KR101238694B1 - Digtal relay being able to check and correct miss wiring and method thereof - Google Patents

Abstract

The present invention relates to a digital relay capable of detecting a wrong wiring and changing a wiring, and a method for detecting a wrong wiring and changing a wiring of a digital relay, the input sensing unit sensing a three-phase current and a three-phase voltage of a power line; A phase comparison unit for detecting and comparing phases between currents, voltages, and currents and voltages according to the sensed currents and voltages; The first control signal for determining whether the wiring is wrong according to the result of the phase comparison, and the second control signal for controlling the connection change to the determined incorrect wiring, and the first control signal for controlling the display of the detected phase or incorrect wiring A control unit for outputting; A status display unit which displays the detected phase or the determined incorrect wiring in accordance with the first control signal; And a wiring changer for changing the wiring according to the second control signal when the wiring is incorrect. Checking incorrect wiring of an external current transformer (CT) and a voltage transformer (PT) of a digital relay by such a configuration. And through incorrect wiring correction function to help the user to easily connect to the normal wiring can reduce a lot of loss in the incorrect wiring, it is possible to fast and stable power monitoring and protection.

Incorrect wiring detection, wiring change

Description

DIGITAL RELAY BEING ABLE TO CHECK AND CORRECT MISS WIRING AND METHOD THEREOF}

The present invention not only checks the voltage and current of the digital protective relay, but also relays the faults of the external current transformer (CT) and the voltage transformer (PT) and displays information on the fault wiring by using the same. The present invention relates to a digital relay capable of detecting a wrong wiring and changing a wiring, and a method of detecting and wiring a wrong wiring of a digital relay.

In general, a digital relay refers to a device having a command function that cuts a part of a circuit when an abnormal state such as a short circuit or eddy current occurs in an electric circuit.

1 is a block diagram of a digital relay according to the prior art.

The digital relay 30 according to the prior art displays the measured data by measuring voltage and current from a current transformer CT 10 connected to a power line and a voltage transformer PT 20 inducing a voltage from the power line. And relay operation.

That is, the digital relay is composed of many terminals such as terminals connecting each of the R phase, S phase, T phase, and N phase, and these terminals should be correctly connected to the power line.

The digital relay according to the prior art is installed and operated in the high and low voltage switchgear, and measures the current and voltage flowing in the system to monitor accidents such as overcurrent / overvoltage, and to control the switchboard breaker to protect customers. It is installed in the system and receives the input of external CT and PT to calculate the voltage and current, and performs the measurement and relaying operation on the electric power such as power factor, power, and power.

However, in the case of the conventional digital relay, only the current and voltage are input from the external CT and PT, and the measurement and relay operation is implemented using the same. Therefore, in the conventional digital relay, when the wiring of the external CT and PT is wrong, the system can not reliably monitor and protect the system by receiving the current and voltage input from the incorrectly connected external CT and PT to perform the error measurement and the error relay.

Also, it takes a lot of time for the user to correct the wrong wiring.

An object of the present invention is to measure and relay the amount of electricity, such as voltage and current input from an external current transformer (CT) and a voltage transformer (PT), as well as check the wiring of the external CT, PT and incorrect wiring By adding the correction function, the user can easily operate the system properly by connecting the system normally. .

In addition, another object of the present invention is to check the incorrect wiring of the external current transformer (CT) and the voltage transformer (PT: Potential Transformer) and to display information on the incorrect wiring by using the normal connection of the user's external CT, PT It is to promote convenience in doing so.

In order to achieve the above object, a digital relay capable of detecting a wrong wiring and changing a wiring according to an embodiment of the present invention includes an input sensing unit for sensing a three-phase current and a three-phase voltage of a power line; A phase comparison unit for detecting and comparing phases between currents, voltages, and currents and voltages according to the sensed currents and voltages; The first control signal for determining whether the wiring is wrong according to the result of the phase comparison, and the second control signal for controlling the connection change to the determined incorrect wiring, and the first control signal for controlling the display of the detected phase or incorrect wiring A control unit for outputting; A status display unit which displays the detected phase or the determined incorrect wiring in accordance with the first control signal; And a wiring change unit for changing the wiring according to the second control signal when the wiring is incorrect.

The input detector may include a current detector configured to detect a three-phase current flowing through the power line; It characterized in that it comprises a voltage sensing unit for sensing the three-phase voltage of the power line.

The phase comparator includes: a phase comparator between currents for comparing phases between phases of the detected currents; An interphase comparison unit for comparing the voltages between the phases of the detected voltages; And a phase comparison unit between current / voltage comparing each phase of the detected current with respect to any phase of the detected voltage.

The controller compares the two different phases with respect to any phase of the voltage or current and applies the second control signal to change the phase of each of the detected voltage or current when the comparison result exceeds the reference phase range. It is characterized by outputting.

The state display unit may include a voltage phase display unit displaying a phase between two remaining phases based on an arbitrary phase of the three-phase voltage; A current phase display unit displaying a phase between the remaining two phases based on an arbitrary phase of the three-phase current; A voltage / current phase display unit for displaying a phase between three phases of the three-phase current based on an arbitrary phase of the three-phase voltage; And an incorrect wiring display unit for displaying whether or not an error of a connection of the input sensing unit with respect to the power line is in accordance with the second control signal.

In order to achieve the above object, an incorrect wiring detection and wiring change method of a digital relay according to an embodiment of the present invention includes: detecting three-phase current and three-phase voltage of a power line; A voltage phase determination step of determining whether a phase between each phase of the sensed voltage is in a normal state; A current phase determination step of determining whether a phase between each phase of the current is normal when the phase between the voltages is normal; A voltage / current phase determination step of determining whether the phase between the voltage and the current is in a normal state when the phase between the currents is normal; And a connection state display step of displaying a connection state between the voltage and current phase and the relay between the power line if the phase between the voltage and the current is normal.

The voltage phase determination step may include: comparing any one phase of the three-phase voltage and the phases of the remaining two phases; Determining that the detected voltage is in a normal state when the result of the phase comparison is within a range of a reference voltage phase, and maintaining the detected voltage connection; And determining that the detected voltage is abnormal when the result of the phase comparison is out of the range of the reference voltage phase, and changing the sensed voltage.

The current phase determination step may include: comparing a phase of any one phase of the three-phase current and the remaining two phases; Determining that the sensed current is in a normal state when the result of the phase comparison is within a range of a reference current phase, and maintaining the sensed current connection; If the result of the phase comparison is outside the range of the reference current phase, it is determined that the connection of the sensed current is in an abnormal state, and changing the connection of the sensed current.

The voltage / current phase determining step may include comparing a phase of any phase of the three-phase voltage with a phase of the world of the three-phase current; If the result of the phase comparison is within a range of reference voltage / current phase, determining that the detected voltage and current connections are in a normal state and maintaining the detected voltage and current connections; And if the result of the phase comparison is outside the range of the reference voltage / current phase, determining that the detected voltage and current wiring is abnormal and changing the detected current wiring.

The step of determining the voltage / current phase may include converting a phase of a current having the smallest comparison error among phases of any phase of the voltage and a phase of the world of the current into a phase of a current corresponding to any phase of the voltage. It is possible to further comprise the step of setting.

According to an exemplary embodiment of the present invention, a method of detecting a wrong wiring and changing a wiring of a digital relay and a method of detecting a wrong wiring of a digital relay may include an external current transformer (CT) and a voltage transformer (PT) of a digital relay. Incorrect wiring check and correction of wrong wiring help user to make normal wiring easily, and it can reduce many losses in correcting wrong wiring, and can provide fast and stable power monitoring and protection.

Hereinafter, with reference to the accompanying drawings of the present invention

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

2 is a block diagram of a digital relay capable of detecting a wrong wiring and changing a connection according to an embodiment of the present invention.

Referring to FIG. 2, a digital relay 100 capable of detecting a wrong wiring and changing a wiring according to an embodiment of the present invention includes an input sensing unit 110 for sensing a three-phase current and a three-phase voltage of a power line; A phase comparison unit 120 for detecting and comparing phases between currents, voltages, and currents and voltages according to the sensed currents and voltages; The first control signal for determining whether the wiring is wrong according to the result of the phase comparison, and the second control signal for controlling the connection change to the determined incorrect wiring, and the first control signal for controlling the display of the detected phase or incorrect wiring A control unit 130 for outputting; A status display unit (140) for displaying whether the detected phase or the determined incorrect wiring is in accordance with the first control signal; It includes a connection change unit 150 for changing the connection in accordance with the second control signal when the incorrect connection.

The input detector 110 includes: a current detector 111 for detecting a three-phase current flowing through the power line; It includes a voltage detector 112 for sensing the three-phase voltage of the power line.

In the embodiment of the present invention, the current detector 111 includes a current transformer (CT) to detect the current of the three phases of the power line, and the voltage detector 112 is a voltage transformer (PT) Induction of the three-phase voltage of the power supply line, respectively, to induce a voltage from each of the three phases of the power supply line.

The phase comparator 120 includes an inter-phase phase comparator 121, an inter-phase phase comparator 122, and a current / voltage phase comparator 123.

The phase comparison unit 121 obtains a phase of each current flowing in three phases of the power line and compares phases between phases. The interphase comparison unit 122 obtains a phase of a voltage induced in each phase of the three phases of the power supply line and compares phases between the phases. The phase comparison unit 123 may include comparing each phase of the detected current based on an arbitrary phase of the detected three-phase voltage.

The controller 130 compares two different phases based on an arbitrary phase of a voltage or a current, and changes the phase of each detected voltage or current when the comparison result exceeds a reference phase range. 2 Output the control signal.

The control unit, the phase comparison unit and the state display unit are configured to process real-time input data to detect whether a wiring state is normal.

In this case, the reference phase range has a predetermined error, and the error is preferably in the range of 30 degrees or less.

The state display unit 140 includes a voltage phase display unit 141, a current phase display unit 142, a voltage / current phase display unit 143, and a miswiring display unit 144.

The voltage phase display unit 141 displays the phase difference between the remaining two phases based on any phase of the three-phase voltage, and the current phase display unit 142 displays the remaining two phases based on any phase of the three-phase current. Display the phase of. For example, the phase difference between the voltages is obtained by calculating the phase difference between the phases of the S-phase and T-phase voltages based on the phase of the R-phase voltage among the three-phase voltages, and the phase difference between the currents in the three-phase currents. The phase difference between the phases of the S-phase and T-phase currents is obtained by displaying the phase of the R-phase current as the reference phase.

The voltage / current phase display unit 143 displays a phase between three phases of the three-phase current based on an arbitrary phase of the three-phase voltage. For example, the phase difference between the voltage and the current is referred to the phase of the R phase voltage among the three phase voltages, and the phase difference between the phases of the R, S and T phases of the three phase current is displayed. In this case, the phase of the R phase current is determined as the phase of the current having the smallest difference value between the phase of the R phase voltage and the phase of the three phase current.

The incorrect wiring display unit 144 displays whether or not a connection of the input sensing unit with respect to the power line is in error according to the second control signal.

3 is a flowchart illustrating a method for detecting a miswiring and changing a wiring of a digital relay according to an exemplary embodiment of the present invention.

Referring to FIG. 3, a method of detecting a miswiring and changing a wiring of a digital relay according to an embodiment of the present invention includes detecting a three-phase current and a three-phase voltage of a power line (S10); A voltage phase determination step (S20) of determining whether a phase between each phase of the sensed voltage is in a normal state; A current phase determination step (S30) of determining whether a phase between each phase of the current is in a normal state when the phase between the voltages is normal; A voltage / current phase determination step (S40) of determining whether the phase between the voltage and the current is normal when the phase between the currents is normal; If the phase between the voltage and the current is normal, the connection state display step (S50) for displaying the connection state between the phase of the voltage and the current and the relay of the power supply line.

In the voltage phase determination step (S21), the phase of any one of the three-phase voltage sensed by the input sensing unit and the phase of the remaining two voltages are compared (S21), and the result of the phase comparison is If it is within the range of the reference voltage phase, it is determined that the connection of the sensed voltage is in a normal state, and it is compared whether the phase of the sensed current is in a steady state while maintaining the connection of the sensed voltage. )

However, if the result of the phase comparison is outside the range of the reference voltage phase, and it is determined that the connection of the sensed voltage is in an abnormal state, the connection of the sensed voltage is changed by the connection changing unit, and the voltage is reset. (S23, S24)

In the current phase determination step (S30), the phase of the current flowing in any one of the three-phase current is compared with the phase of the current flowing in the remaining two phases (S31), and the result of the phase comparison is the range of the reference current phase If not, it is determined that the sensed current connection is in a normal state, and the connection of the sensed current is not changed and the voltage-current phase is compared in a normal state (S32, S41).

If it is determined that the result of the phase comparison is outside the range of the reference current phase so that the sensed current is connected to an abnormal state, the sensed current is changed by the connection changer, and the current is redetected. (S33, S34)

In the voltage / current phase determination step (S40), the phase of any phase of the three-phase voltage and the phase of the world of the three-phase current are compared (S42), and the result of the phase comparison is a value of the reference voltage / current phase. If it is within the range, it is determined that the detected voltage and current wiring is in a normal state.

However, if the result of the phase comparison is outside the range of the reference voltage / current phase, it is determined that the detected voltage and current wiring is abnormal and the wiring of the detected current is changed (S43).

The state display unit displays a normal connection state or a miswiring state in which the connection of voltage or current detected during the phase comparison between voltages, phase comparison between currents, and phase comparison between voltages and currents is performed. (S50)

The phase of the current having the smallest comparison error among the comparison values of the phase of any phase of the voltage with the phase of the world of the current is set to the phase of the current corresponding to any phase of the voltage.

In determining whether the voltage is incorrectly connected, it is determined that the steady state, that is, the voltage connection is correct, when the phase between the voltage R phase and the S phase and the phase between the voltage S phase and the T phase maintains a phase difference of 120 degrees. Here, if the phase difference of 120 degrees is a theoretical value, the phase correction is actually 120 ± α in consideration of power cables and other losses.

That is, the phase difference between the voltages has an error of ± α at 120 degrees.

When the phase difference between the voltages does not fall within the phase corrected range, the phase angle of each phase of the voltage calculated inside the digital relay is changed to find a voltage phase having a phase difference within the phase correction value. That is, the wiring of the detected voltage is changed.

In the case of determining whether the voltage is incorrectly connected, it is determined that the steady state, that is, the current connection is correct, when the phase difference between the current R phase and the S phase and the phase between the current S phase and the T phase maintains the phase difference of 120 degrees. Here, the phase difference of 120 degrees is set to 120 + α as in the case of voltage.

It is preferable that α, which is a phase difference error for correcting the phase difference between the voltages, generally has a value within 30 degrees.

When determining whether there is a miswiring between the voltage currents, a phase difference with the phases of the corrected or maintained currents R phase, S phase, and T phase is obtained based on the phase of the corrected or maintained voltage R phase.

In this case, the phase of the current having the smallest phase difference with the phase of the voltage R phase is set as the reference value.

The input sensing unit may be removed from the digital relay, and in this case, the input voltage or current sensed from the external CT or PT may be received.

While the invention has been shown and described with respect to specific embodiments thereof, those skilled in the art can variously modify the invention without departing from the spirit and scope of the invention as set forth in the claims below. And that it can be changed. However, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

1 is a block diagram of a digital relay according to the prior art.

2 is a block diagram of a digital relay capable of detecting a wrong wiring and changing a connection according to an embodiment of the present invention.

3 is a flowchart illustrating a method for detecting a miswiring and changing a wiring of a digital relay according to an exemplary embodiment of the present invention.

Claims (11)

An input sensing unit sensing a three-phase current and a three-phase voltage of the power line; A phase comparison unit for detecting and comparing phases between currents, voltages, and currents and voltages according to the sensed currents and voltages; The first control signal for determining whether the wiring is wrong according to the result of the phase comparison, and the second control signal for controlling the connection change to the determined incorrect wiring, and the first control signal for controlling the display of the detected phase or incorrect wiring A control unit for outputting; A status display unit which displays the detected phase or the determined incorrect wiring in accordance with the first control signal; A digital relay capable of detecting a wrong wiring and changing a wiring, including a wiring changing unit for changing the wiring according to the second control signal when the wiring is incorrect. The method of claim 1, The input detector may include a current detector configured to detect a three-phase current flowing through the power line; And a voltage sensing unit for sensing a three-phase voltage of the power line. The method of claim 1, The phase comparator includes: a phase comparator between currents for comparing phases between phases of the detected currents; An interphase comparison unit for comparing the voltages between the phases of the detected voltages; And a phase comparator between current / voltage comparing each phase of the detected current with respect to any phase of the detected voltage. The method of claim 1, The control unit may compare the two different phases based on an arbitrary phase of the voltage or current and change the phase of each of the detected voltage or current when the comparison result exceeds the reference phase range. Digital relay capable of detecting the wrong wiring and change the wiring, characterized in that for outputting. 5. The method of claim 4, The reference phase range has a predetermined error, the error range is 30 degrees (degree) or less digital relay capable of detecting the wiring and change the wiring. The method of claim 1, The state display unit may include a voltage phase display unit displaying a phase between two remaining phases based on an arbitrary phase of the three-phase voltage; A current phase display unit displaying a phase between the remaining two phases based on an arbitrary phase of the three-phase current; A voltage / current phase display unit for displaying a phase between three phases of the three-phase current based on an arbitrary phase of the three-phase voltage; And a miswiring display unit for displaying whether or not an error of a connection of the input sensing unit with respect to the power line occurs in response to the second control signal. Sensing three-phase current and three-phase voltage of the power line; A voltage phase determination step of determining whether a phase between each phase of the sensed voltage is in a normal state; A current phase determination step of determining whether a phase between each phase of the current is normal when the phase between the voltages is normal; A voltage / current phase determination step of determining whether the phase between the voltage and the current is in a normal state when the phase between the currents is normal; And a connection state display step of displaying a connection state between the phase of the voltage and the current and the relay between the power line if the phase between the voltage and the current is normal. The method of claim 7, wherein The voltage phase determination step may include: comparing any one phase of the three-phase voltage and the phases of the remaining two phases; Determining that the detected voltage is in a normal state when the result of the phase comparison is within a range of a reference voltage phase, and maintaining the detected voltage connection; And determining that the detected voltage is abnormal when the result of the phase comparison is outside the range of the reference voltage phase, and changing the wiring of the sensed voltage. How to detect and change wiring. The method of claim 7, wherein The current phase determination step may include: comparing a phase of any one phase of the three-phase current and the remaining two phases; Determining that the sensed current is in a normal state when the result of the phase comparison is within a range of a reference current phase, and maintaining the sensed current connection; And determining that the detected current is in an abnormal state when the value of the phase comparison is outside the range of the reference current phase, and changing the connection of the sensed current. And wiring changes. The method of claim 7, wherein The voltage / current phase determining step may include comparing a phase of any phase of the three-phase voltage with a phase of the world of the three-phase current; If the result of the phase comparison is within the range of the reference voltage / current phase, determining that the detected voltage and current wiring is in a normal state and maintaining the detected voltage and current wiring; And if the result of the phase comparison is outside the range of the reference voltage / current phase, determining that the sensed voltage and current wiring is abnormal and changing the sensed current wiring. How to detect incorrect wiring and change wiring. 11. The method of claim 10, And setting the phase of the current having the smallest comparison error among the comparison values of the phase of any phase of the voltage with the phase of the world of the current to the phase of the current corresponding to the arbitrary phase of the voltage. How to detect incorrect wiring and change wiring of digital relay.

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