Research On Frequency Emergency Control System Of UHV AC And DC Interconnected Power Network

At present,China’s interconnected power grid is developing rapidly.With the construction of ultra-high voltage direct current(UHVDC),many power grids are in the condition of multiple direct current(DC)inrush.The fault into DC will lead to large power shortage,frequency is in danger of collapse.It is necessary to configure the corresponding frequency emergency control system to restore the normal operation state of the power grid.However,nowadays,the large power grid lacks the unified coordination of the whole network frequency.this paper aims to design a set of frequency emergency control system that can prevent system disassembly and achieve "unified coordination and hierarchical control".The following contents are studied:First of all,this paper is extended from single load frequency characteristics of simple model to the whole network system,the factors affecting the frequency of the interconnected power grid are obtained.Different open operation on the near area of UHV Changzhi be used,and the static stability of the value of long line be obtained.Secondly,the priority of each measure is determined.The model of various frequency control measures is built,and the influence of the primary frequency modulation parameters on the frequency modulation capacity of the unit is studied.The rationality of frequency emergency control is demonstrated.Thirdly,this paper designs a set of frequency emergency control system.The design principles and expected functions of the construction control system are clearly defined.The controllable resources of central China Power Grid in each link are calculated.On the basis of the original emergency control system,a new unified coordination site is set up.A unified control system is designed by using the coordinated control theory.Finally,the load loss of the application of low frequency load red ucing and frequency emergency control measures is compared with PSD-BPA software under different faults.The rationality of the frequency emergency control system is verified.And a control strategy that can prevent the UHV AC line from dissolving is configured.This paper improved the existing power grid safety control system,it effectively reduces the load loss of the system and ensures the stability and safety of the power grid.