KR100688913B1 - Voltage monitoring apparatus and alternating current power supply using thereof - Google Patents

Abstract

A voltage monitoring device and an AC(Alternating Current) power system using the same are provided to let a user cope with surge and overvoltage by providing information about a history of surge, overvoltage, and power failure/power restoration to the user by separately storing and managing the surge and overvoltage generation information. A voltage monitoring device(130) is composed of a surge discriminating unit(131) detecting surge included in AC input power and outputting surge information if the surge is detected; an overvoltage discriminating unit(135) detecting whether the voltage of the AC input power is over a reference voltage or not and outputting overvoltage information informing an overvoltage state if over; and a zero voltage discriminating unit(133) checking the time when the voltage of the AC input power passes 0V and outputting zero voltage information about the time point to a control unit(150); a display unit(141) displaying the surge and overvoltage information to be visually recognized, according to a control signal of the control unit; and the control unit outputting the generation time of surge and overvoltage and overvoltage size information to the display unit if the surge and overvoltage information are input and outputting a cut-off control signal for cutting off the AC input power at the time when the voltage of the AC input power becomes zero, on the basis of the zero voltage information output from the zero voltage discriminating unit in receiving the overvoltage information from the overvoltage discriminating unit.

Description

Voltage monitoring apparatus and alternating current power supply using same

1 is a block diagram of an AC power input terminal provided with a voltage monitoring device according to an embodiment of the present invention;

2 is a circuit diagram of a surge discriminator according to an embodiment of the present invention;

3 is a circuit diagram of a zero voltage discrimination unit according to an embodiment of the present invention, and

4 is a circuit diagram of an overvoltage discriminating unit according to an embodiment of the present invention.

The present invention provides a voltage monitoring system that detects surges and overvoltages generated in AC power, displays the detection results, and stores and manages the history of surges and overvoltages so that the user can appropriately deal with them. A device and an AC power system using the same.

 Various digital equipment or computer devices are very sensitive devices, and the stabilization of the power supply for the operation is very important, and the importance of the simple personal system as well as the industrial large system will be more important.

One of the biggest influences on the stability of these power sources, particularly AC power sources, is surge and overvoltage. If the AC power source includes a surge or the AC power source is in an overvoltage state, the AC circuit or DC circuit in the rear stage may be fatally damaged.

An object of the present invention is to detect a surge and an overvoltage generated in an AC power supply, display the detected result to the user, and store and manage the history of surge and overvoltage occurrence so that the user can appropriately deal with it. The present invention provides a voltage monitoring device.

Still another object of the present invention is to monitor the load and surge voltage state of the AC power supply by using the above voltage monitoring device, to remove the surge and noise components, and to protect the load circuit by cutting off the AC power when an overvoltage occurs. The present invention provides an AC power supply system using a voltage monitoring device.

In order to achieve the above object, the voltage monitoring apparatus according to the present invention includes a surge discriminating unit, an overvoltage discriminating unit, a display unit and a control unit.

The surge discriminator detects a surge included in an AC input power and outputs surge information when a surge is detected, and the overvoltage discriminator detects whether the voltage of the AC input power is greater than or equal to a reference voltage, and when the surge voltage is greater than or equal to the reference voltage, an overvoltage condition. Outputs overvoltage information indicating that The display unit displays the predetermined information so that it can be visually recognized.

The control unit outputs the information on the generation time of the surge information to the display unit when receiving the surge information, and outputs the information on the magnitude of the overvoltage and the generation time of the overvoltage information to the display unit when receiving the overvoltage information. Can be.

The voltage monitoring device may be configured to display, by the controller, a display command for at least one of information on the surge information generation time, a magnitude of the overvoltage, and information on the overvoltage information generation time, and information stored in the memory from a user. The display apparatus may further include an input unit configured to receive an input, and the controller may output the information corresponding to the display command from the information stored in the memory to the display unit when the display command is received from the input unit.

Here, the overvoltage discriminator detects power failure and whether power is restored after the power failure and outputs the power to the controller, and the memory may further store information on power recovery after the power failure and power failure.

In addition, the voltage monitoring device may be configured to perform a predetermined communication with a memory and an external device in which the information on the surge information generation time, the magnitude of the overvoltage and the information on the overvoltage information generation time are stored by the controller. The control unit may further include, when the control unit receives at least one provision request of the information stored in the memory from the external device through the network interface unit, by extracting the information corresponding to the provision request from the memory to the network interface Through the unit can be provided to the external device.

In addition, the input unit receives a transmission request of a user requesting to provide at least one of the information stored in the memory to the external device, and outputs it to the control unit, the control unit corresponding to the transmission request received from the input unit Information may be extracted from the memory and provided to the external device through the network interface unit.

The voltage monitoring apparatus further includes an overvoltage cut-off unit which blocks the AC input power from being applied to the load side according to a predetermined control signal, and wherein the control unit cuts off the AC input power when the overvoltage information is received. The signal may be output to the overvoltage blocking unit.

The voltage monitoring device may further include a zero voltage discrimination unit configured to output zero voltage information, which is information about a time point when the voltage of the AC input power is 0 V, to the controller, and the controller outputs the control signal to the overvoltage cutoff unit. In this case, based on the zero voltage information is controlled so that the voltage of the AC input power supply is approximately 0V.

Here, the zero voltage discriminator decompresses the voltage of the AC input power between the photocoupler and the light output part of the port coupler and the AC coupler, wherein a light emitter is connected to the AC input power, and an output of the light receiver is input to the controller. It can be implemented including a device to.

The overvoltage information output by the overvoltage discriminating unit of the voltage monitoring device is a DC voltage having a voltage magnitude corresponding to the magnitude of the overvoltage, and the control unit converts the DC voltage into a digital value and based on the converted value. The magnitude of the overvoltage may be determined by reading the magnitude of the DC voltage.

The display unit may be any one of an LCD, an organic light emitting diode (OLED), a plasma display panel (PDP), a cathode ray tube (CRT), and a thermal printer.

An AC power supply system according to another embodiment of the present disclosure may be implemented by further including a surge protection unit and an overvoltage blocking unit in the voltage monitoring device. The surge protector removes and outputs a surge included in an AC input power, and the overvoltage interrupter outputs an AC power output from the surge protector to a load side, when the voltage of the AC power is in an overvoltage state according to a predetermined control signal. The AC power is cut off from being output to the load side.

The AC power supply system further includes a zero voltage discrimination unit for outputting zero voltage information, which is information about a time point when the voltage of the AC input power is 0 V, and a network interface unit capable of performing predetermined communication with an external device. The control unit outputs the control signal to the overvoltage cutoff unit when the AC power cutoff command is received from the external device, when the voltage of the AC input power source is approximately 0 V based on the zero voltage information. can do.

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

1 is a block diagram of an AC power supply system having a voltage monitoring apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the AC power supply system 100 of the present invention includes a surge / overvoltage cutoff unit 110 and a voltage monitoring device 130, and includes a surge, noise, and inrush current that may be included in an AC power source. And the spark voltage and the like. In addition, the AC power supply system 100 detects an overvoltage state and blocks the AC power in the overvoltage state from being output. In addition, the AC power supply system 100 manages the history of occurrence of surge, overvoltage or power failure on the AC power supply, and displays and manages predetermined information for the user to easily monitor.

The surge / overvoltage cutoff unit 110 receives AC power (for example, 220V), blocks surges and noise introduced into the AC power, and controls the voltage monitoring device 130 when the AC power is in an overvoltage state. AC power is cut off. In addition, the surge / overvoltage blocking unit 110 allows the AC power to be applied to the output terminal again under the control of the voltage monitoring device 130 when the AC power in the overvoltage state returns to the normal voltage. In addition, the surge / overvoltage blocking unit 110 removes the inrush voltage or the spark voltage generated in the AC power source.

Referring to FIG. 1, the surge / overvoltage blocking unit 110 may include a first surge protection unit 111, an overvoltage blocking unit 113, a second surge protection unit 115, and a spark killer 117. Include. However, the surge / overvoltage blocking unit 110 is not limited to the configuration of FIG. 1, and various configurations for blocking surge, noise, overvoltage, and spark voltage are possible.

The first surge protector 111 removes a surge that may flow between the AC power lines and a surge that may flow into the AC power line from the ground. The first surge protector 111 protects the circuit of the rear stage from the large-capacity surge by using an element having a high clamping voltage characteristic. The first surge protector 111 may include discharge devices, metal oxide varistors (MOV), transient voltage suppressor (TVS) suppressors, or discharge devices and suppressors, such as a gas tube (Spark Gap Arrester). It can be implemented by a combination.

 The overvoltage cutout 113 is connected between the first surge protector 111 and the second surge protector 115 and is output from the first surge protector 111 under the control of the voltage monitoring device 130. The AC power is blocked from flowing into the second surge protector 115. The overvoltage blocking unit 113 may be implemented using a switching device such as a relay. In addition, the overvoltage blocking unit 113 may output the AC power cut off under the control of the voltage monitoring device 130 to the second surge protection unit 115 again.

In FIG. 1, the overvoltage blocking unit 113 is illustrated as being included in the surge / overvoltage blocking unit 110. However, since the overvoltage blocking unit 113 is a device under the control of the voltage monitoring device 130, the overvoltage blocking unit 113 may be classified and described as a component of the voltage monitoring device 130 according to an embodiment.

The second surge protector 115 removes a surge that may flow between the AC power lines and a surge that may flow into the AC power line from the ground. The second surge protector 115 uses a device having a low clamping voltage characteristic to protect the circuit of the subsequent stage from the small capacity surge.

The spark killer 117 bypasses sparking high frequency noise that may occur during operation of an inrush current or an inverter generated when the AC power is turned on or off. To protect the circuit afterwards.

The voltage monitoring device 130 receives an AC power and detects whether a surge is included in the input AC power or whether the AC power is an overvoltage higher than a predetermined reference voltage. The voltage monitoring device 130 manages the history of the occurrence of surge and overvoltage on the AC power supply and displays and manages predetermined information for the user to easily monitor. In addition, the voltage monitoring device 130 may monitor the occurrence of power failure and the restoration of power and time information thereof.

When an overvoltage occurs above the reference, the voltage monitoring device 130 controls the surge / overvoltage cutoff unit 110 to block the AC power from being applied to the output terminal. When the normal voltage state is reached, the AC power is automatically applied to the output terminal. You can do that. The voltage monitoring device 130 may detect a time point when the AC power voltage is zero voltage so as to minimize noise generation when the AC power is cut off in an overvoltage state, such that the AC power cutoff is performed at zero voltage.

The voltage monitoring device 130 includes a surge discriminator 131, a zero voltage discriminator 133, an overvoltage discriminator 135, a memory 137, a network interface 139, a user interface 140, and a controller ( 150).

The surge discrimination unit 131 detects a surge flowing into the AC power. The surge discriminator 131 detects a corresponding surge when a surge is introduced into the AC power, and outputs 'surge information', which is information on the detected surge, to the controller 150. To this end, the surge discriminating unit 131 may generate a predetermined pulse and output the predetermined pulse to the controller 150 when detecting the AC power supply voltage higher than the surge determining reference voltage. The controller 150 stores information such as when a surge is generated and displays it to the user based on a pulse (that is, surge information) provided to the surge discriminator 131. The surge discrimination unit 131 may use the circuit disclosed in the applicant's registered patent No. 10-0567133, which will be described again below.

The zero voltage discrimination unit 133 checks a time point when the voltage of the AC power supply passes 0 V and outputs the 'zero voltage information' to the controller 150. The zero voltage discrimination unit 133 may be implemented in various ways, and may be simply detected by using a photo coupler including two diodes, which are connected in inverse parallel to each other, as a light emitting unit. .

When the overvoltage discriminator 135 detects an overvoltage higher than a reference voltage (or rated voltage) in the AC power source, the overvoltage discriminator 135 outputs 'overvoltage information' including the magnitude of the overvoltage to the controller 150. The overvoltage discriminator 135 may change a reference voltage for detecting an overvoltage state so as to change the overvoltage detection reference voltage according to a user's request. In addition, the overvoltage discriminating unit 135 may detect power failure and whether power is restored from the power failure.

The memory 137 may include various active and inactive memories, and various programs or data of the controller 150 may be stored. In addition, the memory 137 may correspond to a large capacity flash memory, a hard disk, and the like. The memory 137 stores information such as a time point of occurrence of surge, a time point of occurrence of overvoltage, a magnitude of overvoltage, whether power failure and power recovery, and a power failure and power recovery time by the controller 150.

The network interface unit 139 may be connected to an external device (not shown) through a predetermined wired or wireless network, and transmits data output from the controller 430 to an external device (not shown) by a wired or wireless communication method. The controller transmits data transmitted from an external device (not shown) to the controller 150. Here, the external device (not shown) may correspond to a personal computer (PC), a central power control system and other facility management system. The network interface unit 139 may simply correspond to an RS-232 interface.

Through the network interface unit 139, the voltage monitoring device 130 outputs monitoring information on the state of the AC power to an external device (not shown), and receives a control command by an external device (not shown) and the like. You can perform the operation.

The user interface unit 140 includes a display unit 141 and an input unit 143.

The display unit 141 displays the information transmitted from the controller 150 so that the user can visually recognize it. The display unit 141 may correspond to an LCD, an organic light emitting diode (PDP), a plasma display panel (PDP), or a cathode ray tube (CRT). In addition, a thermal printer or the like may correspond to the display unit 141. Whenever predetermined information is provided from the control unit 150, the record is printed by printing the information on the printing paper. Can be.

The input unit 143 corresponds to a key pad for receiving a character and pointing means such as a direction key for moving a pointer on the display unit 141 and various other keys.

When a specific event occurs in the AC power source, the input unit 143 receives a user's setting about a matter to be displayed through the display unit 141 and outputs it to the controller 150. In addition, when the display unit 141 displays a predetermined icon in order to receive a user's command, the input unit 143 receives a user selection for selecting one of the icons displayed on the display unit 141 to the controller 150. You can print

The input unit 143 receives from the user information about the display of the surge related information and the overvoltage related information stored in the memory 137 through the display unit 141 and the output to the external device (not shown) through the network interface unit 139. To the controller 150.

The controller 150 includes a data processor 151 and an overvoltage processor 153, and controls the overall operation of the voltage monitoring device 130.

When the data processor 151 receives the overvoltage information from the overvoltage discriminator 135, the data processor 151 stores the magnitude of the overvoltage in the memory 137 based on the overvoltage information and generates information on when the overvoltage information is received (that is, overvoltage generation). Information on timing) is also stored and managed in the memory 137. When the overvoltage information is provided from the overvoltage discriminator 135 as a DC voltage corresponding to the overvoltage, the data processor 151 may analyze and store the overvoltage information by converting the DC voltage into a digital value.

The data processor 151 may determine whether there is a power failure based on the overvoltage information from the overvoltage discriminator 135. When the overvoltage information is provided with a voltage having a predetermined size, when a power failure occurs, the voltage of the overvoltage information is maintained at 0 V, so that the data processor 151 can confirm that a power failure has occurred, and can also check the restoration of the power supply. . This power failure and power recovery information is stored in the memory 137.

In addition, when the surge processor 151 receives the surge information from the surge discriminator 131, the data processor 151 stores and manages the information on when the surge information is received (that is, when the surge occurs) in the memory 137.

The data processor 151 may display the surge related information and the overvoltage related information stored in the memory 137 through the input unit 143 through the display unit 141 or to the external device (not shown) through the network interface unit 139. When the information about the output is received, the information extracted from the memory 137 is output through the display unit 141 or the network interface unit 139.

In addition, when the data processing unit 151 receives a predetermined control command from an external device (not shown) through the network interface unit 139, the data processing unit 151 stores data stored in the memory 137 in response to the control command. The power supply may be controlled or the supply of AC power may be cut off by controlling the overvoltage blocking unit 113.

When the overvoltage processor 153 receives the overvoltage information, the overvoltage blocking unit 113 controls the AC power to be blocked from being output to the second surge protector 115. At this time, the overvoltage processor 153 controls the AC voltage to be cut off in the state closest to the zero voltage or the zero voltage based on the zero voltage information received from the zero voltage discriminator 133.

Hereinafter, an example of the surge discriminator 131, the zero voltage discriminator 133, and the overvoltage discriminator 135 will be described with reference to FIGS. 2 to 4.

2 is a circuit diagram of a surge discriminating unit according to an exemplary embodiment of the present invention, based on FIG. 1 of Patent No. 10-0567133.

Referring to FIG. 2, the surge discriminator 200 includes a filter 210, a rectifier 230, a signal converter 250, and a pulse generator 270, and the surge discriminator 131 of FIG. 1. Corresponds to one example.

The filtering unit 210 filters the noise signal from the AC power source when the AC power source includes a noise signal (surge) having a frequency higher than or equal to a reference frequency. In the case of FIG. 2, the filtering unit 210 includes the coil L so that the impedance of the coil L has a non-zero value only when the surge is included in the AC power supply, thereby filtering the surge that is the noise signal.

The AC power including the surge is rectified through the rectifier 230, and then charged in the capacitor C21, which is the signal converter 250, to change the sustain time of the surge so that the pulse generator 270 may generate a pulse.

The pulse generator 270 generates a pulse having a duty corresponding to a time when the surge output from the signal converter 250 is maintained, and outputs the pulse to the controller 150. The pulse output from the pulse generator 270 corresponds to the 'surge information'.

3 is a circuit diagram of a zero voltage discrimination unit according to an embodiment of the present invention, and the zero voltage discrimination unit 300 corresponds to an example of the zero voltage discrimination unit 133 of FIG. 1.

Referring to FIG. 3, in the zero voltage discrimination unit 300, the light emitting unit of the photo coupler U3 is connected to the AC power source through the resistor R31. However, the AC power source connected to the resistor R31 is preferably decompressed at an appropriate ratio by a transformer or the like. The driving voltage Vcc is connected to the collector terminal of the phototransistor which is the light receiving part of the photo coupler U3, and the resistors R32 and R33 are connected to the emitter terminal. The diode D31 is connected in parallel with the light emitting portion of the photo coupler U3. However, the diode D31 is connected in the reverse direction to the light emitting diode of the photo coupler U3.

The light emitting unit of the photocoupler U3 outputs a driving voltage Vcc (High) to the output through the resistor R33 when the AC power supply voltage is higher than the operating voltage of the light emitting diode. However, when the AC supply voltage is below the diode operating voltage, the transistor turns off and the output goes to 0 V (Low). Therefore, the zero voltage information becomes a pulse in which High or Low is repeated approximately in accordance with the zero voltage of the AC power supply. The controller 150 may know that the AC power supply passes the zero voltage based on the pulse output from the zero voltage discriminator 300.

4 is a circuit diagram of an overvoltage discriminating unit according to an embodiment of the present invention, and the overvoltage discriminating unit 400 corresponds to an example of the overvoltage discriminating unit 135 of FIG. 1.

The overvoltage discriminating unit 400 may be implemented in various ways. The embodiment of FIG. 4 is a method of converting an AC power supply voltage into a predetermined range by stepping down the voltage of an AC power supply using a transformer and outputting the DC voltage within a predetermined range. Detects an overvoltage condition.

Referring to FIG. 4, the AC power source is connected to the primary side of the transformer T41 via a resistor R41, and the secondary side of the transformer T41 is connected to the bridge rectifier circuits D41, D42, D43, and D44. The AC power supply which has been decompressed at a predetermined rate while passing through the transformer T41 is rectified while passing through the bridge rectifier circuits D41, D42, D43, and D44. The rectified power supply voltage is voltage-divided by the resistors R42 and R43 and converted into a predetermined direct current voltage by the smoothing capacitor C41. The capacitor C42 is for removing noise, and the diodes D45 and D46 allow the output overvoltage information to be within a predetermined voltage range.

The reference voltage for determining that the overvoltage discriminator 400 is an overvoltage may be determined by the resistors R42 and R43, and the resistor R42 may be configured to change the reference voltage according to a user's request by using a variable resistor.

The overvoltage information output from the overvoltage discriminator 400 is represented by a voltage value within a predetermined range, and the controller 150 converts the voltage value output from the overvoltage discriminator 400 into a digital signal to convert a value corresponding to the voltage value. The voltage of the AC power supply in the overvoltage state can be obtained.

The invention can be implemented in methods, devices and systems. In addition, when the present invention is implemented in computer software, the components of the present invention may be replaced with code segments necessary for performing necessary operations. The program or code segment may be stored in a medium that can be processed by a microprocessor and transmitted as computer data coupled with carrier waves via a transmission medium or communication network.

The media that can be processed by the microprocessor include electronic circuits, semiconductor memory devices, ROMs, flash memory, electrically erasable programmable read-only memory (EEPROM), floppy disks, optical disks, and hard disks. (Hard) Includes the ability to transmit and store information such as disks, fiber optics, wireless networks, and the like. Computer data also includes data that can be transmitted over electrical network channels, optical fibers, electromagnetic fields, wireless networks, and the like.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the above-described specific embodiment, the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

As described above in detail, the voltage monitoring apparatus according to the present invention may detect surges and overvoltages generated in AC power and display the detection results to the user.

The voltage monitoring device may provide the user with information on the history of surge, overvoltage, power failure, and power recovery by separately storing and managing the surge occurrence information and the overvoltage generation information, and may provide the external device through a network. This allows the user to cope with surges and overvoltages based on statistical data.

In addition, the AC power supply system using the voltage monitoring device of the present invention, by using the voltage monitoring device, not only monitors the surge and overvoltage state of the AC power, but also removes the surge and noise components, and when the overvoltage occurs, By blocking, the load circuit can be protected.

Claims (13)

A surge discrimination unit detecting a surge included in an AC input power and outputting surge information when a surge is detected; An overvoltage discriminating unit detecting whether the voltage of the AC input power is greater than or equal to a reference voltage, and outputting overvoltage information indicating an overvoltage condition when the voltage of the AC input power is greater than or equal to the reference voltage; A zero voltage discrimination unit which checks a time point at which the voltage of the AC input power passes 0 V and outputs zero voltage information which is information on the time point of the 0 V to a control unit below; A display unit configured to visually recognize predetermined surge and overvoltage information according to a control signal of the controller; And When the surge information and the overvoltage information are respectively inputted from the surge discriminator or the overvoltage discriminator, the occurrence time and magnitude information of the overvoltage are output to the display unit, and the zero voltage discriminator is received when the overvoltage information is received from the overvoltage discriminator. And a controller which outputs a cutoff control signal for shutting off the AC input power when the voltage of the AC input power is approximately 0V based on the zero voltage information output from the controller. The method of claim 1, A memory for storing information on the surge information generation time, the magnitude of the overvoltage, and the information on the overvoltage information generation time by the controller; And And an input unit configured to receive a display command for at least one of information stored in the memory from a user. The control unit, when receiving the display command from the input unit, the voltage monitoring device, characterized in that to output the information corresponding to the display command of the information stored in the memory to the display unit to be displayed. The method of claim 1, A memory for storing information on the surge information generation time, the magnitude of the overvoltage, and the information on the overvoltage information generation time by the controller; And It further includes a network interface unit for performing a predetermined communication with the external device, When the control unit receives at least one provision request of the information stored in the memory from the external device through the network interface unit, the controller extracts information corresponding to the provision request from the memory to the external device through the network interface unit. Voltage monitoring device, characterized in that provided by. The method of claim 1, A memory for storing information on the surge information generation time, the magnitude of the overvoltage, and the information on the overvoltage information generation time by the controller; A network interface unit capable of performing predetermined communication with an external device; And And an input unit configured to receive a display command for at least one of information stored in the memory from a user. When the control unit receives the display command from the input unit, the control unit outputs and displays the information corresponding to the display command from the information stored in the memory to the display unit, and is stored in the memory from the external device through the network interface unit. When receiving at least one transmission request of the information, the voltage monitoring device, characterized in that the information corresponding to the transmission request is extracted from the memory and provided to the external device through the network interface unit. The method of claim 4, wherein The input unit receives a transmission request of a user requesting to provide at least one of the information stored in the memory to the external device, and outputs it to the controller, The controller may extract information corresponding to a transmission request received from the input unit from the memory and provide the external device to the external device through the network interface unit. The method according to any one of claims 1 to 5, And an overvoltage cut-off unit operating according to a cutoff control signal of the controller to block the AC input power from being applied to the load side. The control unit, when receiving the overvoltage information voltage monitoring device, characterized in that for outputting the control signal to cut off the AC input power to the overvoltage blocking unit. delete The method of claim 1, The zero voltage discrimination unit A photocoupler having a light emitting unit connected to the AC input power and an output of the light receiving unit being input to the controller; And And a device for reducing a voltage of the AC input power between the light emitting unit of the porter and the AC input power. The method according to any one of claims 1 to 5, The overvoltage information output by the overvoltage discriminator is a DC voltage having a voltage magnitude corresponding to the magnitude of the overvoltage, And the control unit converts the DC voltage into a digital value and reads the magnitude of the DC voltage based on the converted value to determine the magnitude of the overvoltage. delete The method of claim 1, The overvoltage discriminator detects power failure and whether power is restored after the power failure, and outputs the power to the controller. A memory in which the control unit stores information on the power recovery after the power failure and the power failure, information on the surge information generation time, magnitude of the overvoltage, and information on the generation time of the overvoltage information; And And an input unit configured to receive a display command for at least one of information stored in the memory from a user. The control unit, when receiving the display command from the input unit, the voltage monitoring device, characterized in that to output the information corresponding to the display command of the information stored in the memory to the display unit to be displayed. delete A surge protection unit for removing and outputting a surge included in an AC input power source; A surge discrimination unit detecting a surge included in the AC input power and outputting surge information when a surge is detected; An overvoltage discriminating unit detecting whether the voltage of the AC input power is greater than or equal to a reference voltage, and outputting overvoltage information indicating an overvoltage condition when the voltage of the AC input power is greater than or equal to the reference voltage; A zero voltage discrimination unit which checks a time point at which the voltage of the AC input power passes 0 V and outputs zero voltage information which is information on the time point of the 0 V to a control unit below; An overvoltage blocking unit for supplying AC power output through the surge protection unit to a load side, and blocking the AC input power from being applied to the load side according to a control signal of the following controller when the voltage of the AC power source is in an overvoltage state; A display unit configured to visually recognize predetermined surge and overvoltage information according to a control signal of the controller; A network interface unit capable of performing predetermined communication with an external device; And When the surge information and the overvoltage information are respectively inputted from the surge discriminator or the overvoltage discriminator, the occurrence time and magnitude information of the overvoltage are output to the display unit, and the zero voltage discriminator is received when the overvoltage information is received from the overvoltage discriminator. And a control unit for outputting a cutoff control signal to an overvoltage cut-off unit when the voltage of the AC input power is approximately 0V based on the zero voltage information output from the controller.

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