The Multiple Protection Design of Charging Piles：Ensuring the Safety of Charging Equipment and Users

Introduction: The Importance of Protection

Charging piles provide us with convenient energy replenishment. However, as electrical devices, they involve factors such as voltage and current during use, which, if not handled carefully, could result in equipment damage or safety hazards. To ensure the highest level of safety for both equipment and users, charging piles are designed with a series of protective mechanisms that guarantee safe, stable, and efficient charging.

Common Types of Charging Pile Protection

1. Residual Current Protection

Residual current detection and protection is an essential feature for every charging pile's mainboard, directly safeguarding user safety and eliminating fire risks caused by sustained ground fault currents.

Common residual current detection and protection modules (RCD) are categorized into four types: Type A, Type B, Type F, and Type AC. These categories are based on the different characteristics of the fault currents they detect.

2. Overload Protection

Overload protection is designed to prevent overheating and damage of the main power supply circuit by adding protection devices to prevent overload.

3. Over/Under Voltage Protection

Over voltage protection disconnects the power supply or reduces the voltage of controlled devices when the voltage exceeds a preset maximum value. Under voltage protection is triggered when the voltage drops below a critical level, mainly to prevent equipment damage due to overload.

4. Short Circuit Protection

Short circuit protection safeguards against faults caused by electrical conductors that short-circuit in the power supply system.

5. Earth Leakage Protection

Earth leakage refers to current unexpectedly flowing through unintended paths, such as through the human body or the ground. Earth leakage protection devices can detect even tiny leakage currents within milliseconds and quickly cut off the power supply to prevent electric shock incidents.

6. Ground Protection

Ground protection involves connecting the metal parts of electrical devices (which should not normally be live but might become energized due to insulation damage or other factors) to the ground using reliable conductors.

7. Surge Protection

Surge protectors, also known as lightning arresters, are typically connected in parallel within the electrical system. During a lightning strike, they redirect excess current into the ground, minimizing the potential damage caused by electromagnetic pulses.

8. Over Temperature Protection

Over temperature protection monitors the internal temperature of the charging pile and its battery. If the temperature rises too high, charging is paused to prevent fire hazards or damage to the equipment and battery.

How These Protections Work?

(Injet Swift 2.o coming soon......) 

1. Residual Current Protection (RCD)

In a charging pile system, residual current protection (RCD) is crucial for user safety, especially when used outdoors. RCDs are installed both at the input and output ends of the charging pile to respond to any ground faults or accidental contact with live parts. When even a tiny leakage current (e.g., through the human body or the ground) is detected, the RCD will cut off the power within 30 milliseconds to prevent electric shock.

If the RCD is triggered, the charging pile immediately stops charging and records event information, including time and current strength, for future analysis and maintenance. This helps identify potential safety risks and take preventive measures.

2. Overload Protection

The built-in intelligent control system of the charging pile continuously monitors the output current. Once it detects a load that exceeds the set range, it will reduce or stop the power supply and notify the user to check the connected device or charging parameters, ensuring that the vehicle battery or other components are not damaged by prolonged high-current charging.

3. Over/Under Voltage Protection

These protections are usually implemented through voltage monitoring devices. When the voltage deviates from the normal range, they trigger actions to adjust the voltage or cut off the power supply. Charging piles are equipped with high-precision voltage sensors that continuously monitor grid voltage levels. If any voltage abnormalities are detected, the charging pile will adjust the output voltage according to a preset program to maintain a stable and reliable charging process.

4. Short Circuit Protection

Short circuits occur when current bypasses the normal load path and forms a direct loop, causing an instantaneous surge of current through the wire, which is dangerous. Charging piles are designed with multiple layers of short circuit protection, from the power input to the output interface. Once a short circuit is detected, the system will respond quickly, cutting off the power supply and recording fault data for subsequent analysis, which helps maintenance personnel quickly locate the issue.

5. Earth Leakage Protection

Earth leakage protection works by monitoring whether the total incoming and outgoing current in the circuit is balanced. If a tiny current is detected flowing into an unintended path, such as the device casing or the ground, the earth leakage protection device will immediately disconnect the power supply to prevent potential electric shock hazards. It not only protects user safety but also helps prevent electrical faults and fires caused by current leakage, making it a critical safeguard for charging pile safety.

6. Ground Protection

Ground protection is simply the process of connecting a part of the device that is normally not live (but may become energized in case of insulation failure or other issues) to the ground using a grounding device. Charging piles are designed in strict accordance with grounding standards, ensuring that all accessible metal parts are reliably grounded.

In addition, they feature continuity monitoring, checking the ground connection before each use to ensure a safe charging environment for the user.

7. Surge Protection

Charging piles are equipped with dedicated surge protection modules that provide an additional safety barrier during transient voltage fluctuations caused by lightning strikes or switching operations. This feature is especially important for facilities like public charging stations exposed to environmental elements, ensuring safe charging even under harsh conditions.

8. Over Temperature Protection

The charging pile is equipped with multiple temperature monitoring points covering areas prone to heat generation, such as power converters and cable joints. When the temperature at any point reaches a warning level, the charging pile will automatically reduce the charging power and activate cooling fans. If the temperature continues to rise to dangerous levels, charging will stop entirely to ensure system safety.

Why Choose Injet New Energy?

Injet New Energy's charging piles, especially DC chargers, are equipped with a multi-protection design. For example, the Injet Ampax, a DC fast charger meeting European and American standards, integrates multiple safety mechanisms including over voltage protection, under voltage protection, overload protection, over-power protection, over-temperature protection, surge protection, and short circuit protection, ensuring the system operates safely and reliably, and effectively preventing accidents. Combined with our in-house developed Programmable power controller(PPC), Injet New Energy offers reliable "hardware strength."

(Injet Swift 2.0 - AC charger for both Residential and Commercial use) 

For AC chargers, the protective design is equally comprehensive and robust. The upgraded Injet Swift 2.0, with an IP65 protection rating, includes residual current protection, overload protection, over/under voltage protection, ground protection, and earth leakage protection. In addition to its innovative "click-to-install" for easier installation, it also guarantees enhanced safety during operation.

Injet New Energy prioritizes product quality and customer value, providing the most reliable and safest charging solutions to the market through continuous technological innovation and strict protective designs.

Safety and Peace of Mind

The safety of charging piles is a critical factor in ensuring the protection of charging equipment and user safety. Every design is aimed at ensuring a safe, stable, and efficient charging process. We encourage users to choose charging piles with these protective features. Injet New Energy deeply understands the user safety-centered design philosophy and promises to provide high-standard, well-protected products to safeguard each charging session, contributing to a safer, smarter, and more sustainable future.