Along with our country economic developed rapidly, both the enterprises and amount of the using power are increase rapidly. The scale of the electrical power system expands with the time passed and the structure of the power network structure become complex. Environmental and economical factors, along with the capacity and distance that the electrical power transmit, make the old electrical transmission system unstable and approach to the critical state.
In this paper, principles and methods of the voltage frequency urgent control is studied. By analyzing the relationship between voltage and frequency with system stability, the key that adjustment the voltage and the frequency in emergency is obtained. The methods that obtain the correlation data through the electrical gauging size and make the system to restore the state of equilibrium by cutting extra burden are described. A device, which control electrical voltage frequency emergency, is designed in this paper. This device can measure frequency, electric voltage and variety rate quickly, distinguish short circuit breakdown, judging the size of power deficiency vacancy inside a system. Once the electric power system appears unsteady, it can cut off the burden that is equal to the power deficiency vacancy quickly. The decrease of voltage and frequency of the electrical power system is controlled. The safety of the electrical power system and the supplying of the important customer will be guaranteed.
Key words Electrical power system； frequency； voltage； control
