CN103760470A - Electric transmission line inter-phase short circuit fault direction discriminating method based on discrete sampled values - Google Patents

Abstract

The invention discloses an electric transmission line inter-phase short circuit fault direction discriminating method based on discrete sampled values. The electric transmission line inter-phase short circuit fault direction discriminating method includes the steps of measuring fault inter-phase voltage sampled values, fault inter-phase current sampled values and fault inter-phase negative sequence current sampled values at the protection installation position of an electric transmission line at sampling moments, calculating whether an electric transmission line inter-phase short circuit fault direction criterion is workable or not through the fault inter-phase electric component sampled values at the three adjacent sampling moments, and if the electric transmission line inter-phase short circuit fault direction criterion is workable, judging that an inter-phase short circuit fault in the corresponding direction is generated on the electric transmission line. According to the electric transmission line inter-phase short circuit fault direction discriminating method, the electric transmission line inter-phase short circuit fault direction criterion is calculated only through the fault inter-phase electric component sampled values at the three adjacent sampling moments, a required data window is short, Fourier algorithm operation is not referred, the operation amount is small, and the calculating speed is high; the discriminating result is not influenced by the factors such as electric system oscillation, the fault position, transition resistance and a load current, and the fault direction of the electric transmission line inter-phase short circuit fault is accurately discriminated.

Description

Based on discrete sampling value transmission line of electricity phase fault discriminating direction method

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to a kind of based on discrete sampling value transmission line of electricity phase fault discriminating direction method.

Background technology

In actual electric network, trouble spot may be positioned at transmission line of electricity in the other direction, also may be positioned at transmission line of electricity positive dirction.If trouble spot is positioned at transmission line of electricity in the other direction, protected circuit protective relaying device is failure to actuate, but is moved fault isolation by the protective relaying device of adjacent lines.If trouble spot is positioned at transmission line of electricity positive dirction, by the protective relaying device action of protected circuit, the fault on protected circuit is isolated.Existing transmission line of electricity discriminating direction element mainly contains zero sequence power direction element, negative sequence power directional element and zero-sequence direction component, negative-sequence direction component, zero sequence power direction element, negative sequence power directional element and zero-sequence direction component, negative-sequence direction component algorithm electric parameters used are all phasor, need the data window of a whole ripple to participate in computing, relate to comparatively complicated Fourier algorithm computing, therefore traditional transmission line of electricity discriminating direction element real-time is not strong.If when fault is positioned at protected circuit opposite direction near-end; phase current power frequency variation, negative-sequence current and zero-sequence current protection criterion be action rapidly; now traditional transmission line of electricity discriminating direction element cannot be in time by protective relaying device locking; cause the misoperation of protected circuit protective relaying device; cause fault coverage to expand; the stabilization of power grids is impacted, be unfavorable for power network safety operation.

Summary of the invention

The invention provides one based on discrete sampling value transmission line of electricity phase fault discriminating direction method, it has overcome the deficiencies in the prior art described in background technology.

The technical scheme adopting that the present invention solves its technical matters is:

Based on discrete sampling value transmission line of electricity phase fault discriminating direction method, it comprises following sequential steps:

Step 1, negative-sequence current sampled value between current sampling data and fault phase between voltage sample value, fault phase between the fault phase of each sampling instant of protective device Real-time Collection line protection installation place;

Step 2, protective device judgement

$\frac{u_{\mathrm{\&phi;\&phi;}}\left(t\right)i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-u_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}{[l_1\frac{i_{\mathrm{\&phi;\&phi;}}\left(t\right)-i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}\left(t\right)]i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-[l_1\frac{i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})-i_{\mathrm{\&phi;\&phi;}}(t-2\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})]i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}<0$

Whether set up, if set up, protective device judges that phase fault occurs transmission line of electricity in the other direction;

Wherein: u _{φ φ}(t), u _{φ φ}(t-Δ t) is respectively voltage sample value between the fault phase of t, t-Δ t sampling instant; i _{φ φ 2}(t), i _{φ φ 2}(t-Δ t) is respectively negative-sequence current sampled value between the fault phase of t, t-Δ t sampling instant; i _{φ φ}(t), i _{φ φ}(t-Δ t), i _{φ φ}(t-2 Δ t) is respectively current sampling data between the fault phase of t, t-Δ t, t-2 Δ t sampling instant; Δ t is the sampling interval time; l ₁, r ₁be respectively unit length transmission line of electricity positive sequence inductance, positive sequence resistance; φ φ is that AB is alternate, BC is alternate, CA is alternate;

Step 3, protective device judgement

$\frac{u_{\mathrm{\&phi;\&phi;}}\left(t\right)i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-u_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}{[l_1\frac{i_{\mathrm{\&phi;\&phi;}}\left(t\right)-i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}\left(t\right)]i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-[l_1\frac{i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})-i_{\mathrm{\&phi;\&phi;}}(t-2\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})]i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}>0$

Whether set up, if set up, protective device judges transmission line of electricity positive dirction generation phase fault;

Wherein: u _{φ φ}(t), u _{φ φ}(t-Δ t) is respectively voltage sample value between the fault phase of t, t-Δ t sampling instant; i _{φ φ 2}(t), i _{φ φ 2}(t-Δ t) is respectively negative-sequence current sampled value between the fault phase of t, t-Δ t sampling instant; i _{φ φ}(t), i _{φ φ}(t-Δ t), i _{φ φ}(t-2 Δ t) is respectively current sampling data between the fault phase of t, t-Δ t, t-2 Δ t sampling instant; Δ t is the sampling interval time; l ₁, r ₁be respectively unit length transmission line of electricity positive sequence inductance, positive sequence resistance; φ φ=AB, BC, CA are alternate.

The technical program is compared with background technology, and its tool has the following advantages:

The inventive method is measured between the fault phase of each sampling instant of line protection installation place between voltage sample value, fault phase negative-sequence current sampled value between current sampling data and fault phase; utilize electrical quantity sampling value computing electric power line phase fault direction criterion between the fault phase in three neighbouring sample moment whether to set up; if set up, judge the phase fault of transmission line of electricity generation respective direction.The inventive method only need be used the fault direction criterion of electrical quantity sampling value computing electric power line phase fault between the fault phase in three neighbouring sample moment, and desired data window is short, does not relate to Fourier algorithm computing, and operand is little, and computing velocity is fast.The inventive method differentiation result is not subject to the impact of the factors such as power system oscillation, abort situation, transition resistance, load current, accurately differentiates the fault direction of transmission line of electricity phase fault.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the invention will be further described.

Fig. 1 is application circuit transmission system schematic diagram of the present invention.

Embodiment

Please refer to Fig. 1, in Fig. 1, CVT is voltage transformer (VT) 2, and CT is current transformer 3.Protective device 1 is by negative-sequence current sampled value between current sampling data and fault phase between voltage sample value, fault phase between the fault phase of each sampling instant of voltage transformer (VT) 2 summation current transformer 3 Real-time Collection line protection installation places;

And then protective device 1 judges

$\frac{u_{\mathrm{\&phi;\&phi;}}\left(t\right)i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-u_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}{[l_1\frac{i_{\mathrm{\&phi;\&phi;}}\left(t\right)-i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}\left(t\right)]i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-[l_1\frac{i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})-i_{\mathrm{\&phi;\&phi;}}(t-2\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})]i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}<0$

Whether set up, if set up, protective device judges that phase fault occurs transmission line of electricity in the other direction;

Wherein: u _{φ φ}(t), u _{φ φ}(t-Δ t) is respectively voltage sample value between the fault phase of t, t-Δ t sampling instant; i _{φ φ 2}(t), i _{φ φ 2}(t-Δ t) is respectively negative-sequence current sampled value between the fault phase of t, t-Δ t sampling instant; i _{φ φ}(t), i _{φ φ}(t-Δ t), i _{φ φ}(t-2 Δ t) is respectively current sampling data between the fault phase of t, t-Δ t, t-2 Δ t sampling instant; Δ t is the sampling interval time; l ₁, r ₁be respectively unit length transmission line of electricity positive sequence inductance, positive sequence resistance; φ φ is that AB is alternate, BC is alternate, CA is alternate;

Then, protective device 1 judges

$\frac{u_{\mathrm{\&phi;\&phi;}}\left(t\right)i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-u_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}{[l_1\frac{i_{\mathrm{\&phi;\&phi;}}\left(t\right)-i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}\left(t\right)]i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-[l_1\frac{i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})-i_{\mathrm{\&phi;\&phi;}}(t-2\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})]i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}>0$

Whether set up, if set up, protective device judges transmission line of electricity positive dirction generation phase fault;

Wherein: u _{φ φ}(t), u _{φ φ}(t-Δ t) is respectively voltage sample value between the fault phase of t, t-Δ t sampling instant; i _{φ φ 2}(t), i _{φ φ 2}(t-Δ t) is respectively negative-sequence current sampled value between the fault phase of t, t-Δ t sampling instant; i _{φ φ}(t), i _{φ φ}(t-Δ t), i _{φ φ}(t-2 Δ t) is respectively current sampling data between the fault phase of t, t-Δ t, t-2 Δ t sampling instant; Δ t is the sampling interval time; l ₁, r ₁be respectively unit length transmission line of electricity positive sequence inductance, positive sequence resistance; φ φ=AB, BC, CA are alternate.

The inventive method is measured between the fault phase of each sampling instant of line protection installation place between voltage sample value, fault phase negative-sequence current sampled value between current sampling data and fault phase; utilize electrical quantity sampling value computing electric power line phase fault direction criterion between the fault phase in three neighbouring sample moment whether to set up; if set up, judge the phase fault of transmission line of electricity generation respective direction.The inventive method only need be used the fault direction criterion of electrical quantity sampling value computing electric power line phase fault between the fault phase in three neighbouring sample moment, and desired data window is short, does not relate to Fourier algorithm computing, and operand is little, and computing velocity is fast.The inventive method differentiation result is not subject to the impact of the factors such as power system oscillation, abort situation, transition resistance, load current, accurately differentiates the fault direction of transmission line of electricity phase fault.

The above, only for preferred embodiment of the present invention, therefore can not limit according to this scope of the invention process, the equivalence of doing according to the scope of the claims of the present invention and description changes and modifies, and all should still belong in the scope that the present invention contains.

Claims (1)

1. based on discrete sampling value transmission line of electricity phase fault discriminating direction method, it is characterized in that, comprise following sequential steps:

Step 1, negative-sequence current sampled value between current sampling data and fault phase between voltage sample value, fault phase between the fault phase of each sampling instant of protective device Real-time Collection line protection installation place;

Step 2, protective device judgement

$\frac{u_{\mathrm{\&phi;\&phi;}}\left(t\right)i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-u_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}{[l_1\frac{i_{\mathrm{\&phi;\&phi;}}\left(t\right)-i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}\left(t\right)]i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-[l_1\frac{i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})-i_{\mathrm{\&phi;\&phi;}}(t-2\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})]i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}<0$

Whether set up, if set up, protective device judges that phase fault occurs transmission line of electricity in the other direction;

Wherein: u _{φ φ}(t), u _{φ φ}(t-Δ t) is respectively voltage sample value between the fault phase of t, t-Δ t sampling instant; i _{φ φ 2}(t), i _{φ φ 2}(t-Δ t) is respectively negative-sequence current sampled value between the fault phase of t, t-Δ t sampling instant; i _{φ φ}(t), i _{φ φ}(t-Δ t), i _{φ φ}(t-2 Δ t) is respectively current sampling data between the fault phase of t, t-Δ t, t-2 Δ t sampling instant; Δ t is the sampling interval time; l ₁, r ₁be respectively unit length transmission line of electricity positive sequence inductance, positive sequence resistance; φ φ is that AB is alternate, BC is alternate, CA is alternate;

Step 3, protective device judgement

$\frac{u_{\mathrm{\&phi;\&phi;}}\left(t\right)i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-u_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}{[l_1\frac{i_{\mathrm{\&phi;\&phi;}}\left(t\right)-i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}\left(t\right)]i_{\mathrm{\&phi;\&phi;}2}(t-\mathrm{\&Delta;t})-[l_1\frac{i_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})-i_{\mathrm{\&phi;\&phi;}}(t-2\mathrm{\&Delta;t})}{\mathrm{\&Delta;t}}+r_1{i}_{\mathrm{\&phi;\&phi;}}(t-\mathrm{\&Delta;t})]i_{\mathrm{\&phi;\&phi;}2}\left(t\right)}>0$

Whether set up, if set up, protective device judges transmission line of electricity positive dirction generation phase fault;

Wherein: u _{φ φ}(t), u _{φ φ}(t-Δ t) is respectively voltage sample value between the fault phase of t, t-Δ t sampling instant; i _{φ φ 2}(t), i _{φ φ 2}(t-Δ t) is respectively negative-sequence current sampled value between the fault phase of t, t-Δ t sampling instant; i _{φ φ}(t), i _{φ φ}(t-Δ t), i _{φ φ}(t-2 Δ t) is respectively current sampling data between the fault phase of t, t-Δ t, t-2 Δ t sampling instant; Δ t is the sampling interval time; l ₁, r ₁be respectively unit length transmission line of electricity positive sequence inductance, positive sequence resistance; φ φ=AB, BC, CA are alternate.

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