Surge Protective Device

Among various types of lines such as power distribution, photovoltaic, and communication lines, lightning strikes and grid overvoltages are the main hazards that cause equipment damage - once exposed to lightning strikes or overvoltages, sophisticated equipment like frequency converters and PLCs at the back end are highly prone to being burned out, resulting in increased costs for equipment maintenance and replacement, and even causing production and communication disruptions. Ordinary circuit breakers can only protect against overload and short circuits in the lines and cannot handle overvoltage impacts; they simply cannot provide lightning protection. Surge Protective Device precisely addresses this issue, specifically designed to prevent lightning overvoltages. It quickly discharges surges and limits overvoltages, building a lightning protection safety barrier for the subsequent equipment.

What are the core advantages?

The Surge Protective Device focuses on the core requirements of lightning overvoltage protection, differentiating itself from other lightning protection devices. Each advantage is tailored to the actual usage pain points of the purchasers, ensuring the safety of the equipment while also reducing procurement and operation costs.

Protecting against lightning-induced overvoltage, precisely safeguarding equipment safety: Specifically designed for lightning surges and grid overvoltages, when overvoltage occurs in the line, it can quickly discharge the surge current to the ground, limiting the overvoltage within a safe range, effectively protecting various types of equipment such as frequency converters and PLCs at the rear end, preventing equipment damage due to overvoltage, and covering the lightning protection needs of various distribution scenarios.

ns-level rapid response, eliminating overvoltage transmission: Response time ≤ 25ns. It can respond to surge impacts within an extremely short period of time, quickly discharging the surge current, preventing overvoltage from being transmitted to the rear-end equipment, eliminating the risk of equipment damage at the source, and being faster in response and more timely in protection compared to ordinary lightning protection devices.

Compact and space-saving, suitable for various distribution cabinets: Adopting a compact design, it is small in size and occupies minimal space. It does not require excessive space occupation. Even small distribution cabinets can easily accommodate it. It can perfectly fit distribution cabinets and control cabinets, without the need to expand the cabinet size, saving installation space and costs.

A cost-effective choice, significantly reducing lightning protection costs: Compared to other lightning protection devices, the price is significantly reduced. There is no need to spend a large amount of money on high-end lightning protection devices. For various lightning protection scenarios, using the Surge Protective Device can meet all lightning protection requirements, balancing protection effect and economy, significantly reducing project procurement costs.

Technical Specifications

Product Details

Junray Electrical places great emphasis on the meticulous refinement of its products. Every design aspect takes into account both the protective performance and the ease of practical operation, ensuring the long-term stable operation of the equipment and reducing the cost of subsequent maintenance. The ns-level rapid response design ensures quick action during surge impacts, providing more timely protection; it is equipped with a fault indication function, which can automatically issue an indication when the surge protector malfunctions, facilitating the operators to quickly locate the fault and replace it in time, thereby enhancing the maintenance efficiency; it adopts a dedicated insulation protection design, with reliable insulation performance, effectively preventing potential safety hazards in low-voltage power usage, ensuring the safety of both the equipment and personnel, and is compatible with various complex power distribution environments.

Full-scenario coverage

With its core advantages of rapid response, compact size and high cost-effectiveness, Surge Protective Device is widely applied in various lightning protection scenarios of power distribution lines, becoming the standard standard equipment for lightning protection, precisely matching the lightning protection requirements of different scenarios. In factory power distribution scenarios, it is adapted to factory power distribution lines, protecting production equipment from lightning strikes and overvoltage damage, ensuring production stability; in building power distribution scenarios, it is adapted to building power distribution lines, safeguarding the safety of various electrical equipment in the building; in communication power distribution scenarios, it is adapted to communication lines, preventing overvoltage damage to communication equipment, ensuring smooth communication; in engineering power distribution scenarios, it is adapted to on-site power distribution lines of engineering projects, suitable for complex outdoor environments, ensuring the safety of power supply for construction projects; in photovoltaic power distribution scenarios, it is adapted to photovoltaic power distribution lines, protecting the photovoltaic system from lightning strikes, ensuring the stability of photovoltaic power supply.

FAQ

Question: Is the lightning protection function of Surge Protective Device different from that of ordinary circuit breakers?

Answer: Ordinary circuit breakers can only protect against line overload and short circuits, but they are unable to handle lightning surges and overvoltages. This product is specifically developed for lightning overvoltage protection. It can quickly discharge the surge current and limit overvoltages, and is specifically designed to protect rear-end frequency converters, PLCs, and other equipment. It is a lightning protection device that cannot be replaced by ordinary circuit breakers.

Question: Can it protect the back-end precision equipment?

Answer: The response time is ≤ 25ns. It can act quickly in the instant of a surge impact, discharging the surge current to the ground and limiting the overvoltage within the safe range that the equipment can withstand. It will not allow the overvoltage to be conducted to the back-end equipment, effectively protecting precision equipment such as frequency converters and PLCs, and preventing equipment damage.

Question: Can the current capacity and pole number be customized?

Answer: Yes. The current capacity ranges from 20kA to 100kA, and the pole numbers cover 1P/2P/3P/4P. All of them support customization. According to different scenarios such as factories, photovoltaic, and communication, the lightning protection intensity and line specifications can be tailored to create exclusive equipment that precisely fits various lightning protection needs.

Retrofit Case Study

I. Project Overview

This project involves a lightning protection upgrade for an automated production workshop located in a region in southern China prone to frequent thunderstorms. The workshop is equipped with sensitive low-voltage electronic systems, including PLC central control systems, variable frequency drives (VFDs), sensors, security monitoring systems, and precision instruments. Situated in an open area frequently exposed to summer thunderstorms, the facility's original power distribution system lacked standardized surge protection and relied on only rudimentary lightning protection measures. Following thunderstorms, the facility repeatedly experienced equipment failures—such as VFD breakdowns, PLC module burnouts, monitoring system blackouts, instrument signal instability, and unexplained equipment shutdowns—resulting in production line interruptions, product scrap, and significant economic losses. These incidents were typical cases of equipment damage caused by induced lightning and surge overvoltage.

To fundamentally resolve the issue of precision automated control equipment being damaged by lightning surges and switching overvoltages, a comprehensive, multi-level lightning protection system was implemented. This involved installing Class I, Class II, and Class III Surge Protective Devices (SPDs) at the workshop's main power distribution unit, branch power cabinets, and low-voltage control cabinets, respectively, thereby ensuring the safe and stable operation of both high-power and sensitive electronic equipment.

II. Issues Prior to Retrofit

Lack of multi-level surge protection and poor lightning resilience: The original system lacked standardized SPD installation; consequently, lightning-induced overvoltages and switching surges could not be safely discharged, directly impacting precision electronic equipment.

Frequent burnout of precision automated control equipment: Thunderstorms frequently caused VFD motherboard breakdowns, PLC I/O module damage, sensor signal drift, and monitoring system blackouts.

Switching overvoltage interference with production: The startup and shutdown of high-power equipment generated transient surge voltages, leading to control system malfunctions, data corruption, and unexplained production line shutdowns.

Non-standard grounding and inability to discharge lightning current: The existing lightning protection grounding system was aged and corroded, preventing the rapid dissipation of surge energy into the earth and allowing residual voltage to damage equipment insulation.

Non-compliance with lightning protection acceptance standards: The high- and low-voltage distribution systems lacked matching surge protection devices; the absence of a proper lightning protection system meant the facility could not pass electrical safety standardization inspections. 

III. Equipment Configuration Plan

In accordance with building lightning protection standards and the protection requirements for precision factory equipment, a three-level tiered surge protection configuration is adopted. Layered protection is implemented across the high-voltage side, low-voltage main incoming lines, power distribution branches, and low-voltage (weak-current) terminals to progressively discharge surge energy and clamp voltage.

Core Equipment Specifications

Device Name: Power Surge Protective Device (SPD)

Level 1 (Main Cabinet) SPD: In 50kA, Imax 100kA; used for low-voltage main incoming lines to discharge direct lightning strikes and high-energy surges.

Level 2 (Distribution Cabinet) SPD: In 20kA, Imax 40kA; used for power distribution branch circuits to provide secondary voltage-limiting protection.

Level 3 (Terminal) SPD: In 10kA, Imax 20kA; used for PLC, monitoring, and instrumentation terminals to precisely clamp residual voltage.

Protection Principle: Utilizes varistor characteristics; remains inactive (high impedance) under normal conditions and switches to low impedance upon surge arrival to instantaneously discharge current and clamp voltage.

Structural Features: Includes fault disconnection, remote signaling alarms, and a visual failure indicator window for easy identification of damage.

Installation Standards: Employs standardized short, straight leads, dedicated lightning protection grounding, and equipotential bonding to minimize residual voltage.

Suitable Applications: Industrial automation, precision instruments, low-voltage (weak-current) systems, and power distribution systems in lightning-prone areas.

IV. Construction and Application Highlights

Three-level tiered protection with progressive discharge: Level 1 discharges high-energy lightning surges; Level 2 provides voltage stabilization and filtering; Level 3 offers fine-tuned protection for precision equipment, completely preventing equipment breakdown caused by overvoltage.

Simultaneous protection against induced lightning and switching surges: Protects against induced lightning strikes during storms while also absorbing switching overvoltages caused by equipment startup/shutdown and grid fluctuations.

Failure indication for easy O&M: Features built-in fault disconnection and a visual indicator window; aging or failure is immediately apparent, eliminating the need for specialized testing instruments for troubleshooting.

Nanosecond-level response speed: Ultra-fast response time ensures instantaneous surge discharge without delay or protection gaps, providing precise protection for sensitive chip-level equipment.

Standardized grounding and equipotential bonding: Integrates with the facility's equipotential bonding upgrades to eliminate potential difference interference, resolving persistent issues such as signal instability and equipment malfunction. 

V. Operational Results After Retrofitting

Elimination of lightning-induced equipment damage: Following the retrofit, the system withstood multiple severe thunderstorms with zero damage or malfunctions across PLCs, variable frequency drives (VFDs), monitoring systems, and instrumentation.

Complete elimination of surge interference: No overvoltage interference occurred due to grid fluctuations or equipment startup/shutdown; the automated control system operated stably, free from unexplained shutdowns or data drift issues.

Significantly extended equipment lifespan: The absence of transient high-voltage surges drastically slowed the aging of electronic components and notably improved the equipment's operational integrity.

Substantial reduction in O&M costs: Eliminated the need for mass repairs or equipment replacements during thunderstorm seasons, thereby reducing losses from production downtime and minimizing spare parts consumption.

Compliance with lightning protection standards: The three-level lightning protection configuration is complete and installed according to rigorous standards, passing both the specialized lightning protection inspection and the electrical safety inspection on the first attempt.

VI. Case Summary

Surge Protective Devices (SPDs) are essential for protecting industrial automation systems, precision low-voltage electronics, and facilities in lightning-prone areas. Unlike lightning rods (which protect against direct strikes), SPDs primarily safeguard against induced lightning, surge overvoltages, and switching overvoltages, thereby protecting chip-level precision equipment. Implementing a comprehensive lightning protection system through a tiered (Level I, II, and III) configuration is a critical safety measure—and a mandatory requirement for electrical acceptance—in factories, residential complexes, and municipal engineering projects.

Immediate Purchase

The risks of lightning strikes and overvoltage cannot be ignored. Ordinary circuit breakers cannot provide effective lightning protection. Once the equipment is damaged, it not only increases the maintenance costs but also affects the normal operation of production and communication. Surge Protective Device is the standard configuration for lightning protection. It has a fast response, reliable protection, small size, and high cost performance. It is directly supplied by Junray Electrical, without any middleman price difference. The quality is guaranteed and the price is more favorable. Contact us now to build a lightning protection line for all types of distribution lines and protect the safety of equipment.