KR101908380B1 - Watt-hour meter, transmission line measurement system and measuring method thereof - Google Patents

Watt-hour meter, transmission line measurement system and measuring method thereof Download PDF

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KR101908380B1
KR101908380B1 KR1020160011666A KR20160011666A KR101908380B1 KR 101908380 B1 KR101908380 B1 KR 101908380B1 KR 1020160011666 A KR1020160011666 A KR 1020160011666A KR 20160011666 A KR20160011666 A KR 20160011666A KR 101908380 B1 KR101908380 B1 KR 101908380B1
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South Korea
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phase
line
measuring unit
electrically connected
phase line
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KR1020160011666A
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Korean (ko)
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KR20170091220A (en
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김상준
김범조
박용업
김대한
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한국전력공사
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R21/00—Arrangements for measuring electric power or power factor
    • G01R21/133—Arrangements for measuring electric power or power factor by using digital technique
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R11/00—Electromechanical arrangements for measuring time integral of electric power or current, e.g. of consumption
    • G01R11/02—Constructional details
    • G01R11/04—Housings; Supporting racks; Arrangements of terminals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R21/00—Arrangements for measuring electric power or power factor
    • G01R21/06—Arrangements for measuring electric power or power factor by measuring current and voltage
    • G—PHYSICS
    • G08—SIGNALLING
    • G08C—TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS
    • G08C19/00—Electric signal transmission systems
    • G08C19/02—Electric signal transmission systems in which the signal transmitted is magnitude of current or voltage
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/20—Instruments transformers
    • H01F38/22—Instruments transformers for single phase ac
    • H01F38/28—Current transformers

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Remote Monitoring And Control Of Power-Distribution Networks (AREA)

Abstract

The watt-hour meter according to an embodiment of the present invention includes an a-phase measurement unit for measuring a current between an a-phase line and an a-phase line and a b-phase line, a b-phase measuring unit, and a c-phase measuring unit for measuring the voltage between the c-phase line current and the c-phase line and the b-phase line.

Description

TECHNICAL FIELD The present invention relates to a watt-hour meter, a transmission line measurement system and a measuring method thereof,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a watt-hour meter, a line metering system including the same, and a metering method thereof.

In general, the watt-hour meter can measure the power of a three-phase line by a three-phase three-wire metering system or a three-phase four-wire metering system.

Here, the three-phase three-wire metering system is a method of measuring power through three transformers and two current transformers. In addition, the three-phase four-wire weighing method is a method of measuring electric power through three transformers and three current transformers.

That is, the configuration of the transformer and / or the current transformer may be different depending on the weighing method of the watt-hour meter. If this configuration and the weighing method of the watt hour meter do not match each other, an error may occur in the weighing of the watt hour meter.

However, a change in the configuration of the transformer and / or the transformer can be a major change involving long periods of power outage and high construction costs.

Registration Utility Model No. 20-0305090

An embodiment of the present invention provides a watt hour meter, a line metering system including the watt hour meter, and a metering method thereof.

The watt-hour meter according to an embodiment of the present invention includes an a-phase measurement unit for measuring a current between an a-phase line and a voltage between the a-phase line and a b-phase line; A b-phase measuring unit for measuring the voltage of the b-phase line and the current of the n-phase line; a c-phase measuring unit for measuring a current of the c-phase line and a voltage between the c-phase line and the b-phase line; First and second terminals electrically connected to the a-phase measuring unit and electrically connected to the a-phase current transformer provided on the a-phase line; A third terminal electrically connected to the a-phase measuring unit and electrically connected to the a-phase transformer installed in the a-phase line; A fourth and a fifth terminal electrically connected to the b-phase measuring unit and electrically connected to the n-phase current transformer installed in the n-phase line; A b-phase transformer electrically connected to the b-phase measuring unit and electrically connected to the a-phase transformer and the c-phase transformer installed in the c-phase line; A seventh and an eighth terminal electrically connected to the c-phase measuring unit and electrically connected to the c-phase current transformer installed in the c-phase line; A ninth terminal electrically connected to the c-phase measuring unit and electrically connected to the c-phase transforming unit; A tenth terminal electrically connected to the a-phase measuring unit, the b-phase measuring unit and the c-phase measuring unit and electrically connected to the b-phase transforming unit; And a first value corresponding to a product of a current (Ia) and a voltage (Vab) measured by the a-phase measurement unit and a current (Ic) measured by the c-phase measurement unit and a voltage (Vcb) Phase line and the b-phase line by adding or subtracting a third value corresponding to the product of the current (In) and the voltage (Vb) measured by the b- A calculation unit for calculating a total power value of the three-phase line composed of the c-phase line and the n-phase line; . ≪ / RTI >

For example, the watt-hour meter may further include a display unit that displays at least one of the total power value, the value excluding the third value from the total power value, and the third value, 3 < / RTI > value.

For example, the watt hour meter may further include a communication unit for transmitting the total power value, the value excluding the third value from the total power value, the third value, and / or the event to the server have.

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The watt-hour meter and its method according to an embodiment of the present invention can perform both the power metering by the three-phase three-wire metering method and the power metering by the three-phase four-wire metering method.

The line metering system according to an embodiment of the present invention can measure the power of the line regardless of the metering method without making major changes in the configuration of the transformer and / or the current transformer of the customer receiving the power. Thus, even if each of a plurality of customers has a configuration of various transformers and current transformers, each power supplied to a plurality of customers can be efficiently metered.

1 is a view showing a watt-hour meter and a line metering system according to an embodiment of the present invention.
2 is a view showing a watt-hour meter vector at the time of neutral point floating.
3 is a view showing a watt-hour meter vector at the time of neutral point grounding.
4 is a diagram showing a watt-hour meter vector at the time of neutral point grounding.
5 is a view showing a watt hour meter vector at the time of neutral point grounding.
6 is a view showing a watt hour meter vector at the time of neutral point grounding.
7 is a flowchart illustrating a power measurement method according to an embodiment of the present invention.

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of illustration, specific embodiments in which the invention may be practiced. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in order that those skilled in the art can easily carry out the present invention.

1 is a view showing a watt-hour meter and a line metering system according to an embodiment of the present invention.

1, a line metering system according to an embodiment of the present invention includes a watt-hour meter 100, an a-phase line 211, a b-phase line 212, a c-phase line 213, an a-phase transformer 221, an n-phase current transformer 222, a c-phase current transformer 223, an a-phase transformer 224, a b-phase transformer 225 and a c-phase transformer 226.

The a-phase line 211 can supply the a-phase power to the load. An a-phase current transformer 221 and an a-phase transformer 224 may be provided on the a-phase line 211.

The b-phase line 212 can supply b-phase power to the load. The b-phase line 212 may be provided with a b-phase transformer 225.

Here, the b-phase line 212 may not have a current transformer. That is, the line metering system according to an embodiment of the present invention can accurately measure the power even if a current transformer is not additionally provided to the b-phase line 212. The accuracy of weighing will be described later with reference to the following equations (1) and (2).

The c-phase line 213 can supply c-phase power to the load. The c-phase line 213 may include a c-phase current transformer 223 and a c-phase transformer 226.

the phase of the a-phase power source and the phase of the b-phase power source and the phase of the c-phase power source may differ by 120 ° from each other.

The n-phase line 214 is commonly connected to the a-phase line 211, the b-phase line 212 and the c-phase line 213, thereby providing a neutral point. Therefore, when the a-phase, the b-phase, and the c-phase are balanced with each other, the potential of the n-phase line 214 may be 0V. An n-phase current transformer 222 may be installed in the n-phase line 214.

the fluctuation range of the voltage and the current of the n-phase line 214 may be smaller than the fluctuation range of the voltage and current of the a-phase line 211, the b-phase line 212 and the c-phase line 213. Therefore, the size or the capacity of the n-phase current transformer 222 may be smaller than that of the a-phase current transformer 221 and the c-phase current transformer 223.

Accordingly, unlike the a-phase current transformer 221 and the c-phase current transformer 223, the n-phase current transformer 222 can be installed on the n-phase line 214 without involving a long period of power failure and a large construction cost. Therefore, even if the b-phase line 212 and the n-phase line 214 of the customer receiving power are not provided with a current transformer, the n-phase current transformer 222 can be easily provided. The n-phase current transformer 222 can improve the metering accuracy of the watt-hour meter 100. Specific details will be described later with reference to Equation 1 and Equation 2 below.

The watt hour meter 100 is connected to an a-phase current transformer 221, an n-phase current transformer 222, a c-phase current transformer 223, an a-phase transformer 224, a b-phase transformer 225, Can be measured.

For example, the watt-hour meter 100 may be a single three-phase four-wire watt-hour meter. That is, even if the configuration of the transformer and the current transformer provided in the line is adapted to the three-phase three-wire metering method, the three-phase four-wire type watt hour meter 100 can measure the power without changing the configuration of the transformer and the current transformer. Thus, even if each of a plurality of customers has a configuration of various transformers and current transformers, each power supplied to a plurality of customers can be efficiently metered.

1, a watt-hour meter 100 according to an embodiment of the present invention includes an a-phase measuring unit 110, a b-phase measuring unit 120, a c-phase measuring unit 130, a tenth terminal 140, The first terminal 141, the second terminal 142, the third terminal 143, the fourth terminal 144, the fifth terminal 145, the sixth terminal 146, the seventh terminal 147, An eighth terminal 148, a ninth terminal 149, an operation unit 150, a display unit 160, and a communication unit 170.

The a-phase measuring unit 110 can measure the current Ia of the a-phase line 211 and the voltage Vab between the a-phase line 211 and the b-phase line 212.

The b-phase measuring unit 120 can measure the voltage Vb of the b-phase line 212 and the current In of the n-phase line 214. [

The c-phase measuring unit 130 can measure the current Ic of the c-phase line 213 and the voltage Vcb between the c-phase line 213 and the b-

For example, each of the a-phase measuring unit 110, the b-phase measuring unit 120, and the c-phase measuring unit 130 may include a resistance element having a reference resistance value.

The first and second terminals 141 and 142 may be electrically connected to the a-phase measuring unit 110 and the a-phase current transformer 221, respectively. That is, the a-phase measuring unit 110 can measure the a-phase current Ia through the first and second terminals 141 and 142. [

The third terminal 143 may be electrically connected to the a-phase measuring unit 110 and the a-phase transformer 224. The tenth terminal 140 may be electrically connected to the a-phase measuring unit 110 and the b-phase transformer 225. That is, the a-phase measuring unit 110 can measure the voltage Vab between the a-phase line 211 and the b-phase line 212 via the third and tenth terminals 143 and 140.

The fourth and fifth terminals 144 and 145 may be electrically connected to the b-phase measuring unit 120 and the n-phase current transformer 222, respectively. That is, the b-phase measuring unit 120 can measure the n-phase current In through the fourth and fifth terminals 144 and 145. [

The sixth terminal 146 may be electrically connected to the b-phase measuring unit 120 and the ground. The tenth terminal 140 may be electrically connected to the b-phase transformer 120 and the b-phase transformer 225. That is, the b-phase measuring unit 120 can measure the voltage (Vb) of the b-phase line 211 through the sixth and tenth terminals 146 and 140.

The seventh and eighth terminals 147 and 148 may be electrically connected to the c-phase measuring unit 130 and the c-phase current transformer 223, respectively. That is, the c-phase measuring unit 130 can measure the c-phase current Ic through the fourth and fifth terminals 147 and 148. [

The ninth terminal 149 can be electrically connected to the c-phase measuring unit 130 and the c-phase transformer 226. The tenth terminal 140 may be electrically connected to the c-phase measuring unit 130 and the b-phase transformer 225. That is, the c-phase measuring unit 130 can measure the voltage Vcb between the c-phase line 213 and the b-phase line 212 through the ninth and tenth terminals 149 and 140.

Accordingly, the watt hour meter 100 can measure Ia, In, Ic, Vab, Vb, and Vcb. The Ia, In, Ic, Vab, Vb, and Vcb may be used for power calculation.

The operation unit 150 can calculate the power W1 according to the following equation (1). Equation (1) is a mathematical expression for expressing the power when the power factor of the line is 100% in order to simplify the calculation.

Figure 112016010104973-pat00001

If the peripheral neutral first-order neutral point around the watt-hour meter is ungrounded, the power of the line may be the power (W2) according to Equation (2) below.

Figure 112016010104973-pat00002

When a watt-hour meter measures power using a three-phase, three-wire metering system, power can be accurately measured even if the current is measured only through an a-phase current transformer and a c-phase current transformer. Therefore, when the first neutral point of the peripheral period around the watt-hour meter is not grounded, the watt-hour meter can measure the power by the three-phase three-wire metering method.

However, when the first neutral point of the peripheral period around the watt-hour meter is grounded, the power of the line may be the power according to Equation (1). Here, when the watt-hour meter measures power by a three-phase three-wire metering method, the difference between the actual power of the line and the power according to the measurement may be a product of Vb and In.

The watt-hour meter 100 according to an embodiment of the present invention can calculate the power according to Equation (1). Therefore, the watt-hour meter 100 can accurately measure the power of the line regardless of whether the primary neutral point of the main transformer around the watt-hour meter is grounded.

The display unit 160 may display the power according to Equation (1) and the power according to Equation (2). For example, the display unit 160 can visually display electric power using a display device, and can display electric power audibly using a speaker.

Also, the display unit 160 may display an event based on the magnitude of the difference power between the power according to Equation (1) and the power according to Equation (2). For example, the display unit 160 may additionally indicate to the user of the watt-hour meter 100 that the power of the n-phase line 214 is greater than a predetermined power. The user can easily recognize the load condition of the line by checking the event. The smaller the power of the n-phase line 214 is, the closer the line load becomes to the equilibrium.

The communication unit 170 may transmit the power according to Equation (1), the power according to Equation (2), and the event to the server. Accordingly, the manager who manages the power supply can efficiently manage the power passing through the watt hour meter 100.

2 is a view showing a watt-hour meter vector when a neutral point is floating.

Referring to FIG. 2, the total power Wt of the line can be calculated according to the following equation (3). Here,? Represents a phase of the power factor of the line. For example, when cosθ is 1, the line power factor is 100%.

Figure 112016010104973-pat00003

When the neutral point is floating, the total power of the line measured by 3-phase 3-wire method and the total power of the line measured by 3-phase 4-wire method may be the same.

3 is a view showing a watt-hour meter vector at the time of neutral point grounding.

Referring to FIG. 3, the total power Wt of the line can be calculated according to the following equation (4). Where Vab and Vcb are the square root of 3, Ib is 0, and the power factor is 100%. On the other hand, the polarity of VbIn means the connection direction to the current transformer.

Figure 112016010104973-pat00004

When neutral ground is grounded, the total power of the line measured by 3-phase 3-wire method and the total power of line measured by 3-phase 4-wire method may be different from each other. That is, the total power (Wt) of the lines measured by the three-phase three-wire system can be measured as 3VI because W2 is not reflected.

4 is a diagram showing a watt-hour meter vector at the time of neutral point grounding.

Referring to FIG. 4, the total power Wt of the line can be calculated according to the following equation (5). Where Vab and Vcb are the square root of 3 and the power factor is 100%. Compared with FIG. 3, Ib is 1.2A, not zero.

Figure 112016010104973-pat00005

When neutral ground is grounded, the total power of the line measured by 3-phase 3-wire method and the total power of line measured by 3-phase 4-wire method may be different from each other. That is, the total power (Wt) of the lines measured by the three-phase three-wire system can be measured as 3VI because W2 is not reflected.

5 is a view showing a watt hour meter vector at the time of neutral point grounding.

Referring to FIG. 5, the total power Wt of the line can be calculated according to the following equation (6). Where Vab and Vcb are the square root of 3, Ib is 0, and the power factor is 100%. 3, the polarity of VbIn is changed.

Figure 112016010104973-pat00006

6 is a view showing a watt hour meter vector at the time of neutral point grounding.

Referring to FIG. 6, the total power Wt of the line can be calculated according to the following equation (7). The total power Wt of the line can be calculated according to the following equation (7). Where Vab and Vcb are the square root of 3 and the power factor is 100%. Compared with FIG. 5, Ib is 1.2A, not zero.

Figure 112016010104973-pat00007

7 is a flowchart illustrating a power measurement method according to an embodiment of the present invention.

7, a power measurement method according to an embodiment of the present invention includes a phase measurement step S11, a b phase measurement step S12, a c phase measurement step S13, a calculation step S20, Step S30 and communication step S40. Since the power measurement method can be performed by the watt-hour meter described above with reference to FIG. 1, the same or corresponding contents are not duplicated.

The watt hour meter in the a phase measurement step (S11) can measure the current between the a-phase line and the voltage between the a-phase line and the b-phase line.

The watt-hour meter in the b-phase measuring step (S12) can measure the voltage of the b-phase line and the current of the n-phase line.

The watt hour meter in the c-phase measuring step (S13) can measure the current between the c-phase line and the voltage between the c-phase line and the b-phase line.

The watt-hour meter in the calculation step S20 can calculate the power according to the above-mentioned equation (1).

The watt-hour meter in the display step S30 can display the calculated power.

The watt hour meter in the communication step S40 can transmit the calculated power to the server.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Anyone can make various variations.

100: watt hour meter 110: a phase measuring unit
120: b-phase measuring unit 130: c-phase measuring unit
140: tenth terminal 141: first terminal
142: second terminal 143: third terminal
144: fourth terminal 145: fifth terminal
146: sixth terminal 147: seventh terminal
148: eighth terminal 149: ninth terminal
150: computing unit 160:
170: communication unit 211: a phase line
212: b-phase line 213: c-phase line
214: n-phase line 221: a-phase current transformer
222: n-phase current transformer 223: c-phase current transformer
224: a phase transformer 225: b phase transformer
226: c-phase transformer

Claims (9)

an a-phase measuring unit for measuring a current (Ia) of the a-phase line and a voltage (Vab) between the a-phase line and the b-phase line;
A b-phase measuring unit for measuring a voltage (Vb) of the b-phase line and a current (In) of the n-phase line;
a c-phase measuring unit for measuring a current (Ic) of the c-phase line and a voltage (Vcb) between the c-phase line and the b-phase line;
First and second terminals electrically connected to the a-phase measuring unit and electrically connected to the a-phase current transformer provided on the a-phase line;
A third terminal electrically connected to the a-phase measuring unit and electrically connected to the a-phase transformer installed in the a-phase line;
A fourth and a fifth terminal electrically connected to the b-phase measuring unit and electrically connected to the n-phase current transformer installed in the n-phase line;
A b-phase transformer electrically connected to the b-phase measuring unit and electrically connected to the a-phase transformer and the c-phase transformer installed in the c-phase line;
A seventh and an eighth terminal electrically connected to the c-phase measuring unit and electrically connected to the c-phase current transformer installed in the c-phase line;
A ninth terminal electrically connected to the c-phase measuring unit and electrically connected to the c-phase transforming unit;
A tenth terminal electrically connected to the a-phase measuring unit, the b-phase measuring unit and the c-phase measuring unit and electrically connected to the b-phase transforming unit; And
Phase measuring unit and a voltage value corresponding to the product of the first value corresponding to the product of the current Ia measured by the a-phase measuring unit and the voltage Vab and the product of the current Ic and the voltage Vcb measured by the c- Phase line, the b-phase line and the b-phase line by adding or subtracting a third value corresponding to a product of a current (In) and a voltage (Vb) measured by the b- a calculation unit for calculating a total power value of the three-phase line composed of the c-phase line and the n-phase line; .
delete delete delete The method according to claim 1,
And a display unit for displaying at least one of the total power value, the value in which the third value is excluded from the total power value, and the third value,
And the display unit displays an event based on the magnitude of the third value.
6. The method of claim 5,
And a communication unit for transmitting to the server at least one of the total power value, the value excluding the third value from the total power value, the third value, and the event. delete delete delete
KR1020160011666A 2016-01-29 2016-01-29 Watt-hour meter, transmission line measurement system and measuring method thereof KR101908380B1 (en)

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JP2005043231A (en) * 2003-07-23 2005-02-17 Yokogawa Electric Corp Wattmeter

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