Research On Network Security And Stability Analysis And Strategy Of Severe Fault Conditions

In recent decades, a number of power blackout accidents in parts of the world due to system instability, these incidents caused great economic losses and social impact, but also reflects the significance of research on the network security and stability.With the rapid development of Tianjin, the grid have been expanding gradually increased the number of components, the risk of occurring overlap or multiple faults have increased. Also rising as the load level, the system increasingly linked, the correlation between the components to further strengthen, a chain of power fault is also likely to increase, which would threaten the safety of the grid. Therefore, in the year to year changes in network structure and operating mode, it is necessary to analyze in-depth on power faults in the event of a serious situation of security and stability, and power in the grid structure in Tianjin and insecurity that exist in components, proposed solutions.This paper, using BPA software, simulated various types of severe power faults in 500kV and 220kV grid of Tianjin. Run by the summer of 2010, for example, security and stability were carried out static and transient stability analysis of safety, and appeared for the analysis does not meet the requirements of insecurity stability criterion, the corresponding measures and improvement measures to ensure grid security and stability.Calculation and analysis results show that: operating mode in summer 2010, Tianjin, one of 500kV power lines, transformers, bus occurs 3-phase fault, protection and proper action after switching the system can remain stable. 500kV tie-line while running parallel fault, Tianjin Power Transmission Grid stability limit for the section is 8000MW. Tianjin 220kV main network accord with one or two stable standard, that any of the lines, transformers, generators, bus, power tie-line, double lines in parallel occurs 3-phase fault, after the protection, switching and reclosing acted accurately, the system could maintain stability. For the three stability criteria, namely, ring line, bus 3-phase fault occurs, switch tripping, protection tripping, there is possibility of power instability. So, proposed to increase the circuit breaker level to ensure that no tripping situation; proposed to make the SangguLin and WeiguoDao and other ancient substation's bus protection doubled as soon as possible; proposed Ren-Qu double lines, Liu-Qu double lines, Liu-Hua double lines to replace the large cross-section wire to ensure the stability of the system after faults clearing.