Electromagnetic Transient Analysis on 750kV New Large Capacity Multi-FACTS Devices

摘要

In recent years, the development and application of the flexible AC transmission devices (FACTS)rnare vigorously carried out in China. It is aimed at achieving a flexible, intelligent control of the keyrnparameters of the grid, in order to enhance the performance of grid operation and meet customerrnneeds. China is building a large-scale, long-distance 750kV interconnection tie line project in thernnorthwest power grid. It consists of several 750kV stations and lines, with the 750kV line length ofrnalmost 1100 km. As a predominant characteristic, there are large-scale wind power and solar energy inrnthe near zone of the project, which will be sending out through the project, causing outstandingrnvoltage fluctuation problems. The weak ties of the local network and the great charging power ofrn750kV long transmission lines also make this issue much worse. For the long distance, there also existrnrisks on electromagnetic transient issues such as over-voltages for some 750kV lines. For controllingrnthe voltage, several large capacity dynamic reactive power compensation devices are designed to bernapplied in the project, including 4 sets of thyristor stepped controlled shunt reactors (SCSR) on eachrnside of 750kV two circuit lines, 1 set of magnetic controlled shunt reactor (MCSR) on 750kV bus barrnand 1 set of 360Mvar static var compensator (SVC) installing on 66kV side of 750kV transformer.rnControlled shunt reactors are usually applied for dealing with the contradiction of reactive powerrncompensation balance and over-voltage. For the lines installed with SCSR, when it occur suchrnscenarios as line fault, circuit breaker opening after fault or no fault, the operating capacity, adjustingrnmode and response time have a great impact on the electromagnetic issues such as power frequencyrnover-voltages, secondary arc current, and non-full phase power frequency resonant over-voltages. Inrnthis paper, basing on the plan power grid and design parameters of the FACTS devices, detailed modelrncalculations are carried out by EMTP simulation tool. The over-voltage and over-current levels andrnsuggestions for restriction measures are put forward, so are to the electromagnetic control strategiesrnfor the FACTS devices. According to the results, taking on quick linkage adjustment measures forrnboth sides SCSR of the fault lines play a significant limit effect for 750kV line load rejectionrnfrequency voltages, secondary arc current, and non-full phase power frequency resonant over-voltages.rnThe factors of reliability and difficulty of engineering implementing need to be considered in order tornfinalize the engineering applications. Combined with practical engineering design conditions, thisrnpaper proposed the need of electromagnetic transient coordination control strategy for the multi-rnFACTS devices, which provides the basis for equipment and substation control and protection systemrndesign.