The Type 2 DC SPD is used on the DC side of photovoltaic systems and is typically installed at inverter DC inputs or within combiner boxes to limit transient overvoltages caused by lightning-induced and switching events.
LSP Type 2 DC SPD is designed and manufactured in accordance with IEC/EN 61643-31. It is suitable for PV systems with rated voltages of 600V, 1000V, and 1500V DC, and is applied in coordinated surge protection concepts for DC distribution systems.
In photovoltaic installations, the Type 2 DC SPD is used in combination with Type 1 or Type 1+2 SPDs as part of a coordinated surge protection architecture to reduce residual overvoltage and protect downstream DC equipment.
Typical applications include rooftop PV systems, utility-scale solar plants, floating PV systems, and energy storage systems, installed at combiner boxes and inverter DC input terminals.
Type 2 DC SPD
Secondary surge protection for PV DC systems
8/20 μs Waveform
DC Input Installation
IEC / EN 61643-31
Standard for PV DC surge protection
LSP Type 2 DC SPD is a surge protection device installed on the DC side of photovoltaic systems. It is designed to protect inverters, combiner boxes, and PV modules from lightning-induced surges and switching transient overvoltages.
The Type 2 DC surge protector limits residual overvoltage and directs surge currents to the grounding system, reducing the risk of equipment damage and supporting continuous operation of the PV system.
Parallel Connection
Type 2 DC SPD is connected in parallel with the DC lines and supports both common-mode and differential-mode protection.
Common-Mode Protection
MOVs are connected between DC+ to PE and DC- to PE to limit line-to-ground voltage, protecting both equipment and personnel.
Differential-Mode Protection
MOVs are connected between DC+ and DC- to limit the voltage difference between positive and negative lines, protecting inverter input terminals.
Surge Response
When transient overvoltages occur, the MOVs conduct rapidly, directing surge currents to the grounding system and limiting residual voltage.
Thermal Disconnection
Built-in thermal disconnection disconnects the SPD in case of component degradation, preventing thermal runaway.
Modular Design and Remote Monitoring
Pluggable module design of Type 2 DC surge protector allows on-site replacement, and remote signal terminals provide operational status monitoring.
Type 2 DC SPD is a surge protection device installed on the DC side of photovoltaic systems. It is tested with an 8/20 µs waveform to withstand lightning-induced surges and switching transient overvoltages.
Typically mounted at inverter DC inputs or inside combiner boxes, Type 2 DC surge protector provides secondary or supplementary protection by limiting residual voltage and safeguarding inverters and other DC equipment from surge-related damage.
The Type 2 DC SPD is a surge protection device installed on the DC side of photovoltaic systems, tested with an 8/20 µs waveform (In and Imax) to absorb lightning-induced surges and switching transient overvoltages.
The Type 2 DC SPD forms a low-impedance path between the DC lines and ground. When transient overvoltage exceeds the equipment’s withstand level, the Type 2 DC surge protector directs surge current to the grounding system, limiting residual voltage and protecting inverters, combiner boxes, and PV modules.
The Type 2 DC SPD is tested with an 8/20 µs surge current waveform to verify its performance under lightning-induced and switching surges.
The 8/20 µs waveform simulates surge currents with an 8 µs rise time and a 20 µs half-value duration.
In (Nominal Discharge Current): The repeated 8/20 µs surge current rating of the Type 2 DC surge protector, indicating long-term durability.
Imax (Maximum Discharge Current): The single-event maximum 8/20 µs surge current withstand capability.
Up (Voltage Protection Level): The residual voltage at the equipment after surge discharge; lower Up provides better protection.
The Type 2 DC SPD is connected in parallel with the photovoltaic DC lines.
Under normal conditions, the MOV remains in a high-impedance state and does not affect system operation.
When transient overvoltage occurs, the MOV conducts rapidly and its resistance decreases sharply, allowing the Type 2 DC surge protector to direct surge current to the grounding system.
During discharge, the voltage across the MOV is clamped to a defined level, limiting residual voltage at the equipment.
After the surge, the MOV returns to a high-impedance state and normal operation resumes.
If the MOV degrades due to repeated surges or sustained overvoltage, the integrated thermal disconnection mechanism isolates the device to prevent thermal runaway.
MOV (Metal Oxide Varistor)
The MOV is the core protection element of the Type 2 DC SPD, based on zinc oxide material. It remains in a high-impedance state under normal voltage and conducts rapidly under surge conditions, absorbing and dissipating surge energy with nanosecond response time.
Thermal Disconnection
The thermal disconnection mechanism monitors temperature and disconnects the circuit when overheating occurs due to component degradation, preventing thermal runaway.
Status Indication Window
The status windows provide a visual indication of the Type 2 DC surge protector condition. Green indicates normal operation, while red indicates degradation or disconnection.
Remote Signaling Module
The remote signaling module is an optional feature providing dry-contact outputs for status indication, enabling integration with monitoring or SCADA systems.
Ucpv (Maximum Continuous Operating DC Voltage)
Ucpv defines the maximum DC voltage that the Type 2 DC SPD can withstand continuously and should not be lower than the PV system open-circuit voltage (Voc) at the lowest ambient temperature.
In (Nominal Discharge Current)
In represents the repeated surge current withstand capability of the Type 2 DC SPD, indicating long-term durability.
Imax (Maximum Discharge Current)
Imax represents the maximum surge current the Type 2 DC surge protector can withstand for a single event.
Up (Voltage Protection Level)
Up defines the residual voltage at the equipment after surge discharge; lower values provide better protection.
| Parameter | Symbol | SLP-PV |
| Maximum continuous operating voltage | Ucpv | 600 / 1000 / 1200 / 1500 V DC |
| Nominal discharge current | In | 20 kA (8/20 µs) |
| Maximum discharge current | Imax | 40 kA (8/20 µs) |
| Voltage protection level | Up | ≤ 5.2 kV |
In photovoltaic systems, the DC side typically adopts a coordinated surge protection structure, where the Type 2 DC SPD serves as secondary or supplementary protection.
The Type 2 DC SPD is typically installed at inverter DC inputs or within combiner boxes to protect inverters, combiner boxes, and PV modules.
When no external lightning protection is provided, when the inverter is located inside the building (LPZ 1 or higher), or when upstream Type 1+2 SPDs are installed, the Type 2 DC surge protector limits residual voltage and protects downstream equipment.
In a complete surge protection concept, DC and AC protection form a coordinated system. The Type 2 DC SPD protects against lightning-induced and switching surges on the DC side, working together with AC SPDs to ensure continuous system operation.
Type 2 DC SPD is designed for surge protection on the DC side of photovoltaic systems. It combines PV-specific voltage matching, thermal disconnection mechanism, arc-safe structural design, and high discharge capability to ensure reliable surge current diversion and controlled residual voltage, providing long-term operational stability and protection for inverters and PV modules.
The DC terminal area adopts an arc-resistant barrier structure, optimizing creepage distance and electrical clearance, effectively reducing the risk of DC arcing under high-energy surge conditions.
Each Type 2 DC SPD is tested in accordance with IEC/EN 61643-31, including 8/20 µs surge current impulse tests, thermal stability, glow-wire, and salt mist tests, ensuring long-term reliability in PV DC surge protection applications.
Type 2 DC SPD is designed for protection against induced lightning surges and switching transients in photovoltaic DC systems. It is widely used in residential, commercial, utility-scale PV and energy storage systems. It provides protection on the DC side for inverters, combiner boxes, and power electronic equipment, reducing the impact of surge events on system operation.
Type 2 DC SPD is designed and tested in accordance with IEC/EN 61643-31 standards for photovoltaic and DC power systems. The product is certified by TÜV, CB, and CE, ensuring full compliance with international safety, performance, and quality requirements.
Type 2 DC SPD provides reliable surge protection performance for PV installations, supporting system integrators and end users with trusted electrical protection in both residential and commercial applications.
LSP operates under an ISO 9001 certified quality management system, ensuring standardized control across the entire manufacturing process of Type 2 DC SPD for photovoltaic and DC power systems, from raw material sourcing to final product inspection.
Each unit undergoes comprehensive multi-parameter testing before shipment to ensure consistent surge protection performance, long-term reliability, and product quality stability in PV system applications.
The design of Type 2 DC SPD is continuously optimized based on field operating data and application feedback. Structural improvements and core component upgrades enhance reliability, installation convenience, and surge protection performance in photovoltaic and DC power systems.
Type 2 DC SPD is used for surge protection in photovoltaic and DC power systems, typically applied in inverters, combiner boxes, and DC distribution equipment. Proper installation location, wiring practice, and grounding design are essential to ensure effective surge energy discharge, reduce the impact of transient overvoltage on system components, and improve long-term system reliability.
When used in photovoltaic DC systems, the correct wiring and installation of Type 2 DC SPD are critical for ensuring effective surge protection performance.
Type 2 DC surge protector should be installed close to the inverter or combiner box to minimize lead length and reduce additional voltage rise.
DC cables should be kept as short and straight as possible, with correct polarity connection (positive, negative, and ground terminals).
Reliable grounding must be ensured, complying with IEC 61643-11 or relevant local electrical standards.
Proper wiring layout helps reduce residual voltage and improves overall surge protection performance.
Remote signaling terminals are used to indicate the operating status of the Type 2 DC SPD, enabling system-level monitoring and maintenance management.
Real-time status monitoring – Provides operational feedback of the Type 2 DC surge protector for system supervision.
Fault signal output – Sends alarm signals in case of failure or end-of-life condition, supporting preventive maintenance.
Improved maintenance efficiency – Enables faster fault localization and device replacement, reducing system downtime.
The global field feedback of Type 2 DC SPD across photovoltaic, energy storage, and DC power systems, including rooftop PV, utility-scale solar plants, floating PV, industrial PV, and EV charging infrastructure.
The cases reflect real-world operational conditions under 600V to 1500V DC systems, focusing on system stability, maintenance practices, and long-term operational performance.
A Type 2 DC SPD is a surge protective device designed in accordance with IEC 61643-31 to limit transient overvoltages in DC systems.
In photovoltaic applications, it is typically installed at subsystem level, such as inverter DC inputs or combiner boxes, to protect equipment against switching surges and residual lightning-induced overvoltages.
Type 2 DC SPDs are installed at DC distribution points within the PV system, including inverter DC inputs, combiner boxes, and energy storage interfaces.
Their placement ensures coordinated protection within the DC system and reduces surge stress on downstream equipment.
A Type 2 DC SPD limits transient overvoltages by diverting surge energy to earth through its internal protective components (MOV / GDT-based designs depending on topology).
It reduces voltage stress on PV strings, inverter DC inputs, and DC-linked equipment during switching events or indirect lightning surges.
The rated voltage Uc of the SPD should be selected based on the maximum open-circuit voltage (Voc) of the PV string under the lowest ambient temperature conditions.
Proper coordination between system voltage and SPD Uc ensures stable operation without unintended operation under normal DC conditions.
The response characteristic of a Type 2 DC SPD determines how quickly it transitions from high impedance to low impedance during surge events.
This fast switching behavior helps limit the magnitude of overvoltage applied to connected DC equipment, improving system protection coordination.
Type 1 DC SPDs are installed at the service entrance to discharge high-energy lightning currents, while Type 2 DC SPDs handle residual transient overvoltages within the DC system.
Together, they form a coordinated protection concept for PV and DC power systems in accordance with IEC surge protection principles.
Yes. A complete protection concept typically includes:
Both are required to ensure system-wide surge protection coordination.
Type 2 DC SPDs typically include visual status indicators and optional remote signaling contacts.
Replacement is required when the end-of-life indication is activated or after exposure to significant surge stress events to maintain system protection integrity.
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