The Research Of The Load Shedding Scheme Under Frequency Based On The System Characteristic

With the high development of large scale of units,high voltage and wide power network in power systems,the frequency issue is increasingly evident.In this article,the significance of the research for the automatic load shedding under frequency of power systems together with the evolvement in and abroad are demonstrated,illustrating the principle of the load shedding under frequency of power systems.,discussing about some problems relative with the definition of the power system frequency and analyzing the static and dynamic characteristic of power system frequency in detail.Depending on such conclusion,a load shedding scheme under frequency based on the characteristic of the system frequency are proposed,say that,considering "the changing rate and the actual value of the frequency variation" as the starting-up symbol,according to the maximum of the power deficiency exist in power system likely,the load shedding modes named as "emergency wheel & rough regulating wheel & detailed regulating wheel" are suggested,testing with the simulation of the load shedding scheme under frequency for the Northwest network in 2009,which is verified to be feasible.