The lightning arrester is an important device used in power systems to protect electrical equipment from lightning overvoltage and operating overvoltage. Among the many technical parameters of the lightning arrester, the continuous operating voltage and the rated voltage are two key parameters. There is a close technical relationship between them and they have an important impact on the performance and reliability of the lightning arrester.
First, the definitions of these two parameters are clarified. The rated voltage of the lightning arrester refers to the maximum effective value of the power frequency voltage at which the lightning arrester can work reliably under the specified conditions of use. It is determined based on factors such as the nominal voltage and overvoltage level of the power system and is an important basis for the design and selection of the lightning arrester. The continuous operating voltage refers to the effective value of the power frequency voltage allowed to be applied to both ends of the lightning arrester for a long time. At this voltage, the lightning arrester should be able to operate normally and its performance will not be significantly deteriorated.
The rated voltage determines the range of the continuous operating voltage to a certain extent. Generally speaking, the continuous operating voltage will be lower than the rated voltage. This is because during the operation of the lightning arrester, it is necessary to take into account the normal operating voltage fluctuations of the power system and possible temporary overvoltages. If the continuous operating voltage is set too high, the lightning arrester may be subjected to excessive voltage stress during normal operation, which may accelerate its aging or even damage. Therefore, the continuous operating voltage is usually determined reasonably based on the rated voltage and the actual operation of the power system, so that it can ensure the normal operation of the lightning arrester and ensure that it has sufficient safety margin.
The continuous operating voltage has a direct impact on the aging characteristics of the lightning arrester. When the lightning arrester is subjected to the continuous operating voltage for a long time, its internal nonlinear resistors and other components will age to a certain extent. If the continuous operating voltage is close to or exceeds the tolerance of the lightning arrester, the aging process will accelerate, causing the performance of the lightning arrester to gradually deteriorate, such as increased residual voltage and increased leakage current. The rated voltage is a basic parameter of the lightning arrester. It determines the overall design and insulation level of the lightning arrester, and thus affects the aging characteristics of the lightning arrester under the continuous operating voltage. For example, the lightning arrester with a higher rated voltage usually has better performance of its internal insulation structure and resistor, and can maintain relatively good stability under a higher continuous operating voltage, delaying the aging process.
The continuous operating voltage and rated voltage jointly affect the protection performance of the lightning arrester. The rated voltage determines the maximum overvoltage level that the lightning arrester can withstand, while the continuous operating voltage affects the performance stability of the lightning arrester under normal operating conditions. Only when the two are matched and reasonably selected can the lightning arrester effectively play a protective role in the power system. If the rated voltage is not selected properly, the lightning arrester may not provide sufficient protection when encountering overvoltage; and if the continuous operating voltage is not selected properly, the lightning arrester may have performance problems during normal operation, affecting its response speed and protection effect to overvoltage.
In practical applications, the selection of the continuous operating voltage and rated voltage of the lightning arrester requires comprehensive consideration of multiple factors. In addition to the nominal voltage and overvoltage level of the power system, the grounding method of the system, the operating environment conditions, and the insulation level of the electrical equipment need to be considered. For example, in a neutral point ungrounded system, since the non-fault phase voltage will increase when a single-phase grounding fault occurs, it is necessary to select a suitable rated voltage and continuous operating voltage to ensure that the lightning arrester can still work reliably in this case. At the same time, for different operating environments, such as high temperature and high humidity, the continuous operating voltage and rated voltage also need to be appropriately adjusted to ensure that the performance of the lightning arrester is not affected by environmental factors.
There is a close technical relationship between the continuous operating voltage and the rated voltage of the lightning arrester. The rated voltage provides the basis for the value range of the continuous operating voltage, and the continuous operating voltage directly affects the aging characteristics and protection performance of the lightning arrester. In practical applications, these two parameters must be reasonably selected and matched according to the specific conditions of the power system to ensure that the lightning arrester can operate safely and reliably and effectively protect electrical equipment from various overvoltages.
