Research On Short-circuit Current Characteristics And The Countermeasure In Guangzhou Power Grid

Guangzhou power grid is located in the center area of high-density load in ChinaSouthern Power Grid, and also the terminations of several long-distance direct-currentTransmission lines. In recent years, With the continuous expansion of the power grid,the power supplies continuous putting into operation, the network structure gettingmore intensive, the load levels getting more and more higher. Affected by thesefactors, the short circuit current level of Guangzhou power grid was the continuedgrowth trend. The short circuit current exceed the standard problem has become oneof the main problems influencing the safe and stable-operation of Guangzhou powergrid. The Dispatching Department was forced to make the network operating inseveral partitions, or make outage of some equipment, which is useful to limitingshort-circuit current. But these Methods significantly reduces the power margin ofsafety and reliability of power supply, and also reduce the efficiency in the use ofassets, and even get a serious threaten to the operation of power grid.Making a depth study in the Distribution characteristics and influencing factors of theshort circuit current of Guangzhou power system, has great significance. This reportanalyses the structure of power grid, power supply distribution, regional difference,time-dimension, etc, by the use of equivalent circuit, sensitivity analysis. This reportmakes a further analysis of the distribution and development trend of Guangzhoupower system short circuit current, fully reveals the Guangzhou grid short-circuitcurrent distribution characteristics and influencing factors, provide theoretical supportfor the short circuit current limiting measures existing in the operation. On this basis,make analysis and evaluation on the short circuit current limiting measures such as network-partition-operation, installing low-Impedance reactor at neutral point of theTransformer, installing short circuit current limiter and so on. And also, this reportchecks the effects of these control measures, calculates the short circuit current levelin500kV side、220kV side of all the500kV substations in Guangzhou power grid,verified the validity of these control measures. This report Put forward the mainoperation measures and power grid planning in2013-2020in Guangzhou power gridInhibiting the level of short-circuit current, which is putting forward a reasonable wayto realize the comprehensive control of short circuit current problem.