CN101576580A - Non-invasive unitized current on-line measurement method of electric equipment - Google Patents

Abstract

The invention discloses a non-invasive unitized current on-line measurement method of electric equipment, which is used for conducting the decomposition and monitoring of load and power consumption, electricity consumption analysis, load and energy conservation, load prediction and load modeling for an electric system; the method comprises the following steps: information on voltage and current is monitored at the entrance of electrical load and whether the electric equipment is input, if not, monitoring continues; if so, the next step is conducted; steady voltage and current data of the electrical load before and after the input of the electric equipment are recorded; harmonic analysis is conducted to data recorded at the previous step to obtain a current expression; difference value of the steady current of the electrical load before and after the input of the electric equipment is calculated; and the difference value of the current calculated in the previous step is unitized to obtain parameters of unitized current of the electric equipment. Without influence on the regular production and life of power consumers, the method can obtain the parameters of the unitized current of the main internal electric equipment and is more beneficial to the implementation of non-invasive electrical load decomposition.

Description

Non-invasive unitized current on-line measurement method of electric equipment

Technical field

The present invention relates to the online method for measurement of a kind of consumer cell current.Particularly relate to a kind of non-invasive unitized current on-line measurement method of electric equipment that can under the situation that does not influence power consumer ordinary production, life, obtain its inner main consumer cell current parameter.

Background technology

The electric load decomposition data all has crucial meaning to whole society's (comprising Utilities Electric Co. and power consumer) is energy-conservation with Power System Planning and operation.

Consumer cell current parameter is the data basis that the non-intrusion type electric load decomposes, the method for obtaining main at present employing off-line statistics of parameter.The power consumer that the off-line statistical method mainly is suitable for laboratory study or has better independent measurement condition.Laboratory study is exactly to buy some consumers targetedly, and it is carried out a large amount of measurements and statistics; But because consumer is of a great variety, the consumer of all kinds can't be bought in the laboratory, if user's measuring condition allows also can carry out a large amount of measurements and statistics to consumer in user inside.

The off-line statistical method is undoubtedly a kind of ten minutes science, accurately obtains the method for consumer cell current parameter, but because the restriction of the complicated various and condition of measurement of electric load can't realize that each class consumer is all carried out a large amount of separately sampling statistics obtains its cell current.

Summary of the invention

Technical matters to be solved by this invention is that a kind of non-invasive unitized current on-line measurement method of electric equipment that can obtain its inner main consumer cell current approximation parameters under the situation that does not influence power consumer ordinary production, life is provided.

The technical solution adopted in the present invention is: a kind of non-invasive unitized current on-line measurement method of electric equipment, be used for that decomposition of power system load energy consumption and monitoring, electrical energy consumption analysis, load are energy-conservation, load prediction and load modeling, and comprise the steps:

The first step: at electric load porch monitoring voltage, current information, and judged whether the consumer input, if not then continue monitoring, if having then change next step over to;

Second step: steady state voltage, current data that the record consumer drops into forward and backward electric load;

The 3rd step: the previous step recorded data is carried out frequency analysis obtain current expression;

The 4th step: calculate the difference that consumer drops into front and back electric load steady-state current;

The 5th step: the difference of the electric current that previous step is calculated is carried out blocking, obtains the cell current parameter of consumer.

The 3rd step, resulting current expression was:

$i_a^{\′}\left(t\right)=\underset{\∀k\∈N^{*}}{\mathrm{\Σ}}{\mathrm{\α}}_{k,a}\·\cos (\mathrm{k\ωt}+{\mathrm{\θ}}_{k,a})$

In the formula, i ' _a(t) be the cell current of a certain consumer, subscript a represents consumer; K ∈ N ^*, promptly k is a positive integer; K ω represents the angular frequency of k order harmonic components in the cell current; θ _{K, a}The initial phase angle of k order harmonic components in the expression cell current; α _{1, a}=1, when k＞1, α _{K, a}Be one less than 1 nonnegative real number.

The difference of electric load steady-state current is before and after the described consumer input of the 4th step:

i _a(t)＝i _l，new(t)-i _l(t)

＝I _l1，new·[1·cos(ωt+θl _1，new)+…+α _lk，new·cos(kωt+θ _lk，new)+…]

-I _l1·[1·cos(ωt+θ _l1)+…+α _lk·cos(kωt+θ _lk)+…]

＝I _a1·[1·cos(ωt+θ _a1)+…+α _ak·cos(kωt+θ _ak)+…]

In the formula, i _{L, new}(t), I _{L1, new}, θ l _{1, new}, α _{Lk, new}And θ _{Lk, new}Represent respectively consumer come into operation the back i _l(t), I _L1, θ _L1, α _LkAnd θ _LkNew value; i _a(t) be the instantaneous value of this consumer steady operation electric current of calculating; I _A1It is the amplitude of consumer steady operation current first harmonics component; θ _A1It is the initial phase angle of consumer steady operation current first harmonics component; α _AkThe scale-up factor of expression consumer steady operation electric current k order harmonic components amplitude and fundametal compoment amplitude; θ _AkThe initial phase angle of k order harmonic components in the expression consumer steady operation electric current.

The 5th step cell current parameter of described consumer is, can obtain the cell current of this consumer according to the steady operation electric current, and is as follows:

i′ _a(t)＝1·cos(ωt+θ _a1)+…+α _ak·cos(kωt+θ _ak)+…

In the formula, i ' _a(t) be the cell current of this consumer; θ _A1It is the initial phase angle of consumer steady operation current first harmonics component; α _AkThe scale-up factor of expression consumer steady operation electric current k order harmonic components amplitude and fundametal compoment amplitude; θ _AkThe initial phase angle of k order harmonic components in the expression consumer steady operation electric current.

Non-invasive unitized current on-line measurement method of electric equipment of the present invention, can obtain the parameter of its inner main consumer cell current under the situation that does not influence power consumer ordinary production, life, it more helps carrying out of non-intrusive electrical load decomposition.

Description of drawings

Fig. 1 is the process flow diagram of non-invasive unitized current on-line measurement method of electric equipment of the present invention;

Fig. 2 is starting of air conditioner overall process load measurement voltage, current waveform figure;

Fig. 3 is starting of air conditioner preload actual measurement steady state voltage, current waveform figure;

Fig. 4 is starting of air conditioner afterload actual measurement steady state voltage, current waveform figure.

Embodiment

Below in conjunction with embodiment and accompanying drawing non-invasive unitized current on-line measurement method of electric equipment of the present invention is made a detailed description.

As shown in Figure 1, non-invasive unitized current on-line measurement method of electric equipment of the present invention, be used for that the decomposition of power system load energy consumption and monitoring, electrical energy consumption analysis, load are energy-conservation, load prediction and load modeling, comprise the steps:

The first step: at electric load porch monitoring voltage, current information, and judged whether the consumer input, if not then continue monitoring, if having then change next step over to;

Second step: steady state voltage, current data that the record consumer drops into forward and backward electric load;

The 3rd step: the previous step recorded data is carried out frequency analysis obtain current expression;

When the present invention carries out the online measurement of non-intrusion type consumer cell current, when supply voltage meets the GB regulation, the cell current of consumer, promptly the perunit value of its current first harmonics amplitude is that 1 o'clock electric current has certain statistical law, can be expressed as following form:

$i_a^{\′}\left(t\right)=\underset{\∀k\∈N^{*}}{\mathrm{\Σ}}{\mathrm{\α}}_{k,a}\·\cos (\mathrm{k\ωt}+{\mathrm{\θ}}_{k,a})---\left(1\right)$

In the formula, i ' _a(t) be the cell current of a certain consumer, subscript a represents consumer; K ∈ N ^*, promptly k is a positive integer; K ω represents the angular frequency of k order harmonic components in the cell current; θ _{K, a}The initial phase angle of k order harmonic components in the expression cell current; α _{1, a}=1, when k＞1, α _{K, a}Be one less than 1 nonnegative real number.

The steady-state current of electric load can be expressed as following form before consumer came into operation:

i _l(t)＝I _l1·[1·cos(ωt+θ _l1)+…+α _lk·cos(kωt+θ _lk)+…](2)

In the formula, i _l(t) instantaneous value of expression electric load steady-state current; Subscript l represents electric load; I _L1The amplitude of expression current capacity steady-state current fundametal compoment; ω is the angular frequency of electric load steady-state current fundametal compoment; θ _L1It is the initial phase angle of electric load steady-state current fundametal compoment; α _LkThe scale-up factor of expression electric load steady-state current k order harmonic components amplitude and fundametal compoment amplitude; θ _LkThe initial phase angle of expression electric load steady-state current k order harmonic components; K ω represents the angular frequency of electric load steady-state current k order harmonic components.

The 4th step: calculate the difference that consumer drops into front and back electric load steady-state current;

After electric load inside had a main consumer to come into operation, its new steady-state current was as follows:

i _l，new(t)＝I _l1，new·[1·cos(ωt+θ _l1，new)+…+α _lk，new·cos(kωt+θ _lk，new)+…](3)

In the formula, i _{L, new}(t), I _{L1, new}, θ _{L1, new}, α _{Lk, new}And θ _{Lk, new}Represent respectively consumer come into operation the back i _l(t), I _L1, θ _L1, α _LkAnd θ _LkNew value.

Load steady-state current before load steady-state current after the steady operation electric current of this consumer can be similar to and come into operation with it deducts it and comes into operation obtains, as the formula (4):

i _a(t)＝i _l，new(t)-i _l(t)

＝I _l1，new·[1·cos(ωt+θ _l1，new)+…+α _lk，new·cos(kωt+θ _lk，new)+…]

-I _l1·[1·cos(ωt+θ _l1)+…+α _lk·cos(kωt+θ _lk)+…](4)

＝I _a1·[1·cos(ωt+θ _a1)+…+α _ak·cos(kωt+θ _ak)+…]

In the formula, i _a(t) be the instantaneous value of this consumer steady operation electric current of calculating; I _A1It is the amplitude of consumer steady operation current first harmonics component; θ _A1It is the initial phase angle of consumer steady operation current first harmonics component; α _AkThe scale-up factor of expression consumer steady operation electric current k order harmonic components amplitude and fundametal compoment amplitude; θ _AkThe initial phase angle of k order harmonic components in the expression consumer steady operation electric current.

The 5th step: the difference of the electric current that previous step is calculated is carried out blocking, obtains the cell current parameter of consumer.

Can obtain the cell current of this consumer according to its steady operation electric current, as follows:

i′ _a(t)＝1·cos(ωt+θ _a1)+…+α _ak·cos(kωt+θ _ak)+…(5)

In the formula, i ' _a(t) be the cell current of this consumer; θ _A1It is the initial phase angle of consumer steady operation current first harmonics component; α _AkThe scale-up factor of expression consumer steady operation electric current k order harmonic components amplitude and fundametal compoment amplitude; θ _AkThe initial phase angle of k order harmonic components in the expression consumer steady operation electric current.

Therefore, when there is main consumer input load inside, and other consumer drops into the cell current that calculates this consumer that forward and backward load steady-state current just can be similar to as long as obtain it when not changing.

Fig. 2 is starting of air conditioner overall process load voltage, the current waveform that actual measurement obtains, and this process can be divided into three parts as shown in FIG.:

(1) starting of air conditioner presteady state;

(2) starting of air conditioner transient state;

(3) stable state behind the starting of air conditioner;

Fig. 3 is voltage, the practical measurement of current waveform of (1) part among Fig. 2.Through frequency analysis, its voltage expression formula is:

The current expression formula is:

Fig. 4 is voltage, the practical measurement of current waveform of (3) part among Fig. 2, and its voltage expression formula is:

The current expression formula is:

Load steady-state current difference before and after the air-conditioning steady-state current can drop into it obtains:

$i_{\mathrm{ac}}\left(t\right)=i_3\left(t\right)-i_1\left(t\right)$

Wherein, i _Ac(t) expression air-conditioning steady-state current.

So, the cell current of air-conditioning is:

i′ _ac(t)＝1.0cos(ωt-3.91°)+0.076cos(3ωt-105.6°)+0.057cos(5ωt-159.31°)

+0.0096cos(7ωt-7.84°)+0.01cos(9ωt-48.44°)+0.0064cos(11ωt-23.35°)

I ' _Ac(t) cell current of expression air-conditioning, promptly its first-harmonic perunit value is 1 electric current.

According to the air-conditioning unit electric current of trying to achieve, the part of (3) among Fig. 2 is carried out load decomposition, the result is as shown in table 1:

Table 1

From decomposition result, this non-intrusion type consumer cell current parameter acquiring method can decompose for the electric load energy consumption preferably provides the data basis, promotes carrying out of load decomposition.

Claims (4)

1. a non-invasive unitized current on-line measurement method of electric equipment is characterized in that, is used for that decomposition of power system load energy consumption and monitoring, electrical energy consumption analysis, load are energy-conservation, load prediction and load modeling, comprises the steps:

The first step: at electric load porch monitoring voltage, current information, and judged whether the consumer input, if not then continue monitoring, if having then change next step over to;

Second step: steady state voltage, current data that the record consumer drops into forward and backward electric load;

The 3rd step: the previous step recorded data is carried out frequency analysis obtain current expression;

The 4th step: calculate the difference that consumer drops into front and back electric load steady-state current;

The 5th step: the difference of the electric current that previous step is calculated is carried out blocking, obtains the cell current parameter of consumer.

2. non-invasive unitized current on-line measurement method of electric equipment according to claim 1 is characterized in that, the 3rd step, resulting current expression was:

$i_a^{\′}\left(t\right)=\underset{\∀k\∈N^{*}}{\mathrm{\Σ}}{\mathrm{\α}}_{k,a}\·\cos (\mathrm{k\ωt}+{\mathrm{\θ}}_{k,a})$

In the formula, i ' _a(t) be the cell current of a certain consumer, subscript a represents consumer; K ∈ N ^*, promptly k is a positive integer; K ω represents the angular frequency of k order harmonic components in the cell current; θ _{K, a}The initial phase angle of k order harmonic components in the expression cell current; α _{1, a}=1, when k＞1, α _{K, a}Be one less than 1 nonnegative real number.

3. non-invasive unitized current on-line measurement method of electric equipment according to claim 1 is characterized in that, the difference of electric load steady-state current is before and after the described consumer input of the 4th step:

i _a(t)＝i _l，new(t)-i _l(t)

＝I _l1，new·[1·cos(ωt+θ _l1，new)+…+α _lk，new·cos(kωt+θ _lk，new)+…]

-I _l1·[1·cos(ωt+θ _l1)+…+α _lk·cos(kωt+θ _lk)+…]

＝I _a1·[1·cos(ωt+θ _a1)+…+α _ak·cos(kωt+θ _ak)+…]

In the formula, i _{L, new}(t), I _{L1, new}, θ _{L1, new}, α _{Lk, new}And θ _{Lk, new}Represent respectively consumer come into operation the back i _l(t), I _L1, θ _L1, α _LkAnd θ _LkNew value; i _a(t) be the instantaneous value of this consumer steady operation electric current of calculating; I _A1It is the amplitude of consumer steady operation current first harmonics component; θ _A1It is the initial phase angle of consumer steady operation current first harmonics component; α _AkThe scale-up factor of expression consumer steady operation electric current k order harmonic components amplitude and fundametal compoment amplitude; θ _AkThe initial phase angle of k order harmonic components in the expression consumer steady operation electric current.

4. non-invasive unitized current on-line measurement method of electric equipment according to claim 1, it is characterized in that, the 5th step cell current parameter of described consumer is, can obtain the cell current of this consumer according to the steady operation electric current, and is as follows:

i′ _a(t)＝1·cos(ωt+θ _a1)+…+α _ak·cos(kωt+θ _ak)+…

In the formula, i ' _a(t) be the cell current of this consumer; θ _A1It is the initial phase angle of consumer steady operation current first harmonics component; α _AkThe scale-up factor of expression consumer steady operation electric current k order harmonic components amplitude and fundametal compoment amplitude; θ _AkThe initial phase angle of k order harmonic components in the expression consumer steady operation electric current.

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