KR20210004386A - method and apparatus for ground potential monitering of battery energy storage system - Google Patents

Abstract

The present invention provides a system for monitoring an accurate operation and state of a ground wire fastened to a rack frame in a battery energy storage system (BESS), wherein the C-mode ground potential and the D-mode potential of a connecting line, which measure the potential of each node of a mesh ground network generated by an induced current by surge and a leakage current flowing when insulation breakdown of the rack frame and internal battery cells occurs, is detected, a ground current is detected, and a state of each ground wire is monitored through the same.

Description

Ground potential monitoring apparatus for battery energy storage system

The present invention monitors the grounding system so that electricity generated from solar power can always be maintained at a stable ground potential in a ground potential monitoring of battery energy storage system (BESS), thereby providing adequate maintenance and insulation breakdown and voltage of the BESS. Grounding of the battery energy storage device to prevent the malfunction of the battery management system (BMS) or power management system (PMS) due to communication failure due to the rise of the ground potential due to induction and fire caused by errors. It relates to a potential monitoring method and an apparatus therefor.

Although it is said that the use of new and renewable energy centered on solar power is on a steadily increasing trend, there is a trend of increasing with problems due to intermittent output fluctuations or fires, etc. Registered Patent No. 10-1732436 (name of the invention: Technologies such as the smart fire protection system of solar power generation devices and energy storage devices (hereinafter referred to as'conventional technologies') have been developed.

This prior art installs temperature sensors in the photovoltaic power generation device and the energy storage device, respectively, and when a fire occurs, when the temperature sensor detects that the temperature exceeds a specific temperature, the automatic fire extinguishing device is operated to extinguish fires. It has a configuration that allows it to be made.

In such a conventional technique, when insulation breakdown occurs between battery cells or between battery cells and stacked racks, when the grounding condition of the rack becomes poor, a battery management system (BMS) or There is a possibility that a fire may occur due to malfunctions and errors of the Power Management System (PMS). However, as in the prior art, if the root cause of the ground fault is not solved even if the fire extinguisher is operated when the temperature is above the set temperature by simply sensing the temperature in the battery storage space, the battery management system (BMS) or power management system There are cases where it leads to a fire because it cannot detect a risk factor due to malfunction of management devices such as the system (Power Management System; PMS).

Therefore, in order to establish stable operation of the energy storage device and prevent and prevent fire due to electrical factors caused by malfunction of the management device and communication failure, it can be said that the constant monitoring system of the ground potential of the racks is essential.

The present invention is to solve such a problem, and the problem of the present invention is to establish a monitoring system that can constantly monitor the ground potential of a battery energy storage device, and thereby a battery management system (BMS) or power management system. This is to prevent and prevent fire from electrical factors caused by malfunctions and errors of the system (Power Management System; PMS).

In addition, another problem of the present invention is the potential of the D-mode (differential mode) generated between the ground lines of the racks together with the ground potential of the C-mode (common mode) of the ground lines of the racks with battery cells installed therein. It is to monitor.

In addition, another problem of the present invention is to constantly monitor the ground current due to insulation breakdown of racks with battery cells installed therein.

In addition, another problem of the present invention is to repair ground faults by displaying normal and abnormal conditions on the monitor according to the values of c-mode, d-mode, and ground current of a specific part monitored among racks of battery energy storage devices. And, it is to prevent fire due to electrical factors caused by malfunction of the management device.

The solution means for solving the above problem is a power line having a rack frame and a plurality of racks consisting of a plurality of battery cells installed inside the rack frame, and the battery cells of the racks having output terminals (+) and (-). It is connected in series to the racks, and TBMS (Tray Battery Management System) for detecting insulation breakdown of the rack frame and internal battery cells is installed at the racks, and BMS for detecting surge inflow into the power line at the output terminal A battery energy storage device for monitoring the grounding status of the ground wires connected in a mesh form consisting of the ground wires connected to the rack frame of the BESS (Battery Energy Storage System) where the (Battery Management System) is installed and the connection wires connected between the ground wires. A ground potential monitoring apparatus, comprising: a C-mode potential detector for detecting a C-mode ground potential, which is a ground potential of each ground wire; A D-mode potential detector for detecting a D-mode potential, which is a voltage detected at both ends of the connecting lines connecting the ground lines to each other; When a surge is introduced or an insulation breakdown occurs between the rack frame and the battery cells inside the rack frame, the data input to the C-mode potential detection unit and the D-mode potential detection unit are stored in the normal range of the C-mode potential and D-mode potential. It includes a controller that determines whether the ground wire is in a normal or abnormal state by determining whether it is within the range of, and displays it on the display.

In addition, in the present invention, further comprising a ground current detection unit that receives a ground current value from an ammeter installed on each of the ground lines, the controller is abnormal whether the ground current input from the ground current detection unit is a pre-stored ground current within a normal range. It is to determine whether each ground line is in a normal or abnormal state by determining whether it is in the range of the ground current.

In addition, in the present invention, the controller is in charge of O.S and a control module for controlling the connected control object; C-mode ground potentials and D-mode potentials due to the surge inflow, and C-mode ground potentials and D-mode potentials in the normal range and abnormality when insulation breakdown of each rack frame and internal batteries A storage module that is classified and stored in a range; When the C-mode ground potentials detected from the C-mode potential detection unit are compared with the C-mode ground potentials stored in the storage module, the normal state and the abnormal state of each ground line are determined, and when it is determined as an abnormal state, the abnormal state A C-mode potential determination module for detecting the ground wire of the; It compares the D-mode potentials input from the D-mode potential detection unit with the D-mode potential stored in the storage module to determine the normal and abnormal states of each of the connecting wires, and detects the connecting cable that is in an abnormal state when it is determined as an abnormal state. It is preferable to include a; D-mode potential determination module.

In addition, in the present invention, in the storage module, the current values flowing through the respective ground wires due to the surge inflow, and the current values flowing through the ground wires at the time of insulation breakdown of each rack frame and the batteries installed therein are within a normal range, It is classified and stored in an abnormal range, and the controller compares the ground currents input from the ground current detection unit with the ground currents stored in the storage module to determine the normal state and abnormal state of the ground wires. It is preferable to further include a ground current determination module for detecting a ground line in a state.

In addition, in the present invention, the abnormal state is classified into an attention state in a preset range exceeding the normal state and a boundary state exceeding the attention state, and is connected to the controller to correspond to the normal state, the attention state, and the alert state. Therefore, it is desirable to further include a monitor that displays a message by classifying colors.

According to the present invention having the above problems and solutions, it is possible to check the grounding condition connected to the frame of the rack, so that it occurs when a surge is introduced, the grounding potential rises due to poor grounding and insulation breakdown, and the insulation breakdown of the rack frame and battery. By safely discharging the leakage current of the rack, communication between BMS and TBMS and induction disturbances occurring between TBMS and sub-BMS are prevented, thereby preventing malfunction of the device, preventing fire or damage to the device. have.

1 is an electrical system diagram for explaining the overall configuration of an embodiment of the present invention.
2 is a schematic diagram showing the flow of current when the rack frame is incompletely grounded in a state in which the rack frame and batteries are insulated and destroyed in an embodiment of the present invention.
3 is a circuit block diagram for implementing an embodiment of the present invention.
4 is a flow chart illustrating the operation process of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail according to the accompanying drawings.

1 is an electrical system diagram for explaining the overall configuration of an embodiment of the present invention, and FIG. 2 is a block diagram of a system for explaining the overall configuration of the present invention.

BESS operates with a high voltage of around 1,000 V DC depending on the configuration conditions, and for stable system operation, the connection of the battery management system (BMS) and the enclosure of various control devices to the grounding system is an important factor. Various devices in the BESS are connected to communication lines to perform CAN communication and ModBus TCP/IP communication. However, these communication voltages are significantly lower than the BESS charge/discharge level voltages such as 3.3V and 12V, which prevent internal or external disturbances. It has sensitive characteristics.

In addition, depending on the conditions of the installation site, the battery rack may have an internal battery tray installed separately at the site. In this assembly process, malfunctions of various signals and communication equipment may be caused by non-fastening due to an error of an operator or induced voltage generated during operation. In order to stably operate various control equipment of ESS from such induced voltage and noise, stabilize it by using a surge protection device and noise filter suitable for each device purpose, or rack the noise component induced to each device through a stable grounding system. This can be prevented by grounding the frame or the metal enclosure of the control system.

In an embodiment of the present invention, in the BESS, n racks are installed inside a facility such as a container, a plurality of battery cells are connected in series to each of the racks, and batteries stored in the racks (hereinafter referred to as'rack unit Batteries') are also connected in series to rack-unit batteries installed in adjacent racks, so that the electricity accumulated in all the batteries is applied to the output terminals + and-by the voltage of all the batteries.

In addition, to each battery cell, a sensing device for sensing voltage and current of the battery cells, a switch for charge/discharge, a driving means for driving the switch, and a sensing signal detected by the sensing device are transmitted to the outside, and a driving signal is transmitted and received from the outside. Sub-BMS (not shown) consisting of communication modules are installed, and in each of the racks, a sensing device that detects the charging/discharging current and voltage of the unit batteries installed therein, a switch blocking the current, and a driving means for driving the switch TBMS (Tray Battery Management System) consisting of a communication module that transmits and receives the sub-BMSs and control signals and transmits and receives the sensed detection signals and switch drive signals is installed, and the output terminals + and-manage all batteries and control the TBMS. A switch that transmits a signal and blocks the entire charging/discharging current and a BMS equipped with a switch driving means are installed, and the current and applied voltage flowing through the output terminals + and-are displayed.

In addition, each of the racks is grounded by a mesh method in order to discharge the surge current through the ground smoothly. More specifically, a ground line of the resistor Rc1 is installed between the rack R1 and the ground, an ammeter C1 is installed on the ground line of the resistor Rc1, and a resistance Rc2 is installed between the rack R2 and the ground. The ground wire of the resistor (Rc2) is installed, an ammeter (C2) is installed on the ground wire of the resistor (Rc2), and the ground wire of the resistor (Rcn) is installed between the rack (Rn) and the ground in the same way, and the ammeter is the ground wire of the resistor (Rcn). (Cn) is installed. In addition, the connection line of the resistor (Rd1) is installed between the rack (R1) and the rack (R2), the connection line of the resistance (Rd2) is installed between the rack (R2) and the rack (R3), and the rack (Rn-1) and Between the racks (Rn), a connecting line of the resistor (Rn-1) is installed.

If the racks are grounded like this, it is an ideal case, and if the racks and the ground wire are incompletely made due to poor construction, and if the ground wire is disconnected, the resistance of the ground wire becomes very high, and the voltage of a specific node becomes very high. The current flowing through a specific ground line becomes excessive or becomes much smaller than the reference value.

The grounding potential of the node (n1), which is connected to the rack (R1) and where the ground line having the resistance (Rc1) (hereinafter referred to as the'first ground line') and the ground line having the resistance (Rd1) meet is Vn1 and has a resistance (Rc2) The grounding potential of the node (n2) where the ground line (hereinafter referred to as the'second ground line') and the ground line having the resistance (Rd2) meet is Vn2, and the ground line having the resistance (Rcn-1) and the ground line having the resistance (Rdn-1) The ground potential of the node (n-1) where the connection line meets is Vn n-1, and the ground potential of the node (nn) where the ground line with resistance (Rcn) and the connection line with resistance (Rdn-1) meet is Vnn. Likewise, the potential indicated by being connected to each of the racks and ground is called the C-mode ground potential.

In addition, when the grounding condition of each rack is incompletely grounded, a differential voltage or floating voltage is generated between the ground wires connected to the racks when an induced current occurs in the racks due to a surge current. Is done.

In this way, when a surge is introduced into the BESS and an induced current is generated in each rack frame, if the ground wires are normally connected to the rack frame, in a normal state, the induction current induced to the rack frame is combined through the ground wire. It discharges smoothly, and the ground current is measured by an ammeter installed on each ground wire.

However, if a specific ground wire is disconnected or is incompletely connected to the rack frame, so-called'incomplete grounding' occurs, the current flowing through the ground line becomes zero or a so-called'incomplete grounding current' that is less than a preset current flows, and the ammeter is incomplete grounding current Will be measured.

In addition, when an induction current occurs in the rack frame, the current of the incomplete ground line is different from the C-mode ground potential in the normal state, and the potential of the incomplete ground line and the adjacent ground line are different, resulting in a differential voltage between the connection lines connecting the ground lines. Will occur.

Therefore, when an induced current is generated in the rack frames, by detecting the current of each ground line and the differential voltage between the ground lines, it is possible to detect an incomplete grounding state of a specific ground line.

For simplicity of explanation, assuming that only two racks (R1) and rack (R2) are installed in the BESS, when the grounding of the rack (R1) and rack (R2) is normally established, each grounding wire is connected when induced current is induced to the racks Since the current flows through the node (n1) and the node (n2) at the same potential, the current does not flow in the connection line connecting the node (n1) and the node (n2), so the differential voltage △Vn1n2 between these nodes is 0 Becomes. However, for example, when the first ground line is incompletely grounded, current flows in the connection line connecting node n1 and node n2, and differential voltage △Vn1n2 = △V is generated on the connection line connecting node n1 and node n2, and an ammeter ( The ground current flows in C1) less than in normal, and more current flows in the ammeter C2 than in normal. Conversely, if the second ground line is incompletely grounded, current flows from node n2 to node 1 through the connection line, and differential voltage △Vn1n2 = -△V is generated between node n1 and node n2, and the ammeter (C2) is less than normal. Ground current flows or does not flow, and more current flows through the ammeter C1 than normal.

As described above, when the current of each ground line and the differential voltage of the connection line connecting the ground lines are detected, an incomplete grounding state of a specific ground line can be detected.

In addition, when the ground wires grounded in the rack frame are in an incomplete grounding state, the ground current is not discharged smoothly, causing a failure in the communication line, interfering with the smooth charging and discharging of the battery, and even causing a fire.

In addition, when insulation breakdown occurs between the frame of the rack and the battery installed inside the rack, the current flowing from the battery to the rack frame is discharged to the ground terminal through the ground wire.

However, when the rack frame and the ground line through which the battery current flows are incompletely grounded, a small current flows through the connected ground line or does not flow, and a large amount of current flows through the adjacent ground line connected by the connection line.

2 is a schematic diagram showing the flow of current when the rack frame is incompletely grounded in a state in which the rack frame and batteries are insulated and destroyed in an embodiment of the present invention.

A rack (Rp-1) and a rack (Rp+1) are installed in the left and right adjacent positions of the rack (Rp), and the rack (Rp) has an insulation between the rack frame and the internal battery and the insulation is destroyed. There is a leakage current flowing in, and the ground wire of the rack Rp is disconnected.

The current leaked from the battery flows from the frame of the rack (Rp) to the node np along the ground line, and then flows to the connection line connected to the ground line of the adjacent rack (Rp-1) and (Rp+1) (ip-1), ( ip+1), and the branched current flows along the ground line of the racks (Rp-1) and (Rp+1) and then discharges through the ground terminal.

In this way, when a leakage current due to battery insulation breakdown flows in the rack (Rp), if the ground wire connected to the rack (Rp) frame is disconnected, the current does not flow and the installed ammeter (Cp) does not detect the current. Current flows through the ground wire of the rack (Rp-1) and rack (Rp+1), and current is detected in the ammeter (Cp-1) and (Cp+1) installed on each ground wire, and the rack (Rp) frame Differential potential occurs because current flows in the connection line connecting the ground line connected to the adjacent rack (Rp-1) and the rack (Rp+1) frame.

If the ground wire connected to the rack (Rp) frame is not disconnected, but a minute current of less than a predetermined size flows during insulation breakdown, it is determined as incomplete grounding.

In addition, when a leakage current occurs due to insulation breakdown between the rack (Rp) frame and the internal battery, current is detected by the ammeter (Cp-1) when the ground wire connected to the adjacent rack (Rp-1) frame is disconnected, which is a kind of incomplete grounding. The current is detected in the ammeter (Cp) and ammeter (Cp+1), and there is no current flowing in the connection line connecting the ground wire connected to the rack (Rp) frame and the ground wire connected to the rack (Rp-1) frame. Differential voltage does not occur, and a differential voltage is generated because current flows in the connection line connecting the ground wire connected to the rack (Rp) frame and the ground wire connected to the rack (Rp+1) frame.

In this way, when the insulation between the specific rack frame and the internal battery is broken, the amount of current flowing through the current and the differential voltage value generated between each ground wire are different according to the grounding state of the rack frame and the ground wire. By analyzing the results, it is possible to trace the rack where insulation breakdown occurred and the ground wire where incomplete grounding occurred.

3 is a circuit block diagram for implementing an embodiment of the present invention.

The ground potential monitoring device 1 of the battery energy storage device shown in FIG. 3 is a D-mode in which a connection line connecting each ground line from an input C-mode ground potential and C-mode ground potential is applied. (differential mode) A controller 10 that receives a potential and current flowing through each ground wire, detects whether surge is introduced, whether the rack frame and battery is damaged, and detects the incomplete grounding state of the ground wire, and each rack frame A C-mode ground potential detector (11) that detects a potential generated at the connection part of the rack frames and ground wires by the current flowing through the ground wires connected between the ground terminals, and a rack frame adjacent to the connection part of the rack frames and ground wires. A D-mode voltage detection unit 13 that detects voltage generated in the connection lines connecting the connection portions of the ground lines and the ground lines, and a ground current detection unit 15 that receives a current value from ammeters installed in each of the ground lines, By receiving display data from the controller 10 and converting it into an image signal, the display unit 19 displays a normal state, an abnormal state or a normal state, a caution state, and a warning state in different colors according to the grounding state of each ground wire. It consists of a display module 17 to display.

In addition, the controller 10 is in charge of the OS and is applied to the connection part of the respective rack frames and ground wires matching the magnitude of the induced surge current detected by the BMS and the control module 111 that controls the connected control object. The normal range data value of the C-mode ground potential, which is a potential, and the normal range data of the D-voltage generated in each of the connecting lines matching the magnitude of the induced surge current, and each ground line matching the magnitude of the induced surge current. C-mode grounding that is matched to the steady state reference data section in which the normal range data values of the current flowing through the field are stored and the magnitude of the induced surge current, but can trigger an accident such as damage to equipment or fire, etc. The boundary state reference data of the potential and the boundary state reference data of the D-mode potential generated in each of the connecting lines matching the magnitude of the induced surge current and the reference data values of the boundary state of the current flowing through each ground line are stored. Boundary state reference data unit, data of caution state between the C-mode ground potential being less than the boundary state and exceeding the normal state, matched to the magnitude of the induced surge current, and the D-mode potential generated in each of the connecting lines Including a boundary condition reference data unit in which data of the attention state between the boundary state of the above and beyond the normal state and the data of the caution state between the boundary state of the current flowing through the respective ground wires and exceeding the normal state are stored. A storage module 115 is provided.

At this time, in the storage state reference data part of the storage module 115, when insulation is destroyed between the rack frame and the batteries stored in the rack frame, and a leakage current is generated, the C-mode ground of the normal range matching the specific insulation-destructed rack. The potential, the D-mode potential, and the respective ground current are stored. Similarly, the caution state reference data part stores the C-mode ground potential, D-mode potential, and each ground current of the range of caution states that match a specific insulation breakdown rack, and the boundary state reference data part stores a specific insulation breakdown. The C-mode ground potential, D-mode potential, and each ground current of the boundary state range matched to the rack are stored.

In addition, it is preferable to determine the reference data values of the respective steady state ranges, the reference data values of the caution state range, and the reference data values of the alert state range described above through repeated experiments.

In addition, in the present invention, the reference data stored in the storage module 115 may be divided into data designating a range of a normal state and data designating an abnormal state including a caution state and a boundary state, and stored.

In addition, the controller 10 determines the steady state, caution state, and alert state of the C-mode potential by comparing the C-potentials input from the C-mode potential detection unit 11 with the data values stored in the storage module 115. When determining the caution state and the alert state, the C-mode potential determination module 112 extracts a ground line with abnormal data in the range of the caution state and the alert state, and the D- input from the D-mode potential detection unit 13 The mode potentials and the data values stored in the storage module 115 are compared to determine the normal state, the caution state, and the alert state of the D-mode potential. When determining the caution state and the alert state, the caution state and the alert state are determined within the range. The normal state of the ground line by comparing the D-mode potential determination module 113 for extracting the connection line with abnormal data and the ground currents input from the ground current detection unit 15 and the data values stored in the storage module 115, It includes a ground current determination module 114 that determines the caution state and the alert state, and extracts a ground line having abnormal data in a range of the caution state and the alert state when determining the caution state and the alert state.

4 is a flow chart illustrating the operation process of the present invention.

Power lines are connected to the output terminals (+) and (-), and batteries are connected to the power lines. When a surge is introduced into the power line, the BMS installed near the output terminal detects surge inflow (S1), and the rack frame and When the insulation breaks between the batteries inside the rack frame and a leakage current flows, the TBMS installed in each rack detects that the insulation breaks down (S2), and sends the insulation breakdown information and the rack ID information to the BMS connected to the TBMS. send. BMS, when surge inflow information or insulation breakdown information and rack ID information are input, and when surge inflow information or insulation breakdown information and rack ID are received from the control module 111 of the controller 10, C-mode potential determination module 11 , D-mode potential determination module 13, ground potential determination module 15 to determine the grounding state of each ground wire (S3), (S4), (S5), normal state, caution state, alert state information Is transmitted to the control module 111, and the control module 111 causes the display module 17 to display indications of the ground line in the normal state, the ground line in the caution state, and the ground line in the alert state on the display unit 19 (S6). . At this time, it is desirable to mark the ground line in green for a specific ground line, yellow for caution, and red for alert in order to induce an alert to the manager.

10: controller
11: C-mode ground potential detector
13: D-mode potential detection unit
15: ground current detection unit

Claims (5)

A plurality of racks consisting of a rack frame and a plurality of battery cells installed inside the rack frame are installed, the battery cells of the racks are connected in series to power lines having output terminals (+) and (-), and the racks BESS is installed with TBMS (Tray Battery Management System), which detects insulation breakdown of the frame and internal battery cells, and BMS (Battery Management System), which detects the inflow of surge into the power line, is installed at the output terminal. In the grounding potential monitoring device of a battery energy storage device for monitoring the grounding state of ground wires connected in a mesh form consisting of a ground wire connected to a rack frame of (Battery Energy Storage System) and a connection wire connected between the ground wires:
A C-mode potential detector for detecting a C-mode ground potential, which is a ground potential of each ground wire;
A D-mode potential detector for detecting a D-mode potential, which is a voltage detected at both ends of the connection lines connecting the ground lines to each other;
When a surge is introduced or an insulation breakdown occurs between the rack frame and the battery cells inside the rack frame, the data input to the C-mode potential detection unit and the D-mode potential detection unit are stored in the normal range of the C-mode potential and D-mode potential. And a controller configured to determine whether the ground wires are in a normal state or an abnormal state by determining whether the range of is in a normal state or an abnormal state, and displaying the same on a display unit. The method according to claim 1, further comprising a ground current detection unit that receives a ground current value from an ammeter installed in each of the ground lines, the controller is an abnormal range whether the ground current input from the ground current detection unit is a pre-stored normal range ground current Ground potential monitoring apparatus of a battery energy storage device, characterized in that it determines whether each of the ground wires is in a normal state or an abnormal state by determining whether the ground current of. The method of claim 2, wherein the controller
A control module in charge of an OS and controlling a connected control object;
C-mode ground potentials and D-mode potentials due to the surge inflow, and C-mode ground potentials and D-mode potentials in the normal range and abnormality when insulation breakdown of each rack frame and internal batteries A storage module that is classified and stored in a range;
When the C-mode ground potentials detected from the C-mode potential detection unit are compared with the C-mode ground potentials stored in the storage module, the normal state and the abnormal state of each ground line are determined, and when it is determined as an abnormal state, the abnormal state A C-mode potential determination module for detecting the ground wire of the;
Compares the D-mode potentials input from the D-mode voltage detection unit with the D-mode potential stored in the storage module to determine the normal state and abnormal state of each connection line, and detects the connection line in an abnormal state when it is determined as an abnormal state. D-mode potential determination module; Ground potential monitoring device of a battery energy storage device comprising a. The method according to claim 3, wherein the storage module includes a current value flowing through each of the ground wires due to the surge inflow, and a current value flowing through each of the ground wires at the time of insulation breakdown of each rack frame and batteries installed therein. , Classified into an abnormal range, and the controller compares the ground currents input from the ground current detection unit with the ground currents stored in the storage module to determine the normal state and the abnormal state of the ground wires, and determines the abnormal state. Ground potential monitoring device of a battery energy storage device, characterized in that it further comprises a ground current determination module for detecting a ground line in an abnormal state. The method according to any one of claims 1 to 4, wherein the abnormal state is classified into an attention state in a preset range exceeding the normal state and a boundary state exceeding the attention state, and is connected to the controller to match the normal state. And a monitor configured to display a message by classifying colors according to the caution state and the alert state.

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