TDP Modular digital Over & Under Voltage Protector is self-healing phase failure & phase sequence protective relay and it’s a newly developed household electrical equipment protector. The protector can quickly disconnect the power supply to protect the appliances when there is power interruption or the voltage exceeds or falls below the predetermined value. When the power supply recovers, the protector automatically connects the power after 1-2 minutes’ delay. All the protective actions are automatically controlled. Indicators on the panel display the working condition of the protector. This product is convenient in use, reliable in quality and excellent in performance.