A method and system for determining a fault of a magnetically controlled shunt reactor

Abstract

The invention discloses a fault determination method and a fault determination system for a magnetically controlled shunt reactor. The method comprises the following steps: determining an equivalent leakage inductance parameter recognition model in the form of a least square method according to an equivalent circuit of the magnetically controlled shunt reactor; discretizing the equivalent leakageinductance parameter recognition model to obtain an equivalent leakage inductance parameter recognition discrete model; collecting currents and voltages of each winding of the magnetically controlledshunt reactor; determining an equivalent leakage inductance parameter by a recursive least square method according to the equivalent leakage inductance parameter recognition discrete model and the currents and voltages of each winding of the magnetically controlled shunt reactor; determining a three-phase difference degree of the equivalent leakage inductance parameter; and determining the fault winding of the magnetically controlled shunt reactor according to the three-phase difference degree of the equivalent leakage inductance parameter. The fault determination method and the fault determination system for the magnetically controlled shunt reactor provided by the invention have the characteristics of high sensitivity to the inter-turn fault of the control winding and being able to locate the fault, without being affected by the pre-excitation closing and capacity adjustment.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a fault determination method and system for a magnetically controlled shunt reactor. Background technique [0002] With the large-scale and rapid development of wind power and solar power generation, my country's power grid is increasingly showing the characteristics of a high-proportion renewable energy power system. The difficulty of voltage control, and the difficulty of developing a shuntable reactor with both overvoltage suppression and dynamic reactive power balance capabilities. Ultra / UHV Magnetically Controlled Shunt Reactor (MCSR), as a member of the controllable high voltage shunt reactor, can automatically and smoothly adjust its own capacity with the change of line transmission power, and has the ability to suppress ultra / The capacity rise effect, operating overvoltage, submerged current and other phenomena of UHV transmission lines can...

AI Technical Summary

Problems solved by technology

[0004] Compared with the fixed shunt reactor, the structure of the magnetically controlled shunt reactor is more complex, and the working capacity needs to be adjusted according to the needs of the system during operation. The particularity of the structure and working principle makes the magnetically controlled shunt reactor in the protection There are many difficulties in configuration, especially the low sensitivity to inter-turn faults in windings

At present, most of the existing research results use zero-sequence power directional protection with compensation as the main protection scheme for MCSR inter-turn faults. The shunt of the fault current in the branch of the compensation winding is relatively large, so the zero-sequence power directional protection has low sensitivity to the turn-to-turn fault of the control winding, and the negative-sequence power direction protection should be used, but the sensitivity to the turn-to-turn fault of the control winding is still limited

In order to improve the sensitivity of the protection of the inter-turn fault of the control winding, the research has obtained the control winding inter-turn fault protection based on the fundamental frequency component of the total current of the control winding (referred to as the total control current), but the protection scheme will be in the MCSR pre-excitation Misoperation occurs during closing and capacity adjustment

Therefore, neither the zero-negative-sequence power direction protection nor the protection scheme based on the fundamental frequency component of the total control current can locate which winding the inter-turn fault occurs in.

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