Cable theft prevention system

Abstract

To provide a cable theft prevention system that, while being cheaper and simpler to configure than conventional systems, is equipped with a mechanism that can more reliably detect the open state of the lid of a cable storage case that is showing signs of theft. [Solution] A cable theft prevention system (1) comprises a lid open detection mechanism (2) that detects the open state of the lid (14) of a specific cable storage case (10), which houses each bundle of cables (C) extending from a solar cell module (100) to a current collector panel (150) in a connected state inside a case body (11), and covers the upper opening with a lid (14) that can be opened and closed, and a control unit (3) that activates a warning light and an alarm based on a detection signal from the lid open detection mechanism and transmits a notification signal to a security company. In this system, the lid open detection mechanism (2) detects that the lid (14) is in an open state using a limit switch (LS), and each limit switch (LS) is fixed to a position away from the side of the case body (11) via a mounting bracket (40).

Description

Technical Field

[0001] The present invention relates to a cable theft prevention system that can detect signs of theft of cables wired on the outdoor site of a solar power plant. More specifically, the present invention relates to a cable theft prevention system provided with a detection mechanism that detects an open state of a lid portion of a cable storage case and outputs a detection signal.

Background Art

[0002] In recent years, the demand for solar power generation, which is one of the important renewable energy sources, has been increasing. Not only the number of household solar power generation systems but also the number of installations of large-scale solar power plants called so-called megasolar has been increasing.

[0003] A solar power plant includes a power generation unit and a power conditioner 200 as shown in FIG. 6. A large number of solar cell modules 100 that receive sunlight outdoors and generate electricity by photoelectric conversion are connected in series to form a solar cell array 110, and the solar cell arrays 110 are further arranged in multiple rows to form the power generation unit.

[0004] In addition, the DC power generated from each solar cell array 110 is sent to a switchboard 150 and combined into one, and then sent to the power conditioner 200. In the power conditioner 200, the DC power is converted into AC power, and the AC power is transmitted to each substation equipment. The substation equipment converts the AC power into an appropriate voltage and supplies it to each user.

[0005] Since the DC power from each solar cell array 110 is sent to the switchboard 150 via a large number of cables C, many of these cables C are wired on the ground within the site of the solar power plant.

[0006] Typically, these cables C are protected by being bundled together and routed through a cable storage case 10, which is connected and positioned on the ground, as shown in Figure 7. This cable storage case 10 is generally composed of a housing-like case body with an opening at the top and a lid 14 that can be opened and closed to close this opening.

[0007] Furthermore, copper wires are commonly used as cable C in solar power plants because they have high conductivity and are easy to process.

[0008] On the other hand, in recent years, copper has been trading at high prices due to its surge in value, leading to an increase in theft targeting copper wire cables. Solar power plants, in particular, are significantly more prone to theft of copper wire cables than other facilities, as large quantities of copper wire can be easily removed from secluded locations.

[0009] Currently, many solar power plants employ cable theft prevention systems. One common approach involves infrared motion sensors, which activate warning lights 210 and alarms 220 based on detection signals. Some systems also integrate with a notification system that simultaneously alerts a security company. However, such motion sensors have blind spots in large areas, making it impossible to prevent theft in undetected areas.

[0010] Furthermore, since copper wire cables are typically installed in long lengths, they are often pulled out, cut into manageable lengths, and then carried away. Therefore, cable theft prevention systems have been developed that utilize sensors to detect such cable movement and cutting.

[0011] However, it is not practical to install sensors on every single cable that is intended to monitor or detect such cables. In solar power plants, even small ones, which occupy a large area, multiple cables extending from each solar cell module are bundled together, and these numerous bundles then lie along the ground towards the current distribution panel.

[0012] Therefore, the sensors described above are currently installed in several locations, targeting only one cable from each bundle. If cables other than those being monitored or detected are initially targeted for theft and pulled out or cut, the theft detection will be delayed.

[0013] If a cable is cut, even if a warning or report is issued afterward and the theft is interrupted, damage has already occurred. Therefore, it is desirable to have a system that can detect signs of theft before the cable is cut.

[0014] Therefore, as a method that can detect such cable breaks before they actually occur, a detection method is being considered that targets cases where bundles of cables routed on the ground surface are connected to each other and housed inside.

[0015] This system uses sensors to detect when a case lid is opened and closed, and detects that the lid is open as theft has occurred. In this case, it is desirable to have sensors that can be attached to existing cases and that can immediately detect when a case lid is open at various locations on a large property.

[0016] One such sensor that has been developed is one that uses an optical sensor. In this system, the main body of the case, which houses the cables inside, is sealed with a lid that closes the opening at the top, and the displacement of the lid is detected by the optical sensor to determine if it is open or closed.

[0017] For example, Patent Document 1 discloses a monitoring device in which a reflector is placed on the inside of the lid, and a signal transmitted from a wireless communication device placed inside the container body is reflected by the reflector when the lid is blocking the opening of the container body and received by the wireless communication device, and a determination unit determines whether or not the state of the lid has changed based on the received signal. In this monitoring device, if the determination unit determines that the state of the lid has changed by a certain amount or more, an abnormal signal is generated. [Prior art documents] [Patent Documents]

[0018] [Patent Document 1] International Publication No. 2021 / 100870 [Overview of the project] [Problems that the invention aims to solve]

[0019] However, conventional optical sensors, as described above, require the installation of a signal transmitter inside each case body and a reflector on each lid, and furthermore, the angle of the reflector must be adjusted with high precision, making sensor installation a time-consuming and complicated task.

[0020] Furthermore, since such time-consuming installation work would have to be carried out for many cases within the large site of a solar power plant, using optical sensors is a costly and inefficient detection method, as it requires a large number of relatively expensive signal transmitting devices and a great deal of work time.

[0021] Furthermore, because it is installed in a case located outdoors, the risk of malfunctions occurring due to rattling or shaking of the lid or case body caused by strong winds during bad weather increases, as it can lead to misalignment of the reflector or transmitter.

[0022] Therefore, especially for cable theft prevention systems used in solar power plants, there is a need for a system that can detect whether the lid of the cable storage case is open more reliably and at a lower cost than conventional systems.

[0023] In view of the above-mentioned problems, the object of the present invention is to provide a cable theft prevention system that has a lower cost and simpler configuration than conventional systems, while being equipped with a detection mechanism that can more reliably detect the open state of the lid of the cable storage case as a sign of theft. [Means for solving the problem]

[0024] To achieve the above object, the cable theft prevention system according to the invention described in claim 1 is, for example, as shown in FIGS. 1 to 4, within the site of a solar power plant equipped with warning lights and alarms for theft prevention, with multiple cables extending from each solar cell module to the switchboard on the outdoor ground bundled together, each bundle being housed in the case body in a connected state with each other, and a plurality of cable storage cases that cover the upper opening of the case body with a lid that can be opened and closed. For a specific one of the plurality of cable storage cases located at a preselected position, a lid opening detection mechanism for detecting the open state of its lid. In a cable theft prevention system comprising a control unit that activates the warning light and the alarm and transmits a notification signal to a security company based on a detection signal from the lid opening detection mechanism. The lid opening detection mechanism is Respectively installed in the specific cable storage case, and the output signal is switched corresponding to the displacement of the push button when the push button is depressed by the pressing of the back surface of the lid in the closed state where the lid of the cable storage case covers the opening of the case body, and when the pressing is released and the push button returns in the open state where the lid is separated from the opening. A limit switch, Each of the limit switches is wired so that power is supplied from a power source by connection to a predetermined terminal, and the conduction state is switched by connection switching between terminals linked to the displacement of the push button in each limit switch, and the output signal indicating the conduction state corresponding to the open state of the lid of each limit switch is sent to the control unit as the detection signal, and has an electric circuit. Each of the limit switches is characterized in that it is fixed at a position away from the inside from the side surface of the case body via a mounting bracket.

[0025] According to the cable theft prevention system described in claim 1 of the present invention, as the cable theft prevention system, for a specific one at a preselected position of the cable storage case, which is a basic element for protecting the cable to be stolen, a limit switch is used in the lid opening detection mechanism for detecting the open state of the lid. Therefore, simply by fixing an inexpensive existing limit switch to the case body at an appropriate position, a lid detection device can be easily constructed. Note that the specific cable storage cases may be appropriately selected at monitoring intervals according to the actual site area, being located at appropriately dispersed positions within the site as the monitoring targets.

[0026] Due to this lid opening detection mechanism, a detection signal is immediately sent to the control unit based on the output signal from the limit switch obtained in conjunction with the mechanical operation of opening the lid. Therefore, the control unit can surely determine the sign of cable theft by receiving the detection signal based on the output signal from at least one of the limit switches.

[0027] Therefore, according to the present invention, it is possible to operate a warning light and an alarm and at the same time report to a security company at a stage before the cable is cut.

[0028] In addition, in a solar power plant, since a plurality of limit switches are to be installed in cable storage cases set at several points in a wide site in a scattered state, the lid opening detection mechanism uses, as a detection signal, the time point when any one of substantially all the limit switches transmits an output signal indicating the open state of the lid.

[0029] Moreover, the limit switch, which is a contact type sensor interlocked with a mechanical operation, is less affected by the surrounding environment and has higher detection accuracy compared with non-contact types such as optical sensors, so more reliable detection is possible.

[0030] Therefore, the lid open detection mechanism according to the present invention, which utilizes a limit switch, is not affected by shaking or rattling caused by strong winds or other adverse weather conditions. Furthermore, because it does not require the installation of expensive transmitting devices such as optical sensors inside each case body, nor the time-consuming work of installing a reflector on the lid and adjusting its angle with high precision, it can detect the open state of the lid with high precision while having a simpler configuration and less installation effort than conventional methods.

[0031] This makes it possible to implement a more cost-effective and reliable cable theft prevention system, even in large-scale solar power plants with vast areas of land where cables are laid.

[0032] The limit switch of the present invention may have a general device configuration that electrically indicates an on / off state based on mechanical operation. That is, it is constructed by housing a microswitch with an internal snap-action mechanism in a robust switch case.

[0033] The snap-action mechanism switches the connection between three terminals and the contacts of a movable spring between these terminals. The movable spring is displaced when a push button is pressed down and released by the rotation of an actuator part such as a lever, which is linked to the movement of the object being detected.

[0034] Typically, a microswitch has three terminals: a COM (common) terminal, a NO (normally open) terminal, and an NC (normally closed) terminal. The contact on the other end of a movable spring, one end of which is connected to the COM terminal, moves between the NO terminal and the NC terminal in accordance with the displacement of the push button.

[0035] Therefore, when power is supplied to the limit switch from the power source via the electrical circuit, the movable spring, which in its natural state has its contact on the NC terminal side, is also pressed when the lever is rotated by an external force and the push button is pressed down. As a result, the contact moves from the NC terminal side to the NO terminal side, entering a first conductive state and connecting to the COM terminal. At this time, a predetermined first voltage level is output to the NO terminal side. Therefore, this first voltage level can be used as an output signal indicating the ON state of the limit switch.

[0036] Then, when the external force applied to the lever is removed, the push button is released from its pressure and returns to its upward position. This also returns the position of the movable spring, and its contact moves from the NO terminal side to the NC terminal side. The NC terminal is connected to the COM terminal, creating a second conductive state, and a predetermined second voltage level is output to the NC terminal side. Therefore, this second voltage level can be used as an output signal indicating the switch-off state of the limit switch.

[0037] Here, for example, if the second voltage level is set to 0V, only the switch-off state will be detected. Alternatively, by wiring the circuit so that it closes and becomes conductive only when the COM terminal and NC terminal are connected, the switch-off state can be detected by using the electrical output in that conductive state as a detection signal.

[0038] In this invention, the limit switch can be fixed to the case body such that the lever is pressed by the closed lid that seals the opening of the case body, and the push button is pressed down, resulting in a switch-on state. As a result, when the lid is opened, the push button returns to its original position and an output signal indicating the switch-off state is obtained from the limit switch, so the control unit can determine that the switch-off output signal is a detection signal indicating that the lid has been opened.

[0039] Furthermore, the settings are not limited to those described above. The COM terminal can be configured to conduct only when connected to one of the other terminals, and the detection signal can be determined by the presence or absence of conduction. For example, if the electrical circuit configuration is set to conduct only when the COM terminal and NC terminal are connected in the switch-off state, the open state of the lid can be detected by using the output of the limit switch only when it is conducting as the detection signal.

[0040] Furthermore, even though the limit switch is fixed inside the case, the case itself is installed outdoors, so it is desirable that the limit switch of this invention be particularly waterproof. Here, the IP (Ingress Protection Mark) protection rating is used as a standard to indicate the waterproof and dustproof performance of the limit switch.

[0041] The IP rating system is typically a two-digit rating system applied to the enclosures of machinery and electrical products, clearly indicating the product's resistance to various types of ingress. Three definitions of "ingress" are used: the level of protection for the user (hands, fingers, etc.) from mechanical and electrical components; the degree to which the enclosure protects key components from dust, dirt, and other harmful foreign matter; and overall resistance to moisture. IP standards are standardized in most countries, including Japan.

[0042] In particular, the widely accepted "waterproof" ratings for general purposes, IP65, IP66, IP67, and IP68, are assigned to limit switch products as protective structures. For example, IP67 indicates complete dustproofing and the ability to withstand immersion in 1 meter of water for 30 minutes without water ingress, while IP68 indicates complete dustproofing and the ability to withstand prolonged immersion under specified pressure. Currently, many limit switches used in relatively harsh environments have IP67 or IP68 waterproof and dustproof performance. Therefore, it is preferable to use an IP 67 or 68 rated limit switch for the lid open detection mechanism of the present invention.

[0043] Furthermore, someone attempting to steal the cable might suspect that some kind of sensor is attached to the case. In contrast, in this invention, the limit switch is fixed to the inside of the case body via a mounting bracket, so the mounting part is not exposed to the outer surface as it would be if it were directly fixed to the side of the case body by screws or the like, making it difficult to detect the presence of the limit switch.

[0044] In addition, this fixed location is also a somewhat physically protected location that avoids direct access and destruction from the outside, thus contributing to a greater anti-theft effect and further enhancing the effectiveness of the entire cable anti-theft system.

[0045] Furthermore, in order to achieve independence from the main solar power grid, the electricity used to operate solar power plants is usually supplied by external commercial power sources or by individual, independently installed small-scale solar power generation units.

[0046] Therefore, the power required for the cable theft prevention system of the present invention can also be supplied using commercial power or wired power from an independent small-scale solar power generation unit. Power from the independent small-scale solar power generation unit can be supplied by converting high-voltage electricity to a common low voltage such as AC100V via a cubicle lighting panel, or it can be stored in a battery and used.

[0047] The cable theft prevention system according to claim 2, for example as shown in Figures 2 and 3, has a case body with a housing shape in which side walls are erected on both the left and right sides of the bottom surface, and the side walls have horizontal edges in which the upper edges are horizontally bent inward from each other. The lid has a U-shaped cross-section, with its underside resting on the upper surfaces of the horizontal edges on both sides of the case body, thereby closing the opening and closing the top surface of the case body, and with both sides bent downwards. The mounting bracket is characterized by being an L-shaped bracket comprising a horizontal piece that is superimposed on and fixed to the upper surface of one of the horizontal edges of the case body, and a suspension piece that extends downward from the inner end of the horizontal piece of the case body, to which the limit switch is screw-fastened.

[0048] According to the cable theft prevention system described in claim 2 of the present invention, by using an L-shaped bracket composed of a horizontal piece and a suspension piece as the mounting bracket for fixing the limit switch inside the case body, the bracket itself has a simple structure, while efficiently positioning the limit switch away from the side and inward of the case body.

[0049] This L-shaped bracket corresponds to the typical cable storage case structure in which the lid rests on the horizontal edges on both sides of the case, where the upper edges of the left and right side walls are bent horizontally inward to close the case.

[0050] In other words, by simply facing the lower piece of the L-shaped bracket inward towards the case body and overlapping the horizontal piece onto one of the horizontal edges and securing it, the suspension piece itself, to which the limit switch is screwed in, can be positioned away from the side of the case body and inward.

[0051] Therefore, the screw fastening points of the limit switch are not exposed on the outer surface of the case, making it impossible to confirm the presence of the limit switch from the outside.

[0052] The means of securing this L-shaped bracket to the horizontal edge of the case body is not particularly limited as long as it can adequately hold the limit switch, but the configuration should minimize the height difference between the horizontal edge and the lid placed on top of it. In view of this, industrial double-sided tape, which is thin in itself but provides adequate strength and holding power, is suitable.

[0053] Furthermore, the material of the L-shaped bracket itself can be anything that has sufficient strength to hold a moderate limit switch, even if it is thin. For example, galvanized steel sheet with a thickness of 1-2 mm is suitable. Galvanized steel sheet has excellent corrosion resistance, making it suitable for outdoor use, and it has sufficient strength even when thinner than general steel sheet. Other metals with similar functions, such as stainless steel or aluminum alloy, can also be used as substitutes. However, galvanized steel sheet is suitable from a cost perspective as well.

[0054] The cable theft prevention system according to claim 3, for example as shown in Figure 5, includes a lid opening detection mechanism provided in each of the areas into which the site is divided into multiple regions, and each lid opening detection mechanism includes a signal transmitter that transmits the detection signal based on the output signal from the limit switch belonging to that region to the control unit via wireless communication. The control unit is characterized by comprising a signal receiver that receives the detection signals transmitted from each lid opening detection mechanism.

[0055] According to the cable theft prevention system described in claim 3 of the present invention, a lid opening detection mechanism is provided in each of the multiple zones, and the control unit can determine that a theft is about to occur in any of the zones based on the detection signals from each lid opening detection mechanism.

[0056] Therefore, even when targeting large-scale sites such as large-scale solar power plants, it is possible to scale up the cable theft prevention system by distributing the cover opening detection mechanism across multiple areas.

[0057] Furthermore, when distributing multiple lid-open detection mechanisms, connecting all of them to the control unit via wires presents numerous challenges, including wiring costs, construction complexity, maintenance difficulties, and the risk of wire breakage. However, by introducing wireless communication, these challenges can be significantly reduced, further enhancing the operational convenience of large-scale cable theft prevention systems.

[0058] In this case, each lid-open detection mechanism shall transmit a signal from a signal transmitting device based on a detection signal indicating that the lid of the target cable storage case has been opened from one of the limit switches belonging to the area in which the lid-open detection mechanism is located.

[0059] Furthermore, by assigning different types of signals to each area, signals belonging to a particular area can be differentiated. For example, it is conceivable to assign different frequency bands that do not overlap to each other. The control unit can determine which area the cable storage case belongs to by opening its lid based on the type of signal received by the signal receiver, and add that information to the notification signal. In addition, when dealing with such a large site, multiple alarms and warning lights may be installed in a distributed manner.

[0060] The cable theft prevention system according to claim 4 further comprises, for example, a cut detection device that detects the cut state of a specific cable among the cables, as shown in Figure 5. The control unit is characterized in that, based on detection signals from at least one of the lid opening detection mechanism and the cutting detection device, it activates the warning light and the alarm and transmits the notification signal.

[0061] The cable theft prevention system described in claim 4 of the present invention adds an additional detection function to the mechanism that detects the open state of the lid of the cable storage case using a lid open detection mechanism: a cable cut detection device detects cable cuts. This strengthens the cable theft detection network and improves the reliability and defensive capabilities of the entire system.

[0062] This cable break detection device can be widely adopted as long as it uses a method that detects cable breakage, and can utilize conventional methods already used for preventing cable theft. Furthermore, other conventional technologies, such as motion sensors, can be combined as additional detection functions.

[0063] Furthermore, the control unit in the cable theft prevention system of the present invention, which has the above configuration, should be a control method that can activate an alarm or warning light and send a notification signal to a security company after a predetermined time, such as a few seconds, has elapsed since receiving a detection signal from the lid opening detection mechanism. Practical examples include relay-type sequence control using a timer relay, PLC (programmable logic controller) control, or microcontroller control.

[0064] In relay-type sequence control, after receiving a detection signal, the alarm, warning light, and communication device for transmitting notification signals are each controlled to turn on via timer relays. This method has the advantage of a simple structure and is easy to implement for on / off control of relatively small systems.

[0065] However, in large-scale systems, when signals are input from many detection devices and connected to many actuators such as multiple alarms and warning lights, the number of relays becomes enormous, the wiring becomes extremely complex, and power consumption increases significantly. Furthermore, if circuit changes are made due to the addition or modification of functions, the wiring must be physically changed, which is time-consuming.

[0066] On the other hand, in large-scale systems, PLC control allows for easy connection to numerous detection devices and actuators (alarms, warning lights, etc.) via input / output modules, and enables easy addition of functions and modification of control logic simply by changing the program, resulting in high expandability and flexibility.

[0067] Furthermore, because it has a self-diagnostic function and monitoring function via programming software, it is relatively easy to identify the cause of trouble. In addition, it has the advantage of a longer lifespan and stable operation over the long term compared to relays with mechanical contacts. It is also smaller than combining relays and has simpler wiring, so it has the advantage of saving space and wiring.

[0068] Furthermore, when using microcontroller control, the microcontroller itself is very inexpensive, which allows for low overall system component costs. It is also very small, enabling the necessary peripheral components to be miniaturized as well, resulting in a very compact control unit design. Additionally, microcontrollers generally consume very little power, making them advantageous for battery-powered systems or those operating on limited power supplies from solar power, contributing to reduced long-term operating costs (power costs). However, with microcontrollers, expandability, such as adding functions to the system, must be considered during the initial design phase, limiting their flexibility.

[0069] Based on the above, the control method for the control unit should be appropriately selected according to the scale and scalability of the target system in which the cable theft prevention system of the present invention will actually be operated, as well as the conditions such as the actual acceptable cost, miniaturization, and power saving. [Effects of the Invention]

[0070] According to the cable theft prevention system of the present invention, as described above, a lid opening detection mechanism is constructed simply by fixing an existing inexpensive and weather-resistant contact-type mitt switch in an appropriate position.

[0071] Therefore, while the detection configuration is simpler than before, the limit switch reliably sends a detection signal at the stage when there is a hint that the lid of the cable storage case has been opened, issuing an alarm and notifying the security company before the cable is actually cut. As a result, the theft prevention effect, which prevents or minimizes theft damage, is achieved more efficiently and effectively than before.

[0072] In addition, the limit switch is secured via a mounting bracket, preventing external physical interference and being fixed in an inward position on the side of the case body that cannot be seen from the outside. This is expected to improve the detection accuracy of the limit switch and enhance the reliability of the system's cable theft prevention performance. [Brief explanation of the drawing]

[0073] [Figure 1] This is a schematic block diagram showing the overall configuration of a cable theft prevention system according to one embodiment of the present invention. [Figure 2] Figure 1 is a schematic cross-sectional view of a cable storage case, showing the state in which the limit switch is fixed via a mounting bracket inside the cable storage case, which is part of the lid opening detection mechanism incorporated into the cable theft prevention system. [Figure 3] Figure 2 is a partial view showing the configuration of the limit switch and mounting bracket, where (a) is a front view in the fixed state and (b) is a front view showing the limit switch and mounting bracket before fixing. [Figure 4] Figure 1 is a flowchart showing the monitoring operation in the control unit of the cable theft prevention system. [Figure 5] This is a block diagram showing the overall configuration when the cable theft prevention system according to the present invention is applied to a large site. [Figure 6] This is an explanatory diagram showing the typical configuration of a solar power plant. [Figure 7] Figure 6 is a schematic diagram showing the cable protection provided by cable housing cases at a solar power plant. [Modes for carrying out the invention]

[0074] An embodiment of the present invention will be described below with reference to the drawings.

[0075] <Embodiment> The overall configuration of the cable theft prevention system 1 according to one embodiment of the present invention is shown in the schematic block diagram of Figure 1. This embodiment can be easily introduced into a typical solar power plant, similar to those shown in Figures 6 and 7.

[0076] The cables C extending from each solar cell array 110 to the current collection panel 150 on the outdoor ground within the site are housed in bundles of multiple cables, each bundle connected to the others, within a case body 11. These are protected by multiple cable storage cases 10, each with a lid 14 that can be opened and closed to cover the upper opening of the case body 11.

[0077] Furthermore, the cable theft prevention system 1 is equipped with a lid open detection mechanism 2 that detects the open state of the lid 14 of several specific cable storage cases 10 that are scattered throughout the premises.

[0078] The control unit 3, based on the detection signal from the lid opening detection mechanism 2, activates the warning light 210 and alarm 220 installed on the premises, and also transmits a notification signal to the security company 300 via a communication line 4 such as the internet.

[0079] As shown in Figures 1 and 2, the lid open detection mechanism 2 includes limit switches LS fixed via mounting brackets 40 inside each cable body 11 of a specific cable storage case 10, and an electrical circuit 5 that supplies power from a power source to each limit switch LS and sends the voltage from each limit switch LS as an output signal to the control unit 2.

[0080] Each limit switch LS has a microswitch 31 built into a switch case 30 with high mechanical strength, which switches the switch by the instantaneous movement of a movable contact between fixed contacts.

[0081] In other words, the snap action mechanism switches the connection between three terminals—a COM (common) terminal, a NO (normally open) terminal, and an NC (normally closed) terminal—and the contacts of the movable spring 32 between these terminals. The movable spring 32 is displaced when the push button 33 is pressed down and released by the rotation of an actuator part such as a lever 34, which is linked to the movement of the object to be detected.

[0082] Furthermore, while commercially available limit switches LS can be used as the limit switch LS incorporated into the lid opening detection mechanism 2 of this embodiment, since it is installed inside the cable storage case 10 which is installed outdoors, it should be highly resistant to the intrusion of rain, dust, etc. For example, a switch with high waterproof and dustproof performance, such as an IP rating of 67 or 68, is desirable.

[0083] In this embodiment, when power from the power source is supplied to the limit switch LS via the electrical circuit 5, the movable spring 32, which in its natural state has its contact on the NC terminal side, is also pressed when the lever 34 is rotated by an external force and pushes down the push button 33. As a result, the contact of the movable spring 32 moves from the NC terminal side to the NO terminal side, entering a first conductive state. This connects to the COM terminal, and a predetermined first voltage level is output to the NO terminal side.

[0084] Then, when the external force applied to the lever 34 is removed, the push button 33 is released from its pressure and returns to its upward position. This also returns the position of the movable spring 32, and its contact moves from the NO terminal side to the NC terminal side, connecting the NC terminal and the COM terminal to create a second conductive state, and a predetermined second voltage level is output to the NC terminal side when connected to the COM terminal. Here, the first voltage level of the output signal from the limit switch LS is set to indicate the switch-on state, and the second voltage level is set to indicate the switch-off state.

[0085] On the other hand, in this embodiment, each limit switch LS is fixed in a position where the lever 34 is pressed down by the closed lid 14 that covers the opening of the case body 11, causing the push button 33 to be pressed down and the switch to the ON state, and when the lid 14 is opened, the push button 33 returns to its original position and the switch to the OFF state.

[0086] Therefore, since the lid open detection mechanism 2 sends an output signal of a second voltage level indicating the switch-off state from either limit switch LS to the control unit 3, the control unit 3 determines the switch-off output signal from the lid open detection mechanism 2 as a detection signal indicating that the lid 14 has been opened.

[0087] As described above, the lid opening detection mechanism 2 in this embodiment employs a limit switch LS, which is a contact-type sensor that is linked to mechanical operation. Compared to non-contact types such as optical sensors, it is less affected by the surrounding environment, such as shaking and rattling due to strong winds in bad weather, and has higher detection accuracy, thus enabling more reliable detection.

[0088] Furthermore, the limit switch LS is not expensive like an optical sensor, nor does it require time-consuming installation and adjustment. It can be easily installed inside the case body 11 by screwing it in via the mounting bracket 40. This makes it possible to realize a more cost-effective and reliable cable theft prevention system 1 even in solar power plants with vast site areas.

[0089] In this embodiment, the limit switch LS is preferably fixed inside the case body 11 by using an L-shaped bracket as the mounting bracket 40, taking advantage of the shape of the case body 11. That is, in this embodiment, the cable storage case 10 is similar to a general shape, with the case body 11 having a housing shape in which side walls 12 are erected on both the left and right sides of the bottom surface, and the upper edges of both side walls 12 have horizontal edges 13 that are bent horizontally inward from each other.

[0090] The lid portion 14 has a U-shaped cross-section with vertical edges 16 that are bent downwards on both sides, and its underside (top surface 15) rests on the upper surfaces of the horizontal edges 13 on both sides, covering the opening and closing the top surface of the case body 11.

[0091] Therefore, the mounting bracket 40 is an L-shaped bracket consisting of a horizontal piece 41 that is superimposed on and fixed to the upper surface of one of the horizontal edges 13, and a suspension piece 42 that extends downward from the inner end of the case body 11 of the horizontal piece 41, and the limit switch LS is fixed by screwing it into a screw hole 43 formed in the suspension piece 42. The limit switch LS can be any one that is pressed by the lid portion 14 to turn on the button 33, and can be a relatively small one.

[0092] Furthermore, this L-shaped bracket (mounting bracket 40) is made of weather-resistant galvanized steel sheet and has a thickness of approximately 1.5 mm. Due to its thinness, even when the horizontal piece 41 is overlapped with the upper surface of the horizontal edge 13 of the case body 11, it hardly affects the placement of the lid 14. In addition, commercially available industrial double-sided tape T was used to fix the horizontal piece 41 to the upper surface of the horizontal edge 13.

[0093] Most commercially available industrial double-sided tapes typically have an adhesive strength of 10N / 25mm or more, even if they are less than 0.1mm thick (10N (Newtons): a force equivalent to about 1kg is required to peel off a 25mm wide tape stuck to a stainless steel plate in a 180° direction).

[0094] Therefore, by using such a thin industrial double-sided tape with high adhesive strength, it is possible to securely fix an L-shaped bracket to which a small limit switch LS weighing several tens of grams is attached, with sufficient strength to prevent it from coming off even due to vibrations such as rattling caused by strong winds, and without being affected by its thickness, simply by attaching a horizontal piece 41 over a width of several centimeters.

[0095] By using such an L-shaped bracket as the mounting bracket 40, the limit switch LS is fixed in a position away from the side of the case body 11 and inward. Therefore, the screw fastening portion of the limit switch LS is not exposed on the outer surface of the case body 11, and thus the presence of the limit switch LS cannot be confirmed from the outside.

[0096] In addition, this fixed position is also a somewhat physically protected location that prevents direct access or destruction of the limit switch LS from the outside, thus providing a greater anti-theft effect and further enhancing the effectiveness of the entire cable anti-theft system.

[0097] Furthermore, the control unit 3 in this embodiment can be any control method that can activate the warning light 210 and alarm 220 and send a notification signal to the security company 300 after a predetermined number of hours have elapsed since receiving the detection signal from the lid open detection mechanism 2. Examples include relay-type sequence control using a timer relay, PLC (programmable logic controller) control, or microcontroller control.

[0098] If the solar power plant to which this embodiment is intended is relatively small in scale, a timer relay type control unit 3 may be used, which has a simple structure, requires fewer relays, and is easy to implement.

[0099] Furthermore, in relatively small-scale systems, the electrical circuit 5 can be wired. In this case, the power source can be a wired supply of commercial power, power from a small solar power generation unit independent of the power plant's main grid converted to low voltage via a cubicle lighting panel, or power stored in a battery.

[0100] The monitoring operation by the control unit 3 of the cable theft prevention system 1 with the above configuration in a solar power plant will be described below in accordance with the flowchart in Figure 4. First, the power supply to the cable theft prevention system 1 is turned on and the monitoring operation begins. At this point, power is supplied to all limit switches LS.

[0101] When the monitoring operation is started, the control unit 3 first checks for the presence or absence of a detection signal from the lid open detection mechanism 2, either continuously or at preset intervals, as step S1. When a detection signal is received, as step S2, it starts a timer count for a preset elapsed time. As step S3, once the predetermined elapsed time has been counted and the set time has been reached, as step S4, it activates the warning light 210 and alarm 220 and simultaneously sends a notification signal to the security company 300.

[0102] Upon receiving the alert signal, security company 300 dispatches security guards to the site and also reports to the solar power plant's management department. Therefore, the site is checked to determine whether the cable theft was prevented by the activation of the warning lights 210 and alarms 220, and to assess the extent of the damage. Appropriate measures are then taken. In some cases, repairs are carried out on the damaged areas, but solar power generation continues in areas without other problems if possible.

[0103] Finally, the cable theft prevention system 1 is restored to its original state, and the control unit 3, in step S5, checks for the presence or absence of a detection signal from the lid opening detection mechanism 2. If no detection signal is received (it is determined that the lid 14 is closed), in step S6, it stops the operation of the warning light 210 and alarm 220 and the transmission of a notification signal to the security company 300, and temporarily ends the monitoring operation. At this point, the power supply to the cable theft prevention system 1 is also turned off.

[0104] Therefore, once the problem within the facility is resolved and the lid 14 of the cable storage case 10 is fully restored to its closed state, the power supply to the cable theft prevention system 1 can be turned on and the monitoring operation can be restarted.

[0105] Furthermore, the cable theft prevention system 1 according to this embodiment can also be applied to large-scale sites such as large-scale solar power plants. In this case, as shown in Figure 5, the cable theft prevention system can be scaled up by distributing the lid opening detection mechanisms (20A, 20B, ..., 20N) in multiple (N) areas.

[0106] In this case, each lid-open detection mechanism (20A, 20B, ..., 20N) is equipped with a signal transmitter (21a, 21b, ..., 21n), and based on an output signal indicating that the lid 14 of the target cable storage case 10 has been opened, the transmitter transmits a detection signal to the control unit 3 via wireless communication.

[0107] In the distributed arrangement of each lid-open detection mechanism (20A, 20B, ..., 20N) across such a large and vast site, the power sources for the limit switches LS and signal transmitters (21a, 21b, ..., 21n) may be battery-powered or batteries located at designated locations in each area.

[0108] Meanwhile, the control unit 3 is equipped with a signal receiver 23, which, upon receiving a detection signal transmitted from the signal transmitters (21a, 21b, ..., 21n) of the lid open detection mechanism (20A, 20B, ..., 20N), activates the warning light 210 and the alarm 220, and also transmits a notification signal to the security company 300.

[0109] Furthermore, each signal transmitter (21a, 21b, ..., 21n) is assigned a different type of signal, such as a different frequency band, to each area, thereby differentiating the signals belonging to each area. This allows the control unit 3 to determine which area the cable storage case 10 with the open cover 14 belongs to based on the type of signal received by the signal receiver 23, and to add this information to the notification signal before notifying the security company 300.

[0110] The party receiving the report will know in advance which area the cable theft is about to occur in, allowing them to dispatch security guards to the target area, even on a large site. Furthermore, when dealing with such large sites, alarms and warning lights may be installed separately in each area.

[0111] In large-scale solar power plants, introducing wireless communication as described above can mitigate many challenges that may arise due to the scale, such as the cost of laying wiring, the complexity of construction, the difficulty of maintenance, and the risk of cable breakage, thereby improving the operational convenience of large-scale cable theft prevention systems. [Industrial applicability]

[0112] The cable theft prevention system according to the present invention is not limited to its introduction into general solar power plants for selling electricity, but can be applied to self-consumption solar power generation facilities in factories and plant facilities, wind power plants, or various infrastructure facilities where a large amount of cable is used for data centers and power supply, in which cable theft prevention is desired. [Explanation of Symbols]

[0113] 1: Cable theft prevention system 2, 20A, 20B, ..., 20N: Lid open detection mechanism 3: Control Unit 4: Communication lines 5: Electrical circuits C: Cable 10: Cable storage case 11: Case body 12: Side wall section 13: Horizontal edge 14: Lid part 15: Back side 16: Vertical edge 21a, 21b, ..., 21n: Signal transmitters 23: Signal receiver LS: Limit switch 30: Switch Case 31: Microswitch 32: Movable spring 33: Push button 34: Lever 40: Mounting bracket (L-shaped bracket) 41:Horizontal piece T: Industrial double-sided tape 42: Hanging piece 43: Screw hole 100: Solar cell modules 110: Solar cell array 150: Current collector panel 200: Power Conditioner 210: Warning light 220:Alarm 300: Security company

Claims

1. Within the premises of a solar power plant equipped with anti-theft warning lights and alarms, multiple cable storage cases are provided, each containing bundles of cables extending from each solar module to the current collection panel on the outdoor ground, with each bundle connected to the others, and the upper opening of the case body covered by a lid that can be opened and closed. A lid open detection mechanism detects the open state of the lid of a specific cable storage case located at a pre-selected position among the aforementioned plurality of cable storage cases, A cable theft prevention system comprising a control unit that activates the warning light and the alarm and transmits a notification signal to the security company based on a detection signal from the lid opening detection mechanism, The aforementioned lid open detection mechanism is, A limit switch is installed in each of the aforementioned specific cable storage cases, and the output signal is switched in accordance with the displacement of the push button when the push button is pressed down by the back surface of the lid when the lid of the cable storage case is closed and covers the opening of the case body, and when the push button is released and the push button returns to its original position when the lid is open and away from the opening. Each of the limit switches is wired to receive power from a power source by connecting to a predetermined terminal, and to switch the conduction state by switching the connection between terminals in conjunction with the displacement of the push button in each limit switch, and each limit switch has an electrical circuit that sends the output signal indicating the conduction state corresponding to the open state of the cover to the control unit as the detection signal. A cable theft prevention system characterized in that each of the limit switches is fixed to the case body at a position away from the side and inward via a mounting bracket.

2. The case body has a housing shape with side walls erected on both the left and right sides of the bottom surface, and the side walls have horizontal edges where the upper edges are horizontally bent inward from each other. The lid has a U-shaped cross-section, with its underside resting on the upper surfaces of the horizontal edges on both sides of the case body, thereby closing the opening and closing the top surface of the case body, and its side edges are bent downwards. The cable theft prevention system according to claim 1, characterized in that the mounting bracket is an L-shaped bracket comprising a horizontal piece that is superimposed on and fixed to the upper surface of one of the horizontal edges of the case body, and a suspension piece that extends downward from the inner end of the horizontal piece of the case body, to which the limit switch is screw-fastened.

3. The lid opening detection mechanism is provided in each of the areas into which the site is divided into multiple regions, and each lid opening detection mechanism includes a signal transmitter that transmits the detection signal based on the output signal from the limit switch belonging to that region to the control unit via wireless communication. The cable theft prevention system according to claim 1 or 2, characterized in that the control unit includes a signal receiver that receives the detection signal transmitted from each lid opening detection mechanism.

4. The system further includes a break detection device that detects the break state of a specific cable among the aforementioned cables, The cable theft prevention system according to claim 1, characterized in that the control unit activates the warning light and the alarm and transmits the notification signal based on a detection signal from at least one of the lid opening detection mechanism and the cutting detection device.

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