서지 보호 장치의 유형: 유형 1, 유형 2 및 유형 3 설명

In today’s highly electrified and digitized world, our society relies on fragile electronic devices—from smart TVs and computers in homes to precision control units in industrial settings.

Yet an invisible threat lurks within the power grid: electrical surges. These can inflict massive damage within millionths of a second. 서지 보호 장치 (SPDs) serve as the critical defense against this threat. But not all SPDs are created equal.

Understanding the distinctions between Type 1, Type 2, and Type 3 SPDs is essential for building a comprehensive and effective surge protection system. This article reviews the roles, standards, and applications of these three SPD categories, providing you with a complete guide to constructing a robust electronic defense.

What is a Surge Protective Device (SPD)?

Where do surges come from?

A surge, also known as a transient overvoltage, refers to an electrical current pulse with an astronomical duration (microseconds to milliseconds) but a voltage amplitude far exceeding normal operating levels. It can be broadly categorized into two types: external surges and internal surges.

External Surges (Primary Threat)

a) Direct Lightning Strikes: Lightning striking power grids or nearby structures injects millions of volts—the most extreme scenario.

b) Induced Lightning: More common. Even when lightning strikes hundreds of meters away, its powerful electromagnetic field induces overvoltages on indoor power and signal lines, which then propagate into equipment.

Internal Surges (Frequent Occurrences)

Switching operations of high-power equipment within buildings—such as elevators, air conditioning compressors, and welding machines—generate frequent switching transients in the power grid. Even operations like photocopiers and coffee machines produce frequent, lower-energy transient overvoltages.

The cumulative effect of these surges acts like a “miniature hammer” continuously striking electronic components, gradually causing performance degradation, data corruption, and reduced equipment lifespan. A single major surge event, however, is akin to an “electronic heart attack,” capable of instantly causing permanent equipment damage or even triggering fires.

Surge Protective Devices (SPDs) are electronic safety devices specifically engineered to counter these threats. Their core functions can be summarized as “monitor, divert, and clamp.”

Under normal voltage conditions, SPDs present high impedance, having no impact on the circuit. Upon detecting overvoltage, it transitions to a low-impedance state within nanoseconds, establishing a safe discharge path to ground for surge currents while limiting the voltage across its terminals (the clamping voltage) to a safe range within the protected equipment’s tolerance.

Therefore, SPDs are not a luxury but an essential component in any modern electrical system seeking to safeguard assets, ensure business continuity, and protect data.

How does an SPD work?

Under normal conditions, an SPD has no effect on the circuit and remains in a high-impedance state. Upon detecting a dangerous surge, it reacts within nanoseconds, switching to a low-impedance state. This creates a low-resistance path for the surge current, rapidly “diverting” it to ground while simultaneously limiting the voltage across its terminals (known as the clamping voltage) to a safe range. This protects the equipment connected in parallel from damage.

You can visualize it as an intelligent pressure relief valve for high-voltage water flow, as shown below: When water pressure is normal, the valve remains tightly closed. When pressure suddenly spikes (surge), the valve instantly opens, releasing excess water flow (surge current) to ensure the safety of downstream equipment (your appliances).

What damage can power surges cause to LED lighting fixtures?

Many people assume that because LED lighting fixtures are long-lasting and energy-efficient, they are inherently “durable and robust.” However, the reality is quite the opposite—LED lighting fixtures are extremely sensitive to power surges, primarily due to their core component: the driver power supply.

1. Damage to Switching Power Supplies

As shown below, LED chips themselves operate under low DC voltage (e.g., 3V) and constant current. The 220V AC power we use daily must be converted through a component called a “driver power supply.” This driver is essentially a precision switching power supply packed with sensitive semiconductor components (such as MOSFETs, IC controllers, rectifier diodes, etc.).

These semiconductor components are extremely fragile, with voltage tolerance far below that of traditional incandescent or fluorescent bulbs. Even a minor voltage spike can cause them to break down. Therefore, a surge-protected switching power supply is crucial for extending the lifespan of lighting fixtures.

2. Burning Out LED Chips

High currents can directly sever gold wire connections or damage LED chips, causing partial or complete blackening and failure of the chips.

3. Progressive Component Degradation

This type of damage is more subtle and widespread. Repeated minor surges that don’t immediately destroy the fixture cause cumulative damage to its internal semiconductor materials. Over time, fixtures may inexplicably dim, flicker, experience color drift, or emit abnormal noises from the driver.

The expected lifespan of fixtures plummets from 50,000–100,000 hours to just one or two years—or even less. You might assume you’ve purchased a “substandard product,” but the real culprit is likely frequent internal surges.

Benefits of Adding SPDs to Lighting Fixtures

LED lighting fixtures, particularly in commercial, industrial, or outdoor applications (such as streetlights, floodlights, and industrial/mining lights), carry significantly higher procurement and installation costs than traditional fixtures. The damage to a single fixture involves not only the cost of replacing the unit itself but also substantial labor expenses for maintenance/replacement, especially in high-altitude or complex environments.

The cost of installing an SPD is significantly lower than the long-term expenses incurred by frequently replacing LED drivers or entire fixtures due to surge damage. It represents a crucial safeguard for lighting investments.

Therefore, equipping LED lighting systems—especially outdoor, commercial, and industrial lighting—with surge protection devices (SPDs) is not an optional luxury but a necessary protective measure. It enables:

• Prevent sudden, costly equipment failure.
• Avoid hidden, gradual performance degradation and reduced lifespan.
• Lower maintenance expenses and enhance lighting system reliability.
• For individual household fixtures: Use high-quality power strips with built-in basic surge protection.

• For entire buildings or villas: Install Type 2 SPDs in the main distribution panel to provide trunk protection for all household circuits.

• For outdoor LED fixtures (streetlights, landscape lights) and large factory/mall lighting circuits, Type 2 SPDs must be specifically installed for lighting circuits within the corresponding zone distribution panels. For particularly expensive or critical fixtures, consider adding Type 3 SPDs inside the fixture or at the terminal for granular protection.

By investing in SPDs, you are ensuring your LED lighting investment delivers its promised longevity and high performance, thereby delivering true value for money.

How to Understand SPD Grading?

You might ask: If SPDs exist, why categorize them into different types? The answer is no single SPD can independently handle all types of surge threats.

The energy generated by lightning strikes differs vastly in magnitude from that produced by internal switching operations. Therefore, an effective protection strategy involves establishing a layered, synergistic defense system. This concept is known as “energy coordination” or “tiered discharge.” Imagine it as a castle’s defense system:

• Type 1 acts as the sturdy outer walls and gates, designed to withstand the most intense frontal assaults.

• Type 2: The patrol guards within the castle, addressing stragglers who breach the outer walls and internal disturbances.

• Type 3: The personal guards at the king’s bedchamber door, providing the final and most refined layer of protection.

Only when these three lines of defense work together can the castle (your electrical system) receive the most comprehensive protection.

Type 1 SPD: The First Line of Defense Against External Surges

Type 1 SPDs are the highest-rated devices, designed to divert portions of lightning currents caused by direct strikes. Per international standards (e.g., IEC 61643-1), they must withstand testing with a 10/350µs simulated lightning current waveform. This waveform represents the immense energy of a direct lightning strike, featuring an extremely long duration that subjects equipment to severe stress. Installation Location: Installed within the building’s Main Distribution Board (MDB), typically at the power entry point.

특징: Discharges massive lightning currents (often tens of kiloamperes). Its primary purpose is not to limit voltage to very low levels but to safely “absorb” the most lethal initial strike.

Typical Components: Typically employs spark gaps or gas discharge tubes, as these components can withstand extremely high energy impacts.

Applicable Scenarios: Primarily used in buildings equipped with external lightning protection systems (e.g., lightning rods) or those supplied by overhead power lines. It forms the foundation of the entire surge protection system.

Type 2 SPD: Primary Protection, Protecting Distribution Systems

Type 2 SPDs are the most widely used SPDs, serving as the primary protection level in surge protection systems. They are tested using an 8/20µs current waveform, which simulates residual surges transmitted after being limited by Type 1 SPDs, as well as surges generated by internal switching operations.

설치 위치: Installed within sub-distribution boards to provide protection for specific floors, zones, or load groups.

특징: Further limits overvoltages and discharges surge currents not fully handled by Type 1 SPDs, along with internally generated surges. It restricts voltage to levels safe for most household and commercial appliances (e.g., below equipment withstand voltage ratings).

Typical Device: Most commonly a metal oxide varistor (MOV) due to its excellent response speed and clamping voltage characteristics.

애플리케이션 시나리오: An almost indispensable protective device in all electrical installations. In small buildings without external lightning protection systems, it can even serve as the first-level protection.

Type 3 SPD: Precision Protection for End Devices

Type 3 SPD delivers the most refined level of protection, specifically designed for safeguarding highly sensitive or expensive end devices. It is tested using composite waves (1.2/50µs voltage wave & 8/20µs current wave), with significantly lower test current values than Type 2.

Type 3 SPD further suppresses minute residual overvoltages that bypass the first two protection levels. Though low in energy, these voltage spikes can degrade equipment lifespan or cause data corruption through prolonged accumulation. It must never be used alone and should be installed downstream of a Type 2 SPD.

Installation Locations:

– At the equipment end, including power outlets with SPD functionality (e.g., some advanced power strips).

– Dedicated plug-in SPDs.

– Embedded SPD modules inside equipment.

Combination Units: Type 2+3 combination SPDs are also available on the market. These integrate both protection levels into a single module, providing a convenient and efficient solution for scenarios where installing multiple standalone SPDs is impractical.

How to Select and Deploy Your SPD System?

Selecting the appropriate SPD and building a coordinated system is crucial in environments prone to frequent lightning strikes or significant power fluctuations. Proper SPD selection and installation not only prevent costly repairs but also ensure continuity in production and daily life, making it a technical decision requiring comprehensive consideration.

First, assess your building’s environment: lightning strike frequency, isolation status, overhead or underground power supply, presence of lightning rods in the structure, and the value and sensitivity of internal equipment. This will determine whether you require Type 1 protection or if a Type 2+3 combination suffices.

• Follow the hierarchical principle:

– Buildings with external lightning protection systems or high-risk zones: Implement a complete architecture of Type 1 → Type 2 → Type 3.

– Standard commercial or residential buildings: Install at least a Type 2 SPD at the main service entrance and supplement with Type 3 SPDs at critical equipment points.

– Small buildings or apartment units: Install a high-performance Type 2 SPD within the service panel and use Type 3 surge-protected power strips for valuable equipment.

• Voltage Protection Level (Up): This represents the SPD’s clamping voltage. Lower values indicate better protection. Ensure Up is below the withstand voltage rating of protected equipment.

• Nominal Discharge Current (In) and Maximum Discharge Current (Imax): These indicate the SPD’s ability to dissipate surge currents. Higher values signify greater resilience.

• For Type 1 SPDs, focus on the impulse current (Iimp).

• Ensure Proper Installation: SPD performance is highly dependent on installation. Minimizing grounding lead length is critical, as excessively long leads generate induced voltage that significantly degrades protection. Use dedicated tools or busbars to connect the SPD directly and with minimal length to the grounding system.

• Maintenance and Lifespan: SPDs are consumable devices. Particularly MOV-based SPDs gradually degrade after repeated surge events. Select SPDs with remote signal contacts or visual alarm windows to monitor their status and facilitate timely replacement.

Selecting the appropriate SPD type and building a coordinated protection system are key to ensuring electrical equipment safety and extending its service life. Understanding their distinctions and interconnections will help you establish a truly robust “electronic defense line” for your home or business. The appendix provides reference parameters for selecting different SPD types:

Recommended Values for Surge Current and Nominal Discharge Current Parameters of Power Line Surge Protectors

결론

In summary, Type 1, Type 2, and Type 3 SPDs each fulfill distinct roles, forming a layered defense system from macro to micro levels. Investing in a well-designed surge protection system is not only about safeguarding hardware but also a strategic investment in data security, business continuity, and the protection of lives and property. By understanding their respective functions and deploying them synergistically, you can establish a robust barrier for your electronic assets against unpredictable electrical threats.