Comprehensive judgment method and system for power system transient stability based on wams measured trajectory

Abstract

The invention discloses a power system transient stability comprehensive judgment method based on an actually-measured trajectory of a WAMS and system. The method comprises steps: two trajectory criteria with a fast judgment speed and high requirements for data quality and equivalent accuracy are used as early warning links, and other four relatively-reliable criteria with similar judgment speedsbut not high requirements for data quality are used as final stability judgment links. The six selected trajectory criteria are combined by using a logic of early warning and judgment, the early warning links ensure to respond to the possible changes in the transient stability of the system as soon as possible, and time is obtained for subsequent splitting operation; four criteria in the judgmentlinks ensure that the system can accurately and reliably make a system stability judgment in an extreme scenarios; and the successive relationship among trajectories is searched in a time sequence, the respective advantages are made use of for complementation, and the transient stability judgment method with higher reliability is formed.

Description

technical field [0001] The invention relates to the technical field of power system fault discrimination, and specifically designs a power system transient stability comprehensive discrimination method based on a wide-area phasor measurement system (WAMS) measured trajectory. Background technique [0002] At present, the fixed value configuration of the deloading device is determined according to the needs of the power grid and after analysis. Summarizing the major power outages that have occurred in recent years, the interconnection lines between the grids tend to be closely connected electrically, and the third line of defense composed of out-of-step disassembly control is still not strong enough. With the expansion of the grid scale, a grid-like grid is gradually formed. There is no obvious weak section during normal operation, and the disconnected section will be randomly generated with the change of the fault mode. In addition, the variable operation mode in the actual...

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Problems solved by technology

[0005] Trajectory-based transient stability discrimination method is a kind of transient stability analysis method that has developed rapidly in recent years, but most of the research on trajectory is carried out on the basis of a single trajectory, and how to cooperate with multi-source trajectory information is rarely mentioned.

Among the several commonly used trajectory criteria, the EEAC method, the equivalent phase trajectory method, and the maximum equivalent power angle difference method that need to be equivalent to the generator will have accuracy problems in the non-standard two-machine instability mode. , and these methods require real-time monitoring of the electrical quantities of all generators. When the real-time information of a generator is lost under special circumstances such as communication failure or delay, the above criteria may have the risk of failure

The out-of-synchronization criterion based on the electrical quantities of non-generator nodes has relatively few requirements for the quantity and quality of information, and has relatively high reliability. This kind of criterion has a certain degree of conservatism, and the judgment time is not fast enough.

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