A modeling method of the simulation model for the prediction of the lowest point of frequency in the absence of large power

Abstract

A modeling method of a simulation model for predicting the lowest point of frequency in the absence of large power belongs to the field of power system analysis, including the following steps: S1: performing discrete differential operations on the step response curves of the governors of each unit to obtain their impulse response curves; S2: Use polynomials to fit the impulse response curve; S3: Use the least square method to determine the polynomial fitting coefficients; S4: Laplace transform the polynomials obtained in step S2 to solve the approximate transfer function of the governor; S5: Calculate the system equivalent The transfer function of the governor; S6: Based on the transfer function of the equivalent governor of the system obtained in step S5, a simulation model for predicting the lowest point of frequency in the absence of high power is established. The present invention is based on the step response curves of each governor, and utilizes the proposed technical scheme to establish a simulation model for predicting the lowest point of frequency under high power loss, thereby accurately and quickly calculating the maximum frequency offset and the time of the lowest point of frequency under high power loss .

Description

technical field [0001] The invention belongs to the field of power system analysis, and relates to a modeling method of a simulation model for predicting the lowest point of frequency in the absence of large power. Background technique [0002] With the access to a high proportion of renewable energy, new energy units such as wind power and photovoltaics will gradually become the main power source of the power system. Compared with traditional generating sets, the inertial response and frequency response capabilities of new energy generating sets are inherently insufficient, and their large-scale grid connection will make the problem of system frequency stability increasingly prominent. On the other hand, with the development of UHV AC-DC transmission projects, the large power loss caused by DC blocking faults is likely to cause low-frequency accidents where DC is fed into the receiving end grid. The effects of the above two factors will lead to a trade-off between the "off...

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Problems solved by technology

On the other hand, with the development of UHV AC-DC transmission projects, the large power loss caused by DC blocking faults is likely to cause low-frequency accidents where DC is fed into the receiving end grid

The effects of the above two factors will lead to a trade-off between the "offensive and defensive" ends of frequency control, which will pose severe challenges to the frequency stability of the power system.

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