Stability judgment method and system for feeding multiple power electronic devices into complex weak power grid

Abstract

The invention relates to a stability judgment method and system for feeding multiple power electronic devices into a complex weak power grid. The method comprises the following steps: measuring data information in a complex weak power grid power system; establishing a generalized Norton aggregation circuit model according to the network topology structure and the data information of the power system, and obtaining an equivalent aggregation receiving end alternating current power grid DQ model; establishing an s-domain admittance model of the power electronic equipment according to the control structure of the power electronic equipment; calculating the ratio of the s-domain admittance of the power electronic equipment to the s-domain admittance of the equivalent aggregation receiving-end AC power grid to construct an open-loop gain; and judging whether the real part and the imaginary part of the open-loop gain meet the symbiotic forbidden zone condition at the same time to judge whether the power system is stable. Compared with the prior art, the method is used for analyzing and judging the broadband oscillation stability of a system level, does not need to carry out detailed modeling on all system elements, can simply and accurately judge whether broadband oscillation instability happens to the system or not, and avoids dimensionality disasters.

Description

technical field [0001] The invention relates to the field of on-line monitoring and control of power systems, in particular to a method and system for judging the stability of broadband oscillations fed by multiple power electronic devices into complex weak power grids. Background technique [0002] The large-scale development of wind power-based new energy and the extensive application of high-voltage direct current transmission technology have great strategic significance and social value for improving the national energy structure and achieving sustainable economic development. When a large-scale high-voltage direct current is fed into the receiving grid, the grid transforms into a weak grid, which is manifested in low short-circuit ratio and low inertia. With the access of a large number of new energy sources through power electronic equipment, the characteristics of the power grid have undergone further profound changes, from the dynamic characteristics of the power sys...

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Problems solved by technology

As a result, the advantages of the impedance analysis method are greatly weakened

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