How to determine the rated voltage and current carrying capacity of the lightning arrester?
Publish Time: 2025-02-25
As an important device in the power system, the main function of the lightning arrester is to protect electrical equipment from damage caused by lightning overvoltage and operating overvoltage. In order to ensure that the lightning arrester can work reliably, it is crucial to determine its rated voltage and current carrying capacity.
First, the rated voltage of the lightning arrester refers to the maximum allowable power frequency voltage at which the lightning arrester can work reliably and complete the expected action load test. The determination of this parameter needs to consider the maximum short-term power frequency voltage in the power system. In practical applications, the rated voltage of the lightning arrester should be greater than the maximum short-term power frequency voltage that may occur at the installation location to ensure that the lightning arrester will not be damaged due to excessive voltage under normal operating conditions. The measured data of the bus voltage increase caused by load shedding in my country does not exceed 1.37 times the phase voltage. This data can be used as an important reference for determining the rated voltage of the lightning arrester.
Second, the current carrying capacity of the lightning arrester is also one of the key indicators. It indicates the maximum discharge current that the lightning arrester can withstand when it is struck by lightning or operating overvoltage. The determination of this parameter requires comprehensive consideration of the characteristics of the power system, the type of lightning arrester, and the importance of the protected object. Generally speaking, the rated current of the lightning arrester is set by the manufacturer during the manufacturing process according to the design requirements and test standards. In actual applications, the current of the lightning arrester should be less than or equal to its rated current, otherwise it may cause damage to the equipment.
When determining the rated voltage and current withstand capacity of the lightning arrester, other factors such as ground fault factor and system structure characteristics need to be considered. For specific types of lightning arresters such as zinc oxide lightning arresters, the selection of their rated voltage is usually based on the highest value of temporary overvoltage caused by single-phase ground faults, and unfavorable conditions such as load shedding are considered. At the same time, for some complex systems, it may be difficult to determine their maximum temporary overvoltage and its duration, and approximate estimates need to be made through simulation calculations or actual system investigations and studies.
In summary, the determination of the rated voltage and current withstand capacity of the lightning arrester is a complex and important process that requires consideration of multiple factors and conditions. Only by ensuring the accuracy and rationality of these parameters can the reliable operation and effective protection of the lightning arrester in the power system be ensured. Therefore, in practical applications, the lightning arrester should be selected, installed and maintained in strict accordance with relevant regulations and standards to ensure the safe and stable operation of the power system.
