Calculation method of blackout risk in power system with doubly-fed wind farm

Abstract

The invention discloses a power failure risk computing method for an electric power system containing double-fed wind power plant. The power failure risk computing method comprises the steps of pre-establishing multiple models, wherein a simulation process comprises the steps of determining the initial working condition of a system, and setting an initial fault; determining whether a short circuit fault or line broken fault occurs or not, if the short circuit fault occurs, processing according to an off-network model of a wind turbine generator, and then performing island-division searching; determining a frequency fall-off and recovery condition of an electrical island according to a frequency stabilization model, and enabling the electrical island to restore to a power balancing state; carrying out alternating current power flow calculation on the system and determining whether the system is converged or not, if not, solving a power flow convergence boundary, and analyzing voltage weak points; switching loads for the voltage weak points; next, determining whether the system is restored to be stable or not, if not, determining that the current wind power plant system is subjected to global voltage collapse, cutting all loads; and if the system is restored to be stable, determining whether a tangent line exists or not, if so, returning to perform the island-division searching step, and or otherwise, finishing the simulation process. By adoption of the power failure risk computing method, the load reducing amount required by the system for system recovery can be reduced to the minimum, and cascading failure analysis error is lowered.

Description

technical field [0001] The invention relates to the technical field of wind power generation, in particular to a method for calculating the blackout risk of a power system including a doubly-fed wind farm. Background technique [0002] At present, the research on the blackout risk of the wind power new energy system has just started, and the relevant research results at home and abroad are not rich enough. In the aspect of cascading fault handling, the cascading fault model based on DC power flow has been relatively fully researched and widely used, while the cascading fault model using AC power flow calculation is in its infancy. Unlike synchronous units, wind turbines are currently mainly double-fed asynchronous wind generators (DFIG, Double-Fed InductionGenerator), which are wound asynchronous generators directly connected to the fixed-frequency three-phase grid by the stator windings and installed on the rotor windings. Composed of bidirectional back-to-back IGBT voltag...

AI Technical Summary

Problems solved by technology

For example, doubly-fed wind turbines use asynchronous generators, and their operating characteristics are somewhat different from those of synchronous generators; wind turbines are controlled by power electronic converters, and their reactive power output has its own characteristics, and its reactive power constraints are also different from those of synchronous generators; The wind turbine has almost no inertia contribution to the system; the short-circuit fault response of the wind turbine may cause the wind turbine to go off-grid, resulting in power shortage or voltage problems, etc.

[0006] In summary, the cascading failure simulation processing method including wind farms in the prior art is too simple and rough to calculate the risk of power outage, resulting in large errors in the calculation results

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