Electric power system static voltage stability assessment method considering electric automobile charging characteristic and load fluctuation limit

Abstract

The invention particularly relates to an electric power system static voltage stability assessment method considering the electric automobile charging characteristic and the load fluctuation limit. The method comprises the steps of establishing of a power grid node injection power random mode, Sobol sequence construction in a QMC sampling method, electric power system static voltage stability critical state searching and establishing of a static voltage indictor assessment system. The defect that the conventional analysis method can only analyze the static voltage stability limit of the system under the single load growth mode can be improved, the influence of the charging characteristic and the load random fluctuation on the static voltage stability of the system after an electric automobile accesses to the power grid can be researched and considered and different static voltage instable states of the power grid can be searched. The operation process is rapid, efficient and accurate; and the analysis conclusion is that an electric power system static voltage stability weak area can act as the key monitoring object of actual power grid operation so that power grid operation personnel are enabled to timely take corresponding load shedding measures, the accident of whole grid voltage collapse can be avoided and the engineering practicality is high.

Description

technical field [0001] The invention relates to the technical field of static voltage stability analysis of a power system main network, in particular to a voltage stability analysis method based on quasi-Monte Carlo sampling (QMC, Quasi-Monte Carlo) considering the charging characteristics of electric vehicles and load fluctuation limits. Background technique [0002] In recent years, the world has been actively responding to the greenhouse effect brought about by massive carbon dioxide emissions, and has gradually reduced the use of fossil energy in the automotive industry. Many cities in China have invested heavily in the construction of electric vehicle (EVs, Electric Vehicles) charging facilities, and advocate the use of clean energy. The uncertainty brought by electric vehicles connected to the power grid and the random fluctuation of traditional loads make the operation of the power grid closer to its limit state than before, and the voltage instability accidents of t...

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Problems solved by technology

The limitations of this analysis method are: (1) Deterministic power flow models are generally used, so the determined system operating limits are often too conservative, and it is difficult to reflect the influence of various uncertain factors, such as the disturbance of generator output power, etc.; ( 2) The influence of random fluctuations of new energy and load fluctuations on the operating limits of the system cannot be considered

[0004] In the research on the random fluctuation of the output power of new energy after it is connected to the power system, the probability flow method is not widely used in the analysis of the voltage stability of the power system. Most of the existing methods set the output power of new energy as Different step values, based on Monte Carlo sampling (MC, Monte Carlo) to simulate different scenarios of new energy output, this method can only consider the volatility of new energy alone, and cannot take into account other disturbance factors in the power grid; and the MC sampling method It is only suitable for situations where the dimension of the random variable is small. When the dimension of the system random variable exceeds a certain value, the calculation speed of the MC method is very slow, and the sampling accuracy is significantly reduced.

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