Surge protection for DC systems
Protect important components from failure and damage
Direct current (DC) is driving the energy revolution. And not only in Germany, but throughout Europe and, in some cases, worldwide. Whether it's in photovoltaics, battery storage, electromobility or modern building technology, DC systems form the backbone of efficient power distribution. However, with increasing prevalence, there is also a growing urgent need to protect these systems reliably.
Power surges caused by lightning or switching operations can destroy expensive components in seconds. We offer comprehensive, standard-compliant protection solutions that reliably secure DC applications in all areas. This keeps systems safe, stable and economical. Learn more about the areas of application and the appropriate DEHN protection concepts.
Maximum safety for your DC applications
DEHN is your reliable system partner for direct current protection. Our innovative solutions ensure maximum system availability, safe installation and long-term investment protection. From planning to implementation, we support you with comprehensive expertise and international experience.
Shaping standards, driving innovation
As an active member of the Open Direct Current Alliance (ODCA), we are driving forward global standards for DC technologies. Together with international partners, we are making direct current safer – whether in energy, industry, mobility or buildings. Forecasts show that the global DC market will grow to over USD 800 million by 2035.
DC – Key technology of the future
With certified, scalable protection solutions, DEHN is actively shaping the future of direct current. Our commitment to the further development of standards and protection concepts makes us a leading driver for secure and efficient DC infrastructures around the globe.
Your investment in quality that pays off for you
Maximum system availability
DEHN SPDs prevent unplanned outages caused by overvoltages – your systems run stably and reliably.
Standard-compliant solutions
They comply with international standards and requirements, thereby simplifying planning, installation and acceptance.
Safety for people and technology
In critical situations, you avoid endangering employees and increase operational safety.
Economic efficiency
You avoid high repair costs, production downtimes and insurance claims. DEHN solutions can be seamlessly integrated into your systems and are easy to maintain.
Protection of your DC components
You protect expensive inverters, battery storage systems or charging stations from damage and extend their service life.
System expertise and consulting
DEHN not only provides you with protection solutions, but also with expertise – from planning to implementation.
Forward-looking solutions
Your DC protection is scalable and optimally prepared for the requirements of the energy revolution and digitalisation.
E-Mobility
Reliable surge protection secures the DC side of PV systems, increases operational safety and service life, and complies with all relevant standards.
Battery storage
Reliable surge protection safeguards battery storage systems, prevents damage, and ensures stable, standard-compliant operation of modern BESS systems.
Photovoltaics
Reliable surge protection protects the DC side of PV systems, increases safety and service life, and complies with all relevant standards.
Telecommunications
Protection solutions secure critical DC telecommunications infrastructures, increase availability and fire protection, and reduce long-term maintenance and operating costs.
Industrial automation
Protection solutions secure industrial DC systems, increase plant availability and fire protection, and enable safe, standard-compliant operation.
Building security
Reliably protecting smart buildings: DC protection solutions secure power supply and communication and increase operational safety in accordance with all relevant standards.
DC systems: high voltages, stringent protection requirements
In DC applications, the challenge when using surge protective devices (SPDs) is that, unlike alternating current, direct current does not have a zero crossing. This makes it significantly more difficult to quench the electric arcs that occur when a surge voltage is discharged. In addition, DC systems often operate at higher and continuously constant voltages, resulting in higher thermal loads and requiring more careful design of SPDs.
Particularly in applications such as photovoltaic systems, battery storage systems or electromobility, protective devices must be selected and designed with particular care due to the varying voltage levels and short-circuit currents.
IEC/EN 61643-31 (SPDs for PV DC circuits) and IEC/EN 61643-41 (SPDs for DC power supply systems in general), among others, apply to the standardisation and testing of surge protective devices in DC applications.
Planning DC systems safely and in accordance with standards
IEC
60364-4-44,
Clause -443
Surge protection in low-voltage installations, also for DC up to 1500 V.
IEC
61643-31
Surge protection devices for DC circuits of PV installations up to 1500 V.
IEC
61643-41
Updated standard for surge protective devices in DC low-voltage systems, up to 1500 V.
IEC
60364-7-712
Installation requirements for PV systems, including DC.
IEC
60364-5-53,
Clause -534
Selection and installation of SPDs in Low-Voltage Systems, including DC.
DIN EN IEC
62305
External and Internal Lightning Protection, also covering DC-related aspects.
IEC
61851-23:2023
Safety and surge protection requirements for DC charging stations.
Valuable knowledge for your planning
We recommend our online seminars and e-learning courses on e-mobility and photovoltaics - applications that use DC exclusively or for the most part.
DEHN is your full-service provider
We accompany your project from planning to realisation and beyond. Take advantage of our wide range of practical tools and services.
We take action today - for a safe tomorrow
Thinking sustainably – shaping the future with DC: Discover how DEHN takes responsibility by combining energy efficiency, resource protection, and innovation.
FAQs
What are the most important standards and certifications for DC surge protective devices in photovoltaic and energy storage systems?
IEC 61643-xx is the international standard for surge protective devices (SPDs). In particular, parts -31 (PV applications) and -41 (linear DC sources) are of interest. These normative requirements are verified by independent testing institutes such as DEKRA or VDE and certified through their test marks. For North American approval, UL 1449 applies, which is also confirmed by the UL organization.
How do you determine the correct design of surge protective devices for high-voltage DC applications such as EV charging infrastructure?
The relevant parameters for the application are defined in IEC 61851-23. For example, it specifies that the rated voltage (Udc) of the SPD must correspond to or exceed the system voltage. Likewise, the voltage protection level (Up) of the surge protective device must not exceed 2.5 kV. Furthermore, when selecting the SPD, coordination with upstream fuses and a short-circuit withstand capability higher than the maximum possible system fault current must be taken into account.
How does the placement of surge protective devices in a DC circuit affect the overall safety and performance of the system?
According to the applicable installation standards, surge protective devices should be installed as close as possible to the power feed point - i.e., at PV strings or battery terminals - to minimize the impact of lightning and surges on the rest of the installation. At system boundaries or lightning protection zone transitions, they protect the interfaces between DC and AC systems, for example at the inverter input or at the cable entry of a DC hypercharger. Short cable runs keep the protection level of the surge protective devices as low as possible. Proper grounding is essential for the effectiveness and safety of the SPDs.
How can a comprehensive protection concept for DC systems – including surge and lightning protection – be optimally planned?
Planning a complete protection system for DC installations requires in-depth knowledge of standards, risk analysis and system integration. The DEHNacademy offers practical training courses on surge and lightning protection to assist you with your design work. In addition, DEHN offers professional support with its engineering services: from consulting to the complete planning of a tailor-made solution for your installation.
Any questions?
We are here for you!
We look forward to hearing from you.