Optimization Of OUPA

IEC international standard commands a choice of three kinds of the low voltage power supply and distribution system,and various countries choose the corresponding low voltage power supply and distribution systems according to their own national conditions.A single-phase distribution system is used in the United States and Japan,while China and EU adopt the three-phase distribution system.In the three-phase distribution system,the occurrence of fault phenomena such as the unbalanced load and the Zero fault which so that making the neutral line potential offset and resulting in the occurrence of overvoltage and undervoltage in single-phase lines.The European Union adopts some measures such as increasing the diameter of the neutral line,welding joint and regular maintaining and son on to avoid the threaten of user life and electrical equipment.And the way of the installation of the "self-compound overvoltage and undervoltage protector" at the entrance of single-phase subscriber line,which was used in china to prevent the occurrence of the accidents.The research object of this paper: the self-compound overvoltage and undervoltage protector,a kind of power relay protection device,which installs at the entrance of single-phase subscriber line.When an overvoltage or an undervoltage occurs in a line,the protector can cut off the downstream line in time and automatically connect the downstream line when the voltage is restored to be normal.Research contents: mainly study the SAGQ type self-compound overvoltage and undervoltage protector which has been used in the 08D800 diagram of the "Electrical design and construction of civil buildings".It has studied the matching problem between the filter capacitor and the reactive power of the power grid in the sampling circuit of the protector,and also has researched the influence of the power supply circuit of the protector on the setting value.It has improved the power supply circuit and sampling circuit by using the Analog circuit technology.Boolean algebra is used to design program algorithm and implement the program algorithm with C language on the PIC16F684 single chip microcomputer,which has ultimately improved the reliability of the products.Research results: Improved the reliability of the self-compound overvoltage and undervoltage protector,which has the important reference significance for setting up a safe and intelligent low voltage distribution network.