CN103543317A - Method for measuring IEC (International Electrical Commission) standard voltage flicker - Google Patents

Abstract

The invention relates to a method for measuring IEC (International Electrical Commission) standard voltage flicker. The method includes initializing a measuring system, collecting voltage peak, preprocessing data, processing data based on a table look-up algorithm, processing data based on a frequency compensation algorithm, calculating short-time voltage flicker value, and calculating long-time voltage flicker value. With the simplified calculating process, RAM storage space occupancy rate is reduced, sampling continuity is guaranteed, and measurement accuracy is ensured.

Description

For measuring the method for IEC normal voltage flickering

Technical field

The present invention relates to a kind ofly for measuring the method for IEC normal voltage flickering, be applied to Power Quality Detection and the analysis of power supply-distribution system in electric system.

Background technology

According to the applicant understood, voltage flicker (Voltage Flicker) refers to that incandescent lamp reacts because voltage fluctuation causes the unsettled human eye vision of lamp illuminance.Why selecting incandescent lamp as with reference to standard, is because in office, commercial, covil construction, incandescent lamp occupies sizable ratio, and square being directly proportional of the luminous power of incandescent lamp and line voltage, and had the greatest impact by voltage fluctuation.In electric system, voltage flicker is one of parameter important in quality of power supply evaluation criteria.

Because national government is advocated sustainable development, require Devoting Major Efforts To Developing and utilize regenerative resource, in following novel electric power system, the new forms of energy such as sun power, wind energy will be connected to the grid on a large scale, because these energy are limited to geographical conditions, weather, can only be connected to the grid by clearance-type, at them, start to be incorporated to and moment of departing from electrical network can produce larger disturbance to electrical network like this, cause the jumping of line voltage cycle time stage, bust, be unfavorable for guaranteeing that the quality of power supply is stable.Simultaneously, following novel power rush and wavy load can get more and more, as steel-making arc stove, rolling mill by thyristorized supply, electric welding machine, electric locomotive etc., even tens0000 kilowatts up to several ten thousand kilowatts of its power, because the power factor of this class interference load is generally compared with low and reactive power variable quantity is large, these loads will cause the significantly change fast of voltage magnitude of points of common connection (PCC) when operation, when serious, may make other electrical equipment cisco unity malfunction under same electromagnetic environment, to production, bring the impact in economy and benefit, brought inconvenience to people's life.This just need to have high-precision voltage flicker measuring method, and accurately measuring voltage flickering, for electric system takes measures to provide early warning.

Existing voltage flicker measuring method adopts Fast Fourier Transform (FFT) (FFT) to carry out computing (for example Chinese invention patent application of application number 201110124225.4 publication No. CN102288807A) mostly, but the problem of this method is: the calculating process more complicated of Fast Fourier Transform (FFT), during computing, need take a large amount of RAM storage spaces, can affect the operation of master routine task, make whole measuring system easily therefore lose ripple in sampling process, cause measuring accuracy accurate not.

Summary of the invention

Technical matters to be solved by this invention is: the problem existing for prior art, propose a kind of for measuring the method for IEC normal voltage flickering, with the calculating process of simplifying, reduce RAM storage space occupancy, ensure sampling continuity, thereby guarantee measuring accuracy.

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

A kind of for measuring the method for IEC normal voltage flickering, it is characterized in that, be applied to the measuring system being formed by controller and three-phase electrical energy computation chip, described controller and three-phase electrical energy computation chip communication connection, described three-phase electrical energy computation chip is in order to automatic calculating and deposit voltage peak, and described voltage peak is voltage wave peak value or voltage wave valley; Said method comprising the steps of:

The first step, start to measure; Measuring system initialization, empties all voltage weighted data U _j, and make j=1, empty all short time voltage flickering value P _st[n], and make n=1;

Second step, controller gather voltage peak:

S1. initialization, empties all voltage data u _i, and make i=1;

S2. read the voltage peak that three-phase electrical energy computation chip is deposited, deposit this voltage peak in voltage data u _i, start from zero timing simultaneously;

S3. judge whether i equals the first predetermined value N, when making if not i=i+1 and waiting for timing to the second predetermined value T, go to S2, if go to the 3rd step;

The 3rd step, controller preprocessed data:

S4. calculating voltage data u _imean value then calculate modulated wave data u' _i, $u_i^{\′}=\left|u_i\right|-\stackrel{\‾}{u},1$ $\≤i\≤N;$

S5. calculate by modulated wave data and formed each zero crossing time value zero[k of living in sine modulation ripple], k=(i-1)+N * (j-1);

S6. calculating voltage weighted data $U_j=\frac{1}{\stackrel{\‾}{u}}\×\sqrt{\frac{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\left(\right|u_i|-\stackrel{\‾}{u})}^2}{N}};$

S7. judge whether j equals the 3rd predetermined value M, makes if not j=j+1 and goes to second step, if go to the 4th step;

Pass between described the first predetermined value N and the 3rd predetermined value M is:

described the second predetermined value T is the electric power wave semiperiod; Described the 3rd predetermined value M>=1000;

The 4th step, controller are by the algorithm process data of tabling look-up:

S8. calculate the vibration frequency f of modulated wave _Ω,

f _wfor electric power wave angular frequency;

S9. according to IEC standard, provide the instantaneous flicker S=1 of unit time voltage fluctuation table, search f _Ωfrequency separation of living in, makes f ₁<f _Ω<f ₂; Calculate visual sense degree COEFFICIENT K fx, Kfx=[(f _Ω-f ₁) * d ₂+ (f ₂-f _Ω) * d ₁]/(f ₂-f ₁); Go to the 5th step;

The 5th step, controller are pressed frequency compensation algorithm process data:

S10. calculate relative voltage changing value ${(\mathrm{\&Delta;u}/\stackrel{\&OverBar;}{u})}_j=2\sqrt{2}\&times;U_j\&times;\mathrm{Kfx},1\&le;j\&le;M;$

The 6th step, controller calculate short time voltage flickering value:

S11. calculate instantaneous flicker visual sense degree $S_j={({(\mathrm{\&Delta;u}/\stackrel{\&OverBar;}{u})}_j/0.25\%)}^2,1\&le;j\&le;M;$

S12. from M instantaneous flicker visual sense degree S _jin count the large value of 99.9%, 99%, 97%, 90%, 50% probability, respectively as P _0.1, P ₁, P ₃, P ₁₀, P ₅₀, then calculate short time voltage flickering value P _st[n], $P_{\mathrm{st}}=\sqrt{{0.0314P}_{0.1}+{0.0525P}_1+{03.0657P}_3+{0.28P}_{10}+{0.08P}_{50}};$

S13. judge whether n equals the 4th predetermined value Z, makes if not n=n+1 and goes to second step, if go to the 7th step; When described the 4th predetermined value Z and length, the pass of voltage flicker X observing time is: Z=X/10 minute;

Voltage flicker value P when the 7th step, controller calculate length _lt,

measure and finish.

Preferably, the first predetermined value N=60, the second predetermined value T=10 millisecond, the 3rd predetermined value M=1000, the 4th predetermined value Z=12.

Applicant, through in depth finally drawing above-mentioned measuring method after practical studies, can, in the situation that not adopting Fast Fourier Transform (FFT) FFT computing, accurately draw short time voltage flickering value P _stvoltage flicker value P during with length _lt.The inventive method adopts mode in batches, take several voltage peaks as a set of samples for every batch, and the computing of each data processing step is simple and quick, RAM storage space occupancy is low, expends time in very short, can realize sampling limit, limit deal with data, and both are independent of each other, thereby guarantee measuring accuracy.

Accompanying drawing explanation

Fig. 1 is the main process schematic diagram of the embodiment of the present invention.

Embodiment

With reference to the accompanying drawings and in conjunction with the embodiments the present invention is described in further detail.But the invention is not restricted to given example.

Embodiment

The present embodiment is for measuring the method for IEC normal voltage flickering, be applied to the measuring system being formed by controller and three-phase electrical energy computation chip, controller and three-phase electrical energy computation chip communication connection, three-phase electrical energy computation chip is in order to automatic calculating and deposit voltage peak, and voltage peak is voltage wave peak value or voltage wave valley.The ATT7022E of three-phase electrical energy computation chip buyable ，Ru Juquan Optoelectronics Technology company; Controller can adopt MCU; Can spi bus communication connection between controller and three-phase electrical energy computation chip.

As shown in Figure 1, the present embodiment method comprises the following steps:

The first step, start to measure; Measuring system initialization, empties all voltage weighted data U _j, and make j=1, empty all short time voltage flickering value P _st[n], and make n=1;

Second step, controller gather voltage peak:

S1. initialization, empties all voltage data u _i, and make i=1;

S2. read the voltage peak that three-phase electrical energy computation chip is deposited, deposit this voltage peak in voltage data u _i, start from zero timing simultaneously;

S3. judge whether i equals the first predetermined value N, when making if not i=i+1 and waiting for timing to the second predetermined value T, go to S2, if go to the 3rd step;

The 3rd step, controller preprocessed data:

S4. the mean value of calculating voltage data ui

then calculate modulated wave data u' _i, $u_i^{\&prime;}=\left|u_i\right|-\stackrel{\&OverBar;}{u},1$ $\&le;i\&le;N;$ In this step, will

as this group voltage data u _idC component, then reject DC component and obtain modulated wave data u' _i.

S5. calculate by modulated wave data and formed each zero crossing time value zero[k of living in sine modulation ripple], k=(i-1)+N * (j-1);

S6. calculating voltage weighted data $U_j=\frac{1}{\stackrel{\&OverBar;}{u}}\&times;\sqrt{\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\left(\right|u_i|-\stackrel{\&OverBar;}{u})}^2}{N}};$

S7. judge whether j equals the 3rd predetermined value M, makes if not j=j+1 and goes to second step, if go to the 4th step;

Pass between described the first predetermined value N and the 3rd predetermined value M is:

described the second predetermined value T is the electric power wave semiperiod; Described the 3rd predetermined value M>=1000;

The 4th step, controller are by the algorithm process data of tabling look-up:

S8. calculate the vibration frequency f of modulated wave _Ω,

f _wfor electric power wave angular frequency;

S9. according to IEC standard, provide the instantaneous flicker S=1 of unit time voltage fluctuation table, search f _Ωfrequency separation of living in, makes f ₁<f _Ω<f ₂; Calculate visual sense degree COEFFICIENT K fx, Kfx=[(f _Ω-f ₁) * d ₂+ (f ₂-f _Ω) * d ₁]/(f ₂-f ₁); Go to the 5th step;

The algorithm of tabling look-up in this step has utilized the quick advantage of tabling look-up, again the precision with raising flicker measurement by formula correction visual sense degree coefficient.

The 5th step, controller are pressed frequency compensation algorithm process data:

S10. calculate relative voltage changing value ${(\mathrm{\&Delta;u}/\stackrel{\&OverBar;}{u})}_j=2\sqrt{2}\&times;U_j\&times;\mathrm{Kfx},1\&le;j\&le;M;$ In this step, according to the unimodal weighted filtering effect centered by 8.8Hz, work out by the relative voltage of 8.8Hz frequency characteristic and change.

The 6th step, controller calculate short time voltage flickering value:

S11. calculate instantaneous flicker visual sense degree $S_j={({(\mathrm{\&Delta;u}/\stackrel{\&OverBar;}{u})}_j/0.25\%)}^2,1\&le;j\&le;M;$

S12. from M instantaneous flicker visual sense degree S _jin count the large value of 99.9%, 99%, 97%, 90%, 50% probability, respectively as P _0.1, P ₁, P ₃, P ₁₀, P ₅₀, then calculate short time voltage flickering value P _st[n], $P_{\mathrm{st}}=\sqrt{{0.0314P}_{0.1}+{0.0525P}_1+{03.0657P}_3+{0.28P}_{10}+{0.08P}_{50}};$

S13. judge whether n equals the 4th predetermined value Z, makes if not n=n+1 and goes to second step, if go to the 7th step; When described the 4th predetermined value Z and length, the pass of voltage flicker X observing time is: Z=X/10 minute;

Voltage flicker value P when the 7th step, controller calculate length _lt,

measure and finish.

In the present embodiment, the first predetermined value N=60, the second predetermined value T=10 millisecond, the 3rd predetermined value M=1000, the 4th predetermined value Z=12.

The present embodiment method is applied to the flicker measurement of south electric network distribution transforming measuring terminal in internal applications test, and in test process, measuring accuracy can be controlled in 5%, meets the requirement of IEC standard, and effect is remarkable.

The present embodiment method efficiency is high, precision is high, can and be subject to it to affect the ripple problem of losing causing from basic solution Fast Fourier Transform (FFT) FFT computing complexity.

The present embodiment method is utilized the voltage peak of three-phase electrical energy computation chip continuous sampling half cycles, and various processes (especially visual sense degree coefficient calculation step) computing is simple, can significantly improve arithmetic speed, improves measuring accuracy, reduces the demand to computing hardware.

In addition to the implementation, the present invention can also have other embodiments.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of requirement of the present invention.

Claims (2)

1. one kind for measuring the method for IEC normal voltage flickering, it is characterized in that, be applied to the measuring system being formed by controller and three-phase electrical energy computation chip, described controller and three-phase electrical energy computation chip communication connection, described three-phase electrical energy computation chip is in order to automatic calculating and deposit voltage peak, and described voltage peak is voltage wave peak value or voltage wave valley; Said method comprising the steps of:

The first step, start to measure; Measuring system initialization, empties all voltage weighted data U _j, and make j=1, empty all short time voltage flickering value P _st[n], and make n=1;

Second step, controller gather voltage peak:

S1. initialization, empties all voltage data u _i, and make i=1;

S2. read the voltage peak that three-phase electrical energy computation chip is deposited, deposit this voltage peak in voltage data u _i, start from zero timing simultaneously;

S3. judge whether i equals the first predetermined value N, when making if not i=i+1 and waiting for timing to the second predetermined value T, go to S2, if go to the 3rd step;

The 3rd step, controller preprocessed data:

S4. calculating voltage data u _imean value

then calculate modulated wave data u' _i, $u_i^{\&prime;}=\left|u_i\right|-\stackrel{\&OverBar;}{u},1$ $\&le;i\&le;N;$

S5. calculate by modulated wave data and formed each zero crossing time value zero[k of living in sine modulation ripple], k=(i-1)+N * (j-1);

S6. calculating voltage weighted data $U_j=\frac{1}{\stackrel{\&OverBar;}{u}}\&times;\sqrt{\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\left(\right|u_i|-\stackrel{\&OverBar;}{u})}^2}{N}};$

S7. judge whether j equals the 3rd predetermined value M, makes if not j=j+1 and goes to second step, if go to the 4th step;

Pass between described the first predetermined value N and the 3rd predetermined value M is:

described the second predetermined value T is the electric power wave semiperiod; Described the 3rd predetermined value M>=1000;

The 4th step, controller are by the algorithm process data of tabling look-up:

S8. calculate the vibration frequency f of modulated wave _Ω,

f _wfor electric power wave angular frequency;

S9. according to IEC standard, provide the instantaneous flicker S=1 of unit time voltage fluctuation table, search f _Ωfrequency separation of living in, makes f ₁<f _Ω<f ₂; Calculate visual sense degree COEFFICIENT K fx, Kfx=[(f _Ω-f ₁) * d ₂+ (f ₂-f _Ω) * d ₁]/(f ₂-f ₁); Go to the 5th step;

The 5th step, controller are pressed frequency compensation algorithm process data:

S10. calculate relative voltage changing value ${(\mathrm{\&Delta;u}/\stackrel{\&OverBar;}{u})}_j=2\sqrt{2}\&times;U_j\&times;\mathrm{Kfx},1\&le;j\&le;M;$

The 6th step, controller calculate short time voltage flickering value:

S11. calculate instantaneous flicker visual sense degree $S_j={({(\mathrm{\&Delta;u}/\stackrel{\&OverBar;}{u})}_j/0.25\%)}^2,1\&le;j\&le;M;$

S12. from M instantaneous flicker visual sense degree S _jin count the large value of 99.9%, 99%, 97%, 90%, 50% probability, respectively as P _0.1, P ₁, P ₃, P ₁₀, P ₅₀, then calculate short time voltage flickering value P _st[n], $P_{\mathrm{st}}=\sqrt{{0.0314P}_{0.1}+{0.0525P}_1+{03.0657P}_3+{0.28P}_{10}+{0.08P}_{50}};$

S13. judge whether n equals the 4th predetermined value Z, makes if not n=n+1 and goes to second step, if go to the 7th step; When described the 4th predetermined value Z and length, the pass of voltage flicker X observing time is: Z=X/10 minute;

Voltage flicker value P when the 7th step, controller calculate length _lt,

measure and finish.

2. according to claim 1 for measuring the method for IEC normal voltage flickering, it is characterized in that the first predetermined value N=60, the second predetermined value T=10 millisecond, the 3rd predetermined value M=1000, the 4th predetermined value Z=12.