A method for simplification of power grid equivalence

Abstract

The invention discloses a grid equivalent simplification method considering the grid frame strength of the system and the effective sending capacity of a generator, and belongs to the technical field of power system analysis. The invention characterizes the grid strength of the retention system and the equivalent system through the equivalent branch impedance of the retention system and the equivalent system, and characterizes the equivalent value through the impedance of the step-up transformer from the equivalent generator to the equivalent bus in the equivalent system The network frame strength inside the system uses the equivalent electromagnetic loop impedance between the equivalent busbars to characterize the electromagnetic ring network connection between different master stations. At the same time, the effective sending power of the generator through the transfer impedance is used to characterize the effective sending capacity of the generator in the equivalent system. The method of the invention can be used for the equivalent of the regional power grid connected through the line and the equivalent of the low-voltage network connected with the main network through the branch circuit of the transformer. Compared with the published power grid equivalent simplification method, the equivalent network can more accurately reflect the topology relationship of the original power grid, and the physical meaning is clear.

Description

technical field [0001] The invention belongs to the technical field of power system analysis, and relates to a power system equivalent method, in particular to a power grid equivalent simplification method that takes into account the system grid strength and the effective sending capacity of a generator. Background technique [0002] With the rapid development of my country's UHV AC-DC power grid, large-scale DC-intensive access, the problem of AC-DC interaction is prominent. Existing power system electromechanical transient simulation programs can only simulate the system under the condition of fundamental wave symmetry. This limitation makes the simulation results different from the actual situation. In order to accurately simulate the transient characteristics of AC / DC power grids with multiple HVDC feed-in, it is usually necessary to use electromagnetic transient simulation analysis methods. Limited by the software scale of electromagnetic transients, it is often diffic...

AI Technical Summary

Problems solved by technology

[0006] 1) The equivalent system is simplified to load, which cannot reflect the generator support capacity in the equivalent system;

[0007] 2) The equivalent system is simplified as a combination of generators and loads, but it cannot reflect the electromagnetic ring network connection and grid strength between different stations in the equivalent system;

[0008] 3) The constant power conversion technology is adopted in the equivalent system, that is, the sum of the loads in the equivalent system is used as the equivalent load level of the equivalent node, and the sum of the power generation in the equivalent system is used as the output of the equivalent generator. The processing method cannot reflect the power consumption characteristics in the vicinity of the generator in the equivalent system

Images