Simulation Analysis Of Jiangxi Power Grid After UHV Accessed To Gan Based On ADPSS

Along with the progress of UHV project construction, The UHV construction hasbecome the inevitable trend of power industry development in our country. UHV transmissionline has the characters of high voltage grade, long transmission distance, and great chargingpower, which would bring affections to the security and stability of power grid. In this paper,taking Jiangxi power grid as an example and using ADPSS simulation system, the factorsafter UHV accessed such as reactive power compensation, power frequency overvoltage,operating overvoltage, security and stability of power grid are investigated. The resultsprovide a meaningful guidance for the introduction of UHV into Jiangxi power grid. The mainwork of this paper includes:Firstly, based on planning and operation mode’s data of China’s central and northern in2015years, and reference to1000kV UHV Shanxi Changzhi-Henan Nanyang-Hubei Jingmendemonstration project, electromechanical transient model of UHV accessed to Jiangxi powergrid and electromagnetic transient model of UHV transmission line are established.Secondly, based on electromechanical transient model, the relationship between differentdegree of compensation and different installation location of UHV shunt reactors withsteady-state voltage is researched. Function expression of relationship between degree ofcompensation with voltage of Wuhan side and Nanchang side is obtained, and functionexpression of relationship between degree of compensation with transmission power is alsogained, by using simulation curve fitting. Considering UHV line loss and voltage deviation ofboth head and end side, the objective function of the optimal degree of compensation isestablished.Once again, based on electromagnetic transient mode, the influence of two importantfactors that shunt reactors’ different degree of compensation and different fault location onpower frequency overvoltage is analyzed under the condition of single-phase ground fault andtwo-phase ground fault by using electromechanical and electromagnetic hybrid simulationtechnology. In the shunt reactor optimal compensation scheme, and under the two operationmodes of transformer neutral grounded and not, operating overvoltage of single-phasereclosing which occurred in different places is analyzed.Finally, based on the entire network electromechanical transient model, the security andstability of Jiangxi power grid is researched after UHV accessed to. Flow calculations areseparately conducted in the normal mode and expected mode (UHV transformer N-1, UHVtwo lines N-1, UHV two lines N-2). Short circuits of Jiangxi power grid500kV and220kVsystem are calculated before and after UHV accessed. Transient stability is analyzed when UHV occurring single line fault and happening double lines fault on the same time, as well asthe small signal stability. Conclusions can be drawn: There is no power over the limit ofcontact lines between Hubei and Jiangxi.500kV and220kV system short circuit levelincreased, but short current is no more than switch breaking capacity. The transient stability inJiangxi power grid is not sick. And low frequency oscillation is not added in the power grid.