Branch circuit similarity-based wide area backup protection method

Abstract

The method discloses a branch circuit similarity-based wide area backup protection method which belongs to the field of relay protection of electrical power systems. The method comprises the following steps of: under the condition of normal operation of an electrical power system, calculating an equivalent injection current of a fault point by using a failure equivalent model first and then forming a branch circuit correlator matrix according to a network topology parameter and a node injection current and determining a failure definition set; after a network topology is changed, realizing fast update of the failure definition set by modifying part of elements in the branch circuit correlator matrix; and when the electrical power system goes wrong, quickly calculating the minimum value of the similarity between the failure definition set and a branch circuit measured value and determining a failure position according to the minimum value. The method avoids the condition of mismatch or insufficient sensitivity easily occurred in conventional backup protection, and can precisely, sensitively and reliably position the failure under the condition of changing networks.

Description

technical field [0001] The invention belongs to the field of relay protection of electric power systems, in particular to a wide-area backup protection method based on branch closeness. technical background [0002] With the rapid growth of my country's electricity demand and the implementation of the strategy of "power transmission from west to east, mutual supply between north and south, and national networking", my country is forming a weakly connected national interconnected power grid. It is estimated that around 2020, the installed capacity of my country's power grid will increase from 850 million kilowatts in 2009 to 1.6 billion kilowatts, the annual power generation will exceed 7.7 trillion kilowatt-hours, and the west-to-east power transmission capacity will exceed 150 million kilowatts. Six verticals" ultra-large-scale multi-receiving terminal interconnection grid. The complexity of grid structure and the difficulty of operation control are also rare in the world. ...

AI Technical Summary

Problems solved by technology

Power system failure is inevitable. If the protection device operates correctly, quickly and reliably, it will effectively curb the deterioration of the system state and play a role in ensuring the safe and reliable operation of the power grid; otherwise, it may accelerate the process of system collapse, resulting in large-scale and long-term power outages

However, the complexity of the power grid structure makes it difficult to set and coordinate the traditional backup protection based only on local quantities, and the non-predetermined changes in the grid structure and operating conditions further exacerbate the gap between the selectivity, sensitivity and reliability of the backup protection. conflict between

In a blackout accident, although the backup protection of the power system operates correctly according to the design principles, it objectively accelerates the system collapse.

Images