Group-based on-line optimization method for optimal power grid topology considering predicted accident sets

Abstract

The invention discloses a group-based on-line optimization method for optimal power grid topology considering predicted accident sets. Under the constraint of the number of lines allowed to be disconnected, a set of optimal disconnection line scheme considering the mathematical model of the optimal disconnection line with enhanced voltage stability and the predicted accident sets is found. The scheme meets the following conditions: maximizing the load margin of the expected ground-state power system after disconnection, and the load margin of all the predicted accidents and the predicted ground-state power system can meet the threshold requirements and the predicted ground-state power system after disconnection can meet the safe operation constraints. The problem of on-line disconnection line identification of power system voltage stability enhancement control is solved through four stages of evaluation, predicted accident grouping, predicted accident representative disconnection lineidentification, predicted ground-state power system disconnection line identification and verification, and finally the disconnection line scheme meeting the voltage stability load margin threshold ofthe predicted ground-state power system and the predicted accidents sets is given to enhance the static voltage stability of the power system.

Description

technical field [0001] The invention relates to a group-based online optimization method for an optimal grid topology taking into account expected accident sets, and belongs to the technical field of on-line voltage stability enhancement control of electric power systems. Background technique [0002] The voltage stability of the power system is one of the important indicators to maintain the normal and stable operation of the power system. With the increasing expansion of the power grid, the high-density and large-scale access of renewable energy, and the increasing demand for power, the operation form of the power system is complex and changeable, and the power system often operates near the stable boundary. The stable operation will be destroyed, which will easily cause the voltage instability of the power system, and even lead to large-scale power outages, resulting in huge economic losses. In order to enhance the voltage stability of the power system, common control me...

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Problems solved by technology

If the expected accident set of the expected ground state power system is taken into account, the problem is more difficult to solve, and the difficulty in solving it mainly lies in: (1) The dimension of the integer variable increases: the broken line can be regarded as an integer variable, "0" It can indicate that the line is disconnected, and "1" can indicate that the line is running on the network; the expected accident can also be regarded as an integer variable in the mathematical model of the problem, so the dimension of the integer variable increases, and the occurrence of the expected accident makes the nonlinear algebraic Equation constraints (that is, the expected active power and reactive power balance equations of the system after the accident) change, which also increases the difficulty of solving the problem; (2) The nature of nonlinear characteristics has a great influence: first, the change of line parameters has a great influence on the voltage The influence of the stability margin is non-linear. When the line is disconnected, the line impedance parameter jumps from the original value to infinity, but the voltage stability load margin cannot be estimated through the change of the parameters; in addition, even if the expected accident load margin can be found The optimal breaking line that satisfies the threshold requirements to a certain extent, but it may also lead to a serious reduction in the load margin of other anticipated accidents, and may even be lower than the threshold requirements

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