Transformer Differential Protection Method Based on Two-Dimensional Space Reconstruction of Current Characteristic Trajectory

Abstract

A transformer differential protection method based on two-dimensional spatial reconstruction of the current characteristic trajectory, at a certain sampling frequency, the current sequence I measured by the current transformer TA on both sides of the transformer is collected 1 and I 2 , in a periodic data window, the number of sampling points is N, I 1 ={I 1 (1), I 1 (2),...,I 1 (i),...,I 1 (N)}, I 2 ={I 2 (1), I 2 (2),...,I 2 (i),...,I 2 (N)}, the two sets of current sequences I will be collected 1 and I 2 Reconstruct the trajectory in the two-dimensional coordinate system to form a reconstructed trajectory sequence L, L={L(1),L(2),...,L(i),...,L(N)}, i=1,2 ,...,N. Calculate the percentage K of the number of points in the reconstructed trajectory sequence L that fall into the first and third quadrants of the two-dimensional coordinate system to the total. Combine the calculated K value with K set Compare, where K set It is the setting value of protection action, if K>K set , then it is judged as a fault in the zone, and the protection action; if K <kset is determined as an out-of-area fault, and the protection is blocked. In this method, the current information on both sides is used to reconstruct the characteristic trajectory in the two-dimensional coordinate system, and the quadrant characteristics of the trajectory under different fault types are quantitatively analyzed to identify the fault type accompanied by TA saturation.< / k

Description

technical field

[0001] The invention relates to a transformer differential protection method based on two-dimensional spatial reconstruction of a current characteristic trajectory, and relates to the technical field of transformer differential protection. Background technique

[0002] Transformer is an important equipment in power system transmission, the correctness of its protection action is particularly important. For a long time, transformer differential protection has been widely used as the main protection of transformers because of its simple principle and only using current to distinguish fault types. Whether the transformer differential protection can operate correctly depends on whether the TAs on both sides can correctly transmit current information. When one side of TA is saturated, the wrong current information transmitted by it will cause abnormal operation of differential protection.

[0003] At present, the ratio braking method, second harmonic braking met...

Examples

Embodiment Construction

[0034] The transformer differential protection method based on two-dimensional spatial reconstruction of the current characteristic trajectory uses the phase characteristic difference of the current on both sides of the transformer under different disturbance conditions, and reconstructs the current on both sides in the two-dimensional space coordinate system to obtain the two sides The characteristic trajectory after current reconstruction is used to construct a new criterion for transformer differential protection by using the characteristic difference of the reconstructed characteristic trajectory in two-dimensional space quadrants under different disturbances. The new criterion can overcome the refusal to operate caused by TA saturation when the fault is inside the traditional differential protection zone and the maloperation problem caused by TA saturation when the fault is outside the zone.

[0035] like Image 6 shown, including the following steps:

[0036] Step 1: At ...

technical field

[0001] The invention relates to a transformer differential protection method based on two-dimensional spatial reconstruction of a current characteristic trajectory, and relates to the technical field of transformer differential protection. Background technique

[0002] Transformer is an important equipment in power system transmission, the correctness of its protection action is particularly important. For a long time, transformer differential protection has been widely used as the main protection of transformers because of its simple principle and only using current to distinguish fault types. Whether the transformer differential protection can operate correctly depends on whether the TAs on both sides can correctly transmit current information. When one side of TA is saturated, the wrong current information transmitted by it will cause abnormal operation of differential protection.

[0003] At present, the ratio braking method, second harmonic braking met...

Examples

Embodiment Construction

[0034] The transformer differential protection method based on two-dimensional spatial reconstruction of the current characteristic trajectory uses the phase characteristic difference of the current on both sides of the transformer under different disturbance conditions, and reconstructs the current on both sides in the two-dimensional space coordinate system to obtain the two sides The characteristic trajectory after current reconstruction is used to construct a new criterion for transformer differential protection by using the characteristic difference of the reconstructed characteristic trajectory in two-dimensional space quadrants under different disturbances. The new criterion can overcome the refusal to operate caused by TA saturation when the fault is inside the traditional differential protection zone and the maloperation problem caused by TA saturation when the fault is outside the zone.

[0035] like Image 6 shown, including the following steps:

[0036] Step 1: At ...

Images