KR101159753B1 - Digital power meter - Google Patents

Abstract

PURPOSE: An electronic watt-hour-meter is provided to measure power which is supplied in an abnormal manner, thereby measuring the total power consumption including abnormally used power. CONSTITUTION: A first current transformer(CT1) allows a first current line of single phase current lines to pass therethrough. A second current transformer(CT2) allows a second current line of the single phase current lines to pass therethrough. A central control device receives measurement signals from the first and the second current transformer to compute and read the signals, computes and stores inspection data and leakage/conduction data, and selects a larger one of first and second wattages calculated from the first and second current transformers to measure and integrate into effective wattage.

Description

Digital power meter

The present invention relates to a power meter that can be metered, including the amount of power that is challenged in an abnormal way.

Power supplied by the utility company is supplied to the general load via an electricity meter that measures the amount of power used. In general, the electricity used by each household is accumulated in the electricity meter, and the power supply company person periodically reads the electricity used from the accumulated electricity meter and charges the electricity usage fee accordingly.

 However, the power used by the power user who wants to abnormally use the power often becomes a challenge without being accumulated in the electricity meter.

As a means for detecting the amount of power used in the single-phase wattmeter as shown in FIG. 1, the current used by the active line 11 is sensed through the current transformer 101, and the amount of power detected through the current transformer is a central controller (not shown in the CPU). Is accumulated by.

 If the power supplied to the load does not pass through the current meter of the electricity meter normally, it is impossible to check whether the power is used. The abnormal power user uses this to operate the current transformer so that it does not go through the current transformer.

Therefore, in order to reduce the electricity bill used by the user, if the electricity is used without passing through the electricity meter normally by branching or grounding the wire between the lead wire and the load line of the electricity meter, it is possible to detect and measure the electricity amount normally. Electronic electricity meter is required.

The present invention provides an electronic electricity meter that can detect all of the power consumption, including abnormal usage, when the user uses electricity by connecting to the electricity meter in an abnormal manner to change the meter reading accumulated in the electricity meter. It is.

It is still another object of the present invention to provide an electronic electricity meter which can reduce abnormal connection by detecting an unfair power user and displaying it on the electricity meter and the accumulated power amount.

When the user uses electricity by connecting to the electricity meter in an abnormal manner to change the meter reading accumulated in the electricity meter, an electronic electricity meter capable of detecting the amount of electricity used, including the abnormal amount of use, can be metered.

An electronic power meter according to an embodiment of the present invention includes a first current transformer installed to penetrate a first current line of single-phase current lines therein,

Receives measurement signals from the second current transformer and the first and second current transformers installed so as to penetrate the second current line among the single-phase current lines therein, calculates and reads signal values, and calculates meter reading data and leakage / conduction data. It includes a central control unit for storing,

The central controller selects a larger value from the first amount of power calculated by the first current transformer and the second amount of power calculated by the second current transformer, and measures and integrates the measured value as an effective amount of power.

The apparatus may further include a third current transformer configured to penetrate the first current line and the second current line therein, wherein a current signal is detected by the third current transformer, and any one of the second current transformer and the first current transformer may be used. When the current signal is detected only in the current transformer, the central controller recognizes it as a bypass type connection and controls to display and store it.

According to the present invention, when the user connects to the electricity meter in an abnormal way and uses electricity, the present invention can detect the amount of electricity and measure the amount of used power including the abnormal usage, thereby preventing economic losses due to the challenge.

In addition, according to an embodiment of the present invention, by detecting that the user is an unfair power user to display it on the electricity meter or the accumulated power amount has an effect that can prevent abnormal access.

FIG. 1 briefly illustrates an internal CT connection diagram of a conventional electronic wattmeter.
Figure 2 briefly shows the internal CT connection diagram of the electronic electricity meter according to an embodiment of the present invention.
3 illustrates an example of a method of bypassing and using an active terminal on a power supply side and an active terminal on a load side.
FIG. 4 illustrates an example of a method in which the active terminal on the power supply side and the active terminal on the load side are reversed and used.
5 illustrates an example of a method of shorting an active terminal of a power supply side and an active terminal of a load side.
6 shows an example of a method of grounding the load side.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, "includes." Or “having”, etc., are intended to indicate the presence of a feature, number, step, action, component, part, or combination thereof described in the specification, and one or more other features or numbers, steps, actions, configurations It is to be understood that it does not preclude the presence or possibility of addition of elements, parts or combinations thereof.

Certain exemplary embodiments will now be described in order to provide an overall understanding of the functionality and principles of use of the methods and apparatus disclosed herein. One or more examples of these embodiments are shown in the accompanying drawings.

The structures specifically described herein and shown in the accompanying drawings are merely exemplary embodiments, and features shown or described in connection with one exemplary embodiment may be combined with features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 briefly shows the internal CT connection diagram of the electronic electricity meter according to an embodiment of the present invention.

Power meter 10 according to an embodiment of the present invention is composed of three current transformers (CT1, CT2, CT3) to measure the amount of power used abnormally.

As shown in FIG. 2, the first current transformers 101 and CT1 pass through the active lines 1S-1L inside the first current transformer CT1 to measure the current flowing through the active lines 11S1-1L. do.

The second current transformers 102 and CT2 are installed to penetrate the neutral lines 2S-2L inside the second current transformer CT2 in order to calculate the current flowing through the neutral lines 12S2-2L.

In one embodiment of the present invention, the third current transformer (103, CT3) is measured by summing the current flowing in the active line (1S-1L) and neutral line (2S-2L) and the third current transformer to detect a short circuit or conduction current The CT3 may be installed to penetrate both the active line 1S-1L and the neutral line 2S-2L.

The current I ₁ flowing between terminals 1S-1L ((21)-(31)) of the electricity meter 10 is measured at CT1. CT2 measures the current I ₂ flowing between terminals 2S-2L of the electricity meter. Since current I ₂ is the same size as current I ₁ and the direction of current is reversed, current I ₁₂ flowing through CT3 is always zero if there is no conduction on the load side. That is, when a current is detected at CT3, it can be seen that a state of conduction or a short circuit.

Pt1 is measured by setting the flow direction (power side from the load side) in the forward direction to I ₁ of FIG. 2, and Pt2 is set to be measured as a positive value by setting the direction flowing in I ₂ (load side from the load side) in FIG. do.

The signals measured by the CT1, CT2, and CT3 calculate and read signal values from a central control unit (CPU, not shown), calculate and calculate meter reading data and leakage / challenge data, and store them as a display unit. Will be displayed.

3 illustrates an example of a method of bypassing and using an active terminal on a power supply side and an active terminal on a load side.

The user may bypass and use the power supply side IS terminal of the active line 1S-1L and the load side 1L terminal as shown in FIG. 3 to use power without passing through the current transformer of the electricity meter.

In this case, I ₁ is not detected in the electricity meter according to the embodiment of the present invention, but current value I ₂ is detected in CT2 and CT3.

The active power metered in CT1 (Pct1) Pct1 = V x I ₁ (= I ₀ = 0) x cosθ = 0.

I ₀ Is 0 and current flowing through CT1 is 0 (Zero).

I ₀ is the current consumption of the watt-hour meter itself and is not metered, so Pct1 = 0.

And the amount of power metering Pct2 in CT2 is measured by _{Pct2 = V x I 2 x cosθ} .

Since I ₂ is an actual current used, when it is determined that the bypass conduction is performed, the normal amount of power can be measured by integrating the amount of power measured by CT2 as the effective power amount.

That is, if the current flowing in CT1 is 0 and the current flows only in CT2, the central control unit (CPU) recognizes this as a bypass type connection, displays and stores it, and converts Pct2, which is the amount of power generated by CT2, into the effective power amount as follows. Accumulation is performed.

Pt = Pct2 (Pct1 <Pct2)

In addition, when Pct1 is smaller than Pct2, it may be determined as a challenge to display and store, and to calculate a larger amount of power.

That is, when the currents of I ₁ and I ₂ are different from each other due to the conduction, the actual amount of power consumed by the load may be set such that the larger current value of I ₁ and I ₂ is the amount of power actually consumed.

FIG. 4 illustrates an example of a method in which the active terminal on the power supply side and the active terminal on the load side are reversed and used.

In this case, in the power meter according to the embodiment of the present invention, CT1 detects I _{1, which} is in the opposite phase to the forward direction, and I ₂ , which has the same magnitude as I ₁ in the opposite phase, flows through CT2.

That is, the amount of power calculated by CT1 is calculated as Pct1 = V x (-I ₁ ) x cosθ = V x I ₁ x cos (180 + θ), and thus the power amount is calculated as a-value. This means a reverse connection.

The effective amount of power Pct2 measured at CT2 is Pct2 = V x I ₂ x cosθ.

The value of Pct2 is positive.

Pct1 and Pct2 have the same magnitude and opposite signs, so Pct1 <Pct2.

In this case, the central controller is set to calculate the total amount of effective power supplied Pt = Pct2 (Pct1 <Pct2).

That is, in one embodiment of the present invention, when the value of Pct1 is measured to be smaller than 0 and the value of Pct2 is calculated with a positive value equal to Pct1, the central control unit (CPU) recognizes this as a reverse connection and displays and stores it. It is set to integrate Pct2, which is the amount of power by CT2, into the amount of effective power.

In addition, if it detects that the phase of voltage and current is different by 180 degrees, the central control unit (CPU) recognizes this as a reverse connection, displays and stores it, and sets Pct2, which is the amount of power by CT2, to be accumulated as an effective amount of power. do. That is, when the phase of the current measured at CT1 and the voltage measured at the power supply point are measured in opposite phases, the CPU is set to recognize it as a reverse connection.

In addition, as shown in FIG. 3, when the currents of I ₁ and I ₂ are different from each other due to conduction, the actual amount of power consumed by the load side may be set such that a larger current value of I ₁ and I ₂ is the amount of power actually consumed.

That is, I ₁ and I ₂ The amount of power calculated by the large current value among the set to the effective power amount.

5 illustrates an example of a method of shorting an active terminal of a power supply side and an active terminal of a load side.

It is a conductive type that shorts the terminals 1S and 1L terminals of the electricity meter with a wire outside the electricity meter. Current flowing through the lead-1S (I ₁₎ flows through the branch with a current (I _{1 -3)} in which flows a short wire and a current (I _{1 -2)} flowing through the CT1.

Note that, in the CT1 only current (I _{1 -2)} portion flows through the metering is CT1.

CT2 flows to I ₂ The current value is detected.

Active power metered in CT1 Pct1 = V x I _{1 -2} x cosθ

Active power metered in CT2 Pct2 = V x I ₂ x cosθ

I _{2 = I 1 -2 + I 1 -} 3 , so I ₂ > I _{1 -2} . (I _{1 -3} > 0)

In this case, I ₂ is because all of the current flow actually used active energy is set so as to measure the power due to the current flowing through the I _2.

Pt = Pct2 (Pct1 <Pct2)

That is, when Pct1 is measured larger than 0 and smaller than Pct2, the CPU recognizes it as a short circuit type between active terminals, displays and stores it, and integrates Pct2, which is the amount of power by CT2, as an effective amount of power. Is set.

In addition, as shown in FIG. 3, when the currents of I ₁ and I ₂ are different from each other due to conduction, the actual amount of power consumed by the load side may be set such that a larger current value of I ₁ and I ₂ is the amount of power actually consumed.

In addition, CT3 can be measured as follows.

Active power measured at CT3

Pct3 = V x (I ₂ -I _{1 -2} ) x cosθ

The actual current used is I _{1 -2} and

Pt = Pct1 + Pct3, CT3 is the current corresponding to the difference between I ₂ and I _{1 -2} , and this current value is equal to I _{1 -3} .

Pt = V x I _{1 -2} x cosθ + V x (I ₂ -I _{1 -2} ) x cosθ

= V x I _{1 -2} x cosθ + V x (I ₁ -I ₂ ) x cosθ I ₂ = V x I ₂ x cosθ

That is, when the sum of the current flowing through CT1 and the current flowing through CT3 is measured to be equal to the current flowing through CT2, the central control unit (CPU) recognizes this as a short-circuit type between active terminals and displays and stores it. The amount of power may be set to integrate with the amount of effective power.

6 shows an example of a method of grounding the load side.

This is a type used by grounding terminal 1L or 2L terminal of the electricity meter outside the electricity meter.

If the terminal 1S of the electricity meter is grounded, it is possible to conduct the electric current between the terminal 2L of the electricity meter and the ground.

Current lead-in terminal 1S of the watt-hour meter in the case (I _{1 -2)} and a current outputted from the terminal 1L of the watt-hour meter (I _{1 -2} ') is the same. That is, I _{1 -2} = I _{1 -2} '.

The current I ₂ between the terminals 2S-2L of the wattmeter flows through the sum of the current I _{1 -4} between the terminal 1S of the wattmeter and the ground and the current I _{1 -2} ′ output from the terminal 1L of the wattmeter. That is, _{I 2 = I 1 -2 '+} I 1 -4.

In CT3, the current corresponding to the current difference between the two wires 11 and 12 is measured, and the measured current value is equal to I ₃ .

The amount of power measured at CT1 is (Pct1), where Pct1 = V x I ₂ x cosθ.

The amount of power Pct2 measured at CT2, Pct2 = V x I ₂ x cosθ.

In this case, I ₂ '= I _{1 -2} ' + I _{1 -4} = I ₂ Since I ₂ > I _{1 -2} . (I _{1 -4} > 0)

In this case, the central control unit is set to integrate the amount of power Pct2 measured in CT2 with the amount of power actually used.

Pt = Pct2 (Pct1 <Pct2)

By metering in this manner, normal metering can be performed even in the case of ground conduction.

That is, when Pct1 is measured larger than 0 and smaller than Pct2, the central control unit (CPU) recognizes this as a type of grounding between short circuits between active terminals or one side of the load side, and displays and stores it. It is set to integrate with the amount of power.

In addition, as described above, when the currents of I ₁ and I ₂ are different from each other due to the conduction, the actual amount of power consumed by the load side may be set such that the larger current value of I ₁ and I ₂ is the amount of power actually consumed.

In addition, when the sum of the current flowing through CT1 and the current flowing through CT3 is measured to be equal to the current flowing through CT2, the central control unit (CPU) recognizes this as a short-circuit type between active terminals and displays and stores it. The amount of power may be set to integrate with the amount of effective power.

In the exemplary embodiment of the present invention, the active terminal and the neutral terminal have been described separately. However, the active terminal and the neutral terminal may be interchanged with each other to obtain the same result.

According to one embodiment of the present invention, when the user connects to the electricity meter in an abnormal manner and uses electricity, the user can detect this and measure all used power including the abnormal usage to prevent economic loss due to the challenge. Can be.

In addition, according to an embodiment of the present invention, by detecting that the user is an unfair power user to display it on the electricity meter or the accumulated power amount has an effect that can prevent the continuous abnormal connection.

1S: Active terminal on power side
1L: Load-side active terminal
2S: Neutral terminal on power side
2L: Load side neutral terminal
10: power meter
11: Active line inside power meter
12: Neutral line inside the meter
21, 22: power line
31, 32: Load line
CT1, CT2, CT3: Current transformer

Claims (7)

A first current transformer installed to penetrate the first current line among single-phase current lines therein;
Receives measurement signals from the second current transformer and the first and second current transformers installed so as to penetrate the second current line among the single-phase current lines therein, calculates and reads signal values, and calculates meter reading data and leakage / conduction data. It includes a central control unit for storing,
The central controller selects a larger value from the first amount of power calculated by the first current transformer and the second amount of power calculated by the second current transformer, and measures and integrates the measured amount as an effective amount of electric power.
The method of claim 1
When the current measurement signal of the first current transformer is 0 and the current measurement signal is detected by the second current transformer, the central control unit (CPU) controls to display and store it as a bypass connection and the second power amount. Electronic power meter, characterized in that to measure and integrate the effective power amount
The method of claim 1
When the value of the first power amount is smaller than 0 and the value of the second power amount is calculated to be the same value as the magnitude of the first power amount and the absolute value, the central control unit (CPU) indicates this as a reverse connection. And control to store the data, and measure and integrate the second power amount as an effective power.
The method of claim 1
When the phase of the current measured by the first current transformer and the phase of the voltage measured by the power supply point are measured in opposite phases, the central control unit (CPU) controls to display and store them in reverse connection, and the second phase Electronic power meter, characterized in that the amount of electricity is measured and integrated as an effective amount of power
The method of claim 1
When the value of the first power amount is greater than zero and the first power amount is less than the second power amount, the central controller recognizes and displays a short circuit between the power supply side and the load side terminal or one line on the load side as a grounded type. And control to store and measure and integrate the second power amount as an effective power amount.
The method of claim 1
And a third current transformer installed therein so as to penetrate the first current line and the second current line, wherein a current signal is sensed by the third current transformer, and only in one of the current transformers of the second current transformer and the first current transformer. When the current signal is detected, the centralized control unit recognizes it as a bypass type connection and controls to display and store it.
The method of claim 1
And a third current transformer configured to penetrate the first current line and the second current line therein, wherein a sum of the current flowing through the first current transformer and the current flowing through the third current transformer corresponds to a current flowing through the second current transformer. In the case of the same measurement, the electronic power meter is characterized in that the central controller is controlled to display and store the short-circuit between the power supply side and the load side terminal or one line on the load side as a grounded type.

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