Dynamic equivalence method of alternating-current-direct-current serial-parallel large power system based on engineering application

Abstract

The invention discloses a dynamic equivalence method of an alternating-current-direct-current serial-parallel large power system based on engineering application, and belongs to the field of electric transformation and distribution. The method of the alternating-current-direct-current serial-parallel large power system based on the engineering application comprises dividing a power grid to be analysed into two parts including an external power grid and an internal power grid, detailedly imitating a 500 kV power grid inside an area, carrying out equivalence simplification on the external power grid and an internal low voltage power grid, obtaining an external simplified power grid from the external power grid through an equivalence generator by using a dynamic equivalence method based on experience, obtaining a final internal simplified power grid by carrying out equivalence simplification on the internal low voltage power grid by using the dynamic equivalence method based on physical equivalent, respectively checking equivalence effects after the external power grid and the internal power grid are in dynamic equivalence, and checking effectiveness of the entire dynamic equivalence principle and method through comparing dynamic response curves of a simplified power grid and an actual power grid in the same fault. The method of the alternating-current-direct-current serial-parallel large power system based on the engineering application has the advantages of reducing quantity of equivalence system state and the number of differential equation, improving system analysis computational efficiency, and being capable of being widely used for analytical calculation of a serial-parallel large power grid and used in the field of dispatching management of power grids.

Description

technical field [0001] The invention belongs to the field of power transformation and distribution, and in particular relates to a dynamic equivalent method for an AC / DC hybrid large power grid. Background technique [0002] At present, my country's power system is developing rapidly. West-to-east power transmission, north-south interconnection, AC-DC joint transmission, and large-scale network operation make the system increasingly large and complex. Even offline electromechanical transient simulations are difficult. Because the number of dynamic components in large-scale power systems is large, the grid structure, characteristics, and operation modes are very complex, and the transient process of the system is a strongly nonlinear process, the required computer storage is large, and the calculation time is also long. The computer's machine time, memory, data preparation, etc. are often not enough to meet the analysis and research of complex large-scale power systems. It i...

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Problems solved by technology

[0007] (1) rely heavily on experience and subjective judgment;

[0008] (2) The method is rough, the precision is poor, and the dynamic characteristics of the original system may be distorted;

[0009] (3) The methods used are not systematic, strict, or universal, etc.

However, it can only be applied to the modeling of the excitation system of the generating set, and cannot be applied to the dynamic equivalent calculation of the AC / DC hybrid large power grid, which is also due to the consideration of engineering applications.

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