Low-voltage load shedding control method based on online monitoring indexes

Abstract

The invention relates to a low-voltage load shedding control method based on an on-line monitoring index, and the method comprises the following steps: S1, determining a necessary condition for a power system to reach a limit transmission power according to a comprehensive dynamic equivalent analysis method, and putting forward an impedance modulus index for measuring the voltage stability degree of the power system; s2, calculating the sensitivity of an impedance modulus index to the power of each node, and obtaining an optimal load shedding point set with a control sequence; and S3, load shedding is carried out according to the optimal load shedding point set, so that the total load shedding amount is minimum when the target impedance modulus is reached. The indexes comprehensively consider the nonlinearity and the time-varying property of the system, the method has the advantages of being rapid in calculation and high in accuracy, the optimal load shedding point set with the control sequence can be determined by calculating the sensitivity of the indexes to the power of each node, load shedding is carried out according to the optimal load shedding point set, and the load shedding efficiency is improved. The total load shedding amount can be minimized when the target impedance modulus is reached, so that the workload is reduced, and the comprehensive practicability is improved.

Description

technical field [0001] The invention belongs to the technical field of power systems, and in particular relates to a low-voltage load shedding control method based on on-line monitoring indicators. Background technique [0002] In recent years, with the increase of social demand for electricity and the increasing pressure of environmental pollution, the scale of regional power grid interconnection has gradually expanded. Control brings further complications. A number of voltage collapse accidents at home and abroad have brought a major impact on the economy and people's lives of various countries. Therefore, it is extremely important to carry out research on voltage stability and find effective measures to prevent voltage instability. [0003] When the disturbance or failure of the system causes the voltage of the system to drop to an unacceptable level, the load shedding control method can be used to improve the voltage stability of the system. Minimum load shedding for s...

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Problems solved by technology

There are already a lot of research results based on this aspect: one is to optimize the distribution of points by sorting the contribution of each control node, and to carry out load shedding with the goal of minimizing the risk of undercut risk and overcut risk; the other is to ensure a certain voltage The recovery value is the goal, and the load shedding scheme is determined based on the PV curve. However, this method needs to use the continuous power flow method to obtain the PV curve of the load node, which is a bit complicated, and it is also impossible to determine the load shedding that improves the node voltage most significantly. The third is based on the impedance matrix of the node network, a low-voltage load shedding control method based on the analytical sensitivity index is proposed

Because these methods find the weak nodes of the system through some way, and then perform load shedding at the weak nodes, but they do not consider how much the weak nodes can shed the load

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