CN105137177A - Harmonic voltage responsibility calculation alarm method for single-point monitoring of power distribution network - Google Patents

Abstract

The invention discloses a harmonic voltage responsibility calculation alarm method for single-point monitoring of a power distribution network. The harmonic voltage responsibility calculation alarm method comprises the following steps of 1) acquiring a basic electric energy parameter of a monitoring point; 2) acquiring harmonic data of a monitoring point; 3) screening data; 4) calculating a harmonic voltage responsibility; and 5) determining a threshold voltage and alarming. According to the harmonic voltage responsibility calculation alarm method, the load-side harmonic voltage responsibility is determined through analyzing the harmonic data of the monitoring point, and furthermore an alarm threshold is generated. Quantification for the harmonic pollution of a feed line is facilitated, and a system-side harmonic pollution responsibility is differentiated from a user-side harmonic pollution responsibility, thereby facilitating targeted treatment by professional personnel and ensuring safe and stable operation of the power grid.

Description

A kind of harmonic voltage responsibility for the monitoring of power distribution network single-point calculates alarm method

Technical field

The present invention relates to a kind of harmonic voltage responsibility for the monitoring of power distribution network single-point and calculate alarm method.

Background technology

Rapidly, a large amount of nonlinear load, use widely as fairing, electric arc furnaces, converter plant etc. obtain in electric system, harmonic pollution becomes day by day serious in modern power electronics technology development.In order to effectively administer harmonic problem, improve the quality of power supply, the harmonic wave distribution in Water demand determination electric system, searches out the source of harmonic pollution, and rationally distinguishes the harmonic pollution responsibility of each harmonic source initiation.

At present, the research based on harmonic source identification and the divisions of responsibility can of single-point monitoring ascribes harmonic impedance and the background harmonics of how computing system to, mainly comprises " intervention formula " method and " non-intervention formula " method." intervention formula " method needs to determine harmonic impedance to the topological structure of harmonic electric current in electrical network or change system, but this method can cause bad impact to the operation of system, the restriction be necessary in engineering reality." non-intervention formula " method is then utilize the measurement parameters at points of common connection PCC place to estimate harmonic impedance and background harmonics, and the operation of these class methods on system does not form impact, becomes an important directions of current harmonic source location and divisions of responsibility can research.

In recent years, linear regression method becomes conventional " non-intervention formula " method, for particular problem, constructs corresponding equation of linear regression solve according to equivalent circuit.Common linear regression method has: binary linear regression method, robustness regression method, partial least-squares regression method, compound linear least square method.No matter be which kind of regression algorithm, be all the harmonic data based on monitoring point, in Practical Project, generally can measure the amplitude obtaining harmonic voltage and electric current, but and phase angle information cannot be obtained, how only to utilize amplitude to determine that harmonic contributions is the problem comparing concern in engineering.

Summary of the invention

Technical matters to be solved by this invention, propose a kind of harmonic voltage responsibility for the monitoring of power distribution network single-point exactly and calculate alarm method, the harmonic voltage of monitoring point and the amplitude data of electric current is utilized to carry out the quantification of harmonic voltage responsibility, and provide the threshold values of harmonic voltage responsibility, be convenient to professional and carry out later stage specific aim improvement.

Solve the problems of the technologies described above, the technical solution used in the present invention is:

Harmonic voltage responsibility for the monitoring of power distribution network single-point calculates an alarm method, it is characterized in that comprising the steps:

1) the basic electrical energy parameter in monitoring point is obtained: comprise bus nominal voltage U _n, feeder line client applies to install protocol capacity S _iand bus total volume S;

2) harmonic data of monitoring point is gathered: comprise harmonic voltage and harmonic current data;

3) data screening: to described step 2) harmonic data that gathers screens, and forms the sample data group met the demands;

4) harmonic voltage responsibility calculates: based on described step 3) in sample data group, form the linear equation of harmonic voltage and harmonic current, solve regression parameter by least-squares linear regression method, determine harmonic voltage responsibility;

5) threshold values is determined and alarm: to described step 1) in basic electrical energy parameter calculate, determine the alarm threshold value of harmonic voltage responsibility, by threshold values and step 4) in the value of trying to achieve compare, provide corresponding alarm.

Step 1 of the present invention) in, the idiographic flow obtaining the basic electrical energy parameter in monitoring point is:

According to the actual conditions of monitoring point, determine the bus nominal voltage that feeder line accesses and bus connect the total volume of load, what the user situation based on subordinate load determined its electricity consumption applies to install protocol capacity

Step 2 of the present invention) in, the idiographic flow gathering the harmonic data of monitoring point is:

Gather the harmonic voltage amplitude in a period of time of monitoring point and harmonic current data, the data of same time point are matched between two, form multi-group data pair; Data group form is as follows:

$\begin{array}{c}{I}_h\left(1\right),U_h\left(1\right)\\ I_h\left(2\right),U_h\left(2\right)\\ .\\ .\\ .\\ I_h\left(m\right),U_h\left(m\right)\end{array};$

In formula, U _hrepresent harmonic voltage amplitude, I _hrepresent harmonic current, m represents the data group number collected.

Step 3 of the present invention) in, the idiographic flow of data screening is:

Based on step 2) the middle data group gathered, following formula process is pressed to it:

$\mathrm{\μ}=\frac{1}{m}\underset{k=1}{\overset{m}{\Σ}}{I}_h\left(k\right)$

${\mathrm{\σ}}^2=\frac{1}{m-1}\underset{k=1}{\overset{m}{\Σ}}{\left|I_h-\mathrm{\μ}\right|}^2;$

In formula, μ is the average of harmonic current, α ²it is the variance of harmonic current;

For the kth group electric current meeting following formula, retaining these group voltage and current data is sample data group;

$\frac{|I_h\left(k\right)-\mathrm{\μ}|}{\mathrm{\σ}}\≤\mathrm{\α};$

In formula, α is sample coefficient.

Step 4 of the present invention) in, the idiographic flow that harmonic voltage responsibility calculates is:

4-1) based on described step 3) in the n group sample data that filters out, substitute into following formula:

U _h＝A·I _h+B；

4-2) solve A and B by following formula:

$S(A,B)=\underset{k=1}{\overset{n}{\Σ}}{(U_h\left(k\right)-(A\·I_h(k)-B))}^2$

$\frac{\∂S(A,B)}{\∂A}=0$

$\frac{\∂S(A,B)}{\∂B}=0;$

4-3) feeder line harmonic voltage responsibility computing formula is as follows:

$T=\frac{A\·I_h}{U_h}.$

Step 5 of the present invention) in, threshold values is determined and the idiographic flow of alarm is:

5-1) based on described step 1) in electrical energy parameter calculate, determine the alarm threshold value of harmonic voltage responsibility:

$T_1={\left(\frac{S_i}{S}\right)}^{\frac{1}{a}}$

T ₂＝kT ₁；

In formula, a is Phase Stacking coefficient, according to the form below value; K is threshold coefficient, following value:

When h value is respectively 3,5,7,11,13 and 9 ∣ > 13 ∣ even,

The value of a is respectively corresponding one by one: 1.2,1.2,1.4,1.8,1.9 and 2;

h	3	5	7	11	13	9 ∣ > 13 ∣ evens
							a	1.1	1.2	1.4	1.8	1.9	2

h	3	5	7	11	13	15	17	19	21	23	25
												k	2.8	1.7	1.6	2.8	1.64	1.64	2.7	1.47	1.63	2.76	1.62

5-2) by threshold values and step 4) in the value of trying to achieve compare, provide corresponding alarm;

Beneficial effect: compared with prior art, the present invention has following beneficial effect:

The present invention is conducive to the application of Practical Project, according to harmonic voltage responsibility computing method proposed by the invention, the harmonic voltage responsibility of feeder line can be determined rapidly and accurately, can judge whether the harmonic voltage responsibility of feeder line exceeds standard, and the feeder line different for harmonic excess degree takes appropriate measures by threshold values.

Accompanying drawing explanation

Fig. 1 is process flow diagram of the present invention;

Fig. 2 is electric energy quality monitoring point position in example.

Embodiment

Below in conjunction with Fig. 1, with an example, technical scheme of the present invention is described further.

Step 1): obtain the basic electrical energy parameter in monitoring point, comprise bus nominal voltage U _n, feeder line client applies to install protocol capacity S _iand the total volume S of bus.

U _N＝10kV

S＝50MVA

S _i＝18600kVA；

Step 2): the harmonic data gathering monitoring point, gather harmonic voltage and the harmonic current data of electric energy quality monitoring point, position, monitoring point is as Fig. 2.

Following table is 5 subharmonic voltages and harmonic current data that collect in certain time period.

Data sequence number	Harmonic voltage	Harmonic current
			1	41.0996	5.0636
2	41.1873	5.4449
			3	40.817	5.2229
4	40.541	5.1666
			5	41.9485	5.3967
6	41.5	5.5684
			7	42.4536	5.4113
8	40.3106	4.9746
			9	39.095	4.5486
10	38.729	4.4472
			11	40.748	4.8374
12	42.1382	5.6638
			13	45.868	6.703
14	47.1952	7.6843
			15	50.0034	8.4617
16	50.286	9.0226

17	52.3084	9.4238
			18	52.1215	9.7168
19	53.5807	9.8206
			20	52.3349	9.5375

；

Step 3): data screening, to described step 2) harmonic data that gathers screens, and forms the sample data group met the demands.

$\mathrm{\μ}=\frac{1}{m}\underset{k=1}{\overset{m}{\Σ}}{I}_h\left(k\right)=6.6058$

${\mathrm{\σ}}^2=\frac{1}{m-1}\underset{k=1}{\overset{m}{\Σ}}{\left|I_h-\mathrm{\μ}\right|}^2=3.9078$

Sample this factor alpha=0.8, the sample data group filtered out is as following table.

Data sequence number	Harmonic voltage	Harmonic current
			13	45.868	6.703
12	42.1382	5.6638
			6	41.5	5.5684
14	47.1952	7.6843
			2	41.1873	5.4449
7	42.4536	5.4113
			5	41.9485	5.3967
3	40.817	5.2229
			4	40.541	5.1666
1	41.0996	5.0636

Step 4): harmonic voltage responsibility calculates, based on described step 3) in sample data group, form the linear equation of harmonic voltage and harmonic current, solve regression parameter by least-squares linear regression method, determine harmonic voltage responsibility.

Solving result is as follows:

A＝2.6358

B＝27.3649；

Corresponding harmonic voltage responsibility is as following table:

Data sequence number	Harmonic voltage	Harmonic current	Harmonic voltage responsibility
				1	41.0996	5.0636	0.3247
2	41.1873	5.4449	0.3484
				3	40.817	5.2229	0.3372
4	40.541	5.1666	0.3359
				5	41.9485	5.3967	0.3391
6	41.5	5.5684	0.3536
				7	42.4536	5.4113	0.3359
8	40.3106	4.9746	0.3253
				9	39.095	4.5486	0.3066
10	38.729	4.4472	0.3026
				11	40.748	4.8374	0.3129
12	42.1382	5.6638	0.3543
				13	45.868	6.703	0.3852

14	47.1952	7.6843	0.4291
				15	50.0034	8.4617	0.4460
16	50.286	9.0226	0.4729
				17	52.3084	9.4238	0.4748
18	52.1215	9.7168	0.4913
				19	53.5807	9.8206	0.4831
20	52.3349	9.5375	0.4803

Step 5): threshold values is determined and alarm, to described step 1) in electrical energy parameter calculate, determine the alarm threshold value of harmonic voltage responsibility, by threshold values and step 4) in the value of trying to achieve compare, provide corresponding alarm.

$T_1={\left(\frac{S_i}{S}\right)}^{\frac{1}{a}}={\left(\frac{18.6}{50}\right)}^{\frac{1}{1.2}}=0.44$

T ₂＝kT ₁＝1.7×0.44＝0.75

By comparing threshold values, can show that 1 ~ 14 number is in normal range, 15 ~ 20 numbers make Level 1Alarming.

Claims (6)

1. the harmonic voltage responsibility for the monitoring of power distribution network single-point calculates an alarm method, it is characterized in that comprising the following steps:

1) the basic electrical energy parameter in monitoring point is obtained: comprise bus nominal voltage U _n, feeder line client applies to install protocol capacity S _iand the total volume S of bus;

2) harmonic data of monitoring point is gathered: comprise harmonic voltage and harmonic current data;

3) data screening: to described step 2) harmonic data that gathers screens, and forms the sample data group met the demands;

4) harmonic voltage responsibility calculates: based on described step 3) in sample data group, form the linear equation of harmonic voltage and harmonic current, solve regression parameter by least-squares linear regression method, determine harmonic voltage responsibility;

5) threshold values is determined and alarm: to described step 1) in electrical energy parameter calculate, determine the alarm threshold value of harmonic voltage responsibility, by threshold values and step 4) in the value of trying to achieve compare, provide corresponding alarm.

2. the harmonic voltage responsibility for the monitoring of power distribution network single-point according to claim 1 calculates alarm method, it is characterized in that, described step 1) in, the idiographic flow obtaining the basic electrical energy parameter in monitoring point is:

According to the actual conditions of described monitoring point, determine the bus nominal voltage that feeder line accesses and bus connect the total volume of load, what the user situation based on subordinate load determined its electricity consumption applies to install protocol capacity.

3. the harmonic voltage responsibility for the monitoring of power distribution network single-point according to claim 1 calculates alarm method, it is characterized in that, described step 2) in, the idiographic flow gathering the harmonic data of monitoring point is:

Gather the harmonic voltage amplitude in a period of time of monitoring point and harmonic current data, the data of same time point matched between two, form multi-group data pair, data group form is as follows:

$\begin{array}{c}{I}_h\left(1\right),U_h\left(1\right)\\ I_h\left(2\right),U_h\left(2\right)\\ .\\ .\\ .\\ I_h\left(m\right),U_h\left(m\right)\end{array};$

In formula, U _hrepresent harmonic voltage amplitude, I _hrepresent harmonic current, m represents the data group number collected.

4. the harmonic voltage responsibility for the monitoring of power distribution network single-point according to claim 1 calculates alarm method, it is characterized in that, described step 3) in, the idiographic flow of data screening is:

Based on step 2) the middle data group gathered, following formula process is pressed to it:

$\mathrm{\μ}=\frac{1}{m}\underset{k=1}{\overset{m}{\Σ}}{I}_h\left(k\right)$

${\mathrm{\σ}}^2=\frac{1}{m-1}\underset{k=1}{\overset{m}{\Σ}}{\left|I_h-\mathrm{\μ}\right|}^2;$

In formula, μ is the average of harmonic current, α ²it is the variance of harmonic current;

For the kth group electric current meeting following formula, retaining these group voltage and current data is sample data group;

$\frac{|I_h\left(k\right)-\mathrm{\μ}|}{\mathrm{\σ}}\≤\mathrm{\α};$

In formula, α is Nai Er coefficient.

5. the harmonic voltage responsibility for the monitoring of power distribution network single-point according to claim 1 calculates alarm method, it is characterized in that, described step 4) in, the idiographic flow that harmonic voltage responsibility calculates is:

4-1) based on described step 3) in the n group sample data that filters out, substitute into following formula:

U _h＝A·I _h+B

4-2) solve A and B by following formula:

$S(A,B)=\underset{k=1}{\overset{n}{\Σ}}{(U_h\left(k\right)-(A\·I_h(k)-B))}^2$

$\frac{\∂S(A,B)}{\∂A}=0$

$\frac{\∂S(A,B)}{\∂B}=0;$

4-3) feeder line harmonic voltage responsibility computing formula is as follows:

$T=\frac{A\·I_h}{U_h}.$

6. the harmonic voltage responsibility for the monitoring of power distribution network single-point according to claim 1 calculates alarm method, it is characterized in that, described step 5) in, threshold values is determined and the idiographic flow of alarm is:

5-1) based on described step 1) in electrical energy parameter calculate, determine the alarm threshold value of harmonic voltage responsibility:

$T_1={\left(\frac{S_i}{S}\right)}^{\frac{1}{a}}$

T ₂＝kT ₁；

In formula, a is Phase Stacking coefficient, according to the form below value; K is threshold coefficient, according to the form below value:

h 3 5 7 11 13 9 ∣ > 13 ∣ evens a 1.1 1.2 1.4 1.8 1.9 2

h 3 5 7 11 13 15 17 19 21 23 25 k 2.8 1.7 1.6 2.8 1.64 1.64 2.7 1.47 1.63 2.76 1.62

5-2) by threshold values and step 4) in the value of trying to achieve compare, provide corresponding alarm;