lines, economical products can be selected on the premise of meeting basic requirements. Life cycle cost analysis helps to make more scientific selection decisions, including considering the expected life of the lightning arrester, maintenance costs and possible failure losses.
With the development of smart grids, the selection of lightning arresters also needs to consider future system changes. Distributed power access, DC transmission technology applications, etc. will affect the overvoltage characteristics of the system. Selecting a lightning arrester with appropriate margin can adapt to the future development needs of the system. Especially for projects that plan to increase voltage at the beginning of construction, it is more necessary to select lightning arrester parameters in a forward-looking manner.
In short, choosing a lightning arrester suitable for different voltage levels is a systematic project, which requires comprehensive consideration of technical parameters, protection characteristics, environmental conditions and economic factors. The correct selection can not only effectively protect power equipment, but also optimize investment costs, providing reliable protection for the safe and stable operation of the power system. With the application of new materials and new technologies, the performance of lightning arresters will continue to improve, providing more complete overvoltage protection solutions for power systems.
