Use efficient lamps: Since the invention of incandescent light bulb by Edison, lighting technology has been renovated by three times, including the 1^st generation of incandescent light bulb (electric bulb), the 2^nd generation of fluorescent lamp (fluorescent tube), the 3^rd generation of high intensity gas discharge lamp (HID, such as HPSL road lamps) and renovation is made towards the 4t^h generation of LED light source at present. Every time of renovation contributes to higher illumination indicator and power consumption efficiency. Therefore, to change lamps can undoubtedly improve power consumption efficiency. However, to change lamps entails high preliminary costs and heavy workload. Many lighting systems have been designed with HID lamps. New lighting LED, featured by high cost, small power and low color rendering index, still needs further improvement before it becomes popular on market. Therefore, to change lamp for the purpose of using efficient light source illuminating system is not the optimal plan. For the illuminating system without using efficient light source, the power saving space is realized by further reducing voltage after light source is changed.

Lamp modification: By modifying the single HID, the power consumption of ballast can be reduced and the variable-frequency flow of single lamp can be lowered to control the lamp consumption power and therefore save energy. Such kind of single lamp modification technology can save energy but it is not the ideal solution due to the considerable modification workload, high comprehensive costs and operation & maintenance costs. In addition, for some products, the silicon controlled phase shift pressure regulating of single lamp can be controlled to save energy. As it cannot adapt to the capacitance compensation, the harmonic wave is serious and the product is therefore forbidden.

Voltage reduction and stabilization of loop system: By reducing the voltage of lighting loop properly, both power can be saved and lamp service life can be prolonged. In addition, it is featured by small circuitry reconstruction, simple project implementation and convenient maintenance and operation, making it the highly economic solution.