A method and system for quickly generating a current phasor diagram of an electric energy metering device

Abstract

The present invention discloses a method and system for rapidly generating a current phasor diagram for an electric energy metering device. The method comprises: obtaining a set of phase-by-phase active power and reactive power values at any moment through the electric energy metering device; converting the power value set into phasor coordinate points under the current phasor diagram; obtaining an overlay graph of the voltage phasor diagram and a plane rectangular coordinate system; and drawing current phasor lines based on the phasor coordinate points on the overlay graph to obtain the current phasor diagram for the electric energy metering device. The present invention can effectively reduce the technical requirements for metering professionals and realize online drawing of current phasor diagrams, thereby assisting metering personnel in remotely determining miswiring of electric energy metering devices, improving work efficiency, and enhancing the level of intelligent work.

Description

Technical Field

[0001] The present invention relates to a method and system for quickly generating a current phasor diagram of an electric energy metering device, and belongs to the technical field of electric energy metering. Background Art

[0002] A current phasor diagram is a graphical representation of the relationship between voltage and current used by on-site calibrators for metering devices. This allows metering personnel to visually visualize the relationship between voltage and current for each phase, assisting in identifying miswiring of metering devices. In theory, an automated meter reading system can remotely read key data items such as the voltage and current for each phase of an electricity meter, including the power factor angle between voltage and current, and the voltage phase sequence. This system can generate a current phasor diagram, allowing metering personnel to easily identify the wiring configuration of the metering device through the system interface. However, different manufacturers have different definitions for data items such as the voltage phase sequence and the power factor angle between voltage and current. Furthermore, obtaining these data items is not a basic function of automated meter reading systems, and some meters may not support this functionality. Therefore, in practice, most automated meter reading systems cannot directly read angle values, making it difficult to draw phasor diagrams. Summary of the Invention

[0003] In order to solve the problems existing in the prior art, the present invention proposes a method and system for quickly generating a current phasor diagram of an electric energy metering device. Based on the basic function of the automated meter reading system that can read power values, the method and system can remotely draw the current phasor diagram of the electric energy metering device, thereby assisting metering personnel in remotely judging the miswiring of the electric energy metering device.

[0004] In order to solve the above technical problems, the present invention adopts the following technical means:

[0005] In a first aspect, the present invention provides a method for quickly generating a current phasor diagram of an electric energy metering device, comprising the following steps:

[0006] Obtain the phase-by-phase active power and reactive power value groups at any moment through the electric energy metering device;

[0007] Convert the power value group into phasor coordinate points under the current phasor diagram;

[0008] Obtain the voltage phasor diagram and the superimposed graph of the plane rectangular coordinate system;

[0009] The current phasor line is drawn on the superimposed graph according to the phasor coordinate points to obtain the current phasor diagram of the electric energy metering device.

[0010] In combination with the first aspect, further, a method for converting the power value group into a phasor coordinate point under a current phasor diagram includes:

[0011] Determine the voltage wiring phase sequence of the electric energy metering device;

[0012] According to the phase sequence discrimination result, the power value group is converted into the phasor coordinate point under the current phasor diagram using the coordinate transformation algorithm.

[0013] In combination with the first aspect, further, in a three-phase three-wire electric energy metering device, the voltage connection is judged as forward phase sequence or reverse phase sequence according to the phase active power and reactive power value groups; in a three-phase four-wire electric energy metering device, except for the case where it is known that the meter is connected in reverse phase sequence, the voltage connection is judged as forward phase sequence by default.

[0014] In combination with the first aspect, further, the phase sequence discrimination condition of the three-phase three-wire electric energy metering device is:

[0015]

[0016] Among them, (p1, p3) and (pq1, q3) are the active power of phase A and phase C and the reactive power of phase A and phase C of the three-phase three-wire electric energy metering device at the same time.

[0017] In combination with the first aspect, further, the coordinate transformation algorithm of the three-phase three-wire electric energy metering device in the forward phase sequence is expressed as follows:

[0018]

[0019] Among them, p a is the horizontal coordinate of phase A, q a is the vertical coordinate of phase A, p c is the horizontal coordinate of phase C, q c is the vertical coordinate of phase C, (p1, p3) and (q1, q3) are the active power of phase A and phase C and the reactive power of phase A and phase C of the three-phase three-wire electric energy metering device at the same time;

[0020] The coordinate transformation algorithm of the three-phase three-wire electric energy metering device with reverse phase sequence is expressed as follows:

[0021]

[0022] In combination with the first aspect, further, the coordinate transformation algorithm of the three-phase four-wire electric energy metering device in the forward phase sequence is expressed as follows:

[0023]

[0024] Among them, p a is the horizontal coordinate of phase A, q a is the vertical coordinate of phase A, p b is the horizontal coordinate of phase B, q b is the vertical coordinate of phase B, p c is the horizontal coordinate of the C phase, q cis the vertical coordinate of phase C, (p1, p2, p3) and (q1, q2, q3) are the active power of phase A, B, and C and the reactive power of phase A, B, and C of the three-phase four-wire electric energy metering device at the same time;

[0025] The coordinate transformation algorithm of the reverse phase sequence of the three-phase four-wire electric energy metering device is expressed as follows:

[0026]

[0027] In combination with the first aspect, further, a method for obtaining the superimposed graph of the voltage phasor diagram and the plane rectangular coordinate system is:

[0028] An X,Y plane rectangular coordinate system is established. On the basis of the X,Y plane rectangular coordinate system, a phasor diagram of the three-phase voltage is generated in a clockwise direction in a manner of zero point overlap and +Y and Ua overlap, wherein the angle between the three-phase voltages is 120°.

[0029] In combination with the first aspect, further, in the superimposed graph, the coordinate origin of the plane rectangular coordinate system and the phasor coordinate point are connected using a connecting line with an arrow to generate a current phasor line, thereby obtaining a current phasor diagram of the electric energy metering device.

[0030] In a second aspect, the present invention provides a system for rapidly generating a current phasor diagram of an electric energy metering device, comprising:

[0031] The power acquisition module is used to obtain the phase-by-phase active power and reactive power value groups at any time through the electric energy metering device;

[0032] A coordinate conversion module, used to convert the power value group into a phasor coordinate point under the current phasor diagram;

[0033] A superimposed graphics module is used to obtain a superimposed graphics of a voltage phasor diagram and a plane rectangular coordinate system;

[0034] The phasor diagram drawing module is used to draw the current phasor line according to the phasor coordinate points on the superimposed graph to obtain the current phasor diagram of the electric energy metering device.

[0035] In combination with the second aspect, further, the coordinate conversion module includes a phase sequence determination submodule and a coordinate conversion submodule. The phase sequence determination submodule is used to determine whether the voltage connection of the three-phase three-wire electric energy metering device is a forward phase sequence or a reverse phase sequence according to the phase active power and reactive power value groups. The coordinate conversion submodule is used to convert the power value group into a phasor coordinate point under the current phasor diagram according to the phase sequence determination result using the corresponding coordinate transformation algorithm.

[0036] The following advantages can be obtained by adopting the above technical means:

[0037] This invention proposes a method and system for rapidly generating current phasor diagrams for electric energy metering devices. Based on the active and reactive power data routinely read by an automated meter reading system, this method converts power data into coordinate points in the current phasor diagram and enables remote drawing of the current phasor diagram on an overlay of a voltage phasor diagram and a plane rectangular coordinate system. This invention effectively reduces the technical requirements for metering professionals and automates the drawing of current phasor diagrams, thereby assisting metering personnel in remotely determining miswiring of electric energy metering devices, improving work efficiency, and enhancing the level of intelligent work. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a flowchart of the steps of a method for quickly generating a current phasor diagram of an electric energy metering device according to the present invention;

[0039] Figure 2 This is an example diagram of the current phasor diagram of the three-phase three-wire electric energy metering device under the forward phase sequence in an embodiment of the present invention;

[0040] Figure 3 This is an example diagram of a current phasor diagram of a three-phase three-wire electric energy metering device under reverse phase sequence according to an embodiment of the present invention;

[0041] Figure 4 This is an example diagram of the current phasor diagram of the three-phase four-wire electric energy metering device in an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The technical solution of the present invention will be further described below with reference to the accompanying drawings:

[0043] The present invention proposes a method for quickly generating a current phasor diagram of an electric energy metering device. Figure 1 As shown, the specific steps include:

[0044] Step A: Obtain the phase-by-phase active power and reactive power value groups at any moment through the electric energy metering device.

[0045] In an automated meter reading system, read the per-phase active power and reactive power values at a specific point in time from current or historical operating data to serve as the basis for the current phasor diagram. When reading data, it is best to select values at times when active power is high, as load conditions are relatively stable at this time. The resulting current phasor diagram will more accurately reflect the wiring conditions of the metering device. Under the three-phase three-wire system, the value groups (p1, p3) and (q1, q3) are obtained, where p1 is the active power of phase A of the three-phase three-wire electric energy metering device, 3 is the active power of phase C of the three-phase three-wire electric energy metering device, q1 is the reactive power of phase A of the three-phase three-wire electric energy metering device, and 3 is the reactive power of phase C of the three-phase three-wire electric energy metering device; under the three-phase four-wire system, the value groups (p1, p2, p3) and (q1, q2, q3) are obtained, where p1 is the active power of phase A of the three-phase four-wire electric energy metering device, p2 is the active power of phase B of the three-phase four-wire electric energy metering device, p3 is the active power of phase C of the three-phase four-wire electric energy metering device, q1 is the reactive power of phase A of the three-phase four-wire electric energy metering device, q2 is the reactive power of phase B of the three-phase four-wire electric energy metering device, and q3 is the reactive power of phase C of the three-phase four-wire electric energy metering device.

[0046] Step B: Convert the power value group obtained in step A into phasor coordinate points under the current phasor diagram. The specific operations are as follows:

[0047] Step B01: Determine the voltage connection phase sequence of the electric energy metering device.

[0048] In an embodiment of the present invention, for a three-phase three-wire electric energy metering device, the voltage connection is determined to be a forward phase sequence or a reverse phase sequence based on the phase-by-phase active power and reactive power value groups; for a three-phase four-wire electric energy metering device, phase sequence determination is not required. Except for the case where it is known that the meter is connected in a reverse phase sequence, the voltage connection is determined to be a forward phase sequence by default.

[0049] In a three-phase three-wire system, when the phase sequence is correctly connected, p1+p3 and q1-q3 are both positive or both negative. When the phase sequence is correctly connected, p1+p3 and q1-q3 are one positive and one negative. Based on this, the voltage connection phase sequence is determined. The expression of the phase sequence determination condition is as follows:

[0050]

[0051] Step B02: Based on the phase sequence identification result, the power value group is converted into phasor coordinate points under the current phasor diagram using a coordinate transformation algorithm. Different electric energy metering devices have different coordinate transformation formulas under different phase sequences.

[0052] In a three-phase three-wire electric energy metering device, if the voltage connection is in forward phase sequence, the coordinate transformation algorithm is expressed as follows:

[0053]

[0054] Among them, p a is the horizontal coordinate of phase A, q a is the vertical coordinate of phase A, p c is the horizontal coordinate of the C phase, q c is the vertical coordinate of phase C.

[0055] In a three-phase three-wire electric energy metering device, if the voltage connection is in reverse phase sequence, the coordinate transformation algorithm is expressed as follows:

[0056]

[0057] In a three-phase four-wire electric energy metering device, the default voltage connection is forward phase sequence, and the coordinate transformation algorithm is expressed as follows:

[0058]

[0059] Among them, p a is the horizontal coordinate of phase A, q a is the vertical coordinate of phase A, p b is the horizontal coordinate of phase B, q b is the vertical coordinate of phase B, p c is the horizontal coordinate of the C phase, q c is the vertical coordinate of phase C.

[0060] When it is known that the meter of the three-phase four-wire electric energy metering device is connected in reverse phase sequence, the coordinate transformation algorithm is expressed as follows:

[0061]

[0062] After the above formula transformation, the three-phase three-wire electric energy metering device can obtain the phasor coordinate point W1(p a ,q a )、W3(p c ,q c ), the three-phase four-wire electric energy metering device can obtain the phasor coordinate point W1(p a ,q a )、W2(p b ,q b )、W3(p c ,q c ).

[0063] Step C: Obtaining the superimposed graph of the voltage phasor diagram and the plane rectangular coordinate system. In the method of the present invention, the method of establishing the superimposed graph of the voltage phasor diagram and the plane rectangular coordinate system is the key to forming the current phasor diagram using coordinate data.

[0064] First, establish an X,Y rectangular coordinate system. Then, based on this X,Y rectangular coordinate system, generate a three-phase voltage phasor diagram in a clockwise direction, with zero points overlapping and +Y and Ua overlapping. The default angle between the three-phase voltages is 120°. For a three-phase, three-wire system, the two-wire voltages (Uab / Ucb) are used to determine the voltage phase sequence based on the results of step B01. For a three-phase, four-wire system, the three-phase voltages (Ua / Ub / Uc) are assumed to be in forward phase sequence by default.

[0065] Step D: Draw the current phasor line on the superimposed graph according to the phasor coordinate points to obtain the current phasor diagram of the electric energy metering device.

[0066] In the superimposed graph, the coordinate origin of the plane rectangular coordinate system is taken as the standard, and the corresponding coordinate point position in the superimposed graph is obtained according to the value of the phasor coordinate point. The coordinate origin of the plane rectangular coordinate system and the phasor coordinate point are connected using a connecting line with an arrow to generate the current phasor line of Ia, Ic or Ia, Ib, Ic, and obtain the current phasor diagram of the electric energy metering device.

[0067] In order to explain the implementation of the present invention in more detail, the following is described with actual data:

[0068] (1) In the embodiment of the present invention, taking a three-phase three-wire electric energy metering device as an example, a group of power points is selected from the automatic meter reading system: (p1, p2) = (51.96kW, 47.4kW), (q1, q2) = (24kvar, -36kvar).

[0069] (2) The phase sequence is determined using step B01. Since p1+p3>0 and q1-q3>0, the voltage connection of the metering device is in a forward phase sequence.

[0070] (3) Use step B02 to calculate the phasor coordinate points, and substitute the values in step (1) into formula (7) to obtain the two phasor coordinate points of the current phasor diagram: W1 (-5.19, 56.99) and W3 (-47.4, -36).

[0071] (4) Based on the phasor coordinate points in step (3), draw the current phasor diagram on the superimposed graph of the voltage phasor diagram and the plane rectangular coordinate system. The result is as follows: Figure 2 shown.

[0072] Similarly, the embodiment of the present invention also provides an example of a current phasor diagram of a three-phase three-wire electric energy metering device under reverse phase sequence and an example of a current phasor diagram of a three-phase four-wire metering device, as shown in FIG. Figure 3 、 4 shown.

[0073] The present invention also proposes a current phasor diagram rapid generation system for an electric energy metering device, which mainly includes a power acquisition module, a coordinate conversion module, a superimposed graphics module and a phasor diagram drawing module.

[0074] The power acquisition module is mainly used to obtain the phase-by-phase active power and reactive power value groups at any time through the electric energy metering device. The power acquisition module can be connected to the automatic meter reading system to directly read the power value from the automatic meter reading system.

[0075] The coordinate conversion module primarily converts the power value group into phasor coordinate points on the current phasor diagram. The coordinate conversion module further includes a phase sequence determination submodule and a coordinate conversion submodule. The phase sequence determination submodule is used to determine whether the voltage connection of the three-phase, three-wire electric energy metering device is in a forward or reverse phase sequence based on the phase-separated active power and reactive power value groups. The coordinate conversion submodule is used to convert the power value group into phasor coordinate points on the current phasor diagram based on the phase sequence determination result using a corresponding coordinate transformation algorithm. The operation of the coordinate conversion module is consistent with step B of the present method.

[0076] The overlay graphics module is mainly used to obtain the overlay graphics of the voltage phasor diagram and the plane rectangular coordinate system, establish the X, Y plane rectangular coordinate system, and create the three-phase voltage phasor diagram in a clockwise direction in a way that the zero point overlaps and +Y and Ua overlap. The default angle between the three-phase voltages is 120°.

[0077] The phasor diagram drawing module is mainly used to draw the current phasor line according to the phasor coordinate points on the superimposed graph to obtain the current phasor diagram of the electric energy metering device. The operation of the phasor diagram drawing module is consistent with step D of the method of the present invention.

[0078] Compared with the existing technology, the method and system of the present invention realize remote drawing of current phasor diagram based on the data source (active and reactive data) conventionally read by the automated meter reading system, which can effectively reduce the technical requirements for metering expertise and automatically realize the drawing of current phasor diagram, thereby assisting metering personnel in remotely judging the miswiring of electric energy metering devices, improving work efficiency, and enhancing the level of intelligent work.

[0079] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for quickly generating a current phasor diagram of an electric energy metering device, characterized in that: The steps include: Obtain the phase-by-phase active power and reactive power value groups at any moment through the electric energy metering device; Convert the power value group into phasor coordinate points under the current phasor diagram; Obtain the voltage phasor diagram and the superimposed graph of the plane rectangular coordinate system; Draw the current phasor line according to the phasor coordinate points on the superimposed graph to obtain the current phasor diagram of the electric energy metering device; The expression of the coordinate transformation algorithm of the three-phase three-wire electric energy metering device in the forward phase sequence is as follows: ； in, is the horizontal coordinate of phase A, is the vertical coordinate of phase A, is the horizontal coordinate of phase C, is the vertical coordinate of phase C, 、 They are respectively the active power of phase A and phase C and the reactive power of phase A and phase C of the three-phase three-wire electric energy metering device at the same time; The coordinate transformation algorithm of the three-phase three-wire electric energy metering device with reverse phase sequence is expressed as follows: ； The expression of the coordinate transformation algorithm of the three-phase four-wire electric energy metering device in the phase sequence is as follows: ； in, is the horizontal coordinate of phase A, is the vertical coordinate of phase A, is the horizontal coordinate of phase B, is the vertical coordinate of phase B, is the horizontal coordinate of phase C, is the vertical coordinate of phase C, 、 They are respectively the active power of phases A, B, and C and the reactive power of phases A, B, and C of the three-phase four-wire electric energy metering device at the same time; The coordinate transformation algorithm of the reverse phase sequence of the three-phase four-wire electric energy metering device is expressed as follows: 。 2. The method for quickly generating a current phasor diagram of an electric energy metering device according to claim 1, characterized in that: Methods for converting a power value group into a phasor coordinate point under a current phasor diagram include: Determine the voltage wiring phase sequence of the electric energy metering device; According to the phase sequence discrimination result, the power value group is converted into the phasor coordinate point under the current phasor diagram using the coordinate transformation algorithm.

3. The method for quickly generating a current phasor diagram of an electric energy metering device according to claim 2, characterized in that: In a three-phase three-wire electric energy metering device, the voltage connection is judged as forward phase sequence or reverse phase sequence based on the phase-by-phase active power and reactive power value groups; in a three-phase four-wire electric energy metering device, the voltage connection is judged as forward phase sequence by default, except when it is known that the meter is connected in reverse phase sequence.

4. The method for quickly generating a current phasor diagram of an electric energy metering device according to claim 3, characterized in that: The phase sequence determination conditions for three-phase three-wire electric energy metering devices are: ； in, 、 They are respectively the active power of phase A and phase C and the reactive power of phase A and phase C of the three-phase three-wire electric energy metering device at the same time.

5. The method for quickly generating a current phasor diagram of an electric energy metering device according to claim 1, characterized in that: The method for obtaining the superimposed graph of the voltage phasor diagram and the plane rectangular coordinate system is: An X,Y plane rectangular coordinate system is established. On the basis of the X,Y plane rectangular coordinate system, a phasor diagram of the three-phase voltage is generated in a clockwise direction in a manner of zero point overlap and +Y and Ua overlap, wherein the angle between the three-phase voltages is 120°.

6. The method for quickly generating a current phasor diagram of an electric energy metering device according to claim 1, characterized in that: In the superimposed graph, the coordinate origin of the plane rectangular coordinate system and the phasor coordinate point are connected by a connecting line with an arrow, so as to generate a current phasor line and obtain a current phasor diagram of the electric energy metering device.

7. A system for rapidly generating a current phasor diagram of an electric energy metering device, characterized in that: include: The power acquisition module is used to obtain the phase-by-phase active power and reactive power value groups at any time through the electric energy metering device; A coordinate conversion module, used to convert the power value group into a phasor coordinate point under the current phasor diagram; A superimposed graphics module is used to obtain a superimposed graphics of a voltage phasor diagram and a plane rectangular coordinate system; A phasor diagram drawing module is used to draw current phasor lines according to phasor coordinate points on the superimposed graph to obtain the current phasor diagram of the electric energy metering device; The expression of the coordinate transformation algorithm of the three-phase three-wire electric energy metering device in the forward phase sequence is as follows: ； in, is the horizontal coordinate of phase A, is the vertical coordinate of phase A, is the horizontal coordinate of phase C, is the vertical coordinate of phase C, 、 They are respectively the active power of phase A and phase C and the reactive power of phase A and phase C of the three-phase three-wire electric energy metering device at the same time; The coordinate transformation algorithm of the three-phase three-wire electric energy metering device with reverse phase sequence is expressed as follows: ； The expression of the coordinate transformation algorithm of the three-phase four-wire electric energy metering device in the phase sequence is as follows: ； in, is the horizontal coordinate of phase A, is the vertical coordinate of phase A, is the horizontal coordinate of phase B, is the vertical coordinate of phase B, is the horizontal coordinate of phase C, is the vertical coordinate of phase C, 、 They are respectively the active power of phases A, B, and C and the reactive power of phases A, B, and C of the three-phase four-wire electric energy metering device at the same time; The coordinate transformation algorithm of the reverse phase sequence of the three-phase four-wire electric energy metering device is expressed as follows: 。 8. The current phasor diagram rapid generation system of an electric energy metering device according to claim 7, characterized in that: The coordinate conversion module includes a phase sequence determination submodule and a coordinate conversion submodule. The phase sequence determination submodule is used to determine whether the voltage connection of the three-phase three-wire electric energy metering device is a forward phase sequence or a reverse phase sequence based on the phase active power and reactive power value groups. The coordinate conversion submodule is used to convert the power value group into a phasor coordinate point under the current phasor diagram based on the phase sequence determination result using the corresponding coordinate transformation algorithm.

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