KR101346159B1 - Apparatus and method for wrong wiring detection of mof - Google Patents

Abstract

The present invention relates to an apparatus and a method for wrong wiring detection between a metering out fit (MOF), including a current transformer and a potential transformer, and a power meter. Provided are a connection error detecting apparatus for the MOF and a method which determines connection between a current transformer cell with a voltage transformer cell for the MOF and the power meter by contrasting either a magnetization curve of a current transformer (CT) or a magnetization curve of a potential transformer (PT) for the examined MOF in a state where the MOF is connected to the power meter with the magnetization curve of either the CT or the PT for a previously set MOF. [Reference numerals] (AA,CC) No; (BB,DD) Yes; (EE) End; (S1) Connecting a current transformer to an MOF; (S11) Similar to a PT magnetization curve of a predetermined standard MOF?; (S13) Right wiring; (S15) Wrong wiring; (S17) Display unit; (S3) Applying the current to two terminals of the MOF with the current transformer; (S5) Measuring the voltage for applying the current; (S7) Measuring a current change according to the voltage change; (S9) Similar to a CT magnetization curve of the predetermined standard MOF?

Description

Method and apparatus for judging incorrect wiring of instrument transformer {APPARATUS AND METHOD FOR WRONG WIRING DETECTION OF MOF}

The present invention relates to an apparatus and method for determining a miswiring of a MOF for determining whether a metering out fit (MOF) and a power meter are correctly connected.

Metering Out Fit (MOF) is very dangerous when high voltage, high current is directly connected to the instrument or relay in the switchboard, so low voltage proportional to voltage, current, e.g. 110V , 1A, or 0.1A, for use as input current for power meters, strategic meters or measuring instruments.

If the connection between the MOF and the electricity meter is incorrect, the phase shift between the voltage and the current occurs, so that normal weighing cannot be performed, and the abnormal metering is always changed according to the load level and the power factor of the load. Because of this, it is impossible to infer a normal weighing value.

Since the electricity meter cannot accept a high voltage, it can be connected to the MOF and receive power in a state in which it is transformed into an acceptable voltage.

Therefore, in general, the electricity meter installed to supply stable power is used in connection with the MOF.

In the MOF, CT and PT terminals are alternately connected when connecting a power meter due to the presence of a current transformer (Currence Transformer) and a Potential Transformer (PT). There is a need for methods to detect such miswiring and prevent damage to the device due to overheating or breakdown.

Therefore, in order to properly connect the MOF terminal and the input channel of the electricity meter, the MOF manufacturer applies voltage directly to the MOF terminal and measures the magnetization to measure the magnetization curve. Therefore, check whether it is the CT terminal of the MOF or PT terminal of the MOF. .

However, when the MOF and the electricity meter were connected, the voltage could not be measured due to a short circuit when the voltage was applied directly. Therefore, the terminal of the MOF could be checked only when the electricity meter was separated from the electricity meter.

Accordingly, the present invention has been made to solve the problems of the prior art as described above, the present invention is a mistransformer of the instrument transformer (MOF) that can determine whether the MOF and the electricity meter is correctly connected without disconnecting the electricity meter It is to provide a wiring determination method and apparatus.

To this end, an apparatus for determining a miswiring line between a metering out fit (MOF) and an electricity meter according to an embodiment of the present invention includes a magnetization curve of the MOF and a preset magnetization curve of the reference MOF while the MOF and the electricity meter are connected. In comparison, it is determined whether at least one of the instrument current transformer terminal of the MOF or the instrument transformer terminal of the MOF is correctly connected to the electricity meter.

In addition, the method for determining the miswiring of the MOF according to an embodiment of the present invention is to determine whether the miswiring of the MOF by using the MOF miswiring determination device in a state in which the MOF including the current transformer for the instrument and the transformer for the meter is connected. The method may include determining whether the MOF is misaligned by comparing the measured MOF magnetization curve with a preset reference MOF magnetization curve.

According to the method and apparatus for determining the miswiring of an instrument transformer (MOF) according to the present invention, the MOF is measured using a voltage supplied from a power supply of the MOF miswiring determination apparatus without separating the wattmeter and the MOF before pressurizing it. We can find wrong wiring without burdening.

In addition, the present invention uses the magnetizing inductance characteristics of the instrument current transformer and instrument transformer of the MOF to increase the accuracy of the determination, and by using a split type current transformer can minimize the failure or stress of the MOF and the electricity meter.

1 is a view showing a state in which the MOF and the electricity meter connected before pressing;
2 is a disconnected diagram of a MOF connected to an electricity meter,
3 is a magnetization curve of the CT for the current transformer measured by the MOF manufacturer,
Figure 4 is a magnetization curve of the instrument transformer (PT) measured by the MOF manufacturer,
5 is a disconnected diagram of a MOF connected to an MOF miswiring determination device and an electricity meter according to an embodiment of the present invention;
6 is a diagram illustrating a process of measuring a miswire using a MOF miswire determination device according to an embodiment of the present invention. Flowchart,
7 is a flowchart illustrating a process of measuring a miswire using a MOF miswire determination device according to another embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

 When a component is referred to as being "connected" to another component, it should be understood that there may be a direct connection to that other component, but other components may be present in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention.

 Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Hereinafter, with reference to the accompanying drawings, the characteristic difference between the magnetizing inductance of the current transformer (Currence Transformer, hereinafter CT) and the instrument transformer (Potential Transformer, hereinafter PT) according to a preferred embodiment of the present invention The following describes a method and apparatus for determining a miswiring connection of a metering transformer (MOF) and a meter.

FIG. 1 is a diagram showing a state 103 in which the MOF 101 and the electricity meter 102 are connected before pressurization, and FIG. 2 is a disconnected diagram of the MOF.

The MOF 101 is provided with an instrument current transformer CT and an instrument transformer PT.

The CT is a current transformer for the instrument that converts the system current into an acceptable value for the instrument. The primary current value of the CT is designed to give a margin to the maximum load current value of the circuit, and the secondary current value is usually designed to match the load input current of about 5A, 1A, or 0.1A. Therefore, the magnetizing inductance characteristic of the CT is determined at design time so as to saturate at the secondary current value, for example, 5 A, 1 A, or 0.1 A.

The PT is an instrument transformer that converts the voltage of the system into an acceptable value of the instrument. The primary voltage value of PT depends on the magnitude of the voltage being pressed, but the secondary side is set at 110V. Therefore, the magnetizing inductance characteristic of PT is determined at design time so that the voltage value of secondary side is saturated at 110V.

(A), (b), and (c) of FIG. 3 are magnetization inductance curves (CT CT magnetization curves) of CT measured in a state in which the MOF 101 manufacturer separates the electricity meter. As the magnitude increases, the slope characteristic changes around 0.1A, and the magnitude of the voltage hardly increases.

(A), (b) and (c) of FIG. 4 are magnetization inductance curves of the PT measured in a state in which the MOF 101 manufacturer separates the electricity meter (hereinafter referred to as the PT magnetization curve). As the magnitude increases, the slope characteristic changes at 110V, and there is almost no change in the magnitude of the current depending on the magnitude of the voltage.

Comparing (a), (b) and (c) of FIG. 3 with (a), (b) and (c) of FIG. 4, it can be seen that the value of the current with respect to the value of a specific voltage is different. In an embodiment, when the voltage (y-axis) is 20 V, the current (x-axis) is read as indicated by the red lines in FIGS. 3 (c) and 4 (c), and FIG. 0.065A, Figure 4 (c) is 0.017A can be seen that the difference between these sizes of about 3 to 4 times.

Therefore, by comparing the current value at a specific voltage, it is possible to distinguish whether the graph is a CT magnetization curve or a PT magnetization curve. Therefore, it is possible to determine whether the CT current transformer or the PT transformer terminal is used. have.

Using this difference in magnetization inductance characteristic, the MOF incorrect wiring for determining whether the CT terminal of the MOF 101 is correctly connected to the current channel of the electricity meter 102 and the PT terminal of the MOF 101 is correctly connected to the voltage channel of the electricity meter 102. With reference to the accompanying drawings, the invention of the measuring device 430 and a method for measuring the MOF misconnection using the device will be described.

FIG. 5 is a schematic diagram of a MOF incorrect wiring determination device and a MOF connected to an electric power meter using a current transformer connected according to an embodiment of the present invention. The configuration using the device is shown.

Referring to FIG. 5, the current transformer 410 is for indirectly applying a voltage since the induced current flows through the terminal of the MOF. The current transformer 410 divides the current transformer so that the connection and detachment of wires or cables passing through the center of the current transformer are free. This can be implemented with a split current transformer. The split type current transformer can be installed in the cable without breaking and dismantling the line through its own separate configuration when the current transformer is expanded and replaced.

The MOF incorrect wiring measurement device 430 includes a power supply unit 431, a measurement unit 432, a comparison unit 433, and a display unit 434.

The power supply unit 431 supplies power of the MOF miswiring measuring device 430, and may be used to supply power by connecting to an external device.

The power supply unit 431 is capable of adjusting the size of the power, and may be freely adjusted when supplying power by connecting to an external device.

The measurement unit 432 is a current applied to the MOF terminal to the current transformer 410 in a state in which the MOF miswiring determination device is connected to the current transformer 410, the voltage required to apply the current, and the current flowing through the MOF terminal and As measuring the voltage, it is designed to be used in connection with the input module 420 that can be connected to the terminal to be measured.

The measurement unit 432 receives a value transmitted from the input module 420 in real time and transmits it to the comparison unit.

The value measured by the measuring unit 432 may be the magnitude of the voltage or current of the CT terminal of the MOF 101 or the magnitude of the voltage or current of the PT terminal of the MOF 101.

In addition, the measurement unit 432 may measure the magnitude of the voltage or current that the power supply unit 431 flows to the current transformer 410.

The comparison unit 433 compares the CT magnetization curve of the MOF or the PT magnetization curve of the MOF with the CT magnetization curve of the reference MOF or the PT magnetization curve of the MOF.

In the comparison section 433, the CT magnetization curve of the MOF and the PT magnetization curve of the MOF, which are measured by the manufacturer of the MOF 101, are preset. Here, when the difference between the CT magnetization curve of the MOF or the PT magnetization curve of the MOF and the measured value of the CT magnetization curve of the MOF or the PT magnetization curve of the MOF is within 10% of the error range, whether it is a normal line or a misline To judge.

The error range is within 10%. For example, when the excitation current is 0.017A when the PT magnetization curve of the preset MOF is 20V, the current is 0.017-0.0017 when the PT magnetization curve of the MOF measured is 20V. The above is the case and 0.017 + 0.0017 or less.

In mathematical terms,

| Measured current value for a specific voltage value-preset current value for a specific voltage value | ≤ a predetermined current value * 0.1 for the specified voltage value.

Here, the current value may be a slope or may be a magnitude of the current.

Various methods for comparing the measured value and the value set by the comparator 433 exist in various ways, and should not be construed as being limited by the above description.

The display unit 434 is connected to the comparison unit 433, and may be represented as a graph showing a result of outputting the comparison result so that the comparison unit 433 receives a comparison result and checks whether the wiring is incorrect. The comparisons can be shown numerically.

Since the MOF erroneous measuring apparatus 430 uses the magnetization inductance characteristic difference, the display unit 434 may express the correlation using the x axis of the graph as the current and the y axis as the voltage. In addition, it is possible to output a comparison of the magnitude of the current value or the slope with respect to a predetermined reference voltage value.

In addition, two or more graphs may be displayed on the display unit. In one embodiment, the preset magnetization curve and the measured magnetization curve may be simultaneously displayed. At the same time as the graph, the current value for a specific voltage can be displayed.

The display unit 434 may be provided with a pair of LEDs for checking whether a miswiring or a correcting wire is present, and there may be a separate LED for indicating an on / off state of a power supply.

In addition, the display unit 434 is provided with an alarm device, it can be set to sound an alarm when a wrong wiring. Alternatively, you can set the alarm to sound when the line is cleared.

The above-described embodiments of the display unit 434 may be simultaneously expressed together, and two or more may be output in a combined form.

For example, a graph and a numerical value can be output at the same time, and an alarm sound can be set when an incorrect wiring is established, and at the same time, an LED indicating an incorrect wiring can be turned on.

The foregoing descriptions are merely exemplary embodiments of an output method of the display unit 434, and there are various forms of one output to the display unit in the conventional measuring device, and the description of the display unit 434 is limited thereto. It should not be interpreted as.

6 is an embodiment for practicing the present invention. This is a flowchart on how to measure whether the MOF and the electricity meter are properly connected by using the MOF miswire measuring device.

5 and 6, first, the current transformer 410 is connected to the MOF miswiring measuring device 430 (S1), two terminals of the MOF 101, that is, the CT terminal (secondary side) and the MOF of the MOF 101 After applying a current to the current transformer 410 to the PT terminal (secondary side) of (S3), the voltage for applying the current to the power supply unit 431 of the MOF miswiring measuring device 430 is measured (S5). The input module 420 measures a voltage for applying current to the two terminals, adjusts the magnitude of the voltage supplied from the power supply unit 431, and measures the current change according to the voltage change (S7).

The value measured by the measuring unit 432 is transmitted to the comparing unit 433, and the comparing unit 433 compares the measured value with a CT magnetization curve of the reference MOF or a PT magnetization curve of the MOF (S9 and S11). ).

Here, the voltage channel at the input of the power meter 102 used in connection with the MOF 101 has an infinite resistance, and the current channel is shorted to have 0 resistance, so that the PT terminal or the MOF 101 of the MOF 101 is shorted. Since the current does not flow even when a voltage is applied when the voltage is connected to the voltage channel of the electricity meter 102, the PT terminal of the MOF 101 connected to the current channel of the input of the electricity meter 102 or the CT of the MOF 101. When the measured value of the terminal is input to the MOF erroneous determination unit 430, and matches with the CT magnetization curve of the preset reference MOF 101 within an error range of 10%, as a normal line (S13), the preset reference MOF ( If the PT magnetization curve of 101) is matched within 10% of the error range, it is determined as a wrong line (S15) (S100).

The error range may be less than 10% when the magnetizing inductance characteristic of the MOF 101 is excellent.

For example, when the error range is 5%, the following equation can be used.

| Measured current value for a specific voltage value-preset current value for a specific voltage value | ≤ preset current value for specified voltage value * 0.05

Due to the characteristics of the input channel of the electricity meter 102, the CT terminal of the MOF 101 is connected to the current channel of the electricity meter 102, and the PT terminal of the MOF 101 is correctly connected to the voltage channel of the electricity meter 102. In this case, current flows only to the CT terminal of the MOF 101, and only the CT magnetization curve of the MOF 101 is measured by the MOF miswiring measuring device 430, and no current flows through the PT terminal of the MOF 101. The PT magnetization curve of the MOF 101 is not measured.

In addition, in the case of a wrong connection where the CT terminal of the MOF 101 is connected to the voltage channel of the electricity meter 102 and the PT terminal of the MOF 101 is connected to the current channel of the electricity meter 102, the PT of the MOF 101 is used. The current flows only in the terminal, and only the PT magnetization curve of the MOF 101 is measured by the MOF miswiring measuring device 430, and no current flows through the CT terminal of the MOF 101, and the CT magnetization curve of the MOF 101 is measured. It doesn't work.

As described above, only the CT magnetization curve of the MOF 101 is measured at the nominal line, and only the PT magnetization curve of the MOF 101 is measured at the wrong line, so that the magnetization curves of the MOF 101 measured by the measuring unit are compared. Comparing with the reference magnetization curve preset in the section 433, it is possible to distinguish between a erroneous line or a pure line.

Therefore, among the reference magnetization curves preset in the comparison unit 433, when compared to the CT magnetization curve of the MOF 101 (S9), the error range is 10% (or less). The determination is made (S13), otherwise, the comparison is made with the PT magnetization curve of the MOF 101 (S11).

As described above, the reason for comparing with the CT magnetization curve of the MOF 101 is because there is more probability in the case of the incomplete line than in the case of the incomplete line, and in the case of the incomplete line, it is not necessary to judge the incomplete line.

In addition, when the result is out of the error range 10% range as compared with the CT magnetization curve of the MOF 101, the accuracy may be increased by comparing the PT magnetization curve of the reference MOF 101 again.

Therefore, when the CT magnetization curve of the reference MOF 101 is set within 10% of the error range, it is determined as a nominal line, and subsequent steps may be omitted.

When the comparison process S100 is completed, the result is transmitted to the display unit 434 (S17), and the result determined by the comparator 433 is output to the display unit 434 (S17). The implementation of the present invention as a method of measuring whether the MOF 101 and the electricity meter 102 are correctly connected using the apparatus ends.

The result output to the display unit 434 may be expressed in various ways as described in the above-described description of the MOF incorrect wiring determination device 430.

FIG. 7 is a flowchart illustrating a process of measuring a miswire using a MOF miswire determination device according to another embodiment of the present invention. FIG. 7 compares the CT magnetization curve of the predetermined reference MOF 101 after the process S7, that is, the process before the comparison process S100 in FIG. 6 (S9), if it is not in the similar range. Judging by the connection (S15), so the comparison process can be completed (S100 '). In the comparison process S100 ′ of FIG. 7, the process of comparing the PT magnetization curve of the reference MOF 101 preset in the comparison process S100 of FIG. 6 is omitted (S11).

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. Accordingly, the embodiments disclosed herein are intended to be illustrative rather than limiting, and the spirit and scope of the present invention is not limited by these embodiments. The scope of the present invention should be construed according to the following claims, and all the techniques within the scope of the present invention should be construed as being included in the scope of the present invention.

101; MOF
102; Watt hour meter
410; deflector
430; MOF incorrect wiring measurement device

Claims (8)

In the device for determining the mis-wiring between the metering out fit (MOF) and meter meter including a meter current transformer and a meter transformer,
Compare the magnetization curve of the MOF and the preset reference magnetization curve measured while the MOF and the electricity meter are connected to determine whether at least one of the current transformer terminal of the MOF or the transformer terminal of the MOF is correctly connected to the electricity meter. The misconnection determination device of the MOF.
The method of claim 1,
A power supply unit for supplying power to a current transformer to be connected to the MOF incorrect wiring determination device and the MOF incorrect wiring determination device;
A measuring unit measuring a current applied to the MOF terminal in the current transformer and a voltage required to apply the current;
A comparison unit comparing the magnetization curve of the MOF measured from the current and voltage measured by the measurement unit with the magnetization curve of the preset reference MOF; And
MOF incorrect wiring determination device including a display unit for displaying whether or not in accordance with the comparison result in the comparison unit.
3. The method of claim 2,
And the magnetization curve of the MOF is a CT magnetization curve or a PT magnetization curve. The method of claim 3, wherein
And a value to be compared by the comparing unit is a magnitude of a current when the voltage becomes a reference of the magnetization curve of the MOF or a slope of the magnetization curve of the MOF.
A method of determining whether a MOF is incorrectly connected by using a MOF incorrect wiring determination device in a state in which a MOF including an instrument current transformer and an instrument transformer are connected to each other, and the MOF measured by the MOF incorrect wiring determination device connected to the current transformer. The method of determining a misconnection of a MOF by comparing a magnetization curve with a preset reference MOF magnetization curve to determine whether the MOF is miswiring.
The method of claim 5, wherein
Applying a current to a terminal of the MOF with a current transformer connected to the MOF miswiring determination device;
Measuring the current applied by the current transformer to the terminal of the MOF and the magnitude of the voltage for applying the current to the MOF erroneous determination device;
Comparing the magnetization curve of the MOF input from the measured value with the magnetization curve of a preset reference MOF;
Outputting, on the display unit of the MOF incorrect wiring determination device, whether the incorrect wiring determined by the comparison unit of the MOF incorrect wiring determination device; And
Checking a misconnection determination output from the display unit of the MOF misconnection determination apparatus.
The method according to claim 5 or 6,
Wherein the MOF magnetization curve is a CT magnetization curve of the MOF or PT magnetization curve of the MOF erroneous determination method of the MOF.
The method of claim 7, wherein
The current transformer connected to the MOF incorrect wiring determination device is a fault current determination method of the MOF is a split type current transformer.

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