Integrated Power Quality and Communication Path Management System for Ensuring Display Reliability of Road and Tunnel Variable Message Signs

Abstract

The present invention relates to a power quality and communication path integrated management system for ensuring the display reliability of a Variable Message Sign (VMS) installed on a road or tunnel. The power quality and communication path integrated management system according to the present invention includes a power input protection unit (110) into which AC power is input, an AC / DC converter (120) that converts the AC power into DC power to form a main power bus, an uninterruptible power switching unit (130) that receives the main power bus and battery power as inputs to form a load power bus without interruption, a power measurement unit (140) that measures the voltage and current of the load power bus, an Ethernet-based wired communication unit (310), and a control unit (200) that controls the power switching and the display operation of the VMS by integrally determining the power measurement information and the communication status information. The power measurement unit (140) measures the voltage of the load power bus through a voltage divider circuit, measures the load current through a current sensor, and provides the measured signal to the control unit via an analog-to-digital converter and an isolation interface. The above control unit (200) determines whether power quality deteriorates or communication failures occur, performs uninterrupted switching to battery power when power quality deteriorates, and controls display brightness or message update operations so that essential messages of the electronic sign are maintained even when communication failures occur. Accordingly, the present invention prevents the interruption of display of the electronic sign even in environments where power abnormalities or communication failures occur, and enables the continuous provision of safety information required in road and tunnel environments.

Description

Technology Field

[0001] The present invention relates to a Variable Message Sign (VMS) installed on roads and tunnels, and more specifically, to a power quality and communication path integrated management system that improves the display reliability and operational stability of the VMS by integrally monitoring and analyzing the quality of power supplied to the VMS and the communication status for remote control of the VMS, and actively controlling the power and communication path according to the results. Background Technology

[0002] Electronic road signs installed in road and tunnel sections are critical traffic safety facilities that provide real-time information on traffic flow control, accident and disaster warnings, and traffic restrictions. As most of these signs operate continuously for extended periods in unmanned environments, stable display quality and remote control reliability are essential requirements.

[0003] However, in actual operating environments, the quality of power supplied to road electronic display signs frequently becomes unstable due to factors such as lightning strikes, momentary power outages, voltage drops, and harmonic interference. This leads to issues such as broken characters, flickering, display delays, and controller resets. Furthermore, in sections with poor communication environments, such as tunnels or mountainous areas, problems may arise where remote control of the road electronic display signs becomes impossible due to fiber optic cable disconnection or communication delays.

[0004] Conventional technology is limited to monitoring power failures and communication failures independently or responding only after the fact, making it difficult to effectively ensure the display reliability of road electronic signs in situations where power quality degradation and communication failures occur simultaneously. Prior art literature

[0005] Registered Patent Publication No. 10-2157178 (Publication Date: Oct. 23, 2020) Registered Patent Publication No. 10-2807998 (Publication Date: May 14, 2025) The problem to be solved

[0006] The objective of the embodiments of the present invention for improving the aforementioned problems is to provide a power quality and communication path integrated management system for ensuring display reliability of road and tunnel variable message signs (VMS), which can secure display reliability and remote control stability of the variable message signs even in road and tunnel environments by integrally diagnosing the quality status of the power supplied to the variable message signs and the operational status of the communication path, and performing power control and communication path control in conjunction according to the diagnosis results. means of solving the problem

[0008] To achieve the above objectives, a power quality and communication path integrated management system for securing display reliability of a road and tunnel Variable Message Sign (VMS) according to an embodiment of the present invention comprises: an input terminal portion into which AC power is input; a power input protection portion connected to the input terminal portion and including a fuse for overcurrent protection, a varistor for surge absorption, an inrush current limiting element, and an EMI filter; an AC / DC converter portion connected to the output of the power input protection portion and converting the AC power into DC power to form a main power bus; a power switching portion receiving the main power bus and battery power as inputs, respectively, and including an OR-ing controller of the abnormal diode type and a power MOSFET to form a load power bus supplied to the VMS without interruption; and a power measurement portion including a voltage divider circuit for measuring the voltage of the load power bus and a current sensor for measuring the current flowing through the load power bus. The invention is characterized by comprising: an analog-to-digital converter that converts an analog signal output from the power measurement unit into a digital signal, and an isolation interface unit disposed between the analog-to-digital converter and the control unit to provide electrical isolation; a wired communication unit including an Ethernet connector, an electrostatic discharge protection element, and an Ethernet physical layer converter; and a control unit configured to determine whether power quality deteriorates by comparing power measurement information received through the isolation interface unit with a preset reference value, and to receive communication status information received from the wired communication unit together with the power switching unit when power quality deteriorates or communication failure occurs, and to control the display brightness or message update operation of the road electronic sign to maintain essential display.

[0009] The above control unit is characterized by being configured to determine whether a voltage drop or momentary power outage has occurred using a measurement value received from the power measurement unit, and to maintain the continuity of power supplied to the road electronic display sign by selectively connecting either the main power or the battery power through the OR-ing controller according to the result of the determination.

[0010] The above control unit determines whether a communication failure has occurred using link status information of the wired communication unit, and is characterized by controlling the display brightness or message update operation of the road electronic sign to maintain essential displays when a power quality degradation state and a communication failure state occur simultaneously. Effects of the invention

[0011] A power quality and communication path integrated management system for ensuring display reliability of road and tunnel variable message signs (VMS) according to one embodiment of the present invention constantly monitors the voltage and current status of the power supplied to the variable message signs (VMS) through actual circuit measurement, and by integrally controlling an uninterruptible power switching unit using an abnormal diode method and a communication control circuit by a control unit, it is possible to stably ensure the display reliability of the variable message signs even in situations of voltage drop, momentary power outage, surge, and communication disconnection that frequently occur in road and tunnel environments.

[0012] In addition, one embodiment of the present invention has the effect of preventing the reset, interruption of display, or misdisplay of the road electronic display sign during the power switching process by switching the main power and battery power uninterruptedly through an OR-ing circuit of the abnormal diode type.

[0013] In addition, one embodiment of the present invention quantitatively determines power quality degradation through a power measurement unit and an isolation interface, and by switching to a mode of reducing display brightness, adjusting the message update cycle, or maintaining essential messages based on the determination result, it can continuously provide safety information even in a limited power environment.

[0014] In addition, one embodiment of the present invention can maintain communication continuity with the control center even in the event of a communication failure through redundancy with the wired communication unit and the wireless communication path, and has the effect of prioritizing the maintenance of the core functions of the road electronic display sign based on the integrated judgment of the control unit even in the event of a combination of power abnormalities and communication failures.

[0015] Accordingly, the present invention can significantly improve the operational reliability, safety, and maintenance efficiency of a road electronic signage system.

[0016] Furthermore, while the prior art is limited to providing power or communication functions individually, the present invention provides a technical effect of maintaining the display continuity of road electronic signs even in situations where voltage drops, momentary power outages, or communication failures occur individually or in combination by linking and controlling a power measurement unit, an uninterruptible power switching unit using an abnormal diode method, and a communication status determination unit in a single control unit.

[0017] According to the present invention, unlike the conventional method of managing the power quality and communication status of a road electronic sign individually, power control and communication path control can be performed in conjunction based on display reliability.

[0018] Accordingly, even if voltage fluctuations or communication failures occur, misdisplays and information gaps on electronic road signs can be minimized, and stable traffic information can be provided, especially in harsh environments such as tunnels and mountainous areas.

[0019] According to the present invention, by determining the state of the power supplied to the road electronic display sign through actual circuit measurement and integrally controlling the uninterruptible power switching unit and the communication control circuit, the display reliability of the road electronic display sign can be stably secured even in poor road and tunnel environments such as voltage drop, momentary power outage, and communication disconnection.

[0020] In addition, uninterruptible power switching using an OR-ing circuit based on an abnormal diode can prevent the reset or interruption of display on road electronic signs during power switching, and has the effect of continuously providing essential safety information even in situations where power abnormalities and communication failures occur simultaneously. Brief explanation of the drawing

[0022] FIG. 1 is a block diagram illustrating the overall functional configuration of a power quality and communication path integrated management system for a road electronic sign according to one embodiment of the present invention. Figure 2 is a block diagram illustrating a structure in which power status information and communication status information are integrally determined by the control unit to perform power switching and display control. Figure 3 is a block diagram illustrating the power path from the AC power input to the load power bus and the uninterruptible power switching structure. FIG. 4 is a block diagram illustrating a power measurement and insulation structure that measures the voltage and current of a load power bus, digitizes the measurement signal, and transmits it to a control unit in an isolated state. Figure 5 is a block diagram illustrating a structure in which communication data and communication status information are provided to the control unit through an Ethernet-based wired communication unit. Specific details for implementing the invention

[0023] The present invention as described above will be explained in detail through the attached drawings and embodiments.

[0024] It should be noted that the technical terms used in this invention are used merely to describe specific embodiments and are not intended to limit the invention. Furthermore, unless specifically defined otherwise in this invention, the technical terms used in this invention should be interpreted in the sense generally understood by those skilled in the art to which this invention pertains, and should not be interpreted in an overly broad or overly narrow sense. Additionally, if a technical term used in this invention is an incorrect technical term that fails to accurately express the concept of the invention, it should be replaced with a technical term that can be correctly understood by those skilled in the art. Moreover, general terms used in this invention should be interpreted according to their prior definitions or the context, and should not be interpreted in an overly narrow sense.

[0025] Furthermore, singular expressions used in the present invention include plural expressions unless the context clearly indicates otherwise. In the present invention, terms such as "composed of" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the invention, and should be interpreted as meaning that some of the components or steps may not be included, or that additional components or steps may be included.

[0026] Additionally, terms including ordinal numbers, such as first, second, etc., used in the present invention may be used to describe components, but the components should not be limited by the terms. The terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component.

[0027] Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. Identical or similar components are given the same reference number regardless of the drawing symbols, and redundant descriptions thereof will be omitted.

[0028] Furthermore, in describing the present invention, detailed descriptions of related prior art are omitted if it is determined that such descriptions could obscure the essence of the invention. Additionally, it should be noted that the attached drawings are intended only to facilitate an understanding of the concept of the present invention and should not be interpreted as limiting the concept of the present invention.

[0029] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. This embodiment is described as an example of a power quality and communication path integrated management system applied to a Variable Message Sign (VMS) installed on a road or tunnel, but is not limited thereto.

[0030] FIG. 1 is a block diagram illustrating the overall functional configuration of a power quality and communication path integrated management system for a road electronic sign according to an embodiment of the present invention; FIG. 2 is a block diagram illustrating a structure in which power status information and communication status information are integrally determined by a control unit to perform power switching and display control; FIG. 3 is a block diagram illustrating a power path from an AC power input to a load power bus and an uninterruptible power switching structure; FIG. 4 is a block diagram illustrating a power measurement and isolation structure that measures the voltage and current of a load power bus, digitizes the measurement signal, and transmits it to a control unit in an isolated state; FIG. 5 is a block diagram illustrating a structure in which communication data and communication status information are provided to a control unit through an Ethernet-based wired communication unit.

[0031] As illustrated in FIG. 1, the power quality and communication path integrated management system of the road electronic sign of the present invention includes a power unit (100), a control unit (200), a communication unit (300), and an electronic sign load (400).

[0032] The power supply unit (100) converts AC power input from the outside into DC power suitable for the light-up sign load (400) and supplies it, and is configured to maintain the continuity of power supply even when a power failure occurs.

[0033] The control unit (200) comprehensively determines the power status and communication status to control power switching and the display operation of the road electronic sign, and the communication unit (300) performs wired communication with the control center and provides communication status information to the control unit (200).

[0034] The power supply unit (100) is a functional block for supplying stable power to the light-up sign load (400) and includes a power input protection unit (110), an AC / DC converter unit (120), an uninterruptible power switching unit (130), and a power measurement unit (140).

[0035] The power input protection unit (110) performs the role of protecting the downstream circuit from lightning, surge, overcurrent and electromagnetic noise when an external AC power source is applied through the input terminal. To this end, the power input protection unit (110) includes an overcurrent protection fuse, a surge absorption varistor, an inrush current limiting element, and an EMI filter, and prevents instantaneous abnormal voltage or current that may occur when AC power is applied from being transmitted to the AC / DC converter (120).

[0036] The AC / DC converter (120) converts the AC power that has passed through the power input protection unit (110) into DC power to form a main power bus (24V_MAIN). The AC / DC converter (120) may include a rectifier circuit and a switching power circuit, and capacitors and protection elements for voltage ripple reduction and transient voltage protection are connected to the main power bus to form a stable DC power.

[0037] The uninterruptible power switching unit (130) receives the main power bus (24V_MAIN) and the battery power (BAT) as inputs and forms a load power bus (24V_BUS) supplied to the electronic sign load (400). The uninterruptible power switching unit (130) includes an OR-ing controller of the ideal diode type and a power MOSFET, and automatically selects the power with higher priority by comparing the voltage status of the main power and the battery power. Accordingly, even if a voltage drop or momentary power outage occurs in the main power, the battery power is automatically selected to maintain the load power bus, and the display operation of the road electronic sign is not interrupted.

[0038] The power measurement unit (140) is configured to measure the state of the power actually supplied to the light-up sign load (400) and provide it to the control unit (200). The power measurement unit (140) includes a voltage divider circuit (Rv1, Rv2) for measuring the voltage of the load power bus (24V_BUS) and a current sensor (CT1) for measuring the load current.

[0039] The voltage of the load power bus is converted into a measurable low-voltage signal by a voltage divider circuit, and the load current is converted into a sense signal proportional to the current magnitude by a current sensor. These analog measurement signals are converted into digital data by an analog-to-digital converter (U1). The converted digital data is transmitted to the control unit (200) through an isolation interface (U2), and the isolation interface (U2) prevents damage to the control unit caused by lightning, ground potential difference, or surge by providing electrical isolation between the power measurement area and the control area.

[0040] The control unit (200) determines whether a voltage drop, momentary power outage, or overcurrent occurs using the power measurement data, and controls the uninterruptible power switching unit (130) or controls the display operation of the road electronic sign according to the result of the determination.

[0041] The communication unit (300) is configured to perform wired communication between the control center and the road electronic sign control device and includes a wired communication unit (310). The wired communication unit (310) may include an Ethernet connector, an electrostatic protection element, an Ethernet physical layer converter, and a communication processor.

[0042] The communication signal received from the control center is input through an Ethernet connector, passes through an electrostatic discharge protection element, and is converted into a digital signal by an Ethernet physical layer converter. The converted communication data and communication status information, including link up / down status, are transmitted to the control unit (200) through a communication processor.

[0043] The control unit (200) operates to ensure the display reliability of the road electronic sign by comprehensively determining power measurement information input from the power measurement unit (140) and communication status information input from the communication unit (300). The control unit (200) determines whether the power quality has deteriorated as the power measurement information is compared with a preset reference value, and controls the uninterruptible power switching unit (130) to switch to battery power as necessary.

[0044] Additionally, the control unit (200) controls the display brightness or message update operation so that the light indicator load (400) continuously displays essential messages even when a communication failure occurs. Even when a power quality degradation state and a communication failure state occur simultaneously, the control unit (200) performs display control according to priority to prevent interruption of display.

[0045] Accordingly, the power quality and communication path integrated management system for road electronic display signs according to the present invention can stably maintain the display reliability of the road electronic display signs even in environments where power abnormalities or communication failures occur.

[0046] Referring to FIG. 2, in one embodiment of the present invention, a structure can be seen in which power status information and communication status information are determined integrally by the control unit (200).

[0047] As illustrated in FIG. 2, the power measurement unit (140) measures the voltage and current of the load power bus (24V_BUS) to generate power measurement information, and the power measurement information is input to the control unit (200) via an isolation interface. In addition, the wired communication unit (310) of the communication unit (300) provides the control unit (200) with link up / down status and communication error information detected during the communication process with the control center as communication status information.

[0048] The control unit (200) does not process the power status information and communication status information independently, but rather analyzes them integrally according to a preset judgment logic. For example, when a voltage drop or momentary power outage is detected, the control unit (200) determines that the power quality is degraded and simultaneously considers whether a communication failure has occurred based on the communication status information.

[0049] The control unit (200) controls the uninterruptible power switching unit (130) or adjusts the display brightness, message update cycle, or priority of the display content of the electronic sign load (400) according to the integrated judgment result. Accordingly, control is performed so that the essential message of the road electronic sign is maintained even if a power failure or communication failure occurs.

[0050] Referring to FIG. 3, a power path and an uninterruptible power switching structure can be seen in one embodiment of the present invention.

[0051] As shown in FIG. 3, an external AC power source is input to an AC / DC converter (120) via a power input protection unit (110), and the AC / DC converter (120) converts the AC power source into DC power to form a main power bus (24V_MAIN).

[0052] The above main power bus is provided as the first input of the uninterruptible power switching unit (130), and the battery power (BAT) is provided as the second input of the uninterruptible power switching unit (130). The uninterruptible power switching unit (130) includes an OR-ing controller of the ideal diode type and a power MOSFET, and automatically selects the power with a good voltage state between the main power and the battery power.

[0053] A load power bus (24V_BUS) is formed at the output of the uninterruptible power switching unit (130), and the load power bus is directly connected to the electronic display sign load (VMS) (400) to supply power. Accordingly, even if a voltage drop or momentary power outage occurs in the main power supply, the battery power is automatically selected to maintain the load power bus, and the display operation of the electronic display sign is not interrupted.

[0054] Referring to FIG. 4, a power measurement and insulation structure for measuring the voltage and current of a load power bus in one embodiment of the present invention can be seen.

[0055] As shown in FIG. 4, the voltage of the load power bus (24V_BUS) is converted into a measurable low-voltage signal by a voltage divider circuit (Rv1, Rv2), and the load current is detected by a current sensor (CT1). The analog signals corresponding to the voltage and current are input to an ADC (analog-to-digital converter) (U1) and converted into digital data.

[0056] Digital data output from the ADC (analog-to-digital converter) (U1) is transmitted to the control unit (200) through an isolation interface (isolation IF) (U2). The isolation interface (isolation IF) (U2) provides electrical isolation between the power measurement area and the control area, thereby preventing abnormal voltages that may be caused by lightning, surges, or ground potential differences from being transmitted to the control unit.

[0057] The control unit (200) determines the power quality status using the power measurement data and controls the uninterruptible power switching unit (130) and the display operation of the road electronic sign when a voltage drop, momentary power outage, or current abnormality occurs.

[0058] Referring to FIG. 5, the configuration of a wired communication unit in one embodiment of the present invention can be seen.

[0059] As illustrated in FIG. 5, the wired communication unit (310) includes an Ethernet connector (J3), an ESD protection unit (ESD1), an Ethernet PHY (Ethernet physical layer converter) (U12), and a communication processor (U14). A communication signal received from the control center is input through the Ethernet connector (J3), passes through the ESD protection unit (ESD1), and is converted into a digital signal at the Ethernet PHY (Ethernet physical layer converter) (U12).

[0060] Communication data and link status information converted by the Ethernet PHY (Ethernet Physical Layer Converter) (U12) are transmitted to the control unit (200) through the communication processor (U14). The control unit (200) determines whether a communication failure has occurred by using the communication status information together with power measurement information, and performs display control so that the display reliability of the LED sign load (400) is maintained even if a communication failure occurs.

[0061] Representative embodiments of the present invention are described below with reference to the drawings. These embodiments are exemplified by cases where they are applied to a power quality and communication path integrated management system for ensuring the display reliability of Variable Message Signs (VMS) installed on roads or tunnels, but are not limited thereto.

[0062] [Example 1] Example of integrated power and communication operation under normal operating conditions

[0063] According to one embodiment with reference to FIGS. 1 and 2, when external AC power is supplied normally and wired communication is in a normal state, the AC power passing through the power input protection unit (110) is converted into DC power by the AC / DC converter (120) to form a main power bus (24V_MAIN). The main power bus is transmitted to a load power bus (24V_BUS) through an uninterruptible power switching unit (130), and the light display load (400) receives stable power from the load power bus and performs normal display operations.

[0064] At this time, the power measurement unit (140) continuously measures the voltage and current of the load power bus and provides them to the control unit (200), and the communication unit (300) maintains a link-up state during wired communication with the control center and provides communication status information to the control unit (200). The control unit (200) determines that both the power measurement information and the communication status information are within the normal range and controls the light-up sign load (400) to display a message normally according to the display command received from the control center.

[0065] [Example 2] Example of operation during voltage drop or momentary power outage

[0066] According to one embodiment with reference to FIGS. 2 and 3, when a voltage drop or momentary power outage occurs in an external AC power source, the power measurement unit (140) detects a voltage change in the load power bus (24V_BUS) and transmits voltage measurement information to the control unit (200). The control unit (200) determines that the measurement information has decreased to below a preset reference value and recognizes the power quality deterioration state.

[0067] Accordingly, the control unit (200) allows or controls the operation of the uninterruptible power switching unit (130) so that the battery power is selected instead of the main power bus. The uninterruptible power switching unit (130) automatically connects the battery power to the load power bus by means of an OR-ing structure of an ideal diode method, and in this process, the power supplied to the light sign load (400) is maintained without interruption.

[0068] At the same time, the control unit (200) can perform display control, such as lowering the display brightness of the electronic sign or increasing the message update cycle, to reduce power consumption. Accordingly, the electronic sign continues to display essential messages even in the event of a voltage drop or momentary power outage.

[0069] [Example 3] Example of operation when a communication failure occurs

[0070] According to one embodiment with reference to FIGS. 2 and FIGS. 5, when a link down state is detected in the wired communication unit (310), the communication processor transmits communication status information to the control unit (200). The control unit (200) analyzes the communication status information and determines that a communication failure with the control center has occurred.

[0071] In this case, the control unit (200) recognizes that receiving a new display command is impossible and controls the electronic sign load (400) to maintain the message that was displayed before the communication failure occurred or the pre-stored essential message. Additionally, by restricting the message update operation until the communication failure state is resolved, it prevents abrupt changes in the display content or error displays from occurring.

[0072] Accordingly, the reliability of information provided by electronic road signs to road users is maintained even in the event of communication failures.

[0073] [Example 4] Example of operation when power failure and communication failure occur simultaneously

[0074] According to one embodiment with reference to FIGS. 2 to 5, when a wired communication failure occurs simultaneously with a voltage drop or momentary power outage, the control unit (200) determines the situation by simultaneously considering power status information received from the power measurement unit (140) and communication status information received from the communication unit (300).

[0075] The control unit (200) first controls the uninterruptible power switching unit (130) to select the battery power, thereby maintaining the power supply to the light sign load (400). At the same time, considering the communication failure state, it limits the display brightness and message update operation of the light sign and performs display control so that a preset essential message is maintained.

[0076] In this way, the control unit (200) operates to prevent the interruption of the display of the road electronic sign even in situations where power quality degradation and communication failure conditions occur in combination, and to continue providing the minimum safety information required in road and tunnel environments.

[0077] According to the power quality and communication path integrated management system for ensuring display reliability of road and tunnel electronic display signs (VMS) according to an embodiment of the present invention configured as above, the voltage and current status of the power supplied to the electronic display sign (VMS) are constantly monitored through actual circuit measurement, and the uninterruptible power switching unit and communication control circuit of the abnormal diode type are integrally controlled by the control unit, thereby enabling stable assurance of display reliability of the electronic display sign even in situations of voltage drop, momentary power outage, surge, and communication disconnection that frequently occur in road and tunnel environments.

[0078] Preferred embodiments according to the present invention have been illustrated and described above. However, the present invention is not limited to the embodiments described above, and any person skilled in the art may make various modifications without departing from the gist of the invention as set forth in the appended claims. Explanation of the symbols

[0079] 100: Power supply 110: Power input protection unit 120: AC / DC converter 130: Uninterruptible Power Switching Unit 140: Power measurement section 200: Control unit 300: Communications Department 310: Wired Communications Unit 400: Electronic Sign Load (VMS)

Claims

Claim 1 A power quality and communication path integrated management system for ensuring the display reliability of a Variable Message Sign (VMS) installed on a road or tunnel comprises: an input terminal portion into which AC power is input; a power input protection portion connected to the input terminal portion and including an overcurrent protection fuse, a surge absorption varistor, an inrush current limiting element, and an EMI filter; an AC / DC converter portion connected to the output of the power input protection portion and converting the AC power into DC power to form a main power bus; an uninterruptible power switching portion receiving the main power bus and battery power as inputs, respectively, and forming a load power bus supplied to the VMS uninterruptibly by including an abnormal diode type OR-ing controller and a power MOSFET; a power measurement portion including a voltage divider circuit for measuring the voltage of the load power bus and a current sensor for measuring the current flowing through the load power bus; an analog-to-digital converter for converting an analog signal output from the power measurement portion into a digital signal, and an insulation portion disposed between the analog-to-digital converter and the control portion to provide electrical isolation. Interface unit; wired communication unit including an Ethernet connector, an electrostatic discharge protection element, and an Ethernet physical layer converter; and a control unit configured to determine whether power quality is degraded by comparing power measurement information received through the isolation interface unit with a preset reference value, and to receive communication status information received from the wired communication unit together, and to control the power switching unit when power quality degradation or communication failure occurs, as well as to control the display brightness or message update operation of the road electronic sign to maintain essential display.A power quality and communication path integrated management system for ensuring display reliability of road and tunnel electronic display signs (VMS), comprising: a control unit that determines whether a voltage drop or momentary power outage occurs using a measurement value received from the power measurement unit; controls the OR-ing controller according to the determination result to selectively connect either the main power bus or the battery power to the load power bus to maintain the continuity of power supplied to the road electronic display sign; determines whether a communication failure occurs using link status information from the wired communication unit; if it is determined that a power quality degradation state due to the voltage drop or momentary power outage and a communication failure state occur simultaneously, switches to an essential message maintenance mode by reducing the display brightness of the road electronic display sign or adjusting the message update cycle; and controls the road electronic display sign to continuously display an essential message while the power quality degradation state and the communication failure state persist in the essential message maintenance mode. Claim 2 delete

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