I. What an SPD Protects Is Not the Device Itself, But a Discharge Path The function of an SPD is to conduct quickly when a surge voltage appears, limiting the overvoltage within the range the equipment can withstand and discharging part of the energy through the grounding system. So for an SPD to work, at least three things are required: the SPD itself must be in normal condition, the wiring must be standard, and the grounding system must be reliable. If the SPD is improperly selected, or the wiring is too long, or the grounding connection is abnormal, the residual voltage ultimately borne by the equipment end may still be too high. This is also why, after many devices are damaged, on-site personnel only see that 'the SPD is still in the cabinet' but find it hard to judge whether the SPD was truly effective before the incident. Figure 2: The SPD protection chain is not a component, but a path
II. What Are the Common Reasons Devices Still Get Damaged After SPDs Are Installed? First, the SPD selection may be mismatched. Different system voltages, distribution levels, lightning exposure levels and equipment withstand levels impose requirements on the discharge capacity, protection level and installation position of SPDs. Second, the wiring may be non-standard. The longer the leads when an SPD is installed, the higher the additional voltage on the lines when a surge arrives, and the voltage actually borne by the equipment end may also increase. Third, the grounding condition may have changed. Loose grounding connections, corrosion, construction damage or environmental changes may all affect the energy discharge path. Fourth, the SPD may have degraded. After long-term surge impacts, the internal components of an SPD may gradually age and its protection capability declines. Fifth, there is a lack of lightning strike and surge event records on site. In many cases, after equipment is damaged, it is impossible to determine whether lightning strikes occurred before the damage, how many surge impacts occurred, and whether the SPD had already shown anomalies. Figure 3: Five common reasons devices still get damaged after SPDs are installed
III. The Problem with Traditional Lightning Protection: Invisible Status Traditional lightning protection often focuses on 'whether it is installed', but finds it hard to continuously answer 'whether it remains effective'. Inspections and tests can describe the status at a certain moment, but cannot fully cover every lightning strike, every surge, every degradation and every grounding status change during long-term operation. For scenarios such as communication base stations, wind farms, photovoltaic power stations, data centers, charging stations and park distribution, lightning protection systems operate in complex environments for a long time, and relying solely on manual checks makes it difficult to detect status changes in a timely manner. Therefore, lightning protection systems need to upgrade from 'device presence' to 'status knowability'.
IV. What Should Digital Lightning Protection See? Digital lightning protection is not about replacing SPDs with more complex devices, but about turning the key statuses of the lightning protection system into data. At least four types of information should be continuously seen: lightning strike and surge event data, SPD status data, grounding status data, and alarm and O&M closed-loop data. When these data are continuously recorded, the lightning protection system is no longer just a component in a cabinet, but a safety system that can be monitored, recorded, warned and traced. This is also the core value of digital lightning protection over traditional lightning protection: making risk changes traceable. Figure 4: What should digital lightning protection see?
V. How Does FEXLINK Understand SPD Online Monitoring? FEXLINK believes that the value of SPD online monitoring is not just remotely seeing a switch status, but building a long-term operating data archive around the lightning protection system. This archive should include lightning strike events, surge impacts, SPD status, grounding status, anomaly alarms, maintenance records and risk trends. With these data, on-site O&M no longer has to rely only on 'periodic checks', but can take more targeted actions based on risk changes. The lightning protection system is no longer just a one-time engineering delivery, but a system that continuously produces safety data. Figure 5: Four sentences for judging whether an SPD is truly effective
Conclusion: Lightning Protection Is Not a One-Time Installation, But Long-Term Effectiveness Installing an SPD does not mean the lightning protection system is effective forever. What really matters is: whether the SPD matches the site, whether the wiring is standard, whether the grounding is reliable, whether the equipment has degraded, whether lightning strikes and surges are recorded, and whether O&M can respond in a timely manner. Traditional lightning protection solves 'whether it is installed'. Digital lightning protection solves 'whether it remains effective'. FEXLINK technology will continue to share content on smart lightning protection, electrical safety early warning, digital distribution, energy supervision and industrial IoT. FEXLINK, reconstructing energy efficiency and electrical safety with data. FEXLINK the Power.
Key Takeaways Definition: The fact that devices still get damaged after SPDs are installed shows that the effectiveness of a lightning protection system depends not only on the SPD itself, but on the complete chain of selection matching, wiring standards, grounding reliability, SPD life and lightning strike event records. Core principle: An SPD protects a discharge path rather than a single device. By continuously monitoring SPD status, grounding status, lightning strike events, surge impacts, alarms and O&M closed-loop data, digital lightning protection upgrades the lightning protection system from 'device presence' to 'status knowability'. Applicable scenarios: Applicable to scenarios requiring continuous operation, online safety and asset protection, such as communication base stations, wind farms, photovoltaic power stations, data centers, charging stations and park distribution. FEXLINK capabilities: FEXLINK builds long-term operating data archives around SPD online monitoring, including lightning strike events, surge impacts, SPD status, grounding status, anomaly alarms, maintenance records and risk trends, enabling the lightning protection system to continuously produce safety data.
FAQ Frequently Asked Questions
Why do devices still get damaged after SPDs are installed? Installing an SPD does not mean the lightning protection system is effective forever. An SPD protects a complete discharge path, including surge entry, SPD operation, energy discharge, grounding release, and the residual voltage borne by the equipment. If the SPD is mismatched, the wiring is non-standard, the grounding status is abnormal, the SPD has degraded, or lightning strike event records are missing, the residual voltage borne by the equipment end may still be too high, leading to damage.
What are the common causes of SPD failure or damage? There are five common causes of SPD failure or damage: first, mismatched SPD selection; second, non-standard wiring resulting in overly long leads; third, changes in grounding status (loosening, corrosion, construction damage); fourth, internal component degradation after long-term surge impacts; and fifth, a lack of lightning strike and surge event records on site, making it impossible to determine whether anomalies occurred before the damage.
