Surge Protection for EV Charging

Surge Protection for EV Charging

Created by: Glen Zhu | Updated Date: Sep 14, 2023

The sky was thundering as I charged my electric car, and I was constantly worried that my vehicle would be struck by lightning.

Do you worry about this in the same way?  Well, we have to say that concern over this is definitely necessary.

Lightning Strikes – Risk to Your E-mobility

Surge protective device SPD for e-mobility-EV charging station

As electric vehicles (EVs) become more widely available in many countries, the availability and safety of electric vehicles and charging stations have been identified as critical factors. Daily maintenance is essential, especially to safeguard the stations from lightning strikes.


More than 90% of charging stations are linked to the electrical power grid, and the risk of surge voltages flowing through from lightning events or switching operations must be carefully considered. Once transient voltages are coupled into the vehicle through this galvanic connection, they become a serious threat.

Our risks are:

a). Damage to the EV charger

b). Damage to the car

c). Damage to the electrical installation

Protection against transient overvoltages

Electrical vehicles, due to their embedded electronics, are rated at 2.5 kV (Overvoltage category II): this is often not sufficient to provide relevant safety in case of heavy surge voltages occurrence. because incoming surges are often exceeding these ratings, which means failures with undefined consequences for the connected vehicle electronics during an active charging process.

That’s where the surge protection device(SPD) comes in, which detects voltage surges and directs the transient voltage over a preset threshold to a ground line, into the earth—protecting your EV chargers from the surge.

Existing international technical standards must be used in order to select the right SPD configuration and its relevant ratings for EV infrastructures:

> IEC 60364-7-722

“Requirements for special installations or locations - Supplies for electric vehicles”

This part of the IEC standards covers specific aspects for the power supply of electric vehicles on the low-voltage grid. The section 722.443 mentions the need for surge protection against transient overvoltages due to atmospheric influences or during switching operations. This is ensured by the use of type 1 or type 2 surge protective device (SPD) with a protection level of Up ≤ 2.5 kV, which complies with IEC 61643-11. It is also explicitly required for charging points in publicly accessible facilities.

Choose the Right SPD for Your EV Charger

Hence, it is crucial to choose the appropriate SPD and design it in accordance with the need for EV charging stations. Depending on the location and characteristics of the threat, a customized tection concept is required.

On the basis of the IEC 61851-1 standard, 4 distinct charging modes are often distinguished. These numerous charging modes explain distinct installation kinds; based on these modes, the surge protection system may change.

Charging Mode of electrical vehible(EV).webp

Charging Mode 1:  EV is charged directly from the AC mains through conventional single-phase domestic sockets.

Charging Mode 2: EV is charged via a conventional single-phase domestic socket with a charging cable containing a control and protection device, a so-called In-Cable Control and Protecting Device (ICCPD).

Charging Mode 3: EV is charged via a permanently installed charging station designed as a wall box or charging station, which with a rated power of > 4.6 kVA must be connected to a 3-phase AC system

Charging Mode 4: The electric vehicle is charged directly with DC current. The charging cable is permanently attached to the charging station. The charging power starts at 24 kW, but is often significantly higher (up to 350kW) and is connected to 3-phase AC power

PS.: The protection of the communication interface must be taken into account, especially for wall boxes and charging stations. This extremely important interface should not only be considered due to the recommendation of IEC 60364-4-44, as it represents the link between the vehicle, the charging infrastructure, and the energy system. Here too, protection modules tailored to the application ensure the reliable and safe operation of electric mobility

Solution

> For protection against type 1+2 transient overvoltage, the FLP12,5 series element guarantees high protection against transient overvoltage for power supply lines at the entrance of the building, including those produced by direct lightning discharges.

Source: LSP

It is a type 1 and 2 protectors according to the standard IEC/EN 61643-11. Its main characteristics are:

  • Impulse current per pole (limp) of 12,5 kA and a protection level of 1,5 kV.
  • It is formed by gas discharger devices.
  • It has been signed for the state of the protections.

> For protection against type 2 transient overvoltage, we recommend the SLP40 series.

Source: LSP

LSP could provide you with all the protection you need to design an all-around protection concept to keep your charging station ready for use – day or night, and in all weather conditions.

Surge protection for Indoor EVSE & Outdoor EVSE

> For Indoor Electric Vehicle Supply Equipment (EVSE)

  • SPD for Indoor EVSE – without a lightning protection system (LPS) – public access

The IEC 60364-7-722 requires protection against transient overvoltage for all locations with public access. The usual rules for selecting the SPDs can be applied.

Surge protection device SPD for indoors EVSE-without lightning protection-system

When the building is not protected by a lightning protection system:

a). A type 2 SPD is required in the main low-voltage switchboard (MLVS)

b). Each EVSE is supplied with a dedicated circuit.

c). An additional type 2 SPD is required in each EVSE, except if the distance from the main panel to the EVSE is less than 10m.

d). A type 3 SPD is also recommended for the Load Management System (LMS) as sensitive electronic equipment.

  • SPD for Indoor EVSE – without lightning protection system (LPS) – installation using busway – public access
Surge protection device SPD for indoors EVSE-without lightning protection-system-installation-using-busway

This example is similar to the previous one, except that a busway (busbar trunking system) is used to distribute the energy to the EVSE.

In this case, LSP recommends:

a). A type 2 SPD is required in the main low voltage switchboard (MLVS)

b). EVSEs are supplied from the busway, and SPDs (if required) are installed inside busway tap-off boxes

c). An additional type 2 SPD is required in the first busway outgoer feeding an EVSE (as generally the distance to the MLVS is more than 10m).

d). If this additional type 2 SPD has Up < 1.25kV (at I(8/20) = 5kA), there is no need to add any other SPD on the busway: all following EVSEs are protected.

e). A type 3 SPD is also recommended for the Load Management System (LMS) as sensitive electronic equipment.

  • SPD for Indoor EVSE – with lightning protection system (LPS) – public access
Surge protection device SPD for indoors EVSE-with lightning protection-system

When the building is protected by a lightning protection system (LPS):

a). A type 1+2 SPD is required in the main low voltage switchboard (MLVS)

b). Each EVSE is supplied with a dedicated circuit.

c). An additional type 2 SPD is required in each EVSE, except if the distance from the main panel to the EVSE is less than 10m.

d). A type 3 SPD is also recommended for the Load Management System (LMS) as sensitive electronic equipment.

Note: if you use a busway for the distribution, apply the rules shown in the example without LTS, except for the SPD in the MLVS = use a Type 1+2 SPD and not a Type 2, because of the LPS.

> For Outdoor EVSE

  • SPD for outdoor EVSE – without lightning protection system (LPS) – public access
Surge protection device SPD for outdoors EVSE-without lightning protection-system

In this example, LSP recommend:

a). A type 2 SPD is required in the main low voltage switchboard (MLVS)

b). An additional type 2 SPD is required in the sub panel (distance generally >10m to the MLVS)

  • SPD for outdoor EVSE – with lightning protection system (LPS) – public access

The main building is equipped with a lightning rod (lightning protection system) to protect the building.

Surge protection device SPD for outdoors EVSE-with lightning protection-system

In this case, LSP recommend:

a). A type 1 SPD is required in the main low voltage switchboard (MLVS)

b). An additional type 2 SPD is required in the sub-panel (distance generally >10m to the MLVS)

In a word, for the charging stations themselves, the choice of the correct solution depends on whether the station is within the protection zone of the external lightning protection system. If this is the case, a T2 arrester is enough. In outdoor areas, a T1 arrester must be used according to the risk.

The table below provides an overview of the different types of surge protection available:

Overview of different surge protection SPD types

LSP puts at your disposal the necessary products to protect the charging points against transient and permanent surges, ensuring the conservation of the vehicle. In case you are interested in acquiring protection against overvoltages, you can rely on the help of our expert staff in the matter here.

Installation Tips for EV Surge Protectors

Surge protector SPD for electric mobility-EV charging station

The following tips could help you ensure your EV charger installation is done right:

  • Overvoltages caused by direct or indirect lightning strikes into the alternating current (AC) network must be diminished up to the input of the main distributor of the EV charging device. We recommend installing surge protection devices (SPDs) that conduct the impinging surge current to earth, directly after the main circuit breaker. 

 

  • All metallic cable lines that lead into or out of a building, such as gas, water, or electricity, are potential surge voltage transmission elements. As a result, such possibilities should be considered in a risk assessment, and appropriate lightning/surge protection should be considered as close to the sources of interference or building entry points as possible.

 

  • An additional SPD must be put directly at the AC side terminals if charging devices are more than 10 meters from the main distribution board, where the primary surge protection is located.

 

  • when installing an at-home charger for an electric vehicle (EV), it is advisable to rely on a skilled electrical contractor, particularly one who is versed in EV installations, rather than doing it yourself. It is risky and may be fatal to work with high-voltage electronics and panels.

Conclusion

It is essential to rely on a reputable contractor from the start to guide you through the selection and installation process because EV technology is intricate and constantly changing.

As your partner, our LSP team is always at your side in terms of protection solutions. For more information and assistance on the SPD of EV charger stations, contact us freely.

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E-Mobility Surge Protection Device SPD Price

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