KR101164009B1 - Automatic Meter Reading, remote meter reading service electric meter which includes a leakage rheometry function - Google Patents

Abstract

The present invention relates to a remote meter reading meter having a leakage current measuring function, and calculates the pulse time difference between the leakage current and the line voltage detected by using an image current transformer installed inside the meter. Resistive leakage current (Igr) and reactive components (capacitive leakage current, Igc) are classified and transmitted to the upper server with the power consumption of the customer.

According to the present invention, by dividing the active and reactive components of the leakage current in the electricity meter and transmitting the data to the upper server to notify the actual leakage measurement value in the electricity bill, the leakage state is easily checked at the customer, and the leakage is corrected by itself. Reduces the risk of electric shock and fire caused by leakage current.

Power meter, leakage current, remote meter reading, leakage current

Description

Automatic meter reading, remote meter reading service electric meter which includes a leakage rheometry function

The present invention is a remote meter reading power meter that includes a leakage current measurement function to measure the power consumption and the leakage current by adding a function to measure the resistance current and capacitive leakage current inside the electricity meter installed in the customer to read the power consumption It is about.

In general, when the covering of wires and the insulation of electrical equipment are aged or damaged, the insulator is damaged so that the leakage current flows from the wire path to the ground through the location. If the human body touches the place where the leakage current flows, there is a risk of electric shock.In the place where the excessive leakage current flows, overheating occurs due to the arc, and it is ignited by the flammable material around, which may cause the leakage material. The dangerous leakage current is called an effective leakage current (resistive leakage current, Igr).

In addition, the leakage current flows from the cable line to the ground due to the capacitive component between the cable line and the ground in a state where the coating of the wire and the insulation of the electric device are not damaged. .

The magnitude of the effective power for the reactive component (capacitive leakage current) of the leakage current is effective by calculating 'effective power = voltage × capacitive leakage current × cosθ = 0' because the phase difference between voltage and leakage current is 90 degrees. Since the magnitude of the power is zero, the capacitive leakage current does not cause an electric shock or a short circuit fire.

Currently, a method for remotely measuring leakage current is to install a power meter, a remote metering system, or a video current transformer inside a switchgear to detect leakage current of a vector sum for an active component and an invalid component for leakage current. However, this method has a disadvantage in that the reliability of the measured value is low because active ingredients and inactive ingredients are not distinguished.

Therefore, there is a need for a method for distinguishing and measuring the leakage current and the active component, and remotely checking the risk of leakage by using only the active component, and measuring the leakage of the leakage without having to enter or leave the customer's home.

In order to solve the problems of the prior art, the present invention measures a leakage current generated in a customer premises inside a wattmeter measuring power consumption of a consumer, and measures the measured leakage current as a resistive leakage current (Igr) and a capacitive leakage current (Igc). The purpose of the present invention is to provide a remote meter reading power meter that includes a leakage current measurement function capable of remotely monitoring leakage current by transmitting leakage current data together with the power usage data to a higher server by adding a function of classifying a).

In order to achieve the above object, the remote meter reading power meter including the leakage current measuring function of the present invention is a remote meter reading meter is a signal processing method for calculating the timing pulse time difference between the leakage current and the line voltage measured by the internal current transformer Sizes of the active component Igr and the reactive component Igc for the current may be calculated, and transmitted together with the power usage data to the upper server through the communication module.

The present invention provides a power meter for reading the power consumption in the customer and transmitting to the upper server through the communication module, comprising a power calculation module for sensing the voltage and voltage of the line to calculate the amount of power used, and measures the leakage current of the line And a leakage current measuring module configured to generate a pulse signal of the voltage and the leakage current of the line and calculate a resistive leakage current and a capacitive leakage current based on a time difference and a phase difference of the pulse signal. The microcontroller may include a microcontroller integrating the calculated resistive leakage current, capacitive leakage current, and metered power usage, and may include a communication module configured to transmit data integrated by the microcontroller to a higher server.

In the present invention, the leakage current measuring module includes a sensing unit for measuring the leakage current of the line through the image current transformer, and the first and second pulses for generating a pulse signal of each of the line voltage and the leakage current measured by the electricity meter It includes a generator, and includes a time difference comparison unit for receiving the line voltage pulse signal and the leakage current pulse signal from the first and second pulse generator to compare the time difference. And a phase difference calculator configured to calculate a phase difference between the line voltage pulse and the leakage current pulse based on the time difference calculated by the time difference comparator, and calculate the resistive leakage current and the capacitive leakage current through the phase difference, respectively. It may include a leakage current calculation unit for transmitting to the controller.

In the present invention, the resistive leakage current is calculated by multiplying the leakage current measured by the sensing unit and the cosine phase angle (cosθ), and the capacitive leakage current is measured by the leakage current and the sinusoidal phase angle measured by the sensing unit. can be calculated as the product of sinθ).

The present invention may further include a notification display unit which displays a short circuit when it is determined whether the values of the resistive leakage current and the capacitive leakage current calculated by the leakage current measurement unit exceed a reference value.

According to the present invention, the resistive leakage current (Igr) and the capacitive leakage current (Igc) are distinguished and displayed in the electricity meter, and when the leakage current value is out of a certain level, the user is notified in real time by checking the leakage state in the customer. It is effective in inducing security against leakage.

Also, by adding the function of measuring leakage current to the electricity meter of the existing remote metering system, the metered power consumption and measured leakage current are transmitted to the remote server through the communication module. It has the effect of inducing measures against leakage.

In addition, by writing the electric leakage measurement value together with the electric bill to send to the customer there is an effect that can reduce the occurrence of electric shock and fire caused by the electric leakage.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings. In adding reference numerals to components of the following drawings, it is determined that the same components have the same reference numerals as much as possible even if displayed on different drawings, and it is determined that they may unnecessarily obscure the subject matter of the present invention. Detailed descriptions of well-known functions and configurations will be omitted.

1 is a block diagram showing a remote meter reading meter having a leakage current measurement function according to an embodiment of the present invention.

Referring to Figure 1, it shows the configuration of the electricity meter 100 for reading the power supplied to the customer through the line power amount calculation module 110, leakage current measurement module 120, microcontroller 130, communication module ( 140, and a first display unit 150.

The electricity meter calculation module 110 relates to a conventional general electricity meter, and senses the current and voltage flowing through the electricity consumer using the current sensing unit 112 and the voltage sensing unit 114, and measures the detected current value and the voltage value. Transfer to the calculator 116.

The current sensing unit 112 measures the magnitude of the current flowing in the line in a non-contact manner, converts the measured analog signal into a digital signal, and then transmits the measured amount to the power calculating unit 116.

The voltage sensing unit 114 is connected to a line and a neutral line to measure the use voltage of the customer through the voltage difference inputted through the line and the voltage output through the center line, and then converts the analog signal into a digital signal. After conversion to the leakage current measuring module 120 and the power amount calculation unit 116 is transmitted.

 The power calculator 116 calculates the amount of power used by the customer using the current value and the voltage value, and transmits the calculated amount to the microcontroller 130.

Leakage current measurement module 120 is a key component of the present invention by measuring the leakage current flowing in the line by measuring the reactive component and the effective component.

The leakage current measuring module 120 includes the sensing unit 121, the first and second pulse generators 122 and 123, the time difference comparator 124, the phase difference calculator 125, the leakage current calculator 126, and the second. The display unit 127 is included.

The sensing unit 121 measures the difference between the current input through the line and the current output through the neutral line by installing an image current transformer (Zct) on the outer diameters of the line and the neutral line to measure the leakage current in the customer premises. do. In addition, the leakage current measured at this time is a vector sum of the resistive leakage current and the capacitive leakage current, and does not accurately represent the leakage state of the consumer.

The first pulse generator 122 generates an analog signal of the leakage current measured by the sensing unit 121 as a pulse signal which is a digital signal.

The second pulse generator 123 receives the voltage measured by the voltage sensing unit 114 of the wattmeter calculation module 110 and generates the pulse signal as a digital signal.

The time difference generator 124 calculates a time difference between the current pulse signal and the voltage pulse signal received from the first and second pulse generators 122 and 123, and transmits the time difference to the phase difference generator 125. The phase difference of the current with respect to the voltage is calculated by calculating the ratio of the time difference between the current and the voltage pulse with respect to the cycle period.

The leakage current calculator 126 calculates a resistive leakage current as an active ingredient and a capacitive leakage current as an active component using the leakage current measured by the sensing unit 121 and the phase angle calculated by the phase difference generator 125. do.

The calculation of the resistive leakage current and the capacitive leakage current may refer to FIG. 2.

Although the second display unit 127 is not an essential component of the leakage current measuring module 120, the values of the resistive leakage current and the capacitive leakage current are displayed so that the user can recognize them. In addition, a function of generating an alarm when the value of the resistive leakage current and the capacitive leakage current exceeds a threshold set by a user may be additionally installed.

The microcontroller 130 integrates the customer power usage data calculated by the power calculation module 110 and the leakage current (resistive leakage current, capacitive leakage current) data measured by the leakage current measurement module 120 to communicate the module 140. ) To the parent server.

The communication module 140 remotely transmits data by using one communication method selected from power line communication (PLC), Zigbee, or wireless communication (RF), so that not only the power consumption of the customer at the remote server of the remote site is used. Receive and monitor accurate data on leakage current, that is, resistive leakage current and capacitive leakage current.

The first display unit 150 displays the data received from the microcontroller so that the user can see the naked eye. The first display unit 150 displays only the power consumption as in the conventional electricity meter, or the leakage current (resistive leakage current that appears on the second display unit 127). In addition, the risk of leakage may be indicated by the capacitive leakage current value.

2 is a diagram illustrating a signal flow of a leakage current measuring module according to an exemplary embodiment of the present invention.

Referring to FIG. 2, when a component of the capacitive leakage current is generated on the customer side in the current value measured by the sensing unit 121, a phase difference θ preceding the voltage is generated.

Accordingly, the first pulse generator 122 representing the pulse signal for the current generates a pulse at the start point of the sine wave detected by the sensing unit, and then transmits the generated pulse value to the time difference comparator 124.

The second pulse generator 123 representing the pulse signal of the voltage generates a pulse at the start point of the sine wave of the voltage sensed by the voltage sensor 114, and then compares the generated pulse value with the time difference comparator 124. To send).

The time difference comparator 124 receives two pulse signals (current pulse signal and voltage pulse signal) having different phases, calculates the time difference T between the two pulse signals, and then transmits them to the phase difference calculator 125.

The phase difference calculator 125 may calculate a time difference T for one cycle. When the time difference T is calculated, the phase difference calculator 125 may calculate the phase difference θ.

That is, since 60 cycles per second in the waveform of current and voltage, the time of one cycle is 1/60 (0.016666667) seconds. And since the phase angle of one cycle is 360 degrees, the phase angle can be calculated by the following equation.

1/60 second: 360 degrees = T (seconds): X (degrees)

X (degrees) = [T (seconds) × 360 degrees] / (1/60) seconds

For example, if the time difference T is measured as 0.0035 seconds, the phase difference is

It can be calculated at 75.6 degrees by the formula (0.0035 × 360) / (1/60).

The leakage current calculation unit 126 calculates the resistive leakage current and the capacitive leakage current by the following equation by applying the phase angle calculated by the phase difference calculation unit 125.

Resistive leakage current Igr = leakage current (value measured by the sensing unit 121) × Cosθ

Capacitive leakage current Igr = leakage current (value measured by the sensing unit 121) × Sinθ

For example, assuming that the leakage current value measured by the sensing unit 121 is 2 mA and the value measured by the phase difference calculator 125 is 75.6 degrees, the resistive leakage current is 0.5 mA (2 mA × Cos 75.6 degrees). The capacitive leakage current can be calculated as 1.94 mA (2 mA × Sin 75.6 degrees).

For reference, if you check the above calculation, you can see that Root (0.5 ² + 1.94 ² ) = Root (0.25 + 3.75) = 2mA.

According to the present invention, by calculating the time difference with respect to the pulse of the current and voltage, and calculates the magnitude of the resistive leakage current and the capacitive leakage current, respectively, by using a digital signal rather than an analog signal, It can be miniaturized in two circuit chips and improves accuracy.

As described above, it has been described with reference to the preferred embodiment of the present invention, but those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the present invention described in the claims below I can understand that you can.

1 is a block diagram showing a remote meter reading meter having a leakage current measurement function according to an embodiment of the present invention.

2 is a view showing a signal flow of the leakage current measuring module according to an embodiment of the present invention.

            <Explanation of symbols for the main parts of the drawings>

100: power meter 110: power calculation module

112: current sensing unit 114: voltage sensing unit

116: power calculation unit 120: leakage current measuring module

121: sensing unit 122: first pulse generator

123: second pulse generator 124: time difference comparison unit

125: phase difference calculator 126: leakage current calculator

127: second display unit 130: microcontroller

140: communication module 150: first display unit

Claims (4)

delete A power amount calculating module for measuring a voltage and a current of a line to calculate a used power amount and then transmitting the used power amount to a power amount calculating unit; A leakage current measuring module for measuring a leakage current of a line, generating a pulse signal of the voltage and the leakage current of the line, and calculating a resistive leakage current and a capacitive leakage current based on a time difference and a phase difference of the pulse signal; A microcontroller integrating the calculated resistive leakage current, capacitive leakage current and the amount of power used; And A remote meter reading power meter including a leakage current measurement function, comprising: a communication module for transmitting the data integrated by the micro-controller to a higher server, The leakage current measuring module may include: a sensing unit measuring leakage current of the line through an image current transformer; First and second pulse generators generating pulse signals of each of the line voltage and the leakage current measured by the power meter; A time difference comparison unit for receiving the line voltage pulse signal and the leakage current pulse signal from the first and second pulse generators and comparing the time difference; A phase difference calculator for calculating a phase difference between the line voltage pulse and the leakage current pulse based on the time difference calculated by the time difference comparator; And And a leakage current calculating unit configured to calculate a resistive leakage current and a capacitive leakage current through the phase difference, and transmit the calculated leakage current to the controller of the watt-hour meter. The method of claim 2, wherein the resistive leakage current is calculated by multiplying the leakage current measured by the sensing unit and the cosine phase angle (cosθ), and the capacitive leakage current is measured by the leakage current measured by the sensing unit. A remote meter reading power meter with a leakage current measurement function, characterized in that calculated by the product of the phase angle (sin θ). The method of claim 2, further comprising: a notification display unit for determining whether the values of the resistive leakage current and the capacitive leakage current calculated by the leakage current measuring module exceed a reference value, and displaying a short circuit if exceeded. Remote meter reading power meter that includes a leakage current measurement function.

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