CN104076201B - Method for measuring transient frequency of transformer substation busbar voltage without being affected by aperiodic noise - Google Patents

Abstract

The invention discloses a method for measuring transient frequency of transformer substation busbar voltage without being affected by aperiodic noise. The method includes the steps that firstly, voltage instantaneous values of the transformer substation busbar voltage at sampling moments are measured, smoothness coefficients of the transformer substation busbar voltage at the sampling moments are calculated, sliding coefficients of the transformer substation busbar voltage at the sampling moments are calculated, and then the frequency of the transformer substation busbar voltage at the sampling moments is calculated based on weighting estimation according to the smoothness coefficients and the sliding coefficients of the transformer busbar voltage at the sampling moments. According to the method, measuring accuracy is not affected by aperiodic noise signals, data windows are short, operands are small, the algorithm operating speed is high, and instantaneous values of the frequency of the transformer substation busbar voltage at the sampling moments can be accurately measured in real time.

Description

Not by the substation bus bar voltage transient frequency measurement method of influence of noise aperiodic

Technical field

The present invention relates to Relay Protection Technology in Power System field, concretely relate to one not by aperiodic The substation bus bar voltage transient frequency measurement method of influence of noise.

Background technology

Realize electrical network each substation bus bar electric voltage frequency accurately to measure, can be that peak load regulation network frequency modulation provides foundation. Power industry mainly utilizes Fourier algorithm to calculate substation bus bar electric voltage frequency, the method hypotheses at present Substation bus bar electric voltage frequency keeps stablizing constant within a 20ms cycle, utilizes a cycle data amount Extract substation bus bar voltage phase angle, then substation bus bar voltage phase angle is converted into substation bus bar electricity Pressure rate-adaptive pacemaker.Due to Fourier algorithm own limitations, desired data window is a cycle, desired data Window is long, and operand is big, and arithmetic speed is slow, and measurement result also can only react a cycle frequency values, it is impossible to real Time measure substation bus bar electric voltage frequency.Owing to Fourier algorithm cannot filter aperiodicity noise signal shadow Ring so that certainty of measurement is serious by aperiodicity noise impact, it is impossible to meets complex large power grid and adjusts in real time The needs of peak frequency modulation.

Summary of the invention

It is an object of the invention to the deficiency overcoming prior art to exist, it is provided that one is not by noise shadow aperiodic The substation bus bar voltage transient frequency measurement method rung, the method certainty of measurement is not by noise shadow aperiodic Ringing, data window is short, and operand is little, algorithm fast operation, can the most accurately measure the change of each sampling instant Power station busbar voltage frequency instantaneous value.

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

Not by the substation bus bar voltage transient frequency measurement method of influence of noise aperiodic, including the most sequentially Step:

(1) instantaneous voltage of each sampling instant of substation bus bar voltage is measured；

(2) the steady coefficient of the substation bus bar voltage of t sampling instant is calculated Wherein, u (t) is the substation bus bar voltage sample value of t sampling instant；(t-k Δ t) is the change of t-k Δ t sampling instant to u Power station busbar voltage sampled value；(t+k Δ t) is the substation bus bar voltage sample value of t+k Δ t sampling instant to u；Δ t is Sampling interval duration；K is data window length, and is positive integer；

(3) slide coefficient of the substation bus bar voltage of t sampling instant is calculatedWherein, u (t) is the substation bus bar voltage sample value of t sampling instant； (t-k Δ t) is the substation bus bar voltage sample value of t-k Δ t sampling instant to u；(t+k Δ t) is t+k Δ t sampling instant to u Substation bus bar voltage sample value；Δ t is sampling interval duration；K is data window length, and is positive integer；

(4) substation bus bar voltage transient frequency f of calculating t sampling instant:

$f=\frac{1}{2\mathrm{\πk\Δt}}{\cos }^{-1}\left(\frac{\underset{i=-m}{\overset{i=m}{\mathrm{\Σ}}}|\frac{u(t+\mathrm{i\Δt}+\mathrm{k\Δt})}{\sqrt{{\left[u(t+\mathrm{i\Δt}+\mathrm{k\Δt})\right]}^2-{\left[u(t+\mathrm{i\Δt})u(t+\mathrm{i\Δt}+2\mathrm{k\Δt})\right]}^2}}+\frac{u(t+\mathrm{i\Δt}-\mathrm{k\Δt})}{\sqrt{{\left[u(t+\mathrm{i\Δt}-\mathrm{k\Δt})\right]}^2-{\left[u(t+\mathrm{i\Δt})u(t+\mathrm{i\Δt}-2\mathrm{k\Δt})\right]}^2}}|}{\underset{i=-m}{\overset{i=m}{\mathrm{\Σ}}}\frac{2u(t+\mathrm{i\Δt})}{\sqrt{{\left[u(t+\mathrm{i\Δt})\right]}^2-{\left[u(t+\mathrm{i\Δt}+\mathrm{k\Δt})u(t+\mathrm{i\Δt}-\mathrm{k\Δt})\right]}^2}}}\right)$

Wherein, (t+i Δ t) is the substation bus bar voltage sample value of t+i Δ t sampling instant to u；(t+i Δ t-k Δ t) is that t+i Δ t-k Δ t adopts to u The substation bus bar voltage sample value in sample moment；(t+i Δ t+k Δ t) is the substation bus bar of t+i Δ t+k Δ t sampling instant to u Voltage sample value；Δ t is sampling interval duration；K is data window length, and is positive integer；(t+i Δ t-2k Δ t) is u The substation bus bar voltage sample value of t+i Δ t-2k Δ t sampling instant；(t+i Δ t+2k Δ t) is t+i Δ t+2k Δ t sampling instant to u Substation bus bar voltage sample value；I is integer quotient；M is weighting length.

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

The inventive method certainty of measurement is not by influence of noise aperiodic, and data window is short, and operand is little, and algorithm is transported Calculation speed is fast, can the most accurately measure the substation bus bar electric voltage frequency instantaneous value of each sampling instant.

Accompanying drawing explanation

Fig. 1 is the two-terminal transmission systems schematic diagram of the application present invention.

Detailed description of the invention

Below according to Figure of description, technical scheme is expressed in further detail.

Fig. 1 is the two-terminal transmission systems schematic diagram of the application present invention.In Fig. 1, PT is substation bus bar voltage Transformer.

Not by the substation bus bar voltage transient frequency measurement method of influence of noise aperiodic, specifically include following Step:

(1) electric voltage frequency measurement apparatus measures the voltage transient of each sampling instant of substation bus bar voltage in real time Value.

(2) the steady coefficient of the substation bus bar voltage of electric voltage frequency measurement apparatus calculating t sampling instant $\sqrt{{\left[u\left(t\right)\right]}^2-{\left[u(t-\mathrm{k\Δt})u(t+\mathrm{k\Δt})\right]}^2};$

Wherein, u (t) is the substation bus bar voltage sample value of t sampling instant；(t-k Δ t) is t-k Δ t sampling instant to u Substation bus bar voltage sample value；(t+k Δ t) is the substation bus bar voltage sample value of t+k Δ t sampling instant to u； Δ t is sampling interval duration；K is data window length, and is positive integer.

(3) slide coefficient of the substation bus bar voltage of electric voltage frequency measurement apparatus calculating t sampling instant $\frac{u\left(t\right)}{\sqrt{{\left[u\left(t\right)\right]}^2-{\left[u(t-\mathrm{k\Δt})u(t+\mathrm{k\Δt})\right]}^2}};$

Wherein, u (t) is the substation bus bar voltage sample value of t sampling instant；(t-k Δ t) is t-k Δ t sampling instant to u Substation bus bar voltage sample value；(t+k Δ t) is the substation bus bar voltage sample value of t+k Δ t sampling instant to u； Δ t is sampling interval duration；K is data window length, and is positive integer.

(4) substation bus bar voltage transient frequency f of electric voltage frequency measurement apparatus calculating t sampling instant:

$f=\frac{1}{2\mathrm{\πk\Δt}}{\cos }^{-1}\left(\frac{\underset{i=-m}{\overset{i=m}{\mathrm{\Σ}}}|\frac{u(t+\mathrm{i\Δt}+\mathrm{k\Δt})}{\sqrt{{\left[u(t+\mathrm{i\Δt}+\mathrm{k\Δt})\right]}^2-{\left[u(t+\mathrm{i\Δt})u(t+\mathrm{i\Δt}+2\mathrm{k\Δt})\right]}^2}}+\frac{u(t+\mathrm{i\Δt}-\mathrm{k\Δt})}{\sqrt{{\left[u(t+\mathrm{i\Δt}-\mathrm{k\Δt})\right]}^2-{\left[u(t+\mathrm{i\Δt})u(t+\mathrm{i\Δt}-2\mathrm{k\Δt})\right]}^2}}|}{\underset{i=-m}{\overset{i=m}{\mathrm{\Σ}}}\frac{2u(t+\mathrm{i\Δt})}{\sqrt{{\left[u(t+\mathrm{i\Δt})\right]}^2-{\left[u(t+\mathrm{i\Δt}+\mathrm{k\Δt})u(t+\mathrm{i\Δt}-\mathrm{k\Δt})\right]}^2}}}\right)$

Wherein, (t+i Δ t) is the substation bus bar voltage sample value of t+i Δ t sampling instant to u；(t+i Δ t-k Δ t) is that t+i Δ t-k Δ t adopts to u The substation bus bar voltage sample value in sample moment；(t+i Δ t+k Δ t) is the substation bus bar of t+i Δ t+k Δ t sampling instant to u Voltage sample value；Δ t is sampling interval duration；K is data window length, and is positive integer；(t+i Δ t-2k Δ t) is u The substation bus bar voltage sample value of t+i Δ t-2k Δ t sampling instant；(t+i Δ t+2k Δ t) is t+i Δ t+2k Δ t sampling instant to u Substation bus bar voltage sample value；I is integer quotient；M is weighting length.

The substation bus bar electric voltage frequency value of calculation of electric voltage frequency measurement apparatus output t sampling instant.

The inventive method certainty of measurement is not by influence of noise aperiodic, and data window is short, and operand is little, and algorithm is transported Calculation speed is fast, can the most accurately measure the substation bus bar electric voltage frequency instantaneous value of each sampling instant.

The foregoing is only the preferred embodiment of the present invention, but protection scope of the present invention is not limited to This, any those familiar with the art, in the technical scope that the invention discloses, can readily occur in Change or replacement, all should contain within protection scope of the present invention.

Claims (1)

1. The most not by the substation bus bar voltage transient frequency measurement method of influence of noise aperiodic, it is special Levy and be, including following sequential steps:

   (1) instantaneous voltage of each sampling instant of substation bus bar voltage is measured；

   (2) the steady coefficient of the substation bus bar voltage of t sampling instant is calculated

   Wherein, u (t) is the substation bus bar voltage sample value of t sampling instant； (t-k Δ t) is the substation bus bar voltage sample value of t-k Δ t sampling instant to u；U is (when t+k Δ t) is t+k Δ t sampling The substation bus bar voltage sample value carved；Δ t is sampling interval duration；K is data window length, and is Positive integer；

   (3) slide coefficient of the substation bus bar voltage of t sampling instant is calculated

   $\frac{u\left(t\right)}{\sqrt{{\[u\left(t\right)\]}^2-{\[u(t-k\mathrm{\Δ}t)u(t+k\mathrm{\Δ}t)\]}^2}};$

   (4) substation bus bar voltage transient frequency f of calculating t sampling instant:

   $f=\frac{1}{2\mathrm{\π}k\mathrm{\Δ}t}{\cos }^{-1}\left(\frac{\underset{i=-m}{\overset{i=m}{\Σ}}|\frac{u(t+i\mathrm{\Δ}t+k\mathrm{\Δ}t)}{\sqrt{{\[u(t+i\mathrm{\Δ}t+k\mathrm{\Δ}t)\]}^2-{\[u(t+i\mathrm{\Δ}t)u(t+i\mathrm{\Δ}t+2k\mathrm{\Δ}t)\]}^2}}+\frac{u(t+i\mathrm{\Δ}t-k\mathrm{\Δ}t)}{\sqrt{{\[u(t+i\mathrm{\Δ}t-k\mathrm{\Δ}t)\]}^2-{\[u(t+i\mathrm{\Δ}t)u(t+i\mathrm{\Δ}t-2k\mathrm{\Δ}t)\]}^2}}|}{\underset{i=-m}{\overset{i=m}{\Σ}}\frac{2u(t+i\mathrm{\Δ}t)}{\sqrt{{\[u(t+i\mathrm{\Δ}t)\]}^2-{\[u(t+i\mathrm{\Δ}t+k\mathrm{\Δ}t)u(t+i\mathrm{\Δ}t-k\mathrm{\Δ}t)\]}^2}}}\right)$

   Wherein, (t+i Δ t) is the substation bus bar voltage sample value of t+i Δ t sampling instant to u；(t+i Δ t-k Δ t) is u The substation bus bar voltage sample value of t+i Δ t-k Δ t sampling instant；U is (when t+i Δ t+k Δ t) is t+i Δ t+k Δ t sampling The substation bus bar voltage sample value carved；Δ t is sampling interval duration；K is data window length, and is Positive integer；(t+i Δ t-2k Δ t) is the substation bus bar voltage sample value of t+i Δ t-2k Δ t sampling instant to u； (t+i Δ t+2k Δ t) is the substation bus bar voltage sample value of t+i Δ t+2k Δ t sampling instant to u；I is integer quotient； M is weighting length.