External network equivalence method for electric power system applicable to subsynchronous resonance

Abstract

The invention provides an external network equivalence method for an electric power system applicable to subsynchronous resonance, belonging to the technical field of the electric power system. The method comprises the following steps: retaining a plurality of units and series compensation transmission circuits of the electric power system to obtain a primary range of external network equivalence, and an equivalent boundary point; obtaining equivalent impedance after an equivalent boundary point; simplifying mutual impedance branches among a plurality of equivalent boundary points; obtaining an equivalent power parameter of the external network; obtaining the system subsynchronous frequency impedance which is Z1(f) by seeing from the units to a network side in the primary range of external equivalence; expanding a plurality of scales to obtain a system subsynchronous frequency impedance which is Z2(f) by seeing from the units to the network side in a new range of the external network; and determining whether to expand equivalent scales or not by judging the Z1(f) and the Z2(f) so as to obtain an external equivalent result. The method can improve the accuracy of the subsynchronous resonance result, and has important engineering application value in formulation of SSR control strategy and safe and stable operation of the system.

Description

technical field The present invention relates to a method in the technical field of electric power system, in particular to an equivalent method for external network of electric power system applicable to subsynchronous resonance. Background technique As an economical and effective means of large-capacity and long-distance power transmission, series compensation transmission technology is equivalent to shortening the electrical distance of the line, thereby improving line transmission capacity, improving system stability, and saving line corridor resources. With the implementation of my country's west-to-east power transmission plan and the development and construction of large-scale thermal power bases in the north, it has become a common transmission mode in my country to use large-capacity turbo-generator sets to transmit power through series-compensated transmission lines. However, while the series compensation transmission technology brings huge economic benefits to the...

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Problems solved by technology

The method proposed in this paper has certain applicability to the external network equivalent of the "point-to-network" transmission mode system. What method is used for the external network and how much is appropriate to keep the equivalent scale, and AIMS can only test online the equivalent impedance of the transmission network seen from the machine end of a single unit with a specific type of excitation system to the network side, and cannot directly Reflect the equivalent parameters of the external network of the actual multi-machine system

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