KR101327748B1 - Power signal generation method for assessment of power quality classification - Google Patents

Abstract

The disclosed technology relates to a power signal generating method. The virtual power signal generating method randomly generating a power signal which may be generated in a distribution system comprises a step of inputting an irregular first power signal; a step of classifying the inputted first power signal to a type including at least one among an instantaneous voltage drop state, a harmonic state, a normal voltage state, or a transient state according to methods of evaluating power quality; a step of dividing the classified first power signal into one or more segments; a step of generating a successive second power signal using some of the segments; and a step of smoothing the second power signal. Therefore, the power signal generating method is performed to effectively analyze the power quality. [Reference numerals] (110) Inputting a first power signal;(120) Classifying the inputted first power signal to a type;(130) Dividing the classified first power signal into segments;(140) Generating a second power signal;(150) Smoothing;(AA) Start;(BB) End

Description

       Power signal generation method for evaluation of power quality classification method {Power Signal Generation Method for Assessment of Power Quality Classification}

The disclosed technique relates to a method of arbitrarily generating a power signal that can occur in a distribution system, and in more detail, without limitation, power quality of steady state, transient, harmonics distortion, and instantaneous voltage drop. The present invention relates to a method for generating a continuous power signal by applying a statistical probability model for quantitative evaluation of a classification method.

With the development of power technology, the method of classifying the power quality disturbance signal generated by nonlinear load has emerged as an important problem. However, it is difficult to observe anomalous voltage and current waveforms with a single period to obtain power signal data used for evaluating various power quality disturbance signal classification methods. Since it is not efficient to spend long time observing overcurrent waveforms, various simulation devices and power signal generation methods have been developed. However, these conventional methods generate a rule-based standardized power signal, and there is a problem that the discrimination power of the non-standardized signal is lowered because it is evaluated by using the same.

Conventional technology for the classification of power quality is Korean Patent Publication No. 10-2007-0046283 (name of the invention: a power quality disturbance generator and a test method using the same).

The disclosed technique provides a method for generating a continuous power signal of a normal voltage and an irregular fault voltage that may occur in a distribution system for quantitative evaluation of various power quality classification methods.

In order to achieve the above technical problem, a first aspect of the disclosed technology is a virtual power signal generation method for arbitrarily generating a power signal that may occur in a distribution system, the method comprising: inputting an irregular first power signal and inputting a first power signal Classifying the classified into a type including at least one of an instantaneous voltage drop, a harmonics distortion, a normal voltage, or a transient state according to a power quality evaluation method, and classifying the classified first power signal. Providing a power signal generation method comprising dividing into at least one segments, generating a continuous second power signal using some of the at least one segments, and smoothing the second power signal; It is.

Embodiments of the disclosed technique may have effects that include the following advantages. It should be understood, however, that the scope of the disclosed technology is not to be construed as limited thereby, since the embodiments of the disclosed technology are not meant to include all such embodiments.

According to an embodiment of the disclosed technology, the performance of the power quality classification method may be evaluated using the power signal generated by the power signal generation method for the evaluation of the power quality classification method. Therefore, it is possible to reduce the time and cost required to detect an abnormal voltage of the power signal which may occur at any time, thereby providing an effect of efficiently analyzing the power signal.

1 is a flowchart of a method of generating a power signal according to an embodiment of the disclosed technology.
2 is a diagram illustrating the probability of all cases in which a power signal in the power signal generation flow may be generated.
3 is a diagram for a power signal generation method applying a statistical probability model used in an embodiment of the disclosed technology.
4 illustrates an example of a portion of a voltage file and a tag file of a power signal generated in one embodiment of the disclosed technology.
5 is a diagram illustrating a power signal in which a smoothing operation is completed according to one embodiment of the disclosed technology.

The description of the disclosed technique is merely an example for structural or functional explanation and the scope of the disclosed technology should not be construed as being limited by the embodiments described in the text. That is, the embodiments are to be construed as being variously embodied and having various forms, so that the scope of the disclosed technology should be understood to include equivalents capable of realizing technical ideas.

Meanwhile, the meaning of the terms described in the present application should be understood as follows.

The terms "first "," second ", and the like are used to distinguish one element from another and should not be limited by these terms. For example, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "connected" to another element, it may be directly connected to the other element, but there may be other elements in between. On the other hand, when an element is referred to as being "directly connected" to another element, it should be understood that there are no other elements in between. On the other hand, other expressions describing the relationship between the components, such as "between" and "immediately between" or "neighboring to" and "directly neighboring to", should be interpreted as well.

Singular expressions should be understood to include plural expressions unless the context clearly indicates otherwise, and terms such as "include" or "have" refer to features, numbers, steps, operations, components, parts, or parts thereof described. It is to be understood that the combination is intended to be present, but not to exclude in advance the possibility of the presence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof.

Each step may occur differently from the stated order unless the context clearly dictates the specific order. That is, each step may occur in the same order as described, may be performed substantially concurrently, or may be performed in reverse order.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed technology belongs, unless otherwise defined. Terms such as those defined in the commonly used dictionaries should be construed to be consistent with the meanings in the context of the related art and should not be construed as having ideal or overly formal meanings unless expressly defined in this application. .

1 is a flowchart of a method of generating a power signal according to an embodiment of the disclosed technology. Referring to FIG. 1, a method of generating a power signal includes inputting a first power signal 110, classifying a type of a first power signal 120, classifying a power signal into segments 130, and segmenting a segment. Generating a second power signal by using 140; and smoothing the generated second power signal. In step 110, the first power signal is input. For detailed description according to an embodiment of the disclosed technology, hereinafter, the normal voltage and the irregular accident voltage that deviate from the normal voltage range that may occur in the distribution system will be referred to as a first power signal.

As mentioned above, the first power signal in step 110 includes normal and fault voltages that may occur in the distribution system. Irregular fault voltage means that the waveform of the power signal, the voltage cycle is irregular or the waveform is distorted. For example, the first power signal may be an irregular voltage generated due to an abnormal power supply or an irregular change in the power signal due to an obstacle occurring in the distribution system. As another example, the first power signal may be one in which the voltage has lost periodicity due to a lightning strike.

On the other hand, it is impossible to predict when such a first power signal occurs due to the general characteristics of power signals used in the distribution system. That is, since it is not known from which point of time the first power signal occurs, it is necessary to minimize the time and cost required to measure the input of the irregular power signal. In the prior art, a test was performed using a simulation apparatus to determine whether an abnormality of such a power signal occurred, but it was somewhat limited due to the high cost and time required.

In addition, since the power signal used in the simulation apparatus of the prior art is a power signal formulated by a specific rule, there is also a problem of discrimination power. On the other hand, in an embodiment of the disclosed technology, a power signal generated by an Electro-Magnetic Transients Program (EMTP) simulator is separated into a normal signal and an abnormal signal by a power quality evaluation method, and the separated signal is divided into a method for solving these problems. Classified segments are generated by applying statistical probability models based on random values. Therefore, the quality of the discriminating power signal is determined by inputting the power signal that can actually be generated in the distribution system, rather than using the standardized power signal, and using the power signal including an abnormal voltage or an abnormal period to generate a continuous power signal. Create The generation of the continuous power signal is described below.

In step 120, the type of the first power signal received in step 110 is classified. The type of power signal includes at least one of an instantaneous voltage drop (Sag), harmonics (Harmonics Distortion), normal voltage (transient) or transient (transient).

The voltage drop is a type that occurs when a device generating a large load such as an electric accident or an electric motor in an adjacent area is operated, and the frequency sag occurs frequently to account for about 70% of the total disturbance signal.

Harmonics (Harmonics Distortion) are a lot of non-linear loads, especially due to the increase in the load of the motor or switching power supply, such as a computer. In addition, harmonics have frequencies increased by a certain amount of sinusoidal frequencies, thereby reducing the efficiency of the power supply and generating harmful signals such as electromagnetic waves.

A transient signal is a type that occurs when types of sag, harmonics distortion, or normal are converted to each other based on a specific point in time. Detailed description of the transient signal will be described later with reference to FIG. 3.

On the other hand, the power signal type is divided into four voltages: the normal voltage, the transient, the harmonics, and the instantaneous voltage drop.

In operation 130, the first power signal classified by the type is classified into segments. A segment is a segmentation of four voltages separated from the first power signal according to a set reference value. For example, the segment is a segmentation of the first power signal according to a reference value, and the reference value refers to a segmentation range. In other words, the smaller the range of subdivision, the more subdivision is achieved.

In an embodiment of the disclosed technique for classifying segments, Equation 1 below is used.

는 유형을 분류한 제 1 전력신호의 이전 신호이고,

는 유형을 분류한 제 1 전력신호의 현재 신호이다. 그리고

는 미리 설정한 임계값이다. The power signal coming into the input to separate types consists of 1 cycle of data from 1 to 255. From here

Is the previous signal of the first power signal classified the type,

Is the current signal of the first power signal classified by type. And

Is a preset threshold.

For a detailed description of an embodiment of the disclosed technology, the previous signal is called a first section of the first power signal and the current signal is called a second section of the first power signal in the order entered first. Next, the input of the previous signal and the input of the current signal will be described.

의 값과 현재 신호의 입력

의 차이의 절대 값을 모두 더한 값이 수학식 1의 계산에 따라 임계값

보다 크면 현재 입력된 제 1 전력신호의 제 2 구간과 이전에 입력된 제 1전력신호의 제 1 구간이 서로 유형이 다른 것으로 판단하고, 임계값

보다 작으면 현재 입력된 제 1전력신호의 제 2 구간과 이전에 입력된 제 1 전력신호의 제 1 구간이 같은 유형이라고 판단한다. 예컨대, 임계값

는 750일 수 있다.According to this equation, if the input of the previous signal

The value of and the input of the current signal

The sum of all the absolute values of the difference of

If it is greater than the second section of the currently input first power signal and the first section of the previously input first power signal is determined that the type is different from each other, the threshold value

If smaller, it is determined that the second section of the currently input first power signal and the first section of the previously input first power signal are the same type. For example, threshold

May be 750.

In step 140, a second power signal is generated using the segments classified in step 130. The second power signal is a signal in which waveforms, voltages or periods are continuous. In operation 140, a plurality of segments classified from the first power signal are connected to generate a second power signal using a random value of the statistical probability model. In connecting the segments, step 140 connects the segments according to a random cycle. For example, since cycles that can be continued vary according to a random function, the second power signal may be generated by connecting segments by various cycles.

On the other hand, the second power signal generated in step 140 has a continuity, but as described above was generated by connecting a portion of the segment according to a predetermined cycle, there is a possibility that there is a minute crack or unnatural connection in the connected portion There is this. Therefore, in order to solve this problem, the second power signal is smoothed in step 150.

포인트만큼 연결부위의 앞과 뒤 부분을 이동시키며 이동 평균을 구한다. 예컨대,

포인트는 5포인트이고, 현재 포인트와 현재 포인트의 앞과 뒤 부분을 포함한 5포인트의 이동 평균을 구하여 저장하고, 한 포인트씩 이동하면서 부자연스러운 연결부위를 평활화하는 것이다.In operation 150, the generated second power signal is smoothed. Smoothing is based on the connection part of the second power signal.

The moving average is obtained by moving the front and rear parts of the joint by points. for example,

The point is 5 points, and the moving average of 5 points including the current point and the front and rear part of the current point is obtained and stored, and the unnatural connection is smoothed while moving by one point.

 2 is a diagram showing all the probability that a power signal can be generated in a power signal generation flow. As described above, the power signal includes one or more of an instantaneous voltage drop, a harmonics distortion, a normal voltage, or a transient state. However, if it does not go through the transient signal, the probability is almost zero. That is, unlike in FIG. 2, one embodiment of the disclosed technology undergoes a transient state in a process of changing a normal signal into an abnormal signal or vice versa. Therefore, the disclosed technology generates a power signal applying a statistical probability model with reference to FIG. 3. Of course, in some cases, the method of generating a signal is not excluded as shown in FIG. 2, and the method may be fully understood by those skilled in the art.

 3 is a diagram illustrating a flow of power signal generation using a statistical probability model used in an embodiment of the disclosed technology. Referring to FIG. 3, the normal voltage may change into an instantaneous voltage drop or a harmonic state, and the instantaneous voltage drop may change into a normal voltage or harmonic state. And the harmonics can be changed to a steady voltage or instantaneous voltage drop state. As described above, in an exemplary embodiment of the disclosed technology, a transient state is necessarily passed. In other words, the steady voltage cannot be immediately converted into an instantaneous voltage drop or a harmonic state. And the instantaneous voltage drop cannot be converted to the normal voltage or harmonic state. In addition, harmonics cannot be converted directly to steady state or instantaneous voltage drop states.

4 is a diagram illustrating a portion of a voltage file and a tag file for a power signal generated in an embodiment of the disclosed technology. Referring to FIG. 4, whenever the type of the power signal is changed, the tag is sequentially stored. The tag to be stored may be stored in a text editor such as text or Korean.

5 is a diagram illustrating a power signal in which a smoothing operation is completed according to one embodiment of the disclosed technology. As described above, in an embodiment of the disclosed technique, segments are connected according to a reference cycle to generate a second power signal. Smoothing is the smoothing by moving the connection part of the second power signal by a reference point generated in the generation process.

Referring to FIG. 5, an embodiment of the disclosed technique smoothes a randomly generated second power signal to remove unnaturalness of a connection portion to generate a continuous second power signal. Accordingly, it is possible to provide an electric power signal for evaluating an electric power quality classification method by generating an electric power signal having an arbitrary continuity based on the determination of an abnormal electric power signal that may occur in an actual distribution system.

The method for generating a power signal through an embodiment of the disclosed technology has been described with reference to the embodiment shown in the drawings for clarity, but this is merely an example, and those skilled in the art may various modifications and equivalents therefrom. It will be appreciated that other embodiments are possible. Therefore, the true technical protection scope of the disclosed technology should be defined by the appended claims.

110: first power signal input 120: power signal type classification
130: segment classification 140: second power signal generation
150: Smoothing

Claims (6)

In the virtual power signal generation method for randomly generating a power signal that can occur in the distribution system,
Inputting an irregular first power signal;
Classifying the input first power signal into a type including at least one of an instantaneous voltage drop, a harmonics distortion, a normal voltage, and a transient state according to a power quality evaluation method;
Dividing the classified first power signal into at least one segment;
Generating a continuous second power signal using some of the at least one segments; And
And smoothing the second power signal. The method of claim 1, wherein the inputting of the first power signal comprises:
Power signal generation method using an Electro-Magnetic Transients Program (EMTP) simulator. According to claim 1, The power quality evaluation method,
Using a statistical probability model, the statistical probability model generating a unique random number. The method of claim 1, wherein the first power signal,
Including the first section and the second section, the step of classifying the type using the following equation to determine the type of the first section and the second section, the first section is the first power And a second signal is a current signal of the first power signal.

(In the above formula

Is the previous signal of the first power signal classified the type,

Is the current signal of the first power signal classified type,

Is a preset threshold value and the input of the previous signal

The value of and the input of the current signal

The absolute value of the difference of the sum of all the above

If greater than, it is determined that the type classification is different, and the current signal is defined as a new type, and the sum of all the absolute values

If smaller, the current signal is determined to be the same as the previous signal, and the current signal is defined as the same type.) The method of claim 1, wherein the generating of the second power signal comprises:
And generating a second power signal by connecting a part of the at least one segment according to a reference cycle, and setting the reference cycle in advance by a user. The method of claim 1, wherein the smoothing comprises:
The front and rear portions of the connected portion of the generated second power signal

Calculate moving average by point,

And a mean value for moving and smoothing the connection portion of the second power signal by a point.

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