A remote power supply system and cable open circuit anti-false alarm detection method

Abstract

The present invention discloses a remote power supply system and a method for detecting cable open circuits and preventing false alarms. The system includes two local-end devices and a plurality of remote-end devices between the two local-end devices. The remote devices supply power to each power-consuming device. The remote devices include a remote controller and a power converter. The input end of the power converter is connected to the remote controller, and the output end of the power converter is connected to the power-consuming device. The power converter is used to output alternating current or direct current. Two ports of the remote device connected to the power supply cable are each equipped with a current detection component, which respectively detects the current of the power supply cable connected thereto. The local-end device is equipped with a power converter that can output a transmission voltage and has the function of adjusting the transmission voltage. The remote device is equipped with a cable open circuit logic judgment module for determining whether a cable open circuit exists. The present invention can effectively implement the cable open circuit monitoring function and can also accurately locate the cable segment where the cable open circuit fault occurs.

Description

Technical Field

[0001] The present invention relates to the technical field of power open circuit detection, in particular to a remote power supply system and a cable open circuit anti-false alarm detection method. Background Art

[0002] DC remote power supply systems are used in many fields, such as railway inter-area communications. Railway inter-area communications have the following requirements for DC remote power supply systems: stable power supply needs and the ability to promptly detect cable faults in the event of power failures, including the ability to detect open-circuit cable faults.

[0003] Remote power supply systems typically use two central-end devices to power each power point (device) along the line. The voltages output by the two central-end devices are transmitted in opposite directions through the power cable, transmitting power toward each other. However, due to load current and cable impedance, a voltage drop occurs along the line where the power cable is located. When the voltages output by the two central-end devices are equal, the voltages gradually decrease from the central-end device toward the center of the line. Because the voltages are equal, the current at the center of the line is zero. However, when the voltages output by the two central-end devices are unequal, with one output voltage greater than the other, the current at the center of the line is not zero. Instead, the current is zero at a location on the side of the line toward the central-end device with the lower output voltage. This means that the location of the zero current has shifted.

[0004] Existing technology typically uses current detection to detect open-circuit power cables in remote power supply systems. Regardless of whether the two output voltages of the two central-end devices are equal, the current may be zero at some point in the line. However, the line itself is normal and not open (broken). Using current detection directly can lead to false positives, where the line is normally open but mistakenly detected as open. Therefore, it is necessary to address this false positive issue and implement a false positive prevention function. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a remote power supply system and a method for detecting and preventing false alarms of cable open circuits, which can solve the problems described in the background art.

[0006] The technical solution for achieving the purpose of the present invention is as follows: a remote power supply system includes two local-end devices and a plurality of remote devices between the two local-end devices, wherein the remote devices supply power to each power-consuming device. The remote devices include a remote controller and a power converter, wherein the input end of the power converter is connected to the remote controller, and the output end of the power converter is connected to the power-consuming device. The power converter is used to output AC or DC power to supply power to the power-consuming device. The remote controller includes two power transmission ports connected to power supply cables, a cable fault protection switch is configured between the two transmission ports, and a current detection component is configured on each power supply cable on both sides of the cable fault protection switch, and the current detection component respectively detects the current of the power supply cable to which it is connected.

[0007] The remote device of the remote power supply system is equipped with a cable open circuit logic judgment module for judging whether the cable is open circuit, and the local device is equipped with a power converter, which is used to randomly generate a transmission voltage from at least two preset voltage values ​​every preset time period.

[0008] The cable open circuit logic judgment module of the remote device is used to judge whether the current detected by the current detection component is less than the preset cable open circuit detection current threshold within the preset cable open circuit detection time threshold, and judge whether the cable is open circuit based on the judgment result.

[0009] Furthermore, the power converter of at least one of the two central office devices includes a random number generation module and a timing module. The random number generation module is used to generate a random number. Each random number generated is randomly generated from M values, M ≥ 2, and each value is different. Based on the random number randomly generated by the random number generation module, the central office device outputs a corresponding transmission voltage.

[0010] The timing module is used to generate a time period T1, and the random number generation module generates a random number every time period T1, so that the central office device outputs a new transmission voltage every time period T1.

[0011] Furthermore, the cable open circuit logic judgment module of the remote device is electrically connected to the current detection component to receive the current detected by the current detection component. The cable open circuit logic judgment module is used to judge the current currently detected. Whether condition 1 is met, if so, the power supply cable is judged to be open circuit,

[0012] Condition one: , and the duration is > , is the preset cable open detection current threshold, and >0, is the preset cable open detection time threshold, and .

[0013] Furthermore, when the power converters of the two central office devices both include a random number generation module and a timing module, the M corresponding to the random number generation modules of the two central office devices are the same or different.

[0014] Furthermore, when the power converters of the two central office devices both include a random number generation module and a timing module, the time periods T1 generated by the respective timing modules of the two central office devices are the same or different.

[0015] Furthermore, when the power converters of the two central office devices both include a random number generation module and a timing module, the two central office devices are respectively recorded as a first central office device and a second central office device. All transmission voltages that can be generated by the first central office device based on the random numbers generated by its own random number generation module constitute a first transmission voltage set. All transmission voltages that can be generated by the second central office device based on the random numbers generated by its own random number generation module constitute a second transmission voltage set.

[0016] The set elements of the first transmission voltage set and the second transmission voltage set are the same or different.

[0017] Furthermore, the current threshold is preset The current value should be less than the minimum power input current of the remote device when it is unloaded and greater than zero.

[0018] Furthermore, the preset cable open circuit detection current threshold of each remote device is Same or different.

[0019] A cable open circuit detection method for preventing false alarms, the detection method comprising:

[0020] The current sensing component in the remote device is at least Duration detection of the current flowing through;

[0021] One or two local end devices randomly generate a random number according to the preset time period T1, and generate the transmission voltage corresponding to the random number. The time period of each local end device is greater than ,

[0022] One or two local end devices dynamically generate a random number according to their respective time periods T1, and then generate a corresponding transmission voltage according to each random number. Different random numbers correspond to different transmission voltages.

[0023] When the current sensing component is at least The current detected in Both are less than the preset current threshold , it is determined that the power supply cable connected to the port where the current detection component is located is open circuit,

[0024] time Greater than the larger value of the time period T1 in the two central office devices.

[0025] Furthermore, the transmission voltage values ​​of the two central office devices are the same or different, and all transmission voltages of the two central office devices constitute respective sets that are the same or different.

[0026] The present invention effectively implements the open-cable alarm function and avoids the problem of false alarms during current detection of open-cable currents, effectively reducing the probability of false alarms to a negligible level. Furthermore, by providing a current detection component at each end of the cable fault protection switch, the cable segment where the open-cable fault occurs can be accurately located, thereby precisely pinpointing the location of the open-cable fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the remote power supply system of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0029] like Figure 1 As shown, a remote power supply system includes two local end devices, namely the first local end device ( Figure 1 The central office device 1) and the second central office device ( Figure 1 When the remote power supply system of this embodiment operates normally, the output voltages of the two local devices are connected in parallel through the power supply cables and the cable fault protection switches of each remote device ( Figure 1 (cable fault protection in the example), and both the first and second local-end devices are capable of powering all powered devices (powered device 1, powered device 2, ..., powered device N). It is understood that the two local-end devices in this embodiment can be two power supply devices deployed in different locations, or they can refer to two output ports of the same power supply device. It is also understood that the local-end devices can power powered devices using their own power supplies or by connecting to an external power source (such as mains electricity).

[0030] Exemplarily, there is at least one powered device between two local-end devices, and each powered device is configured with a remote device. Each remote device includes a remote controller and a power converter. The input of the power converter is connected to the remote controller, and the output of the power converter is connected to the powered device. The power converter is configured to output AC or DC power to supply power to the powered device. The remote controller is connected to a power cable and detects the current flowing through the power cable in real time.

[0031] It is understood that the remote controller and the power converter can be integrated into one component.

[0032] Exemplarily, the remote controller includes two power transmission ports connected to power supply cables, with a cable fault protection switch disposed between the two transmission ports. A current detection component is disposed on each power supply cable on either side of the cable fault protection switch. The two current detection components are respectively designated as a first current detection component and a second current detection component, and the two current detection components respectively detect the current value of the power supply cable to which they are connected. The cable fault protection switch is closed in normal operation, at which point the two power transmission ports are directly connected. It is understood that the outputs of the two local-end devices are connected in parallel via the power supply cables in normal operation, jointly supplying power to all electrical devices. A diode is connected to each end of the cable fault protection switch, and the two diodes form an "OR" logic isolation diode to power the local output port. That is, if power is present at either end of the cable fault protection switch, power is also present at the local output port. The isolation diode may be an independent diode, or, when the cable fault protection switch includes an available diode structure, the isolation diode may be a diode structure within the switch device, such as the body diode of a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) device, the protection diode in an Insulated Gate Bipolar Transistor (IGBT), etc.

[0033] It is understandable that the current detection component can be any device component that can realize the current detection function, such as a current sensor, an ammeter, a current transformer, etc.

[0034] When a short circuit occurs at a certain position in the power supply cable, the current flowing through the short-circuited power supply cable will increase instantaneously. Therefore, when the remote controller detects that the current flowing through the power supply cable is greater than its overcurrent protection threshold, the cable fault protection switch of the remote controller will be disconnected, thereby achieving fault isolation and playing a protective role. Although the cable fault protection switch of the remote controller is disconnected, the power converter can still be connected to the power supply cables on both sides of the cable protection switch through isolation diodes, so it can still obtain power from one of the first local end device or the second local end device. For example, if Figure 1 As shown, the input end of the power converter that supplies power to local electrical equipment draws power from both ends of the cable fault protection switch through isolation diodes. As long as there is power at either end, the local load can be powered. Therefore, the power supply to the local electrical equipment is not affected by the state of the control switch.

[0035] Exemplarily, the cable fault protection switch is configured at the positive electrode of the transmission voltage output by the central office equipment, that is, the cable fault protection switch is configured on the power supply cable where the positive electrode of the transmission voltage is located. Accordingly, the first current detection component and the second current detection component on either side of the cable fault protection switch are also configured at the positive electrode of the transmission voltage. The anode of the isolation diode is connected to the positive electrode of the transmission voltage, that is, the anodes of the two diodes comprising the isolation diode are respectively connected to the power supply cables on either side of the fault protection switch.

[0036] It is understood that the cable fault protection switch can also be configured at the negative pole of the transmission voltage output by the central office equipment, that is, the cable fault protection switch is configured on the power supply cable where the negative pole of the transmission voltage is located. Accordingly, the first and second current detection components on both sides of the cable fault protection switch are also configured at the negative pole of the transmission voltage. The cathode of the isolation diode is connected to the negative pole of the transmission voltage, that is, the cathodes of the two diodes comprising the isolation diode are respectively connected to the power supply cables on both sides of the fault protection switch.

[0037] Among them, the two current detection components of the i-th remote device respectively detect the currents from the cables connected to the two cable interfaces and are recorded as and For example, Figure 1 As shown, taking 4 power-consuming devices as an example, from the first local device to the second local device, they are the first remote device to the fourth remote device, namely remote device 1 to remote device 4 in the figure. The first current detection component of remote device 2 detects the current of the cable on its left side and records it as (I2-1 in the figure), the second current detection component where the remote device 2 is located detects the current of the cable on its right side and records it as (I2-2 in the figure.) The two current detection components in each other remote device detect currents in a similar manner.

[0038] The power converter in at least one of the local terminal devices (the first local terminal device and the second local terminal device) is configured with a random number generation module. The random number generation module is used to generate random numbers. Each time the random number generated is randomly generated from M values, M≥2, that is, at least two different values ​​can be generated, and each value is different. In other words, each time the random number generation module randomly generates a value (random number), it randomly selects one from M values ​​with different values. For example, if M is 10 and the 10 random numbers are 1-10, then the random number generated by the random number generation module each time is one of 1-10. Based on the values ​​randomly generated by the random number generation module, the local terminal device outputs the corresponding transmission voltage, and the transmission voltages corresponding to different random numbers are also different. Among them, the j-th random number among the M values ​​is recorded as ,j=1, 2, ..., M, random number The corresponding transmission voltage is This means that each random number generated by the random number generation module corresponds to a transmission voltage. If the random numbers generated at different times are the same, the corresponding transmission voltages are also the same. If the random numbers are different, the corresponding transmission voltages are also different. Therefore, the number of transmission voltage values ​​output by the central office device is equal to M, which means that there are as many transmission voltages as there are random numbers, and at least two of these transmission voltages are different. The best performance is achieved when all the voltage values ​​in the transmission voltages are different.

[0039] For example, assume M = 3, meaning only three different random numbers can be generated. These three random numbers are assumed to be 1, 2, and 3. This means each random number can only randomly select one of the three values ​​(1, 2, 3). If the generated random number is 1, the transmission voltage is 1 V; if the generated random number is 2, the transmission voltage is 3 V; and if the generated random number is 3, the transmission voltage is 5 V. Therefore, the transmission voltage output by the central office device in each cycle can only take the following three values: (1 V, 3 V, 5 V).

[0040] The first local-end device outputs multiple transmission voltages, which constitute a transmission voltage set, denoted as the first transmission voltage set. The second local-end device also outputs multiple transmission voltages, which also constitute a transmission voltage set, denoted as the second transmission voltage set. The first transmission voltage set and the second transmission voltage set can be equal sets. Of course, the first transmission voltage set and the second transmission voltage set can also be different sets, or one can be a subset of the other. For example, the first transmission voltage set is a subset of the second transmission voltage set, or the second transmission voltage set is a subset of the first transmission voltage set, or only some of the elements in the two sets are the same, that is, at least one element is the same, but not all elements are the same. For example, the first transmission voltage set includes five voltage values, namely 1 V, 2 V, 3 V, 4 V, and 5 V, with a total of five set elements. The second transmission voltage set also includes five voltage values, namely 6 V, 7 V, 8 V, 9 V, and 10 V. In this case, the two sets are different sets. Assuming that the first transmission voltage set remains unchanged, the second transmission voltage set includes four voltage values, namely 1 V, 2 V, 3 V, and 4 V. This means that the second transmission voltage set is a subset of the first transmission voltage set. Other situations are similar and will not be described in detail here.

[0041] It is understandable that, given a fixed number of set elements, the more identical set elements there are, the greater the probability that two central office devices will simultaneously output the same transmission voltage, which can have an impact on false alarms. Therefore, it is necessary to limit the number of identical set elements, allowing only some or none of them to be identical. Of course, in the case of a large number of set elements, even if the two sets are equal sets, meaning all set elements are identical, the probability of two central office devices simultaneously outputting the same transmission voltage is extremely low, having little impact on false alarms.

[0042] It can be understood that when M=3, the rated output voltage of the central office equipment can be used as one of the transmission voltages, and the voltage increased or decreased by a certain percentage (such as 1%-5%) based on the rated output voltage can be used as the other two transmission voltages.

[0043] At least one of the two central office devices is further configured with a timing module within its power converter. The timing module generates a time period T1, and the random number generation module generates a random number every time period T1, so that the central office device outputs a new transmission voltage every time period T1, while maintaining the current transmission voltage throughout time period T1. In other words, the central office device changes to a new transmission voltage every time period T1, and the new transmission voltage is likely different from the previous transmission voltage.

[0044] It is understood that time period T1 can be set based on actual circumstances. Different time period T1 values ​​can be set for different situations, and time period T1 can be a preset value. For example, time period T1 can be 1 second, 0.5 seconds, or 3 seconds. If time period T1 is set to 1 second, the central office device will switch to a new transmission voltage as the new output voltage every 1 second. The shorter time period T1, the faster the transmission voltage of the central office device changes; conversely, the slower the transmission voltage changes.

[0045] The power converter of the central office equipment includes a timing module and a random number generation module group, and has the function of adjusting the output voltage.

[0046] The current detection component of the remote device continuously and in real time detects the current in the power supply cable. It will be appreciated that the current detection component can continuously measure the current in the power supply cable in real time. Therefore, regardless of how short the time period T1 is, the current detection component can measure multiple currents within a time period T1. Of course, depending on actual needs, it is also possible to measure one or a preset number of currents within a time period T1. In other words, the current detection component can measure currents at a preset sampling rate, but it is always ensured that at least one current corresponding to each new change in the transmission voltage is measured.

[0047] The remote device is also equipped with a cable open circuit logic judgment module, which is electrically connected to the current detection component to receive the current detected by the current detection component. The cable open circuit logic judgment module is used to judge the current currently detected Whether condition 1 is met, if so, the power supply cable is judged to be open circuit, otherwise, the power supply cable is judged to be not open circuit,

[0048] Condition one: , and the duration is > , is the preset cable open detection current threshold, and >0, is the preset cable open detection time threshold, and , which is the preset time threshold Much longer than the time period T1. Generally speaking, when Greater than T1 by one order of magnitude, it can be considered For example, T1 is 1 second, is 10 seconds, which is an order of magnitude different. At this time, it can be considered that .set up The purpose is to reduce the probability that the position where the current is zero due to the transmission voltage output by the two local devices remains unchanged within a certain period of time, so that the probability that the current that can be continuously monitored is less than the current threshold is extremely low, thereby ensuring that the detection cable is truly open is reliable.

[0049] It can be understood that the cable open circuit logic judgment module performs logical operations based on the received current to determine whether condition one is met, and then determines whether the power supply cable is open circuit. Therefore, in addition to being configured in the remote device, the cable open circuit logic judgment module can also be configured in the local device, or configured in any other place in the remote power supply system, and only needs to be able to receive the current sent by the current detection component.

[0050] Exemplarily, the preset cable open circuit detection current threshold The current value is less than the minimum power input current value of the remote device when it is unloaded and greater than zero. The remote device is unloaded when it is not connected to the power device. The minimum power input current value of the remote device when it is unloaded is determined by the static power consumption of the remote device. The current value is usually between mA (milliamperes) and tens of mA (milliamperes). Therefore, the preset cable open circuit detection current threshold of each remote device is The current detected by the current detection component of each remote device may be the same or different, and the current is compared with its own preset cable open circuit detection current threshold. Figure 1 The four remote devices in the embodiment may correspond to four preset cable open circuit detection current thresholds with different or same values.

[0051] Set the cable open detection current threshold The significance of taking a current value less than the minimum power input of the remote device when it is unloaded and greater than zero is that as long as the cable is not open-circuited and the cable segment is not at the electrical center point, the absolute value of the current value of the cable segment must be greater than , and when the cable is truly open, Approximately equal to zero (nanoampere to microampere level, mainly caused by leakage current of cable insulation material and stray current caused by distributed capacitance, etc.).

[0052] by Figure 1 Taking the four remote devices in the example as an example, for remote device 3, two current detection components are provided in remote device 3, and the currents measured by the two current detection components are I3-1 and I3-2 respectively.

[0053] Assume that the current measured from a certain moment to the current moment is less than the preset current threshold , then the corresponding power supply cable is judged to be open circuit. If the current I3-1 measured from the second second is < , and lasts for more than 10 seconds ( = 10 seconds), that is, the current I3-1 measured from the 2nd second to the 12th second is less than During this period, there is no current I3-1 greater than If the current I3-1 is detected, the corresponding power supply cable is judged to be open circuited, that is, the power supply cable where the current detection component where the current I3-1 is detected is judged to be open circuited, that is, Figure 1 An open circuit exists in power cable segment 3. Specifically, this is the power cable segment between remote device 2 and remote device 3, that is, the power cable between one end of the cable fault protection switch on remote device 2 and one end of the cable protection switch on remote device 3. This power cable contains the positive terminal of the transmission voltage. Otherwise, the power cable is determined to be not open.

[0054] In order to avoid the false alarm of the cable being open when it is in normal condition, the two local devices continuously change the transmission voltage according to the random numbers generated, so that the position of the current zero is constantly changing and no longer fixed at a certain position. In other words, the current zero is no longer fixed at the center of the power supply cable or to one side of the center. Instead, the position of the current zero is constantly changing due to the different transmission voltages output by the two local devices. In this case, at time The current detected in Both are less than the preset current threshold , it is highly likely that there is an open circuit in the cable, rather than detecting that the current itself is zero.

[0055] For example, Figure 1 The locations where the current is zero appear randomly at intervals of time period T1 in power cable segments 2, 4, and 2. If the transmission voltage U1 output by the first local-end device is greater than the transmission voltage U2 output by the second local-end device, the location where the current is zero appears in power cable segment 2; when U1 is less than U2, the location where the current is zero appears in power cable segment 4; and when U1 equals U2, the location where the current is zero appears in power cable segment 3.

[0056] Among them, since the two local end devices are constantly changing to generate new transmission voltages based on the random numbers generated by their own internal random number generation modules, the probability that the two local end devices will synchronize to form the same new transmission voltage each time is extremely low. The high probability is that the transmission voltages output by the two local end devices are different. Therefore, the position where the current of the power supply cable is zero is constantly changing, making the current duration at the position of the power supply cable where the current detection component in each remote device is located Specifically, the two central office devices change synchronously every time period T1 to generate a new transmission voltage. The random number generation module can generate M kinds of random numbers, which means that the local equipment can output M kinds of transmission voltages with different voltage values. , ,because , and M≥2, so the false alarm probability P is extremely small. With T1=1 second, = 10 seconds, M = 3 as an example, the false alarm probability P = 1 / 3 10 ≈0.0017%. If the current detection method of the existing technology is used, the false alarm rate is almost 50% (there is a 50% probability that the electrical center point is a remote device, and the two cable interfaces of the remote device will not detect The reason is that it cannot distinguish whether the cable is a true open circuit fault or a false open circuit fault caused by the supply voltage of the two central office devices causing the current to be zero somewhere. Therefore, the false alarm rate of the present invention is reduced from 50% to 0.0017%, which is an extremely low probability. In addition, since M can be adjusted according to the actual situation, the larger the value of M is, the lower the false alarm rate is. Similarly, The larger the setting is and the smaller the T1 setting is, the false alarm rate can be further significantly reduced, and the reduced false alarm rate can be almost negligible.

[0057] It is understandable that the two central office devices generate a random number synchronously. Since both generate a new transmission voltage based on the random number, the new transmission voltage changes synchronously. In this way, the voltage of the new transmission voltage generated by the two central office devices each time is the same, and therefore the false alarm rate is extremely low. Of course, the two central office devices can also generate random numbers asynchronously, for example, the first central office device generates a random number at a time period. Generate a random number, accordingly, the first end device every time period Change to a new transmission voltage. The second terminal equipment Generate a random number, accordingly, the second end device every time period changes to a new transmission voltage. ≠ , so that the new transmission voltage is not changed synchronously, but asynchronously. Similarly, the probability that two local end devices will form the same voltage at the same time (which can be a certain time point or a certain time range) is also small. Similarly, the number of transmission voltages formed by the two local end devices based on their respective random numbers can be different, and the values ​​of the transmission voltages can be the same or different. For example, the first local end device can form random numbers, which can be formed accordingly A transmission voltage; the second local equipment can form random numbers, which can be formed accordingly transmission voltage. ≠ , Transmission voltage neutralization The transmission voltages may have the same voltage value or different voltage values.

[0058] The position where the current of the power supply cable is zero can be changed in a variety of ways, and this change is random, so that it is possible to avoid the current being measured at a certain position as zero for a long time with a very high probability, thereby avoiding the false alarm problem of cable open circuit misdetection and realizing the anti-false alarm function.

[0059] Based on the above remote power supply system, the present invention also provides a cable open circuit anti-false alarm detection method, which includes:

[0060] The current sensing component in the remote device is at least The duration detects the current flowing through.

[0061] Each remote device is provided with two current detection components, and each current detection component detects the current on the corresponding power supply cable.

[0062] The two central office devices randomly generate a random number according to their respective preset time periods and generate the transmission voltage corresponding to the random number. The time periods of the two central office devices are greater than That is, every time the one with the smaller time period of the two local-end devices changes a random number and generates the corresponding transmission voltage, the current detection component needs to detect the current at least once to avoid the situation where a local-end device has changed from the previous transmission voltage to the current transmission voltage while the current detection component has not yet detected the current corresponding to the previous transmission voltage.

[0063] The two central office devices dynamically generate random numbers based on their respective time periods, and then generate corresponding transmission voltages based on each random number, allowing the central office devices to dynamically change to new transmission voltages. A new transmission voltage here does not necessarily mean a different voltage value, but rather a voltage value that is different from the previous value, but may be a voltage value from a previous time.

[0064] When the current detection component is at least the preset cable open detection time threshold The current detected in The absolute value of the cable open circuit detection current threshold is less than the preset , then it is determined that the power supply cable where the current detection component is located is open circuit. Much longer than the larger time period value of the two central office devices, that is, the time Greater than any time period of the two central office devices.

[0065] The present invention effectively avoids the problem of false alarms in current detection of cable open circuits, effectively reducing the probability of false alarms to a negligible level, thereby ensuring effective false alarm prevention. Furthermore, by providing a current detection component at each end of the cable fault protection switch, the cable segment where the cable open circuit fault occurs can be accurately located, thereby precisely pinpointing the location of the cable open circuit fault.

[0066] The embodiment disclosed in this specification is merely an illustration of one aspect of the present invention. The scope of protection of the present invention is not limited to this embodiment. Any other functionally equivalent embodiments fall within the scope of protection of the present invention. Those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all such changes and modifications should fall within the scope of protection of the claims of the present invention.

Claims

1. A remote power supply system comprising two local-end devices and a plurality of remote devices disposed between the two local-end devices. The remote devices provide power to respective power-consuming devices. The remote devices comprise a remote controller and a power converter. The input of the power converter is connected to the remote controller, and the output of the power converter is connected to the power-consuming device. The power converter is configured to output alternating current (AC) or direct current (DC) to power the power-consuming device. The remote controller comprises two power transmission ports connected to power supply cables. A cable fault protection switch is disposed between the two transmission ports. A current detection component is disposed on each power supply cable on either side of the cable fault protection switch to detect the current in the power supply cable to which it is connected. It is characterized by: The remote device of the remote power supply system includes a cable open circuit logic judgment module, and the local device is equipped with a power converter, which is used to randomly generate a transmission voltage from at least two preset voltage values ​​every preset time period; The cable open circuit logic judgment module of the remote device is used to judge whether the current detected by the current detection component is less than the preset cable open circuit detection current threshold within the preset cable open circuit detection time threshold, and judge whether the cable is open circuit based on the judgment result. The power converter of at least one of the two central office devices includes a random number generation module and a timing module. The random number generation module is used to generate a random number. Each random number generated is randomly generated from M values, M≥2, and each value is different. Based on the random number generated by the random number generation module, the central office device outputs a different transmission voltage. The timing module is used to generate a time period T1, and the random number generation module generates a random number every time period T1, so that the central office device outputs a new transmission voltage every time period T1.

2. The remote power supply system according to claim 1, characterized in that: The cable open circuit logic judgment module of the remote device is electrically connected to the current detection component to receive the current detected by the current detection component. The cable open circuit logic judgment module is used to judge the current currently detected Whether condition 1 is met, if so, the power supply cable is judged to be open circuit, Condition one: , and the duration is > , is the preset cable open detection current threshold, and >0, is the preset cable open detection time threshold, and .

3. The remote power supply system according to claim 2, characterized in that: When the power converters of the two central office devices both include a random number generation module and a timing module, the M corresponding to the random number generation modules of the two central office devices are the same or different.

4. The remote power supply system according to claim 3, characterized in that: When the power converters of the two central office devices both include a random number generation module and a timing module, the time periods T1 generated by the respective timing modules of the two central office devices are the same or different.

5. The remote power supply system according to claim 4, characterized in that: When the power converters of the two local-end devices both include a random number generation module and a timing module, the two local-end devices are respectively recorded as a first local-end device and a second local-end device. All transmission voltages that can be generated by the first local-end device based on the random numbers generated by its own random number generation module constitute a first transmission voltage set. All transmission voltages that can be generated by the second local-end device based on the random numbers generated by its own random number generation module constitute a second transmission voltage set. The set elements of the first transmission voltage set and the second transmission voltage set are the same or different.

6. The remote power supply system according to claim 5, characterized in that: Preset cable open detection current threshold The current value should be less than the minimum power input current of the remote device when it is unloaded and greater than zero.

7. The remote power supply system according to claim 6, characterized in that: Preset open cable detection current threshold for each remote device Same or different.

8. A cable open circuit anti-false alarm detection method, characterized in that: The test method includes: The current sensing component in the remote device is at least Duration detection of the current flowing through; One or two central office devices randomly generate a random number according to a preset time period T1, and generate a transmission voltage corresponding to the random number. The time period T1 of each central office device is greater than ; One or two central office devices dynamically generate a random number according to their respective time periods T1, and then generate a corresponding transmission voltage according to each random number. Different random numbers correspond to different transmission voltages. When the current detection component of the remote device is at least within the preset cable open detection time threshold The current detected in Both are less than the preset cable open circuit detection current threshold , it is determined that the power supply cable connected to the port where the current detection component is located is open circuit, time Greater than the larger value of the time period T1 in the two central office devices.

9. The cable open circuit anti-false alarm detection method according to claim 8, characterized in that: The transmission voltage values ​​of the two central office devices are the same or different, and all transmission voltages of the two central office devices constitute respective sets that are the same or different.

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