Electric energy is an essential energy in the production and life of residents. The electric energy is mainly transmitted by the power supply system. The voltage of electric energy is increased to more than ten or even hundreds of thousands of volts through the substation, and then the long-distance transmission is carried out. Moreover, the low resistivity material is used for the transmission line to ensure the lowest electric energy loss. 

The general principle of the power supply system is a reliable power supply, convenient operation, safe and flexible operation, economic and reasonable, with the possibility of development. Reliability of power supply: in the process of power transmission, the high-voltage mode is usually adopted, so the high-voltage transmission lines are mostly carried out in unmanned mountainous areas. When indoor power transmission is carried out, the wireframe should be high, and there are no other buildings around. Convenient operation, safe and flexible operation: in order to make power supply flexible and maintenance convenient, multiple transmission lines are often used for transmission lines. When this line is overhauled, other channels can still work normally to avoid failure of timely power supply. Economical and reasonable: under the premise of low resistivity, the wire used for power transmission should be as cheap as possible. Usually, copper wire or aluminum wire is used for long-distance power transmission. Possibility of development: the wiring mode shall be convenient for future development and meet the needs of construction in different periods.

Outdoor led solar street light can be directly powered by battery, and the optional power supply voltage mode is 12V / 24V. The power supply of various sensors and microcontrollers needs to be 5V, so it needs to use a voltage reducing circuit and voltage stabilizing circuit to stabilize the power supply voltage to 5V. The city power supply system mainly includes a transfer switch, thyristor, etc. In the case of continuous rainy days, the electric energy converted from solar energy to battery will be continuously lost. When the electric power in the battery is lower than the set value, disconnect the power supply circuit between the LED street lamp and battery, and the municipal power will supply power to the LED street lamp. The battery is only responsible for supplying power to the microcontroller and various sensors, and the power consumption of these devices is very low. Some devices also have sleep mode, which can ensure their normal operation for at least 30 days. After the weather turns clear, it will automatically switch back to the battery power supply.