Street lights are installed outdoors, and lightning strikes are a very big threat, ranging from damage to street lights, to fire or casualties, resulting in huge losses. Here, the FAE engineer of Shuokai Electronics has designed an AC220V power supply protection scheme for LED street lamps. The scheme combines two high-efficiency surge protection devices, ceramic gas discharge tube and varistor, which can effectively protect the LED power supply in the shortest time. The following Shuo The Xiaobian of Kai Electronics asks you to introduce the specific content of the plan:

一、Background

1. Global warming, more thunderstorms

2. After the power supply is damaged by lightning, it is very harmful

3. After the power supply is damaged by lightning, the maintenance cost is high

4. High surge protective equipment becomes an industry trend

二、Socay Solution and Components

Gas Discharge Tubes(GDTs)

GDT【SC2E5-600L】DC Spark-over Voltage：600V±20%，Nominal Impulse Discharge Current（8/20μS）：5kA，Maximum Capacitance＜1.0pF，Minimum Insulation Resistance 1GΩ(at 100v); Medium level protection

GDT【SC3E8-600HM】DC Spark-over Voltage：600V±20%，Nominal Impulse Discharge Current（8/20μS）：20kA，Maximum Capacitance＜1.5pF，Minimum Insulation Resistance 1GΩ(at 100v); Advanced Protection

Varisor 

MOV【14D471K】Varistor Voltage（at1mA）：423V-517V，Withstanding Surge Current（8/20μS）：4500A，Maximum Clamping Voltage（at5A）：775V，Medium level protection

MOV【20D471K】Varistor Voltage（at1mA）：423V-517V，Withstanding Surge Current（8/20μS）：6500A，Maximum Clamping Voltage（at5A）：775V，Advanced Protection

三、Application 

The solution can be applied in addition to the surge protection of the LED street lamp power supply, but also in other equipment using AC220V power supply: switch power supply, air conditioning power supply, inverter power supply, computer power supply, induction cooker / rice cooker, other AC94V-AC264V power supply, etc.

四、The Solution Note

1. This power solution meets surge test standards such as IEC61000-4-5, GBT17626.5, etc.

2. In differential mode protection, the use of GDT and MOV can prolong the service life of MOV

3. In common mode protection, GDT and MOV are used together to prevent the leakage current of MOV from flowing to the equipment shell and meet the safety requirements

4. This power solution can pass 1.2/50μS-8/20μS combined wave differential mode and common mode surge test

For more surge protection solutions, please go directly to the Socay website to consult the online customer service http://www.socay.com/.