Does the number of high-voltage lightning arrester actions suddenly increase? Let's first look at these two data: thunderstorm days+grid voltage

2025-09-13 13:31:49

During the inspection of a wind farm operation and maintenance personnel in a certain mountainous area, it was found that the number of 35kV Lightning Arrester actions on the collection line had surged by 30 times within a month, far ahead of the total of several months. Without immediately suspecting the equipment malfunction, they first did two things: retrieving the power grid voltage curve from the thunderstorm day records of the local meteorological bureau and the on-site recorded wave data. The results showed that there were up to 15 thunderstorm days in that month, and due to load fluctuations, the nighttime voltage remained at a high level of 40.5kV for a long time (nominal voltage of 35kV). The truth is revealed: it is the combination of abnormal weather and high grid voltage that has led to an increase in operating frequency, while the lightning arrester itself is still working healthily.

Why do we have to look at these two data first?

The essence of lightning arrester action is to release overvoltage energy. An increase in the number of actions only indicates an increase in the amount of energy that needs to be released. There are two directions for its origin:

1. From external sources: lightning strikes (see "thunderstorm days")

2. Internal: System operation overvoltage or transient overvoltage (see "grid voltage")

Blindly replacing lightning arresters is like dragging the floor without closing the windows on a rainy day, treating the symptoms without addressing the root cause.

Data 1: Thunderstorm Days - Interpretation of External Attack Frequency

-What is it: A thunderstorm day refers to a day when thunder is heard, and it measures the frequency of lightning activity.

-How to check: Obtain accurate data from the local meteorological bureau or lightning location system within the power system.

-How to analyze:

-Horizontal comparison: Compare the number of actions taken in the current month with the historical thunderstorm day data for the same period. If the increase in the number of actions is basically consistent with the increase in thunderstorm days, it is a normal phenomenon.

-Vertical ratio: Compare the number of actions of lightning arresters on different towers on the same line. If the number of movements of a certain tower is abnormally high, it may be due to the location being prone to lightning strikes or equipment problems; If the overall increase is widespread, it can be basically determined to be due to regional weather conditions.

Conclusion: If the number of actions is strongly correlated with thunderstorm day data, it indicates that the lightning arrester is effectively fulfilling its duties and there is no need to worry, just continue to observe.

Data 2: Grid Voltage - Exploring Internal System Health

-What is it: This refers to the operating voltage of the system, especially the consistently high operating voltage.

-How to check: Retrieve the historical voltage curve from the substation monitoring system or power quality online monitoring device, focusing on the voltage data before and after the action occurred.

-How to analyze:

-Check the absolute value: Check whether the system voltage has exceeded the maximum operating voltage for a long time (such as a 35kV system exceeding 40.5kV for a long time). The higher the voltage, the greater the stress that the lightning arrester is already subjected to, and the closer it is to its operating threshold (referring to the continuous operating voltage Uc and rated voltage Ur), the more sensitive it will be to the same overvoltage disturbance.

-Observe fluctuations: Check whether there are capacitor switching, large load shedding, and no-load line operation before and after the action time. These operations can cause overvoltage or transient overvoltage, leading to the operation of the lightning arrester.

Conclusion: If the number of actions is strongly correlated with high or fluctuating system voltage events, it indicates that the internal operating conditions of the power grid are the main cause. It is necessary to optimize reactive voltage control or adjust the operating mode, rather than replacing the lightning arrester.

A table helps you make quick decisions

Operations Action Checklist: What should be done next?

1. Collect evidence: Record the number of actions in a timely manner and take photos to keep the counter display value.

2. Data analysis: Immediately retrieve historical data of thunderstorm days and grid voltage for the above comparative analysis.

3. Preliminary judgment: Make a preliminary judgment based on the table above.

4. Professional testing: If the first two items are excluded and there is suspicion of a problem with the lightning arrester itself, then:

-Use an infrared thermal imager to scan the lightning arrester body and check for overall or local overheating.

-Apply for power outage, and the testing team will test the full current and resistive current to determine if there is aging.

5. Record and report: Record the analysis process, data, and conclusions in the equipment ledger to provide decision-making basis for the next maintenance.

Remember: the lightning arrester action counter is not a decoration, it is the "black box" of the power grid when encountering lightning and internal overvoltage impact. By understanding the data behind it, you can transform from a passive maintenance worker to an active warning system for power grid safety.