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.
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
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:
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.
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 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
> 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:
> 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.
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.
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.
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.
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.
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)
The main building is equipped with a lightning rod (lightning protection system) to protect the building.
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:
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.
The following tips could help you ensure your EV charger installation is done right:
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.
Reliable LSP surge protection device for E-Mobility are designed to meet the protection needs of installations against lightning and surges. Get the price now!
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