CN105044416A

CN105044416A - Method for detecting whether there exists electricity-stealing phenomenon by voltage waveform of electric energy meter

Info

Publication number: CN105044416A
Application number: CN201510411569.1A
Authority: CN
Inventors: 曾亚军; 晏成; 谢春生
Original assignee: Shenzhen Huawo Meter Science & Technology Co Ltd
Current assignee: Shenzhen Huawo Meter Science & Technology Co Ltd
Priority date: 2015-07-15
Filing date: 2015-07-15
Publication date: 2015-11-11
Anticipated expiration: 2035-07-15
Also published as: CN105044416B

Abstract

The invention brings forward a method for detecting whether there exists electricity-stealing phenomenon by voltage waveform of an electric energy meter. The method comprises the following steps: 1, letting a network voltage signal access to an electric energy meter, finding an upward zero crossing point of the voltage signal and recording a satisfied number of sampling values capable of drawing a waveform; 2, accumulating absolute values of the sampling values in the step 1 and multiplying by a coefficient K to obtain instantaneous voltage U; 3, using ratio K1 of the maximum instantaneous value of nominal voltage to the voltage U, multiplying the sampling values in the step 1 by K1 and recording; 4, subtracting two adjacent values obtained in the step 3 to obtain a difference value; 5, calculating a satisfied number of theoretical AD sampling values capable of drawing a waveform of a standard network voltage sinusoidal signal and calculating difference between two adjacent points to obtain a difference value; 6, comparing the two difference values obtained from the step 4 and step 5 so as to obtain waveform distortion rate; and 7, judging whether there exists electricity-stealing phenomenon according to the waveform distortion rate obtained in the step 6. According to the invention, whether there exists electricity-stealing phenomenon can be highly accurately detected at real time.

Description

A kind of electrical energy meter electricity corrugating that utilizes detects stealing whether method

Technical field

The invention belongs to power domain, relate to a kind of electrical energy meter electricity corrugating that utilizes and detect stealing whether method.

Background technology

In reality, always someone utilizes various means stealing, seeks private gain at public expense, and how to judge that stealing place is a troublesome problem, and voltage signal can be made when some stealings occur to produce distortion, cause waveform distortion.Waveform distortion factor can be utilized to judge whether to there is stealing, if with high speed devices such as DSP as processor, although the real-time analysis process of signal is more convenient, but cost is high, in electric energy meter, MCU processor is only optimal selection, but compared with the high speed devices such as DSP, travelling speed is low, should not be used for the real-time analysis process of signal.

Summary of the invention

The present invention, for overcoming above technical matters, proposes to utilize and detects with MCU processor electric energy meter whether there is stealing electricity phenomenon a kind of and utilize electrical energy meter electricity corrugating to detect stealing whether method.

Technical scheme: a kind of electrical energy meter electricity corrugating that utilizes detects stealing whether method, electric energy meter adopts MCU processor, and step one, accesses electric energy meter by mains voltage signal, find the zero crossing upwards of voltage signal, and record meets the sampled value that quantity can draw a waveform; Step 2, is multiplied by COEFFICIENT K after the absolute value of the sampled value of step one is accumulative, draws instantaneous voltage U; Step 3, by the maximum instantaneous value of rated voltage and the ratio K 1 of voltage U, sampled value of then step one being sampled is multiplied by record after K1; Step 4, two of adjacent of value step 3 obtained are subtracted each other, obtain difference; Step 5, calculates standard electrical network voltage sinusoidal signal and meets the theoretical AD sampled value that quantity can draw a waveform, calculate the difference between adjacent two points, obtain difference; Step 6, two groups of differences step 4, step 5 drawn compare, and draw waveform distortion factor; Step 7, judges whether to there is stealing according to the waveform distortion factor of step 6.

Described step one records the sampled value of 82 points; Described step 4 obtains 81 differences; Described step 5 is sampled the theoretical AD sampled value of 82 points, calculates the difference between adjacent two points, obtains 81 differences; Step 6, draws two groups of 81 differences by step 4, step 5.Beneficial effect: make use of the lower-cost electric energy meter containing MCU processor, by showing that waveform distortion factor judges whether to there is stealing, efficient and convenient, can be real-time, high-precision detection.

Accompanying drawing explanation

Fig. 1 is the mains voltage signal oscillogram of standard 50Hz

Fig. 2 is a kind of hardware elementary diagram of equipment of interference voltage waveform;

Fig. 3 is the voltage oscillogram suffering that Fig. 2 equipment disturbs.

Embodiment

In electrical network, voltage signal is generally the sine wave of standard of comparison, if use some illegal means, makes voltage signal produce distortion, then can reach the object of stealing.Therefore solution is as follows:

Suppose that MCU is 4096Hz to the sampling rate of voltage signal sampling, namely when the mains voltage signal access ammeter of the 50Hz of standard, a sine wave can be sampled about 82 points.

Mathematical modeling is as Fig. 1.

The formula of line voltage waveform is as follows:

------------------------formula 1. for=U (max) * sin (w*t)

For real-time voltage, U (max) is crest voltage, and w is angular frequency, w=2* ∏ * f, to formula 1. differentiate:

-------------------formula 2. for '=U (max) * w*cos (w*t)

Formula 2. in ' be formula 1. in corresponding slope, from formula 2. can find, slope and maximum voltage, frequency are relevant, and in actual electric network, U (max) is variable, obtains a U (max) impact on slope and removes, in other words, the variable effect of voltage can not be allowed to the judgement of slope, derive as follows:

Sine formula:

Y=A*sinx------------------------------------formula 3.

3. carry out quadraturing in [0, ∏] to formula:

S=A*--------------------------------formula 4.

The result of integration:

S =-A*cos(∏)-(-A*cos(0))=2A→S＝2A

The physical significance of above-mentioned derivation represents, area in half sine wave is 2 times of its maximum amplitude, and electric energy meter in a sinusoidal cycles to signal sampling 82 points, can be similar to think that the summation of 82 some AD values is multiplied by fixed coefficient K be current voltage maximal value:

U (max)=K*--------------------------------formula 5.

The actual voltage max that calculates and rated voltage maximal value compare, and then the AD value sampled are zoomed in or out in proportion, this addresses the problem under different voltage, the problem that same waveform each point slope is different.

Conveniently calculate, in fact do not need the slope calculating each point, but calculate the AD difference between two sampled points, namely the time interval of giving tacit consent between two sampled points is 1, can reduce the operand of MCU like this.

Treatment scheme is as follows:

<1> calculates the theoretical AD sampled value of standard electrical network voltage sinusoidal signal 82 points.

<2> calculates the difference (be similar to and ask slope) between adjacent two points, and saves, these 81 differences for subsequent calculations

<3> finds the zero crossing upwards of voltage signal, and preserves the sampled value of 82 points.

Be multiplied by COEFFICIENT K (K and actual hardware have relation) after <4> is accumulative by the absolute value of sample 82 points and draw instantaneous voltage U.

<5> calculates the maximum instantaneous value of rated voltage and the ratio K 1 of voltage U, saves after then the original value of sample 82 points being multiplied by K1.

The sampling AD value of 82 points after process is done the identical algorithm of step <2> by <6>.

The difference of two 81 points that step <2> and step <6> calculates by <7> compares one by one, can calculate waveform distortion factor to this.

Be used for after obtaining waveform distortion factor judging whether to there is stealing, the several measurement point of multiselect just can know concrete stealing point position.

It is to be noted that when waveform acquisition, what need in buffer memory to deposit is a complete Wave data, therefore needs to rise when signal upwards zero passage to start to preserve number.

The application example of this method:

There is a kind of equipment of interference voltage waveform, its hardware elementary diagram as shown in Figure 2, the electrical energy meter electricity its output port being received normal work crimps into terminal, will produce the waveform of distortion, thus reach the object affecting electric energy meter and correctly measure during this equipment energising work.Regulate slide rheostat can also change the distortion degree of waveform.Portion waveshape figure as shown in Figure 3, pass through this method, can learn under this distortion state, waveform distortion factor is about 30%, and regulate the voltage of power supply, distortion rate does not have significant change, the distortion rate of 30% exceedes the threshold value preset, generation event is reported power supply management center, or electric energy meter enters the state of punishment metering automatically, reaches the object of electricity theft prevention.

Claims

1. one kind utilizes electrical energy meter electricity corrugating to detect stealing whether method, electric energy meter adopts MCU processor, it is characterized in that: step one, mains voltage signal is accessed electric energy meter, find the zero crossing upwards of voltage signal, and record meets the sampled value that quantity can draw a waveform; Step 2, is multiplied by COEFFICIENT K after the absolute value of the sampled value of step one is accumulative, draws instantaneous voltage U; Step 3, by the maximum instantaneous value of rated voltage and the ratio K 1 of voltage U, sampled value of then step one being sampled is multiplied by record after K1; Step 4, two of adjacent of value step 3 obtained are subtracted each other, obtain difference; Step 5, calculates standard electrical network voltage sinusoidal signal and meets the theoretical AD sampled value that quantity can draw a waveform, calculate the difference between adjacent two points, obtain difference; Step 6, two groups of differences step 4, step 5 drawn compare, and draw waveform distortion factor; Step 7, judges whether to there is stealing according to the waveform distortion factor of step 6.

2. the electrical energy meter electricity corrugating that utilizes according to claim 1 detects stealing whether method, it is characterized in that: described step one records the sampled value of 82 points; Described step 4 obtains 81 differences; Described step 5 is sampled the theoretical AD sampled value of 82 points, calculates the difference between adjacent two points, obtains 81 differences; Step 6, draws two groups of 81 differences by step 4, step 5.