CN104240145A - Application of improved radar chart method in electric energy quality assessment - Google Patents

Abstract

The invention provides an application of an improved radar chart method in electric energy quality assessment. The method includes the steps that 1 weights of electric energy quality indexes are calculated according to different application occasions; 2 the vector angles of fan-shaped areas corresponding to the indexes in a radar chart are distributed according to the sizes of the weights; 3 the assessment indexes of voltage deviation, harmonic waves, three-phase voltage unbalance, frequency deviation, voltage fluctuation and flickering and voltage dip are used as coordinate axes in the radar chart; 4 detection values of indexes of the electric energy quality at one moment are shown in the radar chart through analysis and calculation, and the electric energy quality at the moment can be assessed according to the conditions of the area and the perimeter of a graph. The application has the advantages that the electric energy quality can be assessed accurately by using a small number of discrete data and can be displayed visually through graphic images, and the weights of the indexes can be modified according to different requirements so as to enhance the applicability of the method.

Description

The application of Bradley figure method of wearing in electricity quality evaluation improved

Technical field

The present invention relates to a kind of method of electricity quality evaluation, the application of Bradley figure method of wearing in electricity quality evaluation of more precisely a kind of improvement.

Background technology

In Operation of Electric Systems process, parameter due to each element of system is not desirable or symmetry, the polytrope of power load, the randomness of part throttle characteristics and diversity, operation in power transmission and distribution process, failure and other reasons, system often can not be run with desirable state, so just propose the concept of the quality of power supply.And now, along with the develop rapidly of microelectronic component and Power Electronic Technique, to change new below having occurred in the requirement of the quality of power supply: on the one hand, because the existence of the access electric system of disturbance load or other disturbing sources causes a large amount of power quality problems; On the other hand, due to a large amount of uses of numerous exact instrument based on computing machine, microprocessor controller, equipment, the requirement of user to the quality of power supply is more and more higher.Drawn the demand carrying out assessing classification to the quality of power supply thus, electricity quality evaluation mainly comprises voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker, voltage dip.

Existing electricity quality evaluation method mainly contains analytical hierarchy process, mathematics method etc., although but can rough assessment classification be carried out to the quality of power supply often too limit to, some method is too subjective, and the experience level of appraiser and individual preference may affect to the result of assessment; Though other methods use objective mathematical computations need a large amount of data to verify; These methods just carry out the assessment classification of the quality of power supply by difference numerically can not to people's one visual experience intuitively.

Summary of the invention

The present invention mainly solves the technical matters existing for prior art, thus provide a kind of data discrete on a small quantity can be used to carry out accurate evaluation by the visual in image display of figure to the quality of power supply, evaluation method is simple to operation, need not loaded down with trivial details calculating be carried out too much, and the application of Bradley figure method of wearing in electricity quality evaluation of improvement be suitable for of Enhancement Method of can modifying according to the weight of different demand to index.

Above-mentioned technical matters of the present invention is mainly solved by following technical proposals:

The application of Bradley figure method of wearing in electricity quality evaluation for improvement, comprises the following steps:

Step one: the weight calculating each power quality index according to different application occasion;

Step 2: distribute the vectorial angle of each index wearing sector region corresponding in Bradley figure according to the size of weight;

Step 3: using these evaluation indexes of voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip as wearing coordinate axis in Bradley figure;

Step 4: by analysis and calculation the detected value of each for the quality of power supply in a certain moment index represented and wearing in Bradley figure, area and perimeter situation according to figure can be assessed the quality of power supply in this moment, wherein the quality of power supply of the larger expression check point of area is better, and the less then conclusion of area is contrary; When area equation, girth represents the equilibrium situation of the check point quality of power supply, and girth is less, and the quality of power supply is more balanced, and girth is larger, then harmonious poor.

More optimizedly, in described step one, power quality index comprises voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker, voltage dip.

More optimizedly, in described step one, the weight of each power quality index is compared by analytical hierarchy process and draws;

The flow process of carrying out subjective weights to power index with analytical hierarchy process is as follows:

A, set up level and pass access node structure;

B, form each constructing matrix;

C, Mode of Level Simple Sequence and consistency check;

D, total hierarchial sorting, calculating weight and inspection.

More optimizedly, in described step 2, the distribution formula of vectorial angle is:

${\mathrm{\θ}}_i=\frac{x_i}{\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{x}_k}\×2\mathrm{\π}---\left(1\right)$

Wherein x _ifor the weight corresponding to i-th index, θ _ifor the vectorial angle corresponding to i-th index.

More optimizedly, described step 3 is specially, using these evaluation indexes of voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip as six coordinate axis worn in Bradley figure, and six sector regions are divided into be expressed as voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip by the size of vectorial angle it.

More optimizedly, in described step 4, each index is normalized data processing, and the Plotting data recorded in one group of moment is being worn on Bradley figure, use x ₁, x ₂, x ₃, x ₄, x ₅, x ₆represent voltage deviation, frequency departure, non-equilibrium among three phase voltages, harmonic wave, voltage fluctuation and flicker and voltage dip respectively.

According to China standard GB/T/T12325-2008 " quality of power supply supply voltage deviation ", the index of voltage deviation is calculated by following formula:

$x_1=\frac{u_d-u_0}{u_0}\×100\%---\left(2\right)$

Wherein u _dfor actual measurement voltage, u ₀for nominal voltage;

According to China standard GB/T/T15945-2008 " quality of power supply power system frequency deviation ", the index of frequency departure is calculated by following formula:

$x_2=\frac{f_d-f_0}{f_0}\×100\%---\left(3\right)$

Wherein f _dfor practical frequency, f ₀for nominal frequency;

According to China standard GB/T/T15543-2008 " quality of power supply non-equilibrium among three phase voltages ", the index of non-equilibrium among three phase voltages is calculated by following formula;

$x_3=\frac{u_1}{u_2}\×100\%---\left(4\right)$

Wherein u ₁for voltage positive sequence r.m.s., u ₂for voltage negative phase-sequence r.m.s.;

According to China standard GB/T/T24337-2009 " quality of power supply utility network m-Acetyl chlorophosphonazo ", the index of harmonic distortion is calculated by following formula:

$x_4=\frac{\sqrt{\underset{n=2}{\overset{N}{\mathrm{\Σ}}}{V}_n^2}}{V_1}\×100\%---\left(5\right)$

Wherein V _nrepresent nth harmonic, V ₁represent first-harmonic;

According to China standard GB/T/T12326-2008 " quality of power supply voltage fluctuation and flicker ", the index of voltage fluctuation and flicker can be calculated by following formula:

$x_5=\frac{U_{\mathrm{MAX}}-U_{\mathrm{MIN}}}{U_0}\×100\%---\left(6\right)$

Wherein U _mAX, U _mINfor two extreme values adjacent in the change of series of voltage root-mean-square value, U ₀it is the nominal voltage of system;

According to China standard GB/T/T30137-2013 " quality of power supply voltage dip and short interruptions ", voltage dip amplitude is calculated by following formula:

$x_6=\frac{\sqrt{U_d}}{\sqrt{U_0}}\×100\%---\left(7\right)$

Wherein U _dvoltage during for falling temporarily, U ₀for the nominal voltage of system.

More optimizedly, voltage deviation measurements and calculations obtained, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip value are by the grade scale of each index of the quality of power supply to carry out centesimal system conversion, and reduction formula is as follows:

$y_1=\left\{\begin{array}{cc}90+(10-{5x}_1)& 0\&le;x_1<2\\ 90-2.5\&times;(x_1-2)& 2\&le;x_1<6\\ 80-5\&times;(x_1-6)& 6\&le;x_1<10\\ 60-7\&times;(x_1-10)& 10\&le;x_1\end{array}\right.---\left(8\right)$

$y_2=\left\{\begin{array}{cc}90+(10-{250x}_2)& 0\&le;x_2<0.04\\ 90-200\&times;(x_2-0.04)& 0.04\&le;x_2<0.12\\ 80-200\&times;(x_2-0.12)& 0.12\&le;x_2<0.2\\ 60-200\&times;(x_2-0.2)& 0.2\&le;x_2\end{array}\right.---\left(9\right)$ $y_3=\left\{\begin{array}{cc}90+(10-{25x}_3)& 0\&le;x_3<0.4\\ 90-20\&times;(x_3-0.4)& 0.4\&le;x_3<1.2\\ 80-20\&times;(x_3-1.2)& 1.2\&le;x_3<2\\ 60-20\&times;(x_3-2)& 2\&le;x_3\end{array}\right.---\left(10\right)$

$y_4=\left\{\begin{array}{cc}90+(10-{25x}_4)& 0\&le;x_4<0.4\\ 90-20\&times;(x_4-0.4)& 0.4\&le;x_4<1.2\\ 80-20\&times;(x_4-1.2)& 1.2\&le;x_4<2\\ 60-20\&times;(x_4-2)& 2\&le;x_4\end{array}\right.---\left(11\right)$

$y_5=\left\{\begin{array}{cc}90+(10-{62.5x}_5)& 0\&le;x_5<0.16\\ 90-30\&times;(x_5-0.16)& 0.16\&le;x_5<0.48\\ 80-30\&times;(x_5-0.48)& 0.48\&le;x_5<0.8\\ 60-30\&times;(x_5-0.8)& 0.8\&le;x_5\end{array}\right.---\left(12\right)$

y ₆＝100-x ₆ (13)

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.

Fig. 1 is realization flow figure of the present invention; Fig. 2 is the structural representation wearing Bradley figure used in the present invention; Fig. 3 be gone out by four groups of Plotting data before in the sample in embodiments of the invention wear Bradley figure; Fig. 4 be gone out by group Plotting data of first in the sample in embodiments of the invention wear Bradley figure.

Embodiment

Below in conjunction with accompanying drawing, the preferred embodiments of the present invention are described in detail, can be easier to make advantages and features of the invention be readily appreciated by one skilled in the art, thus more explicit defining is made to protection scope of the present invention.

The advantage of the application of Bradley figure method of wearing in electricity quality evaluation of improvement of the present invention is: data discrete on a small quantity can be used to carry out accurate evaluation to the quality of power supply and by the visual in image display of figure, evaluation method is simple to operation, need not loaded down with trivial details calculating be carried out too much, and can according to the weight of different demand to index modify Enhancement Method be suitable for.

As shown in Figure 1, a kind of application of Bradley figure method of wearing in electricity quality evaluation of improvement, comprises the following steps:

Step one: the weight calculating each power quality index according to different application occasion;

Step 2: distribute the vectorial angle of each index wearing sector region corresponding in Bradley figure according to the size of weight;

Step 3: using these evaluation indexes of voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip as wearing coordinate axis in Bradley figure;

Step 4: by analysis and calculation the detected value of each for the quality of power supply in a certain moment index represented and wearing in Bradley figure, area and perimeter situation according to figure can be assessed the quality of power supply in this moment, wherein the quality of power supply of the larger expression check point of area is better, and the less then conclusion of area is contrary; When area equation, girth represents the equilibrium situation of the check point quality of power supply, and girth is less, and the quality of power supply is more balanced, and girth is larger, then harmonious poor.

In this step one, power quality index comprises voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker, voltage dip.

In this step one, the weight of each power quality index is compared by analytical hierarchy process and draws;

The flow process of carrying out subjective weights to power index with analytical hierarchy process is as follows:

A, set up level and pass access node structure;

B, form each constructing matrix;

C, Mode of Level Simple Sequence and consistency check;

D, total hierarchial sorting, calculating weight and inspection.

In this step 2, the distribution formula of vectorial angle is:

${\mathrm{\&theta;}}_i=\frac{x_i}{\underset{k=1}{\overset{n}{\mathrm{\&Sigma;}}}{x}_k}\&times;2\mathrm{\&pi;}---\left(1\right)$

Wherein x _ifor the weight corresponding to i-th index, θ _ifor the vectorial angle corresponding to i-th index.

As shown in Figure 2, this step 3 is specially, using these evaluation indexes of voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip as six coordinate axis worn in Bradley figure, and six sector regions are divided into be expressed as voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip by the size of vectorial angle it.

In this step 4, each index is normalized data processing, and the Plotting data recorded in one group of moment is being worn on Bradley figure, so just can assess intuitively and compare; Use x ₁, x ₂, x ₃, x ₄, x ₅, x ₆represent voltage deviation, frequency departure, non-equilibrium among three phase voltages, harmonic wave, voltage fluctuation and flicker and voltage dip respectively.

According to China standard GB/T/T12325-2008 " quality of power supply supply voltage deviation ", the index of voltage deviation is calculated by following formula:

$x_1=\frac{u_d-u_0}{u_0}\&times;100\%---\left(2\right)$

Wherein u _dfor actual measurement voltage, u ₀for nominal voltage;

According to China standard GB/T/T15945-2008 " quality of power supply power system frequency deviation ", the index of frequency departure is calculated by following formula:

$x_2=\frac{f_d-f_0}{f_0}\&times;100\%---\left(3\right)$

Wherein f _dfor practical frequency, f ₀for nominal frequency;

According to China standard GB/T/T15543-2008 " quality of power supply non-equilibrium among three phase voltages ", the index of non-equilibrium among three phase voltages is calculated by following formula;

$x_3=\frac{u_1}{u_2}\&times;100\%---\left(4\right)$

Wherein u ₁for voltage positive sequence r.m.s., u ₂for voltage negative phase-sequence r.m.s.;

According to China standard GB/T/T24337-2009 " quality of power supply utility network m-Acetyl chlorophosphonazo ", the index of harmonic distortion is calculated by following formula:

$x_4=\frac{\sqrt{\underset{n=2}{\overset{N}{\mathrm{\&Sigma;}}}{V}_n^2}}{V_1}\&times;100\%---\left(5\right)$

Wherein V _nrepresent nth harmonic, V ₁represent first-harmonic;

According to China standard GB/T/T12326-2008 " quality of power supply voltage fluctuation and flicker ", the index of voltage fluctuation and flicker can be calculated by following formula:

$x_5=\frac{U_{\mathrm{MAX}}-U_{\mathrm{MIN}}}{U_0}\&times;100\%---\left(6\right)$

Wherein U _mAX, U _mINfor two extreme values adjacent in the change of series of voltage root-mean-square value, U ₀it is the nominal voltage of system;

According to China standard GB/T/T30137-2013 " quality of power supply voltage dip and short interruptions ", voltage dip amplitude is calculated by following formula:

$x_6=\frac{\sqrt{U_d}}{\sqrt{U_0}}\&times;100\%---\left(7\right)$

Wherein U _dvoltage during for falling temporarily, U ₀for the nominal voltage of system.

The grade scale of each index of the quality of power supply is as shown in table 1:

Table 1: the grade scale of each index of the quality of power supply

Note: grade 1-5 represents that the quality of power supply is qualified, and class 6-9 represents that the quality of power supply is defective.

Voltage deviation measurements and calculations obtained, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip value are by the grade scale of each index of the quality of power supply to carry out centesimal system conversion, and reduction formula is as follows:

$y_1=\left\{\begin{array}{cc}90+(10-{5x}_1)& 0\&le;x_1<2\\ 90-2.5\&times;(x_1-2)& 2\&le;x_1<6\\ 80-5\&times;(x_1-6)& 6\&le;x_1<10\\ 60-7\&times;(x_1-10)& 10\&le;x_1\end{array}\right.---\left(8\right)$

$y_2=\left\{\begin{array}{cc}90+(10-{250x}_2)& 0\&le;x_2<0.04\\ 90-200\&times;(x_2-0.04)& 0.04\&le;x_2<0.12\\ 80-200\&times;(x_2-0.12)& 0.12\&le;x_2<0.2\\ 60-200\&times;(x_2-0.2)& 0.2\&le;x_2\end{array}\right.---\left(9\right)$

$y_3=\left\{\begin{array}{cc}90+(10-{25x}_3)& 0\&le;x_3<0.4\\ 90-20\&times;(x_3-0.4)& 0.4\&le;x_3<1.2\\ 80-20\&times;(x_3-1.2)& 1.2\&le;x_3<2\\ 60-20\&times;(x_3-2)& 2\&le;x_3\end{array}\right.---\left(10\right)$

$y_4=\left\{\begin{array}{cc}90+(10-{25x}_4)& 0\&le;x_4<0.4\\ 90-20\&times;(x_4-0.4)& 0.4\&le;x_4<1.2\\ 80-20\&times;(x_4-1.2)& 1.2\&le;x_4<2\\ 60-20\&times;(x_4-2)& 2\&le;x_4\end{array}\right.---\left(11\right)$

$y_5=\left\{\begin{array}{cc}90+(10-{62.5x}_5)& 0\&le;x_5<0.16\\ 90-30\&times;(x_5-0.16)& 0.16\&le;x_5<0.48\\ 80-30\&times;(x_5-0.48)& 0.48\&le;x_5<0.8\\ 60-30\&times;(x_5-0.8)& 0.8\&le;x_5\end{array}\right.---\left(12\right)$

y ₆＝100-x ₆ (13)

Table 2 is depicted as the detection data of certain electrical network evaluation point, to be calculated by formula 8-formula 13 for 4 groups of numerical value before table 2 and draw out as shown in Figure 3 wear Bradley figure.

Table 2: the detection data of certain electrical network evaluation point

Separately with the 1st group of data analysis, it wears Bradley figure as shown in Figure 4, the numerical value of node is less than 60 and represents that the power quality index representated by this index is defective, it can thus be appreciated that: in Fig. 4, the index of voltage dip and harmonic distortion is all defective, and the performance of voltage fluctuation and flicker is very outstanding, remaining index all reaches medium above level.Can next step optimization be carried out for voltage dip and harmonic distortion and debug to reach written standards accordingly.

Claims (8)

1. the application of Bradley figure method of wearing in electricity quality evaluation improved, is characterized in that: comprise the following steps:

Step one: the weight calculating each power quality index according to different application occasion;

Step 2: distribute the vectorial angle of each index wearing sector region corresponding in Bradley figure according to the size of weight;

Step 3: using these evaluation indexes of voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip as wearing coordinate axis in Bradley figure;

Step 4: by analysis and calculation the detected value of each for the quality of power supply in a certain moment index represented and wearing in Bradley figure, area and perimeter situation according to figure can be assessed the quality of power supply in this moment, wherein the quality of power supply of the larger expression check point of area is better, and the less then conclusion of area is contrary; When area equation, girth represents the equilibrium situation of the check point quality of power supply, and girth is less, and the quality of power supply is more balanced, and girth is larger, then harmonious poor.

2. the application of Bradley figure method of wearing in electricity quality evaluation of improvement according to claim 1, is characterized in that: in described step one, power quality index comprises voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker, voltage dip.

3. the application of Bradley figure method of wearing in electricity quality evaluation of improvement according to claim 1, is characterized in that: in described step one, the weight of each power quality index is compared by analytical hierarchy process and draws;

The flow process of carrying out subjective weights to power index with analytical hierarchy process is as follows:

A, set up level and pass access node structure;

B, form each constructing matrix;

C, Mode of Level Simple Sequence and consistency check;

D, total hierarchial sorting, calculating weight and inspection.

4. the application of Bradley figure method of wearing in electricity quality evaluation of improvement according to claim 1, is characterized in that: in described step 2, the distribution formula of vectorial angle is:

Wherein x _ifor the weight corresponding to i-th index, θ _ifor the vectorial angle corresponding to i-th index.

5. the application of Bradley figure method of wearing in electricity quality evaluation of improvement according to claim 1, it is characterized in that: described step 3 is specially, using these evaluation indexes of voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip as six coordinate axis worn in Bradley figure, and six sector regions are divided into be expressed as voltage deviation, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip by the size of vectorial angle it.

6. the application of Bradley figure method of wearing in electricity quality evaluation of improvement according to claim 1, it is characterized in that: in described step 4, each index is normalized data processing, and the Plotting data recorded in one group of moment is being worn on Bradley figure, use x ₁, x ₂, x ₃, x ₄, x ₅, x ₆represent voltage deviation, frequency departure, non-equilibrium among three phase voltages, harmonic wave, voltage fluctuation and flicker and voltage dip respectively.

7. the application of Bradley figure method of wearing in electricity quality evaluation of improvement according to claim 6, it is characterized in that: according to China standard GB/T/T12325-2008 " quality of power supply supply voltage deviation ", the index of voltage deviation is calculated by following formula:

Wherein u _dfor actual measurement voltage, u ₀for nominal voltage;

According to China standard GB/T/T15945-2008 " quality of power supply power system frequency deviation ", the index of frequency departure is calculated by following formula:

Wherein f _dfor practical frequency, f ₀for nominal frequency;

According to China standard GB/T/T15543-2008 " quality of power supply non-equilibrium among three phase voltages ", the index of non-equilibrium among three phase voltages is calculated by following formula;

Wherein u ₁for voltage positive sequence r.m.s., u ₂for voltage negative phase-sequence r.m.s.;

According to China standard GB/T/T24337-2009 " quality of power supply utility network m-Acetyl chlorophosphonazo ", the index of harmonic distortion is calculated by following formula:

Wherein V _nrepresent nth harmonic, V ₁represent first-harmonic;

According to China standard GB/T/T12326-2008 " quality of power supply voltage fluctuation and flicker ", the index of voltage fluctuation and flicker is calculated by following formula:

wherein U _mAX, U _mINfor two extreme values adjacent in the change of series of voltage root-mean-square value, U ₀for the nominal voltage of system;

According to China standard GB/T/T30137-2013 " quality of power supply voltage dip and short interruptions ", voltage dip amplitude is calculated by following formula:

Wherein Y _dvoltage during for falling temporarily, U ₀for the nominal voltage of system.

8. the application of Bradley figure method of wearing in electricity quality evaluation of improvement according to claim 7, it is characterized in that: voltage deviation measurements and calculations obtained, harmonic wave, non-equilibrium among three phase voltages, frequency departure, voltage fluctuation and flicker and voltage dip value are by the grade scale of each index of the quality of power supply to carry out centesimal system conversion, and reduction formula is as follows:

y ₆＝100-x ₆ (13)。