As the world's largest consumer of new energy electric vehicles, new energy electric vehicles are developing rapidly, and the safety of electric vehicle charging piles is a top priority: whether the electric vehicle charging pile can avoid random plugging and unplugging during the charging process.
The accident caused by the charging gun, whether it can be automatically powered off after charging, whether it can be insulated and avoid electric shock in rainy days, this is the question of many electric vehicle users at present, what kind of electric vehicle charging pile can ensure the new energy vehicle owners Safe during charging.
This artical discusses and analyzes the application analysis of leakage protection in electric vehicle charging piles.
According to domestic and foreign data statistics, the safety factor of electric vehicle charging piles that meet the national requirements is higher than that of home appliances. Not only will there be no accidents when people touch the charging piles, but even in extreme situations such as wind, rain and lightning strikes, the charging piles can still be guaranteed. Safety. How to analyze the leakage protection in the electric vehicle charging pile is discussed and analyzed in this paper.
Under the national standard, the electric vehicle charging pile should have the protection function. Electric vehicle charging piles should have protection devices such as overvoltage and undervoltage protection, lightning protection, output short-circuit protection, leakage protection and overcurrent protection. Electric vehicle charging piles have leakage protectors. When the electric vehicle charging pile is in standby or charging In case of leakage, it will trip in time to protect the personal safety of customers. The electric vehicle charging pile has an emergency red emergency button. In an emergency, pressing the emergency button will instantly power off the pile to protect personal and property safety.
Generally, leakage current is divided into four types: semiconductor element leakage current, power leakage current, capacitor leakage current and filter leakage current
Due to the size of the leakage current of the filter, which is related to personal safety, all countries in the world have strict standards for it. For 220V/50Hz AC power supply, the leakage current of the noise filter is generally required to be less than 1mA.
Say one is connected to a 480 277vac system with a 10A load and the RCMU will measure it simultaneously. According to Kirchhoff's law, incoming and outgoing currents cancel each other out. The current vector sum of the three bus bars should be zero. As can be seen from the figure, without considering the direction: that is, the leakage current value on the line of the system is 1A. RCMU is based on the design principle of chip type. The difference from passive transformer is that it can detect different leakage components, and belongs to Type-B RCMU.
Having said that, briefly review the leakage current types.
The type leakage protector is developed and designed for the power frequency sinusoidal leakage current, and can reliably protect the sinusoidal leakage current that is suddenly applied and slowly rising.
In addition to the reliable protection of the sinusoidal leakage signal, the leakage protector can also reliably protect the leakage signal containing the pulsating DC component.
3) Type B leakage protector:
Type B leakage protector can reliably protect sinusoidal AC signals, pulsating DC signals and smooth signals
Please see this article to learn more knowledge for Type B current transformer for EV charging