Short circuit current exceeding auxiliary decision method based on node impedance sensitivity

Abstract

The invention provides a short circuit current exceeding auxiliary decision method based on node impedance sensitivity which includes the following steps: obtaining on-line data or off-line data, obtaining connecting relation with a physical bus, arranging power grid and breaking current and short circuit current reducing measure at a priority level; calculating open circuit voltage and short circuit current of a fault point, determining and warning a short circuit current exceeding point within the scope of power grid; as to an exceeding bus, searching measures of reducing the short circuit current; calculating the node impedance sensitivity of each measure of reducing the short circuit current and sorting measures of reducing the short circuit current; forming and verifying the short circuit current exceeding auxiliary decision method. The short circuit current exceeding auxiliary decision method based on the node impedance sensitivity is achieved based on current limiting measures capable of changing the electric power network structure. If short circuit current exceeding exists under the current operation mode, factory stand connection mode, lines and running state of a unit are automatically analyzed, and auxiliary decision and advice are provided.

Description

technical field [0001] The invention belongs to the technical field of power system simulation and calculation analysis, and in particular relates to an auxiliary decision-making method for exceeding the standard of short-circuit current based on node impedance sensitivity. Background technique [0002] Short circuit refers to the situation where all abnormal phases are connected to each other or phase to ground (for a system with a neutral point grounded). The damage to the normal operation of the power system is mostly caused by short-circuit faults. When a short circuit occurs, the system changes drastically from one state to another, accompanied by complex transient phenomena. The main reasons for short circuit: (1) Component damage, such as natural aging of insulating materials, equipment defects caused by poor design, installation and maintenance, develop into short circuits. (2) Deterioration of meteorological conditions, such as flashover discharge or arrester acti...

AI Technical Summary

Problems solved by technology

The main reasons for short circuit: (1) Component damage, such as natural aging of insulating materials, equipment defects caused by poor design, installation and maintenance develop into short circuits

(2) Deterioration of meteorological conditions, such as flashover discharge or arrester action caused by lightning strike

(3) Man-made accidents, such as pulling a knife switch with load

[0003] The hazards of the short circuit mainly include the following aspects: (1) The short circuit fault causes a current many times larger than the normal value to appear in the branch near the short circuit point. Due to the electrodynamic effect of the short circuit current, a large mechanical stress will be generated between the conductors , may damage the conductor bracket and further expand the accident

(2) When the short circuit lasts for a long time, the equipment may be overheated and damaged

(3) The system voltage drops sharply during a short circuit, which has a great impact on users

(4) When the short circuit occurs not far from the power source and lasts for a long time, the generators running in parallel may lose synchronization, causing power outage in large areas, which is the most serious consequence of short circuit

At present, there is no relevant research on short-circuit current auxiliary decision-making at home and abroad.

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