CN105301322A - Transmission line voltage and current negative sequence transient component rapid measurement method - Google Patents

Abstract

The invention discloses a transmission line voltage and current negative sequence transient component rapid measurement method. The method provided by the invention comprises the steps that three-phase voltage and current instantaneous values of each sampling moment are converted to voltage and current instantaneous values in an alpha beta 0 coordinate axis; negative sequence voltage and current instantaneous values of each sampling moment in the alpha beta 0 coordinate axis are calculated; inverse converting is carried out on negative sequence voltage and current instantaneous values of each sampling moment in the alpha beta 0 coordinate axis to acquire three-phase negative sequence voltage and current instantaneous values of each sampling moment. According to the method provided by the invention, complicated complex operation is avoided; the method has the advantages of simple algorithm principle, less operation and fast calculation speed; and the speed of relay protection can be greatly improved.

Description

Transmission line of electricity electric current and voltage negative phase-sequence transient state component method for fast measuring

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to a kind of transmission line of electricity electric current and voltage negative phase-sequence transient state component method for fast measuring.

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 voltage, electric current negative sequence component; 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 voltage, electric current negative sequence component; 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 transmission line of electricity electric current and voltage negative phase-sequence transient state component method for fast measuring is provided.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:

Transmission line of electricity electric current and voltage negative phase-sequence transient state component method for fast measuring, is characterized in that, comprise following sequential steps:

(1) A, B, C three-phase voltage instantaneous value u of each t sampling instant in protective device Real-time Collection line protection installation place _a(t), u _b(t), u _ca, B, C three-phase current instantaneous value i of (t) and each t sampling instant _a(t), i _b(t), i _c(t);

(2) protective device is by A, B, C three-phase voltage instantaneous value u of t sampling instant _a(t), u _b(t), u _ca, B, C three-phase current instantaneous value i of (t) and t sampling instant _a(t), i _b(t), i _ct () is transformed into the instantaneous voltage u of t sampling instant under α β 0 coordinate axis _α(t), u _β(t), u ₀the current instantaneous value i of (t) and t sampling instant _α(t), i _β(t), i ₀(t):

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\left(t\right)\\ u_{\mathrm{\β}}\left(t\right)\\ u_0\left(t\right)\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{u}_A\left(t\right)\\ u_B\left(t\right)\\ u_C\left(t\right)\end{array}\right]$

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\left(t\right)\\ i_{\mathrm{\β}}\left(t\right)\\ i_0\left(t\right)\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{i}_A\left(t\right)\\ i_B\left(t\right)\\ i_C\left(t\right)\end{array}\right]$

(3) negative sequence voltage of t sampling instant under protective device calculating α β 0 coordinate axis with the negative-sequence current of t sampling instant

$i_{\mathrm{\α}}^{-}-\left(t\right)=0.5i_{\mathrm{\α}}\left(t\right)+0.5i_{\mathrm{\β}}\left(t-\frac{T}{4}\right)$

$i_{\mathrm{\β}}^{-}\left(t\right)=-0.5i_{\mathrm{\α}}\left(t-\frac{T}{4}\right)+0.5i_{\mathrm{\β}}\left(t\right)$

$u_{\mathrm{\α}}^{-}\left(t\right)=0.5u_{\mathrm{\α}}\left(t\right)+0.5u_{\mathrm{\β}}\left(t-\frac{T}{4}\right)$

$u_{\mathrm{\β}}^{-}\left(t\right)=-0.5u_{\mathrm{\α}}\left(t-\frac{T}{4}\right)+0.5u_{\mathrm{\β}}\left(t\right)$

$u_0^{-}-\left(t\right)=u_0\left(t\right)$

$i_0^{-}\left(t\right)=i_0\left(t\right)$

Wherein, be respectively β direction of principal axis under α β 0 coordinate axis the instantaneous voltage of sampling instant, current instantaneous value; u _β(t), i _βt () is respectively instantaneous voltage, the current instantaneous value of β direction of principal axis t sampling instant under α β 0 coordinate axis; be respectively α direction of principal axis under α β 0 coordinate axis the instantaneous voltage of sampling instant, current instantaneous value; u _α(t), i _αt () is respectively instantaneous voltage, the current instantaneous value of α direction of principal axis t sampling instant under α β 0 coordinate axis; T is time primitive period; u ₀(t), i ₀t () is respectively instantaneous voltage, the current instantaneous value of 0 direction of principal axis t sampling instant under α β 0 coordinate axis;

(4) protective device calculates A, B, C three-phase negative/positive instantaneous voltage of t sampling instant with A, B, C three-phase negative/positive current instantaneous value of t sampling instant

$\left[\begin{array}{c}{u}_A^{-}\left(t\right)\\ u_B^{-}\left(t\right)\\ u_C^{-}\left(t\right)\end{array}\right]=1.5{\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]}^{-1}\left[\begin{array}{c}{u}_{\mathrm{\α}}^{-}\left(t\right)\\ u_{\mathrm{\β}}^{-}\left(t\right)\\ u_0^{-}\left(t\right)\end{array}\right]$

$\left[\begin{array}{c}{i}_A^{-}\left(t\right)\\ i_B^{-}\left(t\right)\\ i_C^{-}\left(t\right)\end{array}\right]=1.5{\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]}^{-1}\left[\begin{array}{c}{i}_{\mathrm{\α}}^{-}\left(t\right)\\ i_{\mathrm{\β}}^{-}\left(t\right)\\ i_0^{-}\left(t\right)\end{array}\right]$

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

The three-phase voltage current instantaneous value of each sampling instant is transformed into the electric current and voltage instantaneous value of each sampling instant under α β 0 coordinate axis by the inventive method, calculate negative sequence voltage instantaneous value, the negative-sequence current instantaneous value of each sampling instant under α β 0 coordinate axis, three-phase negative/positive instantaneous voltage, the three-phase negative/positive current instantaneous value that coordinate axis inverse transformation obtains each sampling instant is carried out to the negative sequence voltage instantaneous value of each sampling instant under α β 0 coordinate axis, negative-sequence current instantaneous value.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 instantaneous value u of each t sampling instant in protective device Real-time Collection line protection installation place _a(t), u _b(t), u _ca, B, C three-phase current instantaneous value i of (t) and each t sampling instant _a(t), i _b(t), i _c(t).

Protective device is by A, B, C three-phase voltage instantaneous value u of t sampling instant _a(t), u _b(t), u _ca, B, C three-phase current instantaneous value i of (t) and t sampling instant _a(t), i _b(t), i _ct () is transformed into the instantaneous voltage u of t sampling instant under α β 0 coordinate axis _α(t), u _β(t), u ₀the current instantaneous value i of (t) and t sampling instant _α(t), i _β(t), i ₀(t):

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\left(t\right)\\ u_{\mathrm{\β}}\left(t\right)\\ u_0\left(t\right)\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{u}_A\left(t\right)\\ u_B\left(t\right)\\ u_C\left(t\right)\end{array}\right]$

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\left(t\right)\\ i_{\mathrm{\β}}\left(t\right)\\ i_0\left(t\right)\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{i}_A\left(t\right)\\ i_B\left(t\right)\\ i_C\left(t\right)\end{array}\right]$

The negative sequence voltage of t sampling instant under protective device calculating α β 0 coordinate axis with the negative-sequence current of t sampling instant

$i_{\mathrm{\α}}^{-}\left(t\right)=0.5i_{\mathrm{\α}}\left(t\right)+0.5i_{\mathrm{\β}}\left(t-\frac{T}{4}\right)$

$i_{\mathrm{\β}}^{-}\left(t\right)=-0.5i_{\mathrm{\α}}(t-\frac{T}{4})+0.5i_{\mathrm{\β}}\left(t\right)$

$u_{\mathrm{\α}}^{-}\left(t\right)=0.5u_{\mathrm{\α}}\left(t\right)+0.5u_{\mathrm{\β}}\left(t-\frac{T}{4}\right)$

$u_{\mathrm{\β}}^{-}\left(t\right)=-0.5u_{\mathrm{\α}}\left(t-\frac{T}{4}\right)+0.5u_{\mathrm{\β}}\left(t\right)$

$u_0^{-}-\left(t\right)=u_0\left(t\right)$

$i_0^{-}\left(t\right)=i_0\left(t\right)$

Wherein, be respectively β direction of principal axis under α β 0 coordinate axis the instantaneous voltage of sampling instant, current instantaneous value; u _β(t), i _βt () is respectively instantaneous voltage, the current instantaneous value of β direction of principal axis t sampling instant under α β 0 coordinate axis; be respectively α direction of principal axis under α β 0 coordinate axis the instantaneous voltage of sampling instant, current instantaneous value; u _α(t), i _αt () is respectively instantaneous voltage, the current instantaneous value of α direction of principal axis t sampling instant under α β 0 coordinate axis; T is time primitive period; u ₀(t), i ₀t () is respectively instantaneous voltage, the current instantaneous value of 0 direction of principal axis t sampling instant under α β 0 coordinate axis.

Protective device calculates A, B, C three-phase negative/positive instantaneous voltage of t sampling instant with A, B, C three-phase negative/positive current instantaneous value of t sampling instant

$\left[\begin{array}{c}{u}_A^{-}\left(t\right)\\ u_B^{-}\left(t\right)\\ u_C^{-}\left(t\right)\end{array}\right]=1.5{\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]}^{-1}\left[\begin{array}{c}{u}_{\mathrm{\α}}^{-}\left(t\right)\\ u_{\mathrm{\β}}^{-}\left(t\right)\\ u_0^{-}\left(t\right)\end{array}\right]$

$\left[\begin{array}{c}{i}_A^{-}\left(t\right)\\ i_B^{-}\left(t\right)\\ i_C^{-}\left(t\right)\end{array}\right]=1.5{\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]}^{-1}\left[\begin{array}{c}{i}_{\mathrm{\α}}^{-}\left(t\right)\\ i_{\mathrm{\β}}^{-}\left(t\right)\\ i_0^{-}\left(t\right)\end{array}\right]$

A, B, C three-phase negative/positive instantaneous voltage of each t sampling instant that protective device will calculate with A, B, C three-phase negative/positive current instantaneous value of each t sampling instant for relay protection computing.

The three-phase voltage current instantaneous value of each sampling instant is transformed into the electric current and voltage instantaneous value of each sampling instant under α β 0 coordinate axis by the inventive method, calculate negative sequence voltage instantaneous value, the negative-sequence current instantaneous value of each sampling instant under α β 0 coordinate axis, three-phase negative/positive instantaneous voltage, the three-phase negative/positive current instantaneous value that coordinate axis inverse transformation obtains each sampling instant is carried out to the negative sequence voltage instantaneous value of each sampling instant under α β 0 coordinate axis, negative-sequence current instantaneous value.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. transmission line of electricity electric current and voltage negative phase-sequence transient state component method for fast measuring, comprises following sequential steps:

(1) A, B, C three-phase voltage instantaneous value u of each t sampling instant in protective device Real-time Collection line protection installation place _a(t), u _b(t), u _ca, B, C three-phase current instantaneous value i of (t) and each t sampling instant _a(t), i _b(t), i _c(t);

(2) protective device is by A, B, C three-phase voltage instantaneous value u of t sampling instant _a(t), u _b(t), u _ca, B, C three-phase current instantaneous value i of (t) and t sampling instant _a(t), i _b(t), i _ct () is transformed into the instantaneous voltage u of t sampling instant under α β 0 coordinate axis _α(t), u _β(t), u ₀the current instantaneous value i of (t) and t sampling instant _α(t), i _β(t), i ₀(t):

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\left(t\right)\\ u_{\mathrm{\β}}\left(t\right)\\ u_0\left(t\right)\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{u}_A\left(t\right)\\ u_B\left(t\right)\\ u_C\left(t\right)\end{array}\right]$

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\left(t\right)\\ i_{\mathrm{\β}}\left(t\right)\\ i_0\left(t\right)\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{i}_A\left(t\right)\\ i_B\left(t\right)\\ i_C\left(t\right)\end{array}\right]$

(3) negative sequence voltage of t sampling instant under protective device calculating α β 0 coordinate axis with the negative-sequence current of t sampling instant

$i_{\mathrm{\α}}^{-}\left(t\right)=0.5i_{\mathrm{\α}}\left(t\right)+0.5i_{\mathrm{\β}}(t-\frac{T}{4})$

$i_{\mathrm{\β}}^{-}\left(t\right)=-0.5i_{\mathrm{\α}}(t-\frac{T}{4})+0.5i_{\mathrm{\β}}\left(t\right)$

$u_{\mathrm{\α}}^{-}-\left(t\right)=0.5u_{\mathrm{\α}}\left(t\right)+0.5u_{\mathrm{\β}}(t-\frac{T}{4})$

$u_{\mathrm{\β}}^{-}\left(t\right)=-0.5u_{\mathrm{\α}}(t-\frac{T}{4})+0.5u_{\mathrm{\β}}\left(t\right)$

$u_0^{-}\left(t\right)=u_0\left(t\right)$

$i_0^{-}\left(t\right)=i_0\left(t\right)$

Wherein, be respectively β direction of principal axis under α β 0 coordinate axis the instantaneous voltage of sampling instant, current instantaneous value; u _β(t), i _βt () is respectively instantaneous voltage, the current instantaneous value of β direction of principal axis t sampling instant under α β 0 coordinate axis; be respectively α direction of principal axis under α β 0 coordinate axis the instantaneous voltage of sampling instant, current instantaneous value; u _α(t), i _αt () is respectively instantaneous voltage, the current instantaneous value of α direction of principal axis t sampling instant under α β 0 coordinate axis; T is time primitive period; u ₀(t), i ₀t () is respectively instantaneous voltage, the current instantaneous value of 0 direction of principal axis t sampling instant under α β 0 coordinate axis;

(4) protective device calculates A, B, C three-phase negative/positive instantaneous voltage of t sampling instant with A, B, C three-phase negative/positive current instantaneous value of t sampling instant

$\left[\begin{array}{c}{u}_A^{-}\left(t\right)\\ u_B^{-}\left(t\right)\\ u_C^{-}\left(t\right)\end{array}\right]=1.5{\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]}^{-1}\left[\begin{array}{c}{u}_{\mathrm{\α}}^{-}\left(t\right)\\ u_{\mathrm{\β}}^{-}\left(t\right)\\ u_0^{-}\left(t\right)\end{array}\right]$

$\left[\begin{array}{c}{i}_A^{-}\left(t\right)\\ i_B^{-}\left(t\right)\\ i_C^{-}\left(t\right)\end{array}\right]=1.5{\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]}^{-1}\left[\begin{array}{c}{i}_{\mathrm{\α}}^{-}\left(t\right)\\ i_{\mathrm{\β}}^{-}\left(t\right)\\ i_0^{-}\left(t\right)\end{array}\right]$