Eeac-based Cloud Electric Sent To Guangdong, Security And Stability

Yunnan Power Grid becomes the important energy base and main power supply center of Southern China Power Grid relies on its resource superiority. In the year 2010, Yunnan Power Grid will be connected with the Southern China Power Grid through±800kV DC transmission lines and four 500kV AC transmission lines, and supplies 7800MW electric power to Guangdong and Guangxi Power Grid. Interconnection of Power Grid fills the gap between resource distribution and load demand of regions, and also balances region economy. Interconnection of Power Grid has brought huge economic and social benefit. But the unceasing growth of Grid interconnect scale and transfer capacity also make the monitoring and control of its operation more and more difficulty, and also make the analysis of transient stability to be a very tough work. The most havoc menace to the connected power system is the destruction of stability, so the transient stability research is an important topic of power system.At the present time, there are three method used to analyze transient stability. They are: Step by Step Method, Transient Energy Function Method and Extend Equal Area Criterion accordingly. EEAC is the theory fundament of calculation and analysis of this paper. EEAC is the application of complementary-cluster energy-barrier criterion(CCEBC) in power system, by which the task of transient stability analysis is separated into two parts. On the one hand, it can achieve the resultant trajectory by integral calculation in the space of R~n, and preserve integrality and accuracy of the numerical calculation. On the other hand, it can quantitatively analyze the mapping trajectory in the space of R~1, return the result of R~1 to R~n. The CCCOI-RM transformation of full rank assures strictness of the decompounding and aggregation calculation. The research on transient stability problems which happen by accident has great significance to safe and stable operation of Yunnan Power Grid or even to that of the whole Southern China Power Grid.This paper introduces the basic principle, calculation methods and developing stage of EEAC. EEAC developed from static EEAC, via dynamic EEAC to integrated EEAC which integrates EEAC with transient simulation based on SBS method, SEEAC, DEEAC and IEEAC constitute the whole structure of EEAC. This paper also introduces quantitative analysis methods of voltage stability and frequency stability, and presents computational method and the expression of correlative transient stability margin,parameter stability limit value. The flow chart of computation process is also presented.This paper uses FASTEST as simulation tool, which is a software developed by NARI base on EEAC theory. Research work is focused on summer-peak load operation mode of 2010 in this paper. Transient stability problems are calculated and analyzed while system would be interrupted under static load model and dynamic load model. Investigated contingencies include HVDC monopole block, HVDC bipolar block, three-phase permanent fault in each of 500kV single AC transmission lines and some 500kV double AC transmission lines. The importance of research on transfer capacity of interconnected power system are analyzed in this paper, the interconnected lines which connect Yunnan Power and Southern China Power Grid are defined as Yunnan outside transmission interface base on classification principle of transmission interface. The outside transfer capacity of Yunnan Power Grid in transient condition is researched, the outside transfer limit of Yunnan Power Grid outside transfer interface under different load model and different changing mode are calculated, and the influence on transfer limit is analyzed.