CN103163373A - Calculating method suitable for harmonic pollution responsibilities in power quality data interchange format - Google Patents

Abstract

The invention discloses a calculating method suitable for harmonic pollution responsibilities in a power quality data interchange format in the technical field of power. According to the technical scheme, the method comprises the following steps of: calculating system harmonic impedance according to nominal voltage of a power grid and three-phase shortcircuit capacity of a common coupling point; on this basis, calculating harmonic voltage effective value amplitude contributed by a concerned harmonic source to a bus at the common coupling point, and solving background harmonic voltage effective values contributed by rest harmonic sources except the concerned harmonic source at the common coupling point; further calculating an included angle cosine between the harmonic voltage effective value of the bus and the harmonic voltage effective value contributed by the concerned harmonic source; and finally, calculating the harmonic pollution responsibilities generated by the concerned harmonic source at the bus. The calculating method has the advantages that the harmonic pollution responsibilities of the harmonic source can be monitored every day on the basis of the conventional power quality monitoring system; and the calculating method has great significance for the further solving of the harmonic pollution problems and the improvement of the power quality management level.

Description

Be applicable to the computing method of the harmonic pollution responsibility of power quality data Interchange Format

Technical field

The invention belongs to harmonic pollution responsibility computing method design field, relate in particular to a kind of computing method that are applicable to the harmonic pollution responsibility of power quality data Interchange Format.

Background technology

Pollute China's electric power law regulation for Harmonious Waves in Power Systems: " who pollutes, and who administers ", but electric system at present lacks quantitative divisions of responsibility can to various harmonic pollution sources, and the unclear present situation of responsibility has been brought difficulty to harmonic wave control.The harmonic voltage responsibility is to weigh the common counter of harmonic pollution responsibility, and the method for calculating about the harmonic pollution responsibility both at home and abroad mainly can be divided into two classes: based on equivalent electrical circuit abbreviation method and based on data analytical approach.Equivalent electrical circuit abbreviation method has been set up the relation between quantitative harmonic pollution responsibility and points of common connection place's harmonic voltage and electric current and grid side and user's side reference impedance.The method need to be measured harmonic voltage and the electric current at points of common connection place and utilize rational method to extract harmonic component, when grid side or user's side parameter change, needs to adjust reference impedance, therefore is not convenient for practical application.Be different from equivalent electrical circuit abbreviation method, data analysing method has been avoided the foundation of equivalent model, and when grid side or user's side parameter changed, the method was also effective.Data analysing method mainly contains: neural net method, the method for utilizing data variance characteristic, linear regression method and improvement thereof.These class methods utilize points of common connection place's harmonic voltage and current value to calculate harmonic impedance, and and then calculating harmonic pollution responsibility.Yet, no matter be equivalent electrical circuit abbreviation method or data analysing method, be all to complete on the basis of voltage and current instantaneous value, mainly provide the present situation of the statistical values such as effective value not to be inconsistent with the daily monitoring system of the present quality of power supply.Consider that the daily electric energy quality monitoring data of electrical network often are expressed as the actual conditions of quality of power supply swap data form, be necessary to design the harmonic pollution responsibility computing method at the place of points of common connection under quality of power supply swap data form.

Summary of the invention

The deficiency based on electric current and voltage instantaneous value calculating harmonic pollution responsibility for mentioning in the above-mentioned background technology the present invention proposes a kind of computing method that are applicable to the harmonic pollution responsibility of power quality data Interchange Format.

A kind of computing method that are applicable to the harmonic pollution responsibility of power quality data Interchange Format is characterized in that, specifically comprise the following steps:

Step 1: according to the nominal voltage of electrical network and the three-phase shortcircuit capacity of points of common connection, computing system harmonic impedance;

Step 2: the system harmonic impedance that obtains according to step 1 and power quality data Interchange Format provide access points of common connection place pays close attention to the harmonic current effective value amplitude of harmonic source, calculates and pays close attention to harmonic source to the harmonic voltage effective value amplitude of points of common connection bus contribution;

Step 3: the harmonic voltage effective value amplitude of the harmonic voltage effective value amplitude of the concern harmonic source contribution that obtains according to step 2 and the power quality data Interchange Format provides points of common connection place bus, calculate the points of common connection place except the background harmonics voltage effective value amplitude of paying close attention to all the other harmonic sources of harmonic source and contributing at the bus place;

Step 4: the harmonic voltage effective value amplitude of the background harmonics voltage effective value amplitude that obtains according to step 3 and power quality data Interchange Format provide points of common connection place bus, calculate bus harmonic voltage effective value and pay close attention to included angle cosine between the harmonic voltage effective value of harmonic source contribution;

Step 5: the harmonic voltage effective value amplitude of the harmonic voltage effective value amplitude of the concern harmonic source contribution that obtains according to step 2 and the included angle cosine that step 4 obtains and points of common connection place bus, calculate the harmonic pollution responsibility of paying close attention to harmonic source.

In step 1, the formula of computing system harmonic impedance is:

$Z_{\mathrm{hX}}=\frac{{\mathrm{hU}}_N^2}{S_k}$

Wherein, Z _hXIt is the system of bus X place except user D and other user's equivalent system h subharmonic impedance; U _NThe nominal voltage of expression electrical network, unit: kilovolt; S _kBe the three-phase shortcircuit capacity of points of common connection, unit, megavolt-ampere; H represents overtone order.

In step 2, the concern harmonic source to the computing formula of the harmonic voltage effective value amplitude of points of common connection bus contribution is:

U _hX,D=|Z _hX|I _hD

Wherein, U _{HX, D}Pay close attention to harmonic source D to the h subharmonic voltage effective value amplitude of points of common connection bus X contribution; | Z _h|| expression Z _hXAmplitude; I _hDThe access points of common connection place that provides for the power quality data Interchange Format pays close attention to the h subharmonic current effective value amplitude of harmonic source D.

In step 3, points of common connection place all the other harmonic sources except paying close attention to harmonic source in the computing formula of the background harmonics voltage effective value amplitude of bus place's contribution are:

$U_{\mathrm{hX},0}=\frac{{-K}_h{U}_{\mathrm{hX},D}+\sqrt{K_h^2{U}_{\mathrm{hX},D}^2+4\left(U_{\mathrm{hX},D}^2{U}_{\mathrm{hX},D}^2\right)}}{2}$

Wherein, U _{HX, 0}Expression points of common connection place is except the background harmonics voltage effective value amplitude of paying close attention to all the other harmonic sources of harmonic source and contributing at the bus place; U _{HX, D}Pay close attention to harmonic source D to the h subharmonic voltage effective value amplitude of points of common connection bus X contribution; U _hXIt is the harmonic voltage effective value amplitude of the points of common connection place bus that provides of power quality data Interchange Format; K _hBe experience factor, value is as shown in table 1.

Table 1 experience factor K _hValue

In step 4, the computing formula of the included angle cosine between the harmonic voltage effective value of bus harmonic voltage effective value and the contribution of concern harmonic source is:

$\cos \mathrm{\α}=\frac{U_{\mathrm{hX}}^2{U}_{\mathrm{hX},D}^2-U_{\mathrm{hX},0}^2}{{2U}_{\mathrm{hX}}{U}_{\mathrm{hX},D}}$

Wherein, α is the angle between bus harmonic voltage effective value and the harmonic voltage effective value of paying close attention to the harmonic source contribution; U _hXIt is the harmonic voltage effective value amplitude of the points of common connection place bus that provides of power quality data Interchange Format; U _{HX, D}Pay close attention to harmonic source D to the h subharmonic voltage effective value amplitude of points of common connection bus X contribution; U _{HX, 0}Expression points of common connection place is except the background harmonics voltage effective value amplitude of paying close attention to all the other harmonic sources of harmonic source and contributing at the bus place.

In step 5, the harmonic pollution responsibility computing formula of paying close attention to harmonic source is:

${\mathrm{\μ}}_h=\frac{U_{\mathrm{hX},D}\cos \mathrm{\α}}{U_{\mathrm{hX}}}\×100\%$

Wherein, μ _hPay close attention to harmonic source in the harmonic pollution responsibility at points of common connection place; U _hXIt is the harmonic voltage effective value amplitude of the points of common connection place bus that provides of power quality data Interchange Format; U _{HX, D}Pay close attention to harmonic source D to the h subharmonic voltage effective value amplitude of points of common connection bus X contribution; Cos α is the included angle cosine between bus harmonic voltage effective value and the harmonic voltage effective value of paying close attention to the harmonic source contribution.

The invention has the beneficial effects as follows, the harmonic pollution responsibility computing method that are applicable to the power quality data Interchange Format can realize the daily monitoring of harmonic source harmonic pollution responsibility on the basis of existing electric energy quality monitoring system, this is significant to further solution harmonic pollution problem, raising Power quality management level.

Description of drawings

Fig. 1 is the points of common connection place electric energy quality monitoring schematic diagram of the computing method of a kind of harmonic pollution responsibility that is applicable to the power quality data Interchange Format provided by the invention;

Fig. 2 is the phasor relation schematic diagram of the computing method of a kind of harmonic pollution responsibility that is applicable to the power quality data Interchange Format provided by the invention.

Embodiment

Below in conjunction with accompanying drawing, preferred embodiment is elaborated.Should be emphasized that, following explanation is only exemplary, rather than in order to limit the scope of the invention and to use.

Take certain transformer station's bus as example, the nominal voltage of this bus is 10kV, and the three-phase shortcircuit capacity is 100MVA, bus place electrical connection schematic diagram as shown in Figure 1, take 5 subharmonic as example, suppose that user D is the harmonic-producing load of paying close attention to, calculated load D is in the harmonic pollution responsibility at bus X place.The place arranges the electric energy quality monitor device in the monitoring point, and data layout saves as the power quality data Interchange Format.Bus X harmonic voltage amplitude and branch road harmonic current data between intercepting in 0 moment in the moment to 1 in the evening as shown in table 2.With 0: 0: 0 this group data instance, calculate this period load D in the harmonic pollution responsibility at bus X place, carry out following steps:

The part electric energy quality monitoring data of table 2 intercepting

Step 1: the equivalent system 5 subharmonic impedances of calculating the system of bus X place except user D and other user:

Because h=5, $U_N^2={10}^2$ , S _k=100, so $Z_{5X}=\frac{{\mathrm{hU}}_N^2}{S_k}=\frac{5\×{10}^2}{100}=5\left(\mathrm{\Ω}\right)$

Step 2: calculate the harmonic voltage effective value amplitude that harmonic-producing load D contributes bus X:

U _5X,D=|Z _5X|I _5D=5×12.3374=61.687（V）

Step 3: calculate the background harmonics voltage effective value amplitude that except harmonic-producing load D all the other harmonic sources are contributed at bus X place:

${\mathrm{<figure-callout\; id="0"\; label="U"\; filenames="HDA00002997882700012.png"\; state="\{\{state\}\}">U</figure-callout>}}_{5X,0}=\frac{{-K}_h{U}_{\mathrm{hX},D}+\sqrt{K_h^2{U}_{\mathrm{hX},D}^2+4(U_{\mathrm{hX}}^2-U_{\mathrm{hX},D}^2)}}{2}$

$=\frac{{-K}_5{U}_{5X,D}+\sqrt{K_5^2{U}_{5X,D}^2+4(U_{5X}^2-U_{5X,D}^2)}}{2}$

$=\frac{-1.28\&times;61.687+\sqrt{1.28^2\&times;{61.687}^2+4({197.6744}^2-{61.687}^2)}}{2}$

$=152.4279\left(V\right)$

Step 4: calculate bus harmonic voltage effective value and pay close attention to included angle cosine between the harmonic voltage effective value of harmonic source contribution, angle α as shown in Figure 2:

$\cos \mathrm{\&alpha;}=\frac{U_{5X}^2+U_{5X,D}^2-{\mathrm{<figure-callout\; id="0"\; label="U"\; filenames="HDA00002997882700012.png"\; state="\{\{state\}\}">U</figure-callout>}}_{5X,0}^2}{{2U}_{5X}{U}_{5X,D}}$

$=\frac{{197.6744}^2+{61.687}^2-{152.4279}^2}{2\&times;197.6744\&times;61.687}$

$=0.80557$

Step 5: calculate and pay close attention to harmonic-producing load D in the harmonic pollution responsibility at bus X place.

${\mathrm{\&mu;}}_5=\frac{U_{5X,D}\cos \mathrm{\&alpha;}}{U_{5X}}\&times;100\%=\frac{61.687\&times;0.80557}{197.6744}\&times;100\%=25.139\%$

Therefore, 0 o'clock 0 minute 0 second period load D is 25.139% in the harmonic pollution responsibility at bus X place.Corresponding to the data of table 2, constantly time period internal loading D is as shown in table 3 in all result of calculations of the harmonic pollution responsibility at bus X place in 0 moment to 1 in the evening.

Table 3 is for the harmonic pollution responsibility result of calculation of part Monitoring Data

Can find out that from the stationarity of table 3 result of calculation result of calculation is reasonably, and from computation process, method is easy to use in engineering practice.

The above; only for the better embodiment of the present invention, but protection scope of the present invention is not limited to this, anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement are within all should being encompassed in protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claim.

Claims (6)

1. computing method that are applicable to the harmonic pollution responsibility of power quality data Interchange Format, is characterized in that, specifically comprises the following steps:

Step 1: according to the nominal voltage of electrical network and the three-phase shortcircuit capacity of points of common connection, computing system harmonic impedance;

Step 2: the system harmonic impedance that obtains according to step 1 and power quality data Interchange Format provide access points of common connection place pays close attention to the harmonic current effective value amplitude of harmonic source, calculates and pays close attention to harmonic source to the harmonic voltage effective value amplitude of points of common connection bus contribution;

Step 3: the harmonic voltage effective value amplitude of the harmonic voltage effective value amplitude of the concern harmonic source contribution that obtains according to step 2 and the power quality data Interchange Format provides points of common connection place bus, calculate the points of common connection place except the background harmonics voltage effective value amplitude of paying close attention to all the other harmonic sources of harmonic source and contributing at the bus place;

Step 4: the harmonic voltage effective value amplitude of the background harmonics voltage effective value amplitude that obtains according to step 3 and power quality data Interchange Format provide points of common connection place bus, calculate bus harmonic voltage effective value and pay close attention to included angle cosine between the harmonic voltage effective value of harmonic source contribution;

Step 5: the harmonic voltage effective value amplitude of the harmonic voltage effective value amplitude of the concern harmonic source contribution that obtains according to step 2 and the included angle cosine that step 4 obtains and points of common connection place bus, calculate the harmonic pollution responsibility of paying close attention to harmonic source.

2. computing method according to claim 1, is characterized in that, the formula of described computing system harmonic impedance is:

$Z_{\mathrm{hX}}=\frac{h{U}_N^2}{S_k}$

Wherein, Z _hXIt is the system of bus X place except user D and other user's equivalent system h subharmonic impedance; U _NThe nominal voltage of expression electrical network, unit: kilovolt; S _kBe the three-phase shortcircuit capacity of points of common connection, unit: megavolt-ampere; H represents overtone order.

3. computing method according to claim 1, is characterized in that, described concern harmonic source to the computing formula of the harmonic voltage effective value amplitude of points of common connection bus contribution is:

U _hX,D=|Z _hX|I _hD

Wherein, U _{HX, D}Pay close attention to harmonic source D to the h subharmonic voltage effective value amplitude of points of common connection bus X contribution; | Z _hX| expression Z _hXAmplitude; I _hDThe access points of common connection place that provides for the power quality data Interchange Format pays close attention to the h subharmonic current effective value amplitude of harmonic source D.

4. computing method according to claim 1, is characterized in that, described points of common connection place all the other harmonic sources except paying close attention to harmonic source in the computing formula of the background harmonics voltage effective value amplitude of bus place's contribution are:

$U_{\mathrm{hX},0}=\frac{-K_h{U}_{\mathrm{hX},D}\sqrt{K_h^2{U}_{\mathrm{hX},D}^2+4(U_{\mathrm{hX}}^2-U_{\mathrm{hX},D}^2)}}{2}$

Wherein, U _{HX, 0}Expression points of common connection place is except the background harmonics voltage effective value amplitude of paying close attention to all the other harmonic sources of harmonic source and contributing at the bus place; U _{HX, D}Pay close attention to harmonic source D to the h subharmonic voltage effective value amplitude of points of common connection bus X contribution; U _hXIt is the harmonic voltage effective value amplitude of the points of common connection place bus that provides of power quality data Interchange Format; K _hIt is experience factor.

5. computing method according to claim 1, is characterized in that, the computing formula of the included angle cosine between the harmonic voltage effective value of described bus harmonic voltage effective value and the contribution of concern harmonic source is:

$\cos \mathrm{\&alpha;}=\frac{U_{\mathrm{hX}}^2+U_{\mathrm{hX},D}^2-U_{\mathrm{hX},0}^2}{{2U}_{\mathrm{hX}}{U}_{\mathrm{hX},D}}$

Wherein, α is the angle between bus harmonic voltage effective value and the harmonic voltage effective value of paying close attention to the harmonic source contribution; U _hXIt is the harmonic voltage effective value amplitude of the points of common connection place bus that provides of power quality data Interchange Format; U _{HX, D}Pay close attention to harmonic source D to the h subharmonic voltage effective value amplitude of points of common connection bus X contribution; U _{HX, 0}Expression points of common connection place is except the background harmonics voltage effective value amplitude of paying close attention to all the other harmonic sources of harmonic source and contributing at the bus place.

6. computing method according to claim 1, is characterized in that, the harmonic pollution responsibility computing formula of described concern harmonic source is:

${\mathrm{\&mu;}}_h=\frac{U_{\mathrm{hX},D}\cos \mathrm{\&alpha;}}{U_{\mathrm{hX}}}\&times;100\%$

Wherein, μ _hPay close attention to harmonic source in the harmonic pollution responsibility at points of common connection place; U _hXIt is the harmonic voltage effective value amplitude of the points of common connection place bus that provides of power quality data Interchange Format; U _{HX, D}Pay close attention to harmonic source D to the h subharmonic voltage effective value amplitude of points of common connection bus X contribution; Cos α is the included angle cosine between bus harmonic voltage effective value and the harmonic voltage effective value of paying close attention to the harmonic source contribution.

Images