CN105182041A - Power transmission line positive-sequence current and positive-sequence voltage phasor measuring method - Google Patents

Abstract

The invention discloses a power transmission line positive-sequence current and positive-sequence voltage phasor measuring method. The power transmission line positive-sequence current and positive-sequence voltage phasor measuring method comprises the steps of: carrying out alpha beta 0 coordinate axis conversion on three-phase voltage phasors and three-phase current phasors at a protection mounting position of the power transmission line to obtain voltage phasors and current phasors under alpha beta 0 coordinate axes; calculating positive-sequence voltage phasors and positive-sequence current phasors under the alpha beta 0 coordinate axes; and carrying out alpha beta 0 coordinate axis inverse transformation on the positive-sequence voltage phasors and positive-sequence current phasors under the alpha beta 0 coordinate axes to obtain three-phase positive-sequence voltage phasors and three-phase positive-sequence current phasors at the protection mounting position of the power transmission line. The power transmission line positive-sequence current and positive-sequence voltage phasor measuring method does not involve complicated complex operation, is simple in algorithm principle, small in operation amount and fast in calculation speed, and can greatly increase the speed of relay protection action.

Description

Electric transmission line positive sequence electric current and positive sequence voltage phasor measurement method

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to a kind of electric transmission line positive sequence electric current and positive sequence voltage phasor measurement method.

Background technology

That builds along with supergrid improves the Large scale construction with ultrahigh voltage alternating current transmission lines; to power grid security pay attention to day by day; require that protective relaying device has higher responsiveness, rapidly by fault isolation, fault indiffusion can be guaranteed after grid power transmission circuit breaks down.But when existing protective relaying device extraction positive sequence voltage phasor, forward-order current phasor; need to relate to complicated complex operation; operand is large; protective relaying device extracts a big chunk occupying protective relaying device actuation time operation time of positive sequence voltage phasor, forward-order current phasor; seriously govern the raising of protective relaying device responsiveness, bring potential safety hazard to electrical network.

Summary of the invention

The object of the invention is to the deficiency overcoming prior art existence, a kind of electric transmission line positive sequence electric current and positive sequence voltage phasor measurement method are provided.The inventive method carries out α β 0 coordinate axis transform to the three-phase voltage phasor of line protection installation place, three-phase current phasor, obtains voltage phasor, electric current phasor under α β 0 coordinate axis; Calculate the positive sequence voltage phasor under α β 0 coordinate axis and forward-order current phasor; positive sequence voltage phasor under α β 0 coordinate axis and forward-order current phasor are carried out α β 0 coordinate axis inverse transformation, obtain the three-phase positive sequence voltage phasor of line protection installation place, three-phase forward-order current phasor.The inventive method does not relate to complicated complex operation, and algorithm principle is simple, and operand is few, and computing velocity is fast, can greatly improve relay protection responsiveness.

For completing above-mentioned purpose, the present invention adopts following technical scheme:

Electric transmission line positive sequence electric current and positive sequence voltage phasor measurement method, is characterized in that, comprise following sequential steps:

(1) A, B, C three-phase voltage phasor of protector measuring line protection installation place with A, B, C three-phase current phasor

(2) protective device is by A, B, C three-phase voltage phasor with A, B, C three-phase current phasor transform to the voltage phasor under α β 0 coordinate axis and electric current phasor

$\left[\begin{array}{c}{\stackrel{\·}{U}}_{\mathrm{\α}}\\ {\stackrel{\·}{U}}_{\mathrm{\β}}\\ {\stackrel{\·}{U}}_0\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{\stackrel{\·}{U}}_A\\ {\stackrel{\·}{U}}_B\\ {\stackrel{\·}{U}}_C\end{array}\right]$

$\left[\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{\α}}\\ {\stackrel{\·}{I}}_{\mathrm{\β}}\\ {\stackrel{\·}{I}}_0\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{\stackrel{\·}{I}}_A\\ {\stackrel{\·}{I}}_B\\ {\stackrel{\·}{I}}_C\end{array}\right]$

(3) positive sequence voltage phasor under protective device calculating α β 0 coordinate axis with forward-order current phasor

${\stackrel{\·}{U}}_{\mathrm{\α}}^{+}=0.5{\stackrel{\·}{U}}_{\mathrm{\α}}+j\×0.5{\stackrel{\·}{U}}_{\mathrm{\β}}$

${\stackrel{\·}{U}}_{\mathrm{\β}}^{+}=-j\×0.5{\stackrel{\·}{U}}_{\mathrm{\α}}+0.5{\stackrel{\·}{U}}_{\mathrm{\β}}$

${\stackrel{\·}{I}}_{\mathrm{\α}}^{+}=0.5{\stackrel{\·}{I}}_{\mathrm{\α}}+j\×0.5{\stackrel{\·}{I}}_{\mathrm{\β}}$

${\stackrel{\·}{I}}_{\mathrm{\β}}^{+}=-j\×0.5{\stackrel{\·}{I}}_{\mathrm{\α}}+0.5{\stackrel{\·}{I}}_{\mathrm{\β}}$

${\stackrel{\·}{U}}_0^{+}={\stackrel{\·}{U}}_0$

${\stackrel{\·}{I}}_0^{+}={\stackrel{\·}{I}}_0$

Wherein, j is plural multiplier;

(4) protective device calculates A, B, C three-phase positive sequence voltage phasor with A, B, C three-phase forward-order current phasor

$\left[\begin{array}{c}{\stackrel{\·}{U}}_A^{+}\\ {\stackrel{\·}{U}}_B^{+}\\ {\stackrel{\·}{U}}_C^{+}\end{array}\right]=1.5{\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]}^{-1}\left[\begin{array}{c}{\stackrel{\·}{U}}_{\mathrm{\α}}^{+}\\ {\stackrel{\·}{U}}_{\mathrm{\β}}^{+}\\ {\stackrel{\·}{U}}_0^{+}\end{array}\right]$

$\left[\begin{array}{c}{\stackrel{\·}{I}}_A^{+}\\ {\stackrel{\·}{I}}_B^{+}\\ {\stackrel{\·}{I}}_C^{+}\end{array}\right]=1.5{\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]}^{-1}\left[\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{\α}}^{+}\\ {\stackrel{\·}{I}}_{\mathrm{\β}}^0\\ {\stackrel{\·}{I}}_0^{+}\end{array}\right]$

The present invention compared with prior art, has following positive achievement:

The inventive method carries out α β 0 coordinate axis transform to the three-phase voltage phasor of line protection installation place, three-phase current phasor, obtains voltage phasor, electric current phasor under α β 0 coordinate axis; Calculate the positive sequence voltage phasor under α β 0 coordinate axis and forward-order current phasor; positive sequence voltage phasor under α β 0 coordinate axis and forward-order current phasor are carried out α β 0 coordinate axis inverse transformation, obtain the three-phase positive sequence voltage phasor of line protection installation place, three-phase forward-order current phasor.The inventive method does not relate to complicated complex operation, and algorithm principle is simple, and operand is few, and computing velocity is fast, can greatly improve relay protection responsiveness.

Accompanying drawing explanation

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

Embodiment

According to Figure of description, technical scheme of the present invention is expressed in further detail below.

Fig. 1 is application transmission system schematic diagram of the present invention.In Fig. 1, CVT is voltage transformer (VT), and CT is current transformer.In the present embodiment, A, B, C three-phase voltage phasor of protector measuring line protection installation place with A, B, C three-phase current phasor

Protective device is by A, B, C three-phase voltage phasor with A, B, C three-phase current phasor transform to the voltage phasor under α β 0 coordinate axis and electric current phasor

$\left[\begin{array}{c}{\stackrel{\·}{U}}_{\mathrm{\α}}\\ {\stackrel{\·}{U}}_{\mathrm{\β}}\\ {\stackrel{\·}{U}}_0\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{\stackrel{\·}{U}}_A\\ {\stackrel{\·}{U}}_B\\ {\stackrel{\·}{U}}_C\end{array}\right]$

$\left[\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{\α}}\\ {\stackrel{\·}{I}}_{\mathrm{\β}}\\ {\stackrel{\·}{I}}_0\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{\stackrel{\·}{I}}_A\\ {\stackrel{\·}{I}}_B\\ {\stackrel{\·}{I}}_C\end{array}\right]$

Positive sequence voltage phasor under protective device calculating α β 0 coordinate axis with forward-order current phasor

${\stackrel{\·}{U}}_{\mathrm{\α}}^{+}=0.5{\stackrel{\·}{U}}_{\mathrm{\α}}+j\×0.5{\stackrel{\·}{U}}_{\mathrm{\β}}$

${\stackrel{\·}{U}}_{\mathrm{\β}}^{+}=-j\×0.5{\stackrel{\·}{U}}_{\mathrm{\α}}+0.5{\stackrel{\·}{U}}_{\mathrm{\β}}$

${\stackrel{\·}{I}}_{\mathrm{\α}}^{+}=0.5{\stackrel{\·}{I}}_{\mathrm{\α}}+j\×0.5{\stackrel{\·}{I}}_{\mathrm{\β}}$

${\stackrel{\·}{I}}_{\mathrm{\β}}^{+}=-j\×0.5{\stackrel{\·}{I}}_{\mathrm{\α}}+0.5{\stackrel{\·}{I}}_{\mathrm{\β}}$

${\stackrel{\·}{U}}_0^{+}={\stackrel{\·}{U}}_0$

${\stackrel{\·}{I}}_0^{+}={\stackrel{\·}{I}}_0$

Wherein, j is plural multiplier.

Protective device calculates A, B, C three-phase positive sequence voltage phasor with A, B, C three-phase forward-order current phasor

$\left[\begin{array}{c}{\stackrel{\·}{U}}_A^{+}\\ {\stackrel{\·}{U}}_B^{+}\\ {\stackrel{\·}{U}}_C^{+}\end{array}\right]=1.5{\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]}^{-1}\left[\begin{array}{c}{\stackrel{\·}{U}}_{\mathrm{\α}}^{+}\\ {\stackrel{\·}{U}}_{\mathrm{\β}}^{+}\\ {\stackrel{\·}{U}}_0^{+}\end{array}\right]$

$\left[\begin{array}{c}{\stackrel{\·}{I}}_A^{+}\\ {\stackrel{\·}{I}}_B^{+}\\ {\stackrel{\·}{I}}_C^{+}\end{array}\right]=1.5{\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]}^{-1}\left[\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{\α}}^{+}\\ {\stackrel{\·}{I}}_{\mathrm{\β}}^0\\ {\stackrel{\·}{I}}_0^{+}\end{array}\right]$

The inventive method carries out α β 0 coordinate axis transform to the three-phase voltage phasor of line protection installation place, three-phase current phasor, obtains voltage phasor, electric current phasor under α β 0 coordinate axis; Calculate the positive sequence voltage phasor under α β 0 coordinate axis and forward-order current phasor; positive sequence voltage phasor under α β 0 coordinate axis and forward-order current phasor are carried out α β 0 coordinate axis inverse transformation, obtain the three-phase positive sequence voltage phasor of line protection installation place, three-phase forward-order current phasor.The inventive method does not relate to complicated complex operation, and algorithm principle is simple, and operand is few, and computing velocity is fast, can greatly improve relay protection responsiveness.

The foregoing is only preferred embodiment of the present invention; but protection scope of the present invention is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses, the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.

Claims (1)

1. electric transmission line positive sequence electric current and positive sequence voltage phasor measurement method, comprises following sequential steps:

(1) A, B, C three-phase voltage phasor of protector measuring line protection installation place with A, B, C three-phase current phasor

(2) protective device is by A, B, C three-phase voltage phasor with A, B, C three-phase current phasor transform to the voltage phasor under α β 0 coordinate axis and electric current phasor

(3) positive sequence voltage phasor under protective device calculating α β 0 coordinate axis with forward-order current phasor

Wherein, j is plural multiplier;

(4) protective device calculates A, B, C three-phase positive sequence voltage phasor with A, B, C three-phase forward-order current phasor

。