Zero sequence direction security acceleration method based on substation area information

Abstract

The invention provides a zero sequence direction security acceleration method based on substation area information, and a discriminating element is put in when the current collected fulfills the motion of a setting current booting element. Firstly, the size of the zero sequence current of each sub-circuit is calculated, a fault circuit and a fault adjacent circuit are confirmed by using the theory that the branch coefficient of zero sequence current of a fault sub-circuit is the largest. A virtual zero sequence, a virtual current direction and a virtual current amplitude value are generated by using a fault adjacent sub-circuit of the fault circuit, and a fault point position is judged through the combination of the change of the zero sequence and the change of a current direction element. When the zero sequence is in negative direction with the current in a primary stage of a fault and when fault sub-circuit current is close to calculated sum current, the fault point position is judged to be close to the head end of the current on the same side, and zero security motion can be accelerated. When the direction of the zero sequence and direction of the current change from positive direction to the negative direction and when the fault sub-circuit is close to the calculated sum current, the fault point position is judged to be close to the tail end of the line, and the zero security motion can be accelerated. The zero sequence direction security acceleration method based on the substation area information judges accurately, is easy to realize, and has good utilization prospects.

Description

technical field [0001] The invention belongs to the field of power transmission and transformation, and in particular relates to a zero-sequence protection acceleration method based on station domain information. Background technique [0002] Zero-sequence protection is an important ground short-circuit protection. Its structure and working principle are simple, and it is less affected by transition resistance, so it is widely used in power systems. The zero-sequence protection is generally used as the backup protection of the line. When the line has a ground fault and the main protection cannot operate, it will act on the line switch with a set delay to isolate the fault. Zero-sequence protection generally has high sensitivity, but its selectivity is relatively poor, and it is most affected by changes in the operation mode of the power system, so it is not easy to set. The zero-sequence section I protection is set to avoid the maximum zero-sequence current of the fault out...

AI Technical Summary

Problems solved by technology

Zero-sequence protection generally has high sensitivity, but its selectivity is relatively poor, and it is most affected by changes in the power system's operating mode, so it is not easy to adjust

The zero-sequence section I protection is set to avoid the maximum zero-sequence current of the fault outside the zone, with a short delay (within 0.2s) to avoid the zero-sequence current generated when the three-phase phase of the line is not closed at the same time, but often the protection range Very small, cannot reliably cut off ground faults such as at the end of the line

The protection range of other zero-sequence sections is relatively wide, but in order to prevent the backup protection from leapfrogging, the setting time is usually relatively long. Fault

Due to the slow removal of faults, in severe cases, the system will oscillate, and even cause the system to be disconnected, which will bring great harm to the operation of the power system.

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