| In recent years,China's demand for transmission distance and capacity of transmission lines has been increasing,but the distribution of energy is not balanced,and the demand for power is not the same.As the length of the transmission line continues to increase,the reactance in the line showing a trend of increasing and reduce the steady state limit of the transmission line.One of the effective measures to increase the transmission capacity of power lines and ensure the transient stability of the system is to install series compensation devices in the lines.This paper analyzes the transient characteristics of a series-compensated transmissionline when a single-phase ground fault occurs on the 1000kV Jindongnan-Nanyang-Jingmen UHVAC transmission line.Establish a Fixed Series Compensation(FSC for short)simulation model by using the ATP-EMTP transient simulation software,and study the effect of high compensation degree series compensation on secondary arc current under different series compensation arrangements.Choose an appropriate method for suppressing the secondary arc of series compensation transmission lines.Analyze the operating principle of Thyristor Controlled Series Compensation(TCSC for short),establish a simulation model through PSCAD and verify the correctness of the model.This paper studies the influence of TCSC with high compensation degree on the secondary arc and analyzes the optimal configuration scheme of TCSC and FSC under different compensation degrees.First,based on the transient process of the circuit breaker breaking fault after the single-phase ground fault occurred on the transmission line,and the simulation model is established based on the Jindongnan-Nanyang-Jingmen transmission line.Analyze the characteristics of the high compensation degree series compensation device affecting the secondary arc under different series compensation arrangements.The results show that it is the most reasonable way to arrange the two sides of the series compensation double platform dispersed without any suppression measures.Secondly,based on the establishment of a series compensation transmission line simulation model,several measures which are often used to suppress the secondary arc of series compensation transmission line under different series compensation arrangements are analyzed.The simulation results show that the attenuation speed of DC component can be accelerated by using the small resistance short circuit fault series compensation method,the suppression effect is related to the resistance value of the short-connected small resistor and the time of short circuit.It is more conducive to extinguish the arc by adopting the distributed arrangement on both sides of the series-compensated double platform.When the series compensation linkage bypass is adopted,its suppression effect is related to the time when the series compensation is bypassed.Finally,the simulation model is established according to the operation characteristics of TCSC,and the influence of improving the series compensation degree on the characteristics of secondary arc current and recovery voltage is studied.The secondary current current and recovery voltage are analyzed when different FSC and TCSC configuration schemes are adopted.The results show that under different series compensation degrees,the optimal FSC and TCSC configuration scheme can accelerate the zero crossing speed of the secondary arc current.The time required for the system to recover to stable power frequency is greatly reduced,which is conducive to the rapid extinction of the arc and can ensure the stable operation of the system. |
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