Efficient localization of ground faults in energized power systems such as photovoltaic arrays

Abstract

The present disclosure provides a method for efficiently locating a ground fault in an electrical circuit. To implement the method, a transmitter device ("transmitter") is electrically coupled to a first connection location of the electrical circuit. The transmitter is capable of transmitting a tracking signal into the electrical circuit. The tracking signal can be followed to identify the location of a ground fault within the circuit.

Description

Technical Field

[0001] This disclosure generally relates to the location of ground faults. More specifically, this disclosure relates to systems and methods for the efficient location of ground faults in energized DC power systems such as photovoltaic arrays. Background Technology

[0002] A grounding fault is an unintended electrical connection between a current-carrying conductor and a grounding element (typically the metal frame of the system or the earth's ground). Grounding faults can occur when the insulation on wiring is damaged or when a wire comes into contact with a conductive grounded object. Grounding faults are problematic because they allow current to flow along unexpected paths, which can cause overheating, safety hazards, system malfunctions, or electrical fires.

[0003] As an example, in photovoltaic (PV) systems, ground faults can interrupt energy production and pose risks to system components and personnel due to the hazardous voltages involved. For instance, when a ground fault occurs in a PV solar array, the PV array's inverter may shut down, ceasing energy production until the fault is resolved. Locating ground faults is generally a challenging, time-consuming, and potentially hazardous task. Technicians may spend hours using various tools and workflows to detect the fault and manipulate numerous hazardous voltage disconnect / connection points.

[0004] Specifically, a number of factors make ground fault detection difficult. The large scale of many solar arrays, especially utility-scale solar fields, complicates the search for faults that could be located anywhere among the thousands of boards connected to a single inverter. Additionally, the electrical topology of these arrays, characterized by numerous parallel branches of strings and feeders bound to a common bus, means that an abnormal voltage originating from a fault on one string can be seen across many other parts of the system. These problems, combined with the laborious process of disconnecting branches to isolate the fault, contribute to the complexity and time-consuming nature of the task.

[0005] The physical requirements of the process further complicate matters. Making the necessary disconnections and connections can be laborious, especially when it involves manually tightening lugs or wiring terminals. The generally tricky handling of locating or identifying specific wiring between array elements due to their close proximity or ambiguous positioning is also time-consuming. The need to effectively manage this intricate search and elimination process demands significant training and skill, and if handled by less trained technicians, it can potentially lead to errors or additional wasted time.

[0006] In addition to the practical difficulties, the factors mentioned above increase exposure to hazards. Because solar power stations typically generate hazardous voltages even during daylight hours, technicians are repeatedly exposed to dangerous voltage levels, especially when they must connect or disconnect at live terminals. These connections or disconnections place technicians in close proximity to dangerous potentials. For each disconnected wiring, there is a risk that the wiring may be improperly reconnected in an unsafe configuration. Additionally, generally challenging terrain and extreme weather conditions can increase the likelihood of injury, particularly when technicians encounter hazardous voltages while handling wiring or attempting to lift panels. Summary of the Invention

[0007] Aspects and advantages of embodiments of this disclosure will be set forth in part in the following description, or may be learned from the description or by practice of the embodiments.

[0008] One example aspect of this disclosure relates to a method for efficiently locating ground faults in an electrical circuit. To implement this method, a transmitter device (“transmitter”) is electrically coupled to a first connection point in the electrical circuit. The transmitter is capable of generating a tracking signal within the electrical circuit. This tracking signal can be followed to identify the location of a ground fault within the circuit.

[0009] Other aspects of this disclosure relate to various systems, apparatuses, non-transitory computer-readable media, user interfaces, and electronic devices.

[0010] These and other features, aspects, and advantages of the various embodiments of this disclosure will become better understood with reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the relevant principles. Attached Figure Description

[0011] A detailed discussion of embodiments for those skilled in the art is set forth in the specification with reference to the accompanying figures, in which: Figure 1 A block diagram of an example system for detecting the location of a ground fault, according to an example embodiment of the present disclosure, is depicted.

[0012] Figure 2 A flowchart is depicted for an example method for locating a ground fault according to an example embodiment of the present disclosure.

[0013] Figures 3A to 3B A graphical illustration depicts the execution of an example method for locating a ground fault according to an example embodiment of the present disclosure.

[0014] Figures 4A to 4BA graphical illustration depicts the execution of an example method for locating a ground fault according to an example embodiment of the present disclosure.

[0015] Figure 5 A graphical illustration depicts the execution of an example method for locating a ground fault according to an example embodiment of the present disclosure.

[0016] Figures 6A to 6D A graphical illustration depicts an example configuration for locating ground faults according to an example embodiment of the present disclosure.

[0017] Figures 7A to 7D A graphical illustration depicts an example configuration for locating ground faults according to an example embodiment of the present disclosure.

[0018] Figure 8A and Figure 8B A schematic diagram of an example transmitter circuit according to an exemplary embodiment of the present disclosure is depicted. Detailed Implementation

[0019] An exemplary aspect of this disclosure relates to a method for efficiently locating ground faults in an electrical circuit. To implement this method, a transmitter device (“transmitter”) is electrically coupled to a first connection point in the electrical circuit. The transmitter is capable of sending a tracking signal into a conductor of the electrical circuit. This tracking signal can be followed to identify the location of a ground fault within the circuit.

[0020] For example, in a photovoltaic (PV) system, a transmitter can be connected in parallel to a PV array at a specific connection point. A tracking signal is then coupled to the array, allowing it to propagate through the circuitry. The tracking signal can be a specific frequency and / or waveform distinguishable from the normal operating signals in the circuitry.

[0021] To track a tracking signal, a signal detector with a proximity-based sensor can be used. This device can be a handheld wireless receiver or a signal analyzer capable of detecting and analyzing the tracking signal. Technicians or other operators can use the signal detector to follow the tracking signal through electrical circuitry and identify the location where one or more characteristics of the tracking signal change. For example, a change in one or more characteristics can be or include a change in the strength, spectrum, phase, or polarity of the tracking signal. This change in location indicates the location of a ground fault within the circuit.

[0022] For example, in a PV system, a technician can walk through an array of signal detectors, monitoring the strength of the tracking signal along the wiring. As the technician reaches the location of the ground fault, the signal strength of the tracking signal will decrease, terminate, or otherwise exhibit a detectable change in one or more characteristics because some of the tracking signal will travel via the ground fault to the electrical ground, rather than propagating through the rest of the circuit. Specifically, as an example, the strength or polarity of the tracking signal may change at or near the location of the ground fault because the tracking signal may be propagating from a circuit conductor to the system ground. Detecting this change in the characteristics of the tracking signal allows the technician to pinpoint the exact location of the ground fault more efficiently.

[0023] The proposed method for identifying ground faults offers several advantages. First, it significantly reduces the time required to locate ground faults. Instead of manually inspecting and testing each section of the circuit, technicians can quickly trace the fault location using a tracing signal. Second, it reduces the number of times technicians must manipulate, connect, or disconnect high-voltage contacts. The proposed tracing signal method significantly reduces the need for physical proximity to wiring pairs or direct interaction with exposed hazardous voltages, minimizing the risk of electrical accidents. Finally, the method enables a relatively simple workflow even for less-trained technicians. The tracing signal provides clear guidance, allowing even novice technicians to efficiently locate ground faults in electrical circuits.

[0024] According to one aspect of this disclosure, in some implementations, the signal detector includes one or more wireless detection devices configured to wirelessly detect the presence of a tracking signal. The wireless detector may be a current clamp positioned around a circuit conductor (such as wiring between components). Alternatively, the wireless detection devices may be proximity-based sensors capable of wirelessly detecting the tracking signal without requiring any physical connection or specific physical orientation. For example, proximity-based sensors can be distinguished from clamp-based devices that require the clamp to be placed in a location physically surrounding one or more conductors. Thus, proximity-based sensors are capable of detecting tracking signals radiated from the conductors without physical proximity to the conductors or other physical contact with the electrical circuitry.

[0025] For example, a signal detector device can be a portable signal analyzer equipped with an antenna or an inductive detection coil. The detector device can be tuned to a specific frequency or waveform of the tracked signal, allowing it to detect the presence of the signal as it propagates through a PV circuit. The signal detector can also be equipped with a display or indicator to provide technicians with visual feedback regarding the strength and / or direction of the tracked signal.

[0026] By using signal detectors with proximity-based sensors, technicians can easily move around electrical circuits and follow tracking signals without physical contact or proximity to the wiring. This increases the flexibility and ease of fault location procedures, allowing technicians to quickly and accurately locate grounding faults in circuits. Proximity-based signal detectors also allow technicians to follow tracking signals on conductors that are not wiring and cannot be clamped, such as conductors inside PV panels. As an example, if solar panels are mounted against the roof surface, it would be difficult to obtain proximity to the conductor wiring for inspection using clamp-based sensors, and technicians would have to remove the panel to get close to the wiring. In such cases of restricted proximity, proximity-based sensors can detect tracking signals radiating from conductors inside the panel or from wiring beneath the panel.

[0027] According to one aspect of this disclosure, the proposed method for efficiently locating ground faults in electrical circuits is applicable to energized electrical circuits that include one or more voltage sources (e.g., solar panels). For example, the techniques described herein can be applied to DC voltage supply circuits that include one or more energized DC voltage sources (e.g., solar panels). The ability to operate on circuits with energized voltage sources is important because in some cases, the voltage sources cannot be easily disconnected from the circuit. For example, solar panels within a solar array will always generate voltage when illuminated (e.g., during the day) and will have to be disconnected or completely shaded to remove the voltage source from the array. The presence of active voltage sources within the circuit can make efficiently and safely locating ground faults more challenging.

[0028] To address this challenge, the disclosed method utilizes a tracking signal generated by a transmitter. The tracking signal acts as a marker that can be followed to identify the location of a ground fault within a circuit, even in the presence of an active voltage source.

[0029] For example, in an energized electrical circuit such as a power generation system, the transmitter can be connected to a single circuit or to a central location or bus that connects to multiple circuit branches that make up a larger overall circuit. When a tracking signal is sent into the circuit, the signal propagates as current through conductors and components, through a ground fault to ground, and back to the transmitter on the ground, creating a current loop.

[0030] By applying the method to energized electrical circuits, the proposed approach provides a valuable solution for fault location in these types of circuits. It eliminates the need for complex processes that may be impractical for power outages or for locating ground faults in energized circuits, and / or other complex procedures that might be infeasible in certain power generation circuits, such as PV arrays. Instead, technicians can rely on tracing signals to efficiently and safely locate ground faults, minimizing disruption to the operation of the electrical system.

[0031] According to another aspect of this disclosure, the proposed method for efficient location of grounding faults in electrical circuits is particularly suitable for ungrounded electrical circuits. In ungrounded systems (also known as floating systems), no conductor is intentionally connected to the ground (or only a high-impedance connection is used for grounding).

[0032] In some cases, when a PV array is generating power, one side of the system (positive or negative) is intentionally bound to ground. However, when a ground fault occurs, the load is removed, the ground fault protection circuit removes the binding to ground, and the array conductors float relative to ground. Therefore, in a ground fault maintenance state, a PV array can be considered a type of ungrounded power system.

[0033] In various industries, some AC power systems are configured as ungrounded power systems and are also known as "isolated-grounded" (IT) designs. Sometimes, IT designs are used in industries with sensitive equipment or in situations where shutting down due to a ground fault would be very expensive. One of the key characteristics of such systems is that a single ground fault does not cause a large ground fault current because there is no return path to the source. Simultaneously, it is important to locate faults in these systems before a secondary fault occurs that could become hazardous or create an uncontrolled current loop. Detecting and locating faults in these systems, where circuits remain energized, is challenging.

[0034] To address this challenge, the disclosed method utilizes a tracking signal generated by a transmitter as a current in a circuit conductor. When the tracking signal encounters a ground fault, the signal current travels from the conductor through the fault and returns along a path through the ground. This path creates a closed loop or fault path that can be detected and followed by a proximity-based signal detector, allowing technicians to pinpoint the exact location where the signal travels from the conductor to the ground fault.

[0035] For example, in a system such as an ungrounded PV array, a technician can connect a transmitter to the array's bus or terminal and the system ground. The transmitter then sends a tracking signal into the array. As the technician uses a signal detector to track the tracking signal, they can follow the path of the tracking signal through the array conductors, which are part of the fault path. When the technician reaches the point where the tracking signal attenuates from the conductor, the lost signal indicates the presence of a ground fault at that location.

[0036] By applying the method to ungrounded electrical circuits, the proposed approach provides a valuable solution for fault location in these types of circuits. It eliminates the need for complex and time-consuming testing methods that might be required for ungrounded circuits. Instead, technicians can rely on tracing signals to efficiently locate grounding faults, saving time and effort in fault identification and repair.

[0037] The exemplary embodiments of this disclosure will now be discussed in further detail with reference to the figures.

[0038] Figure 1 A block diagram of an example system for detecting the location of a ground fault according to an example embodiment of the present disclosure is depicted. The example system may include an example transmitter device (“transmitter”) (100) and an example signal detection device (“signal detector”) (200). The example transmitter device (100) may include a controller (110), a signal generation circuit (120), a user interface (130), a first connection terminal (140), and a second connection terminal (150). The example signal detector (200) may include a controller (210), one or more detection sensors (220), a signal processing unit (240), and a user interface (250).

[0039] Referring to transmitter (100), signal generation circuit (120) can generate a unique tracking signal that circulates as current within a circuit connected to device terminals (e.g., (140) and (150)). In some implementations, the tracking signal current can be generated by injecting a switching voltage into the circuit. In some other implementations, transmitter (100) can use the voltage of an energized circuit as a source and can generate current by acting as a switching load. Thus, in some implementations, when there is sufficient source voltage within the energized circuit, transmitter (100) can generate a tracking signal by acting as a switching load. However, in cases where there is insufficient source voltage within the circuit, transmitter (100) can actively inject voltage into the circuit to generate a tracking signal. In some implementations, this functionality can be facilitated by a frequency generator that generates an alternating (e.g., sinusoidal or square) waveform and a modulator that modulates that waveform, resulting in a tracking signal with distinct frequencies and modulation patterns. In some implementations, the frequency can be on the order of 100 Hz to 50 kHz. A specific frequency can be selected based on various considerations, such as reducing coupling between conductors, reducing coupling with other circuit elements, or increasing detectability using a signal detector (200). The unique pattern of the tracked signal can also help distinguish it from other signals in the energized circuit.

[0040] Typically, the relationship between the frequency of a tracking signal and its detectability by a proximity-based signal detector (such as signal detector (200)) can be characterized by the principle that higher frequencies tend to enhance detection sensitivity. Proximity-based signal detectors generally utilize magnetic field sensors (such as inductive coils or fluxgates), which are more responsive to higher frequency electromagnetic fields. Higher frequency tracking signals generate more rapidly changing electromagnetic fields, which induce larger voltages in inductive sensors. This results in more distinct and detectable changes that can be more easily identified and tracked by proximity-based detectors, even when the magnetic field generated by the tracking signal is relatively small at a distance.

[0041] This increased sensitivity can be beneficial because the tracking signal current is typically very small (e.g., ranging from approximately 1 to 100 mA), and proximity-based sensors need to effectively detect the signal even at significant distances from the signal current path. In particular, some example implementations control the amplitude of the tracking signal to be small to limit power dissipation and / or avoid damage to the circuit being tracked. This further emphasizes the benefits of high sensitivity in the detection method. Therefore, using a high-frequency tracking signal enhances the overall effectiveness of proximity-based detection, allowing for more accurate and efficient localization of ground faults within electrical circuits.

[0042] In view of the above, example implementations of the transmitter (100) can be configured to generate a tracking signal with a frequency detectable by a proximity-based signal detector. In some implementations, the frequency of the tracking signal can be adjusted to match the operating characteristics of the detection equipment used. In some implementations, the transmitter (100) can be configured to generate a tracking signal with a minimum frequency of 10 Hz. As another example, it can also be configured to generate a tracking signal with a frequency of 50 Hz, which may be more effective in environments with high electrical noise. As yet another example, the transmitter (100) can generate a tracking signal with a frequency of 1 kHz. As yet another example, the transmitter (100) can generate a tracking signal with a frequency of 6 kHz or higher (e.g., 6.25 kHz). As yet another example, the transmitter (100) can generate a tracking signal with a frequency reaching 50 kHz. Therefore, the transmitter (100) can provide higher resolution signal detection through proximity-based signal detectors that are typically more responsive to these higher frequencies. These configurations ensure that the transmitter (100) can be adapted to various detection needs and environmental conditions, optimizing fault location processing.

[0043] In some implementations, the interface and protection circuitry (170) may be electrically positioned between the signal generation circuitry (120) and any of the device terminals (140), (150), and (160). The interface and protection circuitry (170) may be configured to protect the device electronics from high voltages in the energized circuitry and to protect the device electronics from transients without interfering with signal tracking. In some implementations, the interface and protection circuitry (170) may include a voltage divider to divide the voltage present between any device terminals when connected to the energized circuitry. Refer to the figures and... Figure 8B Describe the example interface and protection circuit (170).

[0044] Still refer to Figure 1 The transmitter (100) may feature a controller (110) designed to manage the operation of the signal generation circuit (120). The controller (110) may also act as an intermediary between the user interface (130) and the signal generation circuit (120). The controller (110) may receive user input from the interface (130), process the input, and generate corresponding control signals for the signal generation circuit (120). This processing allows the user to manipulate parameters of the tracking signal, such as its frequency and amplitude, according to their specific needs.

[0045] In some implementations, the controller (110) may include a microprocessor or microcontroller unit (MCU). This unit may execute firmware or software instructions that control the operation of the signal generation circuit (120). For example, the controller (110) may be programmed to control a frequency generator and a modulator, adjusting their operating parameters to generate a desired tracking signal.

[0046] To ensure the proper operation and performance of the signal generation circuit (120), the controller (110) can be designed to continuously monitor the state of the circuit elements. It may include a feedback mechanism to detect problems such as overheating, signal distortion, or operational errors. Upon detecting any such problem, the controller (110) can perform corrective actions such as reducing power supply, changing the operating frequency, or initiating a shutdown to prevent potential damage.

[0047] In one example, the controller (110) can detect an active voltage source in the circuit to which the transmitter is connected. This detection can be based, for example, on measuring the electrical characteristics (e.g., voltage level) of a signal received at a first connection terminal (140). For instance, the controller (110) can continuously monitor the voltage at the first connection terminal (140) of the point connected in the electrical circuit and compare it to a predefined threshold indicating the presence of an active voltage source. If the measured voltage exceeds the threshold, the controller (110) identifies it as an indication of an active voltage source (such as, for example, a photovoltaic panel that generates electricity). Additionally or alternatively, the controller (110) can also monitor the stability and consistency of the voltage over time to distinguish between constant voltage sources and transient voltage spikes.

[0048] Upon detection of an active voltage source, the controller can then initiate further actions, such as engaging the signal generation circuit (120) to generate a tracking signal for fault location. For example, when an active voltage source is detected in a photovoltaic circuit, the controller (110) can be configured to selectively connect a load from the signal generation circuit (120). This connection can occur between a first connection terminal (140) and a second connection terminal (150) of the transmitter 100. The selective connection of the load allows the transmitter (100) to draw current from the active voltage source. This current absorption can generate a tracking signal on the circuit. As described throughout this disclosure, the tracking signal generated by this action can be used as a diagnostic tool. It can propagate through the circuit. It can be used to identify the location of a ground fault within the circuit.

[0049] The controller (110) can also communicate with the battery management system to optimize the power consumption of the signal generation circuit (120). By monitoring the battery level, the controller (110) can adapt the performance of the signal generation circuit (120) to extend battery life. For example, when the battery level is low, it can reduce the signal strength, thereby saving power.

[0050] Furthermore, in some implementations, the controller (110) can interface with a wireless connectivity system, allowing remote control of the signal generation circuitry (120). Users can adjust the settings of the transmitter (100), receive real-time feedback on the operating status of the transmitter (100), and / or provide real-time control of the transmitter (100)'s operating status via a dedicated application on a smartphone or computer, or via user input received at the signal detector (200). This feature enhances user control over the transmitter (100) and facilitates remote operation and monitoring.

[0051] The user interface (130) may include: a power switch that activates the signal generation circuit (120); and a controller (110) that controls the adjustment of the strength and frequency of the tracking signal. An indicator light may also be incorporated to indicate when the transmitter (100) actively transmits the tracking signal.

[0052] The transmitter (100) may include a power source (such as an integrated rechargeable battery) or the ability to be powered from an external source. A battery management system may be incorporated to monitor battery levels and optimize power usage. When the battery is low, the system may alert the user and encourage them to recharge or replace it.

[0053] The display screen can be integrated into the user interface (130) to provide more detailed information and control. The display can show key settings such as the selected frequency, signal strength, battery status, or error messages. User interface elements such as buttons or touch-sensitive controls can help the user easily navigate through settings and adjust parameters.

[0054] To assist in signal tracking and identification, the transmitter (100) may incorporate signal detection and analysis features. This may involve adding receiver circuitry or sensors to detect and analyze nearby signals. The device can display data about the detected signals, such as their frequency, intensity, and waveform characteristics, helping the user distinguish the tracked signal from other environmental signals.

[0055] In some implementations, the transmitter (100) may provide options for recording and logging signal data for further analysis or documentation. This feature may store data about the transmitted signal, such as frequency pattern, signal strength, and timestamps. Users can later access this data for maintenance or to generate reports related to circuit tracing or testing. The storage of the data and / or the interface used to access it may reside on the signal detector (200) and / or the transmitter (100).

[0056] The transmitter (100) can provide signal filtering options to suit various tracking scenarios. These filters allow users to refine the tracking signal by adjusting parameters such as frequency range, modulation type, or signal bandwidth. Custom features can include preset or user-defined profiles to suit specific circuit tracking needs, improving flexibility and accuracy in signal identification.

[0057] The transmitter (100) can also measure the voltage and current present between any of the device terminals (140), (150), and (160). In some implementations, the transmitter (100) can measure these values ​​when no tracking signal is being generated, and in other implementations, the transmitter (100) can measure these values ​​while a tracking signal is being generated. These values ​​can indicate the presence of a fault in the system, and this information can be transmitted or displayed on the user interface (130) of the transmitter (100) or the user interface (250) of the signal detector (200).

[0058] Figure 1 The system illustrated also includes a signal detector (200). As described herein, the signal detector (200) is configured to operate in conjunction with the transmitter (100). The signal detector (200) allows the user to accurately locate and identify signals generated by the transmitter equipment, making circuit tracing and troubleshooting more efficient. Although Figure 1 A single signal detector (200) is illustrated, but it is certainly possible for the system to include or interact with multiple different signal detectors, for example, that may have different sensors, different sensing ranges and / or other operating characteristics that make them more useful for a particular situation or operation.

[0059] The signal detector (200) may include a compact housing that encloses various components designed to detect and analyze signals emitted by the transmitter (100).

[0060] According to one aspect of this disclosure, the signal detector (200) includes one or more detection sensors (220). In some implementations, the detection sensor (220) may be a proximity-based sensor. In this case, the signal detector (200) may be referred to as a proximity-based signal detector. The proximity-based signal detector can operate on a proximity-based principle, detecting and tracking signals without any requirement for physical connection to electrical circuitry or for maintaining a specific physical orientation relative to the circuitry.

[0061] Such proximity-based detection sensors offer distinct advantages over traditional detection methods, such as clamp-based devices. While the latter typically require clamps to be positioned in a manner that physically surrounds one or more conductors within an electrical circuit, proximity-based signal detectors eliminate this necessity. Proximity-based sensors can detect tracking signals without requiring physical proximity to the conductor(s) or any direct physical contact with the electrical circuit.

[0062] This ability to wirelessly detect and track signals enhances the efficiency and safety of fault location procedures. Technicians can easily move around the circuitry to track signals without the constraints imposed by physical contact. This not only saves time but also reduces the risk of any electrical hazards that could result from direct interaction with the electrical circuitry. Technicians can also detect tracking signals on parts of the system that are not individually wired (such as internal traces on a PV board).

[0063] In some implementations, proximity-based sensors may include one or more sensitive devices capable of accurately identifying tracked signals within a specific range. Such sensors can be configured to detect specific frequencies or waveforms of the tracked signal, ensuring accurate and reliable detection. This feature allows proximity-based signal detectors to provide an effective solution for tracking and locating ground faults in electrical circuits. In some implementations, proximity-based detection sensors may include one or more other such sensors, such as inductive coils, fluxgate magnetometers, or magnetoresistive sensors. In some implementations, more than one sensor may be used to form an array, and signals from the array can be analyzed to estimate the position of the signal source relative to the signal detector. In other implementations, specific detection sensors or combinations of sensors can be used to cover a wide frequency range and effectively capture signals.

[0064] In some implementations, the detection sensor (220) may include an antenna system. The antenna system may utilize different types of antennas (such as dipole antennas, monopole antennas, or loop antennas) to cover a wide frequency range and effectively capture signals.

[0065] In some implementations, the detection sensor (220) may include a clamp-based detection sensor. A clamp-based detection sensor can enhance the measurement of the tracking signal. In particular, a clamp-based sensor can be used to more accurately quantify whether two conductors exhibit residual current in order to identify faulty parts of the circuit based on the principle of residual current detection (RCD), known in the art.

[0066] In some implementations, a signal amplification circuit within the signal detector (200) can enhance the weak signal received by the detection sensor (220). The circuit can use a low-noise amplifier and appropriate gain control mechanisms to amplify the received signal, improving the accuracy of tracking and optimal signal detection.

[0067] The signal detector (200) may also include a signal processing unit (240) that analyzes and interprets the signal received by the detection sensor (220). The signal processing unit (240) may employ digital signal processing techniques and algorithms to extract relevant signal information, such as frequency, modulation characteristics, and intensity. It may also incorporate a filtering mechanism to minimize interference from ambient noise and other unwanted signals.

[0068] The signal detector (200) may also include a user interface (250), which includes a display screen that provides visual feedback to the user. The display screen may present information about the detected signal, including frequency, signal strength, and waveform representation. The user interface (250) may also include buttons or touch-sensitive controls to help the user navigate menus, adjust settings, and select operating modes. In some implementations, a communication system may be included to enable bidirectional communication between the signal detector (200) and the transmitter (100). In some implementations, the communication system may execute various communication protocols such as WiFi, Bluetooth, or via signals coupled to conductors of the circuit being evaluated. Bidirectional communication can be used for various purposes, such as allowing the user to adjust settings on the transmitter from the signal detector device interface, or allowing parameters measured by the transmitter, such as voltage and current between terminals, to be displayed on the signal detector.

[0069] In some implementations, to provide audio feedback, the signal detector (200) can integrate an audio output system into the user interface (250). This system may include a speaker or headphone jack to deliver an audible signal corresponding to the detected signal. Even in noisy environments, the audio output can help the user quickly identify the presence and characteristics of the tracking signal. Tactile vibration can be used to replace or supplement the audio output.

[0070] The signal detector (200) may incorporate signal location features to assist the user in accurately locating the source of the detected signal. These features may include signal strength indicators, such as LED bars or graphical representations on a display, providing visual cues to guide the user toward the highest signal strength.

[0071] The signal detector (200) may include a power source (such as a rechargeable battery) and a battery management system. This system ensures efficient power use and alerts the user when the battery needs charging or replacement.

[0072] When used in conjunction with the transmitter (100), the signal detector (200) provides a comprehensive solution for efficient circuit tracing and signal identification. Its compact and portable design, along with the integration of these components, provides users with a powerful tool for detecting, analyzing, and locating signals emitted by the transmitter (100). This device is particularly useful for professionals in various fields of electrical engineering, such as photovoltaic system maintenance.

[0073] According to another aspect of this disclosure, in some implementations, the transmitter (100) may be equipped with additional connection terminals, thus enhancing the versatility of the device and allowing for more complex tracking scenarios. In particular, the three connection terminals may include a first connection terminal (140), a second connection terminal (150), and an optional third connection terminal (160). Each of these terminals may be configured to establish an electrical connection to a specific point in an electrical circuit.

[0074] As an example, the first connection terminal (140) can be designed to be electrically coupled to a first connection location in the electrical circuit. The second connection terminal (150) can be configured to be electrically coupled to the system ground. A tracking signal can be generated on both the first and second terminals to create a tracking signal current that will travel through the electrical circuit until it reaches a ground fault and returns to the second connection terminal (150) connected to the ground. Connecting the second connection terminal (150) to the ground also creates a ground reference and helps ensure the stability of the tracking signal, reducing the possibility of signal distortion or interference.

[0075] The third connection terminal (160) can be designed to be electrically coupled to a second connection location within the electrical circuit. This terminal allows for the introduction of secondary or additional tracking signals or the receipt of signal feedback from the circuit. This can assist advanced tracking techniques, such as residual current detection, differential signal tracking, or bidirectional tracking, which can provide more detailed information about the condition and layout of the circuit.

[0076] By providing three connection terminals, the transmitter (100) offers greater flexibility and adaptability in tracking processing. It can accommodate a wider range of circuit configurations and tracking requirements. Additionally, this embodiment can support more robust and comprehensive fault detection and circuit analysis, thus enhancing the system's effectiveness in maintaining and repairing electrical circuits.

[0077] As an example, in some implementations, the transmitter (100) can be configured to generate separate tracking signals for the positive-to-ground path and the negative-to-ground path. By dividing the signals in this way, the system can provide a more detailed and accurate picture of the condition of the electrical circuit. These tracking signals can be distinguished by their frequencies, or they can be multiplexed (interleaved) with time gaps between the signals. For example, the transmitter (100) can transmit a tracking signal for 500 ms on the positive-to-ground path, wait for 500 ms, then transmit a tracking signal for 500 ms on the negative-to-ground path, wait for 500 ms, and repeat this sequence.

[0078] The value of this approach becomes apparent in various example fault scenarios. For instance, if the fault is located on a string within the combiner, a negative-to-ground tracking signal will guide the technician directly to the correct combiner box. However, if the fault is located on the positive feeder leading to the combiner, the negative-to-ground tracking signal will fail to detect it. In this scenario, sending a tracking signal on the positive-to-ground pair allows for rapid and efficient fault location. By sending signals simultaneously on both paths, the system can efficiently locate the fault in either scenario.

[0079] In some implementations, the transmitter (100) can be designed to control the phase of the signals transmitted on both paths. By intentionally phasing the signals to combine them destructively or constructively, the system can enhance the identification of fault paths. This phase manipulation method can provide a more precise indication of the fault location, thereby further improving the efficiency and accuracy of fault detection and processing.

[0080] As another example, in addition to its primary function of wiring tracing, the transmitter (100) with three connection terminals (140, 150, 160) can also be configured to provide several additional functions that can assist technicians in more effectively locating and characterizing faults and in identifying potential safety hazards. For example, by measuring the voltage between positive to ground (+ / G), negative to ground (- / G), and positive to negative (+ / -) pairs, the device can calculate and display important information to the user.

[0081] One such function involves calculating voltage ratios. These ratios can be used to estimate the location of a fault relative to the nearest board, allowing technicians to bypass the tracing path and proceed directly to the vicinity of the fault. For example, if the string contains 20 boards, each with a voltage of 30V, then voltage readings of (+ / G) = 60V and (- / G) = 540V would indicate that the fault is located between the second and third boards from the positive end of the string. Therefore, this feature can significantly reduce the time and effort involved in fault detection, improving the overall efficiency of the tracing process.

[0082] In another implementation, the presence of a voltage difference between the + / G and / or - / G pairs can indicate the existence of a ground fault. This information can be used not only to confirm the presence of a fault but also to alert the user to the voltage difference or hazard present on the ground. Such a warning can be provided visually or audibly. In cases where the fault is intermittent, an audible buzzer can be particularly useful, thereby alerting the user when the fault suddenly appears or disappears. This information can also be transmitted between the transmitter (100) and the signal detector (200) using the previously mentioned two-way communication system and method.

[0083] Furthermore, voltage measurements can be used to detect less common faults, such as short circuits or open circuits between the positive and negative conductors. In response to such detection, a tracking signal can be automatically applied along the positive-to-negative path, thereby facilitating the tracking of these faults.

[0084] In another implementation, the transmitter (100) can connect a test load to measure the current through that test load, thereby enabling the measurement of leakage current and fault resistance between any of the three pairs. This feature can be particularly beneficial in scenarios where multiple faults exist in the system. Integrating this functionality into the transmitter (100) simplifies user operation and automates the calculation of fault parameters or the optimization of tracking signal parameters.

[0085] The addition of the third terminal (160) also enables the transmitter (100) to operate as a residual current detection (RCD) fault analyzer. This feature facilitates a combined workflow where some tracing steps use residual current clamp measurements instead of wireless sensors. This combined functionality significantly enhances the versatility of the device and provides users with a more comprehensive and efficient solution for circuit tracing and fault detection.

[0086] In particular, in some implementations used as RCD fault analyzers, the transmitter can be connected to the inverter or other combination point where multiple circuits are combined in parallel on positive and negative buses. The transmitter can cause the tracking signal to circulate between ground and one of the bus terminals. A technician can then use a current sensor to detect the tracking signal on each parallel circuit, examining the positive and negative wiring for each circuit. If a circuit branch is not faulty to ground, the positive and negative wiring for that branch should not have residual tracking current between the positive and negative pairs; that is, any tracking signal current entering the positive side should be balanced by the tracking signal current leaving the negative side. The absence of residual tracking signal current on a fault-free branch can be interpreted as indicating the absence of a point where tracking signal current can leak to ground. Alternatively, if a circuit branch does contain a ground fault, tracking signal current can leak to ground, and the current flowing into the positive side of the branch may differ from the current flowing out of the negative side. By using a current sensor to compare the residual current on the positive and negative pairs for each branch, the technician can determine which branch contains a ground fault.

[0087] Therefore, according to another aspect of this disclosure, in some implementations, the transmitter (100) can integrate the dual functions of a wiring tracker and an RCD fault analyzer into a single device, thereby automating and optimizing the processing of fault detection and location in electrical circuits. This embodiment can provide a comprehensive solution for efficient circuit tracing and fault identification, offering users a versatile and user-friendly tool for electrical circuit maintenance and repair.

[0088] For example, in some implementations, the transmitter (100) can be designed to switch between two operating modes: a residual current detection (RCD) mode and a tracking mode. In RCD mode, the transmitter (100) can transmit a signal optimized for RCD fault location and detectable by a residual current clamp. This mode allows for the detection and location of residual current, which can indicate the presence of a ground fault in the circuit.

[0089] On the other hand, in tracking mode, the transmitter (100) transmits a differentiated tracking signal that can be followed to pinpoint the exact location of a ground fault within the circuit. This mode can be particularly useful for tracing the path of a fault through the circuit and accurately locating its exact position.

[0090] The switching between these two modes can be physically performed on the transmitter (100), or it can be wirelessly controlled via the previously mentioned two-way communication method or a dedicated application on a smartphone or computer. In some implementations, the transmitter (100) can automatically alternate between the two modes in an interleaved manner, transmitting appropriate signals for each mode based on frequency or timing synchronization.

[0091] Integrating RCD and tracking modes into the transmitter (100) can significantly simplify the workflow for locating ground faults in electrical circuits. For example, the transmitter (100) can be connected in parallel with the inverter. Technicians can then use current sensors capable of clamping the wiring pair to detect residual current associated with the RCD mode signal.

[0092] Once the correct feeder is identified, the technician can switch to tracing mode and use a wireless signal detector to trace along the feeder to locate any faults present on the feeder line. At the combiner box, with all strings connected, clamps can again be used to test for residual current and locate the faulty string. Once the faulty string is identified, it can be disconnected, and tracing mode can be used to pinpoint the exact location of the fault on the string.

[0093] By integrating these functions into a single device, the transmitter (100) streamlines the process of fault detection and location, saving technicians time and effort. This embodiment provides a valuable solution for efficient and accurate fault detection in electrical circuits, enhancing the overall performance and reliability of electrical system maintenance and repair.

[0094] According to another aspect of this disclosure, transmitter functionality can be further improved by integrating an innovative RCD clamp design. Current clamps used in conventional CGFL systems may not be suitable for solar installations where wiring is tightly packed, has various sizes (e.g., ranging from 10 AWG to 1000 AWG), and where wiring pairs (e.g., positive and negative) may be separated by significant distances. To address these challenges, a novel RCD clamp design can incorporate several improvements.

[0095] One such improvement could be the integration of a flexible coil, such as a Rogowski coil, into the clamp. This flexible design with a large loop allows it to be placed close to congested spaces and to enclose separate wiring within its loop, thus overcoming the proximity problems associated with close-packed wiring and large wiring distances. The clamp can also have a "forked" design, as used in some handheld AC current clamp testers.

[0096] In another implementation, two separate clamps can be used to independently measure the current in the separate cables. The signals from these clamps can then be combined using analog circuitry or digital processing techniques. The two clamps can be connected to the receiving unit via cabling or wirelessly. This flexibility in data communication makes it easier to approach the cabling in the separate pair, thereby enhancing the effectiveness of fault detection and handling.

[0097] Furthermore, the clamp can be designed to interface with a separate RCD receiver unit. Alternatively, the wireless signal detector used in "tracking mode" can be designed to include electronics that support connection to the clamp sensor. This integration results in a single, multi-functional sensor required for tracking, thereby streamlining the fault detection and localization process.

[0098] These improvements to the clamp design significantly enhance the system's versatility and efficiency in detecting and locating ground faults in electrical circuits. By providing a flexible and adaptable solution for approaching and measuring current in isolated and congested wiring, the innovative RCD clamp design contributes to improved overall performance and reliability in electrical system maintenance and repair.

[0099] Figure 2 A flowchart is depicted for an example method for locating a ground fault according to an example embodiment of the present disclosure.

[0100] The method begins at step 2002, where the transmitter is electrically coupled to a first connection point of the system ground and an electrical circuit. In some implementations, the electrical circuit may be a powered electrical circuit including one or more active voltage sources. The coupling of the transmitter to the electrical circuit allows the transmitter to interact directly with the electrical circuit and provides a path for the transmitter to introduce a tracking signal into the circuit. In some implementations, the coupling may be provided through a direct current connection to a conductor, but coupling may also be provided through other means, such as inductive or capacitive coupling.

[0101] In step 2004, the transmitter generates a tracking signal that circulates as current within a portion of the electrical circuit between the system ground and the first connection location. For example, the tracking signal may be or have a specific frequency and / or waveform distinguishable from normal operating signals in the circuit. This tracking signal can act as a marker to identify the location of a ground fault within the circuit, even in the presence of an active voltage source. By introducing this tracking signal into the circuit, the method provides a means for tracing and tracking the path of current through the circuit that can be used to identify the location of a ground fault.

[0102] Following step 2004, in step 2006, a proximity-based signal detector is used to track the tracking signal through the electrical circuit to identify the location where one or more characteristics of the tracking signal change. The proximity-based signal detector can be a wireless detection device configured to wirelessly detect the presence of the tracking signal. The location where one or more characteristics of the tracking signal change can indicate the location of a ground fault within the electrical circuit. For example, the change in one or more characteristics can be or include a change in the amplitude, frequency, phase, or polarity of the tracking signal. The location of the change indicates the location of a ground fault within the circuit. By detecting this change in the characteristics(s) of the tracking signal, technicians can pinpoint the exact location of a ground fault in a more efficient manner.

[0103] This method provides a valuable solution for fault location in energized electrical circuits, significantly reducing the time required to locate grounding faults and minimizing disruption to the operation of electrical systems. For example, the use of wireless detection equipment can increase the flexibility and convenience of fault location procedures, allowing technicians to quickly and accurately locate grounding faults in circuits without the constraints of physical contact.

[0104] Figure 3A and Figure 3B An example scenario is shown where a wiring tracker transmitter is connected to a single photovoltaic (PV) string within a PV array. Specifically, Figure 3A A PV string 300 is shown, comprising four PV panels 302-308 connected in series. PV panels 302-308 may be active voltage sources. A ground fault 310 exists at a location between panels 304 and 306.

[0105] As in Figure 3B As shown, transmitter 312 establishes a first connection to the positive terminal 314 of series 300 and a second connection to system ground 316. In the event of a fault 310, the voltage difference between the positive terminal 314 and ground 316 creates a loop to the energized system. Transmitter 312 can automatically detect this voltage difference and subsequently enter "energized mode," using dedicated circuitry to safely induce a tracking signal current into the energized circuit. This tracking signal current travels along the series conductors to the point of fault 310, where it then flows back through ground 316, forming a tracking signal loop (shown as a dashed line).

[0106] A wireless signal detector 318 can be used to locate a ground fault 310 in a PV string 300. The user activates the tracking mode on the wireless signal detector 318 and positions it near a terminal of the transmitter 312. The wireless signal detector 318 can generate an audible and / or visual response in the vicinity of the tracking signal loop, alerting the user to its proximity to the tracking signal. The user can detect the tracking signal radiating from the wiring between boards, and also the tracking signal passing through the surface of the PV board. The user then moves the sensor along the string 300, following the path of the tracking signal to identify the fault location 310.

[0107] For example, when the wireless signal detector 318 moves past the point of fault 310 (as shown, to the right of the fault), the tracking signal stops continuing along the wiring (or otherwise attenuates or exhibits a change in one or more characteristics), indicating that the signal detector 318 has passed the fault location 310. The user can interpret this change in the tracking signal's characteristics as an indication that they have moved past the fault point 310. To pinpoint the exact fault location, the user can move the detector 318 back and forth around the area where the signal terminates.

[0108] Figure 3A and Figure 3B This provides visual guidance for implementing the described method to locate faults within a single string 300 of a PV array. The technique is applicable even when feeder wiring is connected to the string. A later discussion describes techniques for when other closed loops or circuit branches are present, such as when multiple strings are connected in parallel. The method thus provides a generalized and efficient approach to identifying and locating ground faults in PV arrays or similar electrical circuits.

[0109] As another example, Figure 4A The illustration depicts the initial steps of an example method for locating ground faults in electrical circuits using a transmitter and a handheld signal detector. Figure 4A In this circuit, transmitter 412 is connected to circuit 400 and then powered on. Once powered on, transmitter 412 indicates the presence of fault 410 within circuit 400. Transmitter 412 then generates a tracing signal along the fault path. This tracing signal acts as a marker that can be followed to identify the location of ground fault 410 within the circuit.

[0110] Figure 4B The subsequent steps of an example method for locating a ground fault are further illustrated. A handheld signal detector 418 is used to detect the tracking signal. The handheld detector 418 may include an indicator, such as light or frequency modulation, that signals the proximity of the tracking signal.

[0111] In some implementations, the handheld detector may also include a lever or other extension method, allowing the user to track signals on conductors or strings that may be too far to reach. Extended reach can be helpful, for example, in cases where a string is raised away from ground, on the other side of an obstacle, or in wiring that may be difficult to access by hand. In some implementations, the signal detector may be positioned at the end of an extension lever. In other implementations, the detection sensor may extend from a main signal detector, allowing the main signal detector to be held in the user's hand to observe any indications on the unit.

[0112] The operator can then follow the trace signal through the circuit to locate fault 410. The location of the fault is identified where the characteristics of the trace signal change (e.g., automatically indicated by an indicator such as a light or frequency tuner).

[0113] Figure 4A and Figure 4B This paper describes an efficient and effective method for locating ground faults in electrical circuits. The method can be applied in many different scenarios, including identifying ground faults in the following settings: on feeders or homeruns; in junction boxes; along string lines; and / or on faulty boards.

[0114] Figure 5 This is a graphical illustration of an example method for locating a ground fault in an electrical circuit according to a specific embodiment of the present disclosure. The figure uses "single line" schematic representation, where positive and negative wiring are represented as single lines. Specifically, Figure 5 A method for locating ground faults when there are many parallel string groups in a photovoltaic (PV) system is demonstrated. Figure 5 This includes representations of solar arrays and connections that can exist between multiple string groups.

[0115] like Figure 5 As depicted, on the upstream side of the diagram is an array of multiple PV panels (such as, for example, PV panels 5100 and 5101). Each PV panel is a voltage source. The panels can be connected in series to form a string. As an example, PV panels 5100 and 5101 are connected in series with two other panels to form a string 5102.

[0116] A string can be connected in parallel with any number of other strings to form a string group. For example, a string group can be connected in parallel at a combiner box. As an example, string 5102 is connected in parallel with string 5104 and two other strings at combiner box 5106 to form string group 5108.

[0117] The physical electrical connection of a group of strings connected in parallel (thus forming a string group) can be referred to as a branch combination point. The branch combination point can be located inside the combiner box. In some cases, the branch combination point can take the form of: (1) a positive combiner bus, where one side (e.g., the positive side) of all strings in the group is connected to the positive combiner bus; and (2) a negative combiner bus, where the other side (e.g., the negative side) of all strings in the group is connected to the negative combiner bus.

[0118] String groups can also be connected in parallel to other string groups. For example, string groups can be connected in parallel at an inverter or a multifunction converter. As an example, string group 5108 is connected in parallel at inverter 502 with string group 5110 and another string group.

[0119] The physical conductor existing between the combiner box and the inverter 502 can be referred to as a combiner branch (sometimes alternatively called "feeder wiring"). As an example, combiner branch 5112 conducts power between the inverter 502 and the combiner box 5106.

[0120] As an example, the upstream side of combiner box 5106 can be referred to as the branch side or the series side, and the downstream side of combiner box 5106 can be referred to as the combination side. The downstream side can be connected to the rest of the circuit using combination branch 5112.

[0121] The physical electrical connection of multiple series groups connected in parallel can be referred to as a branch composite point. The branch composite point can be located inside the inverter 502 or the compositer enclosure. In some cases, the branch composite point can take the form of: (1) a positive common bus, with one side (e.g., the positive side) of all combined branches connected to the positive common bus; and (2) a negative common bus, with the other side (e.g., the negative side) of all combined branches connected to the negative common bus.

[0122] The numerous parallel branching layers in a PV array allow appropriate currents from individual boards or strings to be combined for large-scale power generation. However, these numerous parallel branching layers can make identifying and locating ground faults within the circuitry more challenging.

[0123] Figure 5 The diagram illustrates a simplified electrical schematic of a PV array drawn as a "single line," showing only one conductor instead of the paired positive and negative conductors. (As shown in...) Figure 5 As shown, transmitter 512 can be connected to inverter 502 or a branch junction point of the PV system. This connection allows transmitter 512 to send a tracking signal into the electrical circuit. The tracking signal can propagate through any branch of the circuit to reach the location of a ground fault.

[0124] exist Figure 5In this system, an operator (such as a technician or engineer) uses a handheld proximity-based signal detector 518 to track a signal. The operator can follow the tracked signal through any parallel branch of the circuit, even if these branches are not disconnected from each other. By monitoring the amplitude, frequency, phase, or other characteristics of the tracked signal as it moves along the circuit, the operator can identify which branch of the circuit is associated with a fault. Once the operator has isolated the fault to a single branch, they can identify where the characteristics of the tracked signal change. This location indicates the presence of a ground fault within the circuit.

[0125] Figure 5 The illustration thus demonstrates an efficient and safe method for locating ground faults in electrical circuits, such as photovoltaic systems, without disconnecting parallel circuits. This method reduces the time and effort required to locate ground faults, minimizes the risk of electrical hazards, and simplifies fault location procedures.

[0126] Figures 6A to 6D A graphical illustration depicts an example configuration for locating ground faults according to an example embodiment of the present disclosure.

[0127] First refer to Figure 6A , Figure 6A A simplified representation of a photovoltaic (PV) system comprising 100 interconnected panels coupled to an inverter is provided. The system is configured such that five panels are connected in series, resulting in a total string voltage that is five times the voltage of a single panel. This is due to the additive nature of voltages in a series circuit.

[0128] In the depicted configuration, each combiner box receives inputs from five groups of strings connected in parallel at branch connection points at combiner bus terminals within the combiner box. The positive side of each string is connected in parallel to the positive combiner bus, and the negative side of each string is connected to the negative combiner bus. Upstream on the bus side, there is a positive string-to-combiner bus connection point between the positive side of each string and the positive combiner bus. For the negative side of each string and the negative combiner bus, there is a corresponding negative string-to-combiner bus connection point.

[0129] As an example, refer to Figure 6APV panel 602 is included in string 604. String 604 is connected in parallel with four other strings at combiner 608 to form string group 606. One side of the strings in string group 606 is physically connected to combiner 608 at positive combiner bus 610. The other side of the strings in string group 606 is physically connected to combiner 608 at negative combiner bus 612. In some cases, positive combiner bus 610 and negative combiner bus 612 may be referred to as or are representative connection points for the first and second sides of string group 606. Combiner 608 is electrically connected to inverter 614 via combiner branch 615. Inverter 614 includes positive common bus 616 and negative common bus 618. In some cases, positive common bus 616 and negative common bus 618 may be referred to as or are representative connection points for the first and second sides of inverter 614.

[0130] In real PV systems, the type of device used at the serial-to-combiner bus connections (such as those at 610 and 612) can vary. In some systems, the connection device may be a finger-safe fuse holder, an MC4 connector mating device, a manual load break disconnector, or other connections that can be easily connected and disconnected by hand. In other cases, the connection device may be wiring and screw terminals, bolt-on wiring tabs, or other devices that are more time-consuming and hazardous for disconnection. Generally, positive serial-to-combiner bus connectors are finger-safe fuse holders that can be opened and closed relatively easily without tools, while negative serial-to-combiner bus connectors are screw or bolt terminals that require tools and take more time to open or close.

[0131] Downstream of each combiner bus, there is a bus-to-combination branch connector, which may be of the connector device type mentioned above. For example, combiner 608 includes a positive bus-to-combination branch connector 620 and a negative bus-to-combination branch connector 622. Generally, the device on the positive bus-to-combination branch connector is a manual load breaker that can be connected or disconnected by hand, sometimes referred to as a "DC breaker". On the negative side, the connector is generally a tool-operated bolt or screw connection.

[0132] The bus-to-combiner-branch connector connects the positive combiner bus to the positive combiner branch and the negative combiner bus to the negative combiner branch, sometimes referred to as the positive feeder and negative feeder. Feed groups from multiple combiner boxes are typically combined in parallel at another downstream branch combination point on the common bus of the combiner box or the common bus of the inverter (e.g., 616 and 618).

[0133] Figure 6AThe diagram further illustrates the presence of four combiner boxes, each carrying the output from its corresponding string to a central inverter 614 via feeder wiring. At the central inverter 614, the outputs from all combiner boxes are connected to a positive common bus 616 and a negative common bus 618. In effect, this creates a parallel connection of 100 strings through a branched topology, thus allowing for efficient power conversion and transmission to the load or grid. This representation is provided for illustrative purposes only.

[0134] Specifically, although Figure 6A A relatively small-scale PV system is described, but it is worth noting that the principles and configurations described in this paper can be scaled up for use in larger utility-scale systems. This flexible and scalable approach to system design allows for the efficient localization of grounding faults in PV systems of various sizes and complexities.

[0135] Some aspects of the topology in which strings are connected can vary between solar installations. For example, some solar PV systems use a trunk bus system where strings are directly connected to feeder cabling without a combiner box. As another example, some solar farms use string inverters, and the first branch combination point for the string group is the inverter bus. PV systems using board-level devices such as optimizers may also differ in topology and connectivity.

[0136] Figure 6B The diagram illustrates which combination branch or combiner box is in the process of identifying. Figure 6A The diagram illustrates the downstream handling of a fault in a photovoltaic (PV) system. In this handling, the positive combiner bus for each combiner box is opened at the connection point to the positive feeder (i.e., on the downstream side). This can be accomplished, for example, by disconnecting the positive bus to the combiner branch connector. Figure 6B In the diagram, open connections are indicated by shading. By opening the positive bus on each combiner, the parallel electrical connections between combiners and the connection from the combiner to the inverter are interrupted.

[0137] like Figure 6B As illustrated, the next step in fault location processing involves the successful identification of the faulty combiner. With the positive combiner bus open on all combiners, fault detection and location methods, such as the tracking signal method discussed earlier, can be used. For example, using a first connection from the transmitter to the inverter's negative common bus and a second connection from the transmitter to ground, the transmitter can generate a tracking signal between ground and the inverter's negative common bus. For example, in Figure 6AIn this configuration, the transmitter's [S] terminal is connected to the conductor, while the [G] terminal is connected to ground. With all positive combiner buses disconnected, the trace signal will only flow to the combiner box containing the fault. It can be noted that the trace signal also flows through all strings that remain connected to the same combiner bus as the faulty string. The user can identify which combiner branch is faulty by moving a signal detector across each of the negative feeders and observing on which feeder the trace signal is detected.

[0138] In this way, Figure 6B A fault detection and localization method that can be systematically applied across PV systems is described. By opening the positive combiner bus on all combiners (e.g., by disconnecting the positive bus to the combiner branch connector) and moving the signal detector, changes in the tracking signal across the system can be analyzed to efficiently identify and locate which feeder or combiner branch contains the fault. This method also allows users to physically follow the feeder wiring associated with the fault without prior knowledge of its path or layout. This approach significantly reduces the time and effort required to locate faults while minimizing the need for physical interaction with high-voltage components, thereby enhancing the safety of the process.

[0139] Figure 6C The diagram illustrates the steps a user can take to pinpoint the exact location of the fault once they know which branch of the composite structure is connected to it. For example, this can be done based on... Figure 6B The steps illustrated in the diagram are taken after identifying the combined branches containing the fault. In this example, the transmitter could be using a method targeting... Figure 6B The described steps are connected, or can be left in place after completing step 6B. See reference... Figure 6B As noted, if all strings in the string group containing the fault remain connected to the combiner bus connector, the trace signal will flow through all the strings in that group.

[0140] As in Figure 6C As shown, additional disconnections and steps can be used to locate the exact position of the fault. If the serial-to-combiner bus connection is open on the positive side for all strings in the string group containing the fault (e.g., the open serial-to-combiner connection shown is filled with shading within the circle), the trace signal will only flow through the faulty string. Furthermore, within the faulty string, the signal will attenuate or disappear from the conductor and will return to ground at the point of the ground fault. Utilizing... Figure 6C The diagram shows a disconnection and the use of proximity-based sensors. Users can identify the faulty string by checking which string contains the tracking signal, and pinpoint the fault by following the tracking signal to where it decays from the conductor.

[0141] Commonly followed reference Figures 6A to 6CThe described steps determine the location of a fault by following a tracking signal and detecting significant changes or termination in the tracking signal. For all steps, the transmitter can be connected once and remain in one location. No additional connections to high-voltage terminals are required, thus significantly mitigating the risk of exposing or connecting high-voltage terminals.

[0142] In reference Figures 6A to 6C In these described steps, some disconnections are made in the system, but these disconnections are performed systematically (e.g., on all strings in the combiner box). The same systematic disconnection can be performed without requiring the user to have prior knowledge of which branch is associated with the fault. In the illustrated example, the disconnection is made on the positive side, and a tracking signal is generated between ground and the negative side. Alternatively, the same steps can be taken: disconnection on the negative side and a tracking signal is generated between ground and the positive side. Typically in PV systems, the positive or negative side connectors are finger-safe and can be quickly opened or closed without tools. This method reduces the complexity of disconnection and enables efficient and accurate fault location, allowing for timely and targeted responses to problems, thereby minimizing downtime and enhancing the overall reliability of the photovoltaic system.

[0143] Now go to Figure 6D The figure illustrates another configuration utilizing an example transmitter with three terminals. These additional terminals significantly enhance the system's functionality, particularly in terms of fault location. This addresses a key deficiency in existing wiring trackers, which are typically designed with only two inputs, limiting the functionality and automation the device can offer.

[0144] Compared to conventional wiring trackers, Figure 6D The improved transmitter used in the system is designed with three connection terminals. These connections can be simultaneously connected to the system's positive, negative, and ground terminals. This unique configuration enables many novel features that enhance safety and efficiency in fault location.

[0145] exist Figure 6D The paper uses two hypothetical scenarios, "A" and "B," to demonstrate the operational advantages of this improved configuration. In scenario "A," the fault is located on the string upstream of combiner box 2. By sending a trace signal on the negative-to-ground path, a technician can follow the signal path to the correct combiner box. However, in scenario "B," the fault is located on the positive feed line to combiner 2. In this case, the trace signal on the negative-to-ground path is not used for detection but instead fails to reach the fault. Instead, by sending trace signals simultaneously on both the positive-to-ground and negative-to-ground paths, the fault can be located quickly and efficiently, regardless of its location.

[0146] In a further embodiment, the signals transmitted on the two paths can be intentionally phased in a manner that combines them destructively or constructively. This phaseding can be used to highlight the path to the fault, providing an additional layer of accuracy in fault location.

[0147] Figures 7A to 7D A graphical illustration depicts an example configuration for locating ground faults according to an example embodiment of the present disclosure. In particular, Figures 7A to 7D An improved method for tracking faults in a circuit with multiple energized branches connected in parallel is illustrated. The DC voltage sources in the energized branches have a source voltage V and an impedance Z. In some embodiments, the schematic diagram and method may represent a PV array, a battery storage device, or another configuration of voltage sources with a certain impedance. In the following discussion, the PV array illustration is referred to.

[0148] exist Figures 7A to 7D The scene depicted presents an array of multiple parallel strings, each string containing multiple PV boards connected in series. Three strings are connected in parallel to the combiner bus terminals of a combiner box. For ease of reference, the connections to the combiner bus terminals outside the combiner box are not shown. Each string contains three boards, represented as voltage sources and impedances for each board. Between the second and third boards, there is an impedance... The grounding fault occurred on the first string.

[0149] In this example combiner box, strings are connected in parallel to the positive combiner bus bar on the positive side using fuse holders that can be easily opened. On the negative side, strings are connected to the negative combiner bus using terminals that are difficult to disconnect. If all strings are connected in parallel, the trace signal will not only flow on the first string but also along every other closed loop in the system connected to the first string. This dispersion of the trace signal can make it difficult to efficiently locate faults.

[0150] Figure 7A This includes series 702, 704, and 706. Series 702 contains ground faults. For example... Figure 7A As shown, by disconnecting all strings except the faulty string 702 (e.g., strings 704 and 706) from the positive combiner bus, the tracing signal flows significantly only along the shortest path on the faulty string 702. This restricted path allows the tracing signal to guide the technician directly to the fault location, resulting in successful tracing. This improvement generalizes the workflow for tracing faults in parallel branch circuits, minimizing the time required to locate the fault and increasing the overall efficiency of the process.

[0151] Figure 7B This includes series 712, 714, and 716. Series 712 contains ground faults. Figure 7BAnother scenario is depicted where the trace signal is successfully traced even though the random string 714, instead of the faulty string 712, is the only string connected to the positive combiner bus. In this setup, the trace signal is still able to guide the technician to the fault location, albeit via a longer path.

[0152] In this scenario, as before, three strings 712, 714, and 716 are connected in parallel within the combiner box, where each string consists of three boards represented as voltage sources and impedances for each board. Between the second and third boards, there is an impedance... The grounding fault exists on the first 712 series.

[0153] In this case, all strings except the random string 714 (e.g., 712 and 716) are disconnected from the positive combiner bus on the positive side. Figure 7B In the scenario depicted, the trace signal flows along a longer path because the incorrect (i.e., fault-free) string 714 is left as the only connected string. Nevertheless, the tracing is still successful because the trace signal path eventually terminates. The technician will follow the trace signal back along the second (still connected) string 714 toward the negative combiner bus, and then along the first string 712 toward the point of failure. Alternatively, after the technician examines all strings upstream on the negative bus, the technician will recognize that the trace signal exists on both the first string 712 and the second string 714, and can choose to trace along the first string 712 without exploring the second string 714. Therefore, as in... Figure 7A As shown, when the faulty string is left as the only string connected, the tracing process may take longer, but it is still successful, and therefore can be applied to situations where disconnecting the string is particularly laborious and the faulty string is unknown in advance.

[0154] Figure 7B The extended tracing path demonstrated in the paper validates the flexibility and adaptability of the proposed method in locating ground faults, even in complex circuit setups. It shows that even when the exact fault string is unknown beforehand, the tracing signal can still guide technicians to the fault location, ensuring successful and efficient fault identification and repair.

[0155] Figure 7C This includes series 722, 724, and 726. Series 722 contains ground faults. Figure 7C The diagram illustrates a generalized method for successfully tracking a ground fault in a parallel branch circuit. In this method, all strings 722, 724, and 726 are disconnected from the positive combiner bus, and the tracking signal is connected to the negative combiner bus. This configuration significantly simplifies the tracking process because it eliminates the need for what could be time-consuming identification, selection, and disconnection of specific strings on the positive side.

[0156] In particular, such as in Figure 7C As shown, by disconnecting all strings 722, 724, and 726 on the positive side and connecting the trace signal to the negative combiner bus, the trace signal flows only on the faulty string 722 and directly to the fault point. The trace signal, represented by the dashed path, originates from the negative combiner bus and terminates at the fault point indicating the location of a ground fault in the indicator circuit.

[0157] This method offers significant efficiency in fault location procedures. By disconnecting all strings on the positive side, technicians do not need to determine which strings to disconnect, thus saving time. In typical PV system designs, the positive side is relatively easier to disconnect because the connections are typically manually operated or "finger-safe" devices, while the negative side is relatively more difficult to disconnect because the connections are typically screw- or bolt-type and require tools. In some other PV system designs, the negative-side connector may be easier to disconnect than the positive-side connector. The described method is effective if the strings are opened only on the positive side or if all strings are opened only on the negative side, allowing the user to disconnect whichever side is easier or otherwise preferred. Therefore, this method allows relatively more difficult-to-manage connections to remain in place, reducing the time and need for tooling connections in situations where high voltage hazards exist.

[0158] In short, Figure 7C The advantages of establishing a generalized workflow for tracking faults in parallel branch circuits are evident. By disconnecting all strings on one side (the positive side in this example) and connecting the tracking signal to another bus terminal (the negative terminal in this case), the tracking process is significantly simplified and accelerated, overcoming the time-saving limitations previously experienced in systems with parallel circuits.

[0159] Figure 7D This includes series 732, 734, and 736. Series 732 includes ground faults. Figure 7D The illustration shows an alternative scenario where all strings remain connected at both the negative and positive combiner buses. Even though this configuration may complicate tracing processing, ground fault identification and localization remain feasible. Specifically, it allows the tracing signal to flow through all strings 732, 734, and 736, covering a wide path across the entire circuit.

[0160] Despite this extended propagation path, the tracking signal will still show detectable changes in characteristics at the location of the ground fault. These changes can include shifts in the polarity and / or amplitude of the tracking signal, providing a clear indication of the location of the ground fault in the circuit. Even as the signal flows through all the connected strings, technicians can monitor these changes in the tracking signal to pinpoint the fault.

[0161] Figure 7D The configuration depicted highlights the robustness and adaptability of the proposed method. While it may increase the complexity of the tracing process due to the extended paths, it demonstrates the method's ability to locate ground faults even in complex and interconnected circuit settings. Its emphasis on the method's flexibility in identifying and locating ground faults under varying circuit conditions further solidifies its practicality and effectiveness in a wide range of electrical circuit configurations.

[0162] for Figure 7D In the scenario depicted, comparing tracking signals along different paths can be used to locate ground faults. Specifically, Figure 7D The diagram illustrates a schematic representation of a tracking signal propagating through parallel branches of a circuit, which includes both directly faulty strings (string 732) and fault-free strings (strings 734 and 736). The fault-free strings only fail indirectly, simply because they are connected to the same bus terminals as string 732.

[0163] As shown, the direct path of the trace signal travels from the positive side of the direct fault string 732 through the direct fault branch to the fault point opposite to ground. As also shown, the indirect path of the trace signal travels in the indirect path from the positive bus through the fault-free string 736 to the positive side of string 736, then along the negative side of string 736, then along the negative bus, then along the negative side of the direct fault string 732, and then to the fault point opposite to ground. This situation presents a challenge in identifying the location of the fault because the trace signal exists on both sides of the fault and on multiple strings. To overcome this challenge, a method for distinguishing these paths can be implemented, which involves analyzing the characteristics of the trace signal on each path.

[0164] Specifically, the direct path of the tracking signal through the faulty string 732 has a lower total impedance than the indirect path through the fault-free string. The direct path of the tracking signal includes only two boards with impedance Z, thus the path has a total impedance of 2Z, while the indirect path includes the entire string of boards with a total impedance of 4Z plus any additional boards in the path. Because the indirect path has a higher impedance, the current amplitude of the signal on the indirect path will be lower than the current amplitude of the tracking signal on the direct path. By designing a signal detector and associated analysis system to allow a clear comparison of the relative amplitudes of the tracking signals, the two paths can be distinguished, and the fault can be located by following the signal path with the larger current amplitude. This can be achieved by performing measurements using a sensor at a fixed distance from the wiring, so that the measured signal will correspond to a scaled current amplitude of the tracking signal.

[0165] Alternatively, the transmitter can inject a signal that will be impedance-modulated by the fault path in such a way that the difference in impedance will produce a difference in modulation, which can be detected and analyzed by a signal detector and an associated analysis system. For example, two frequencies, F1 and F2, can be injected to be modulated according to the impedance of the current path, and the ratio of I(F1) to I(F2) will indicate the impedance of the tracking signal path to distinguish between directly faulty branches and fault-free branches. This modulation-based approach allows for the realization of subtle differences between directly and indirectly tracking signal paths, further enhancing the power and accuracy of the proposed method.

[0166] Figure 7D The potential applications of constructive and destructive interference are also illustrated to further optimize fault identification and location processing. In particular, the transmitter can be designed to generate specific current waveforms that will create constructive or destructive interference between the direct and indirect paths leading to a ground fault. This approach utilizes the difference in amplitude of the tracking signal that may exist between the direct and indirect fault branches.

[0167] In the case of constructive interference, the transmitter can generate a waveform that enhances the tracking signal on the faulty branch. This can be achieved by adjusting the phase of the synchronization waveform, resulting in an increase in the amplitude of the tracking signal at the location of the fault, or simply an increase in the signal amplitude along the direct fault path. This increased signal strength provides a clear indication of the fault location, assisting technicians in the rapid identification and localization of ground faults.

[0168] Alternatively, in the case of destructive interference, the transmitter can generate a waveform that suppresses the tracking signal on the fault-free branch. This can be achieved by introducing a phase shift into the waveform, resulting in a reduction in the magnitude of the tracking signal along the fault-free branch. This reduced signal strength will further distinguish the faulty branch from the fault-free branch, making it easier for technicians to trace the fault path and locate the ground fault.

[0169] Furthermore, the three-terminal configuration, as previously described, further enables this interference-based approach. Using this configuration, the transmitter can be connected to three points in the circuit, effectively creating two separate paths for signal tracking. By applying the principles of constructive or destructive interference, the tracking signal on one path can be enhanced or suppressed relative to the other, providing a clear distinction between faulty and fault-free branches and facilitating rapid and accurate fault location.

[0170] Figure 8AThe illustration shows an example interface and input protection circuit that can be electrically positioned between the signal generation circuit and either or both of the first and second terminals of the transmitter. The voltage divider circuit is configured to divide the voltage present at the first and second terminals of the transmitter when connected to an electrical circuit. This voltage divider circuit is specifically designed to operate safely under the high voltage conditions of a typical solar field (e.g., up to 1500V CAT III).

[0171] Figure 8A The LT Spice simulation also illustrates a potential design for a protection circuit to limit the voltage seen at the transmitter input. A switch is controlled to switch the load in parallel between the two transmitter inputs R5. The switching frequency can be optimized for the desired frequency of the tracking signal. Resistors R1, R15, and R5 operate to limit the voltage seen at the switch and limit the maximum current through the switch. The combination of R1 and R15 operates as a voltage divider, dividing the input voltage approximately by R15 / R1. The sum of the resistances of R1 and R5 limits the maximum current drawn through the switch. In certain embodiments, a set of switchable resistors or linearly controlled resistor devices such as IGBTs can be used to dynamically adjust the values ​​of R1 and R15 to provide optimal voltage protection and current.

[0172] In some embodiments, the switching device may be an electrically isolated solid-state switch or a FET pairing in a back-to-back configuration to isolate the rest of the system electronics from the switching device. This design enables use in environments requiring voltage ratings of 1000V (such as many commercial and industrial solar applications) and 1500V for many utility-scale applications. The design also allows for the inclusion and isolation of high-voltage components at the front end of the device, taking into account large component separation distances for creepage and clearance requirements, and allows the rest of the device to be designed for much lower voltages, facilitating a smaller form factor. Additional options for the switching device include, for example, commercially available off-the-shelf SiC FETs, such as SiC FETs rated for 2000V or 3000V.

[0173] Figure 8BAn example circuit is depicted that allows coupling between faulty circuitry at input terminals A and B and transmitter electronics at the output terminals. Resistors R111 and R222 form a voltage divider network that reduces the DC voltage between IN_A and IN_B (e.g., which could be a connection to a PV array) to a smaller value between OUT_A and OUT_B (e.g., which is connected to the transmitter electronics). This voltage divider circuit is specifically designed to operate safely under the high voltage conditions of a typical solar field (e.g., up to 1500V CAT III). Without additional components, the resistors in the voltage divider network would significantly limit the amplitude of the tracking signal current that the transmitter can generate. By adding a bypass capacitor C111, the DC voltage is affected by the voltage divider network, but the AC voltage and current associated with the tracking signal can bypass the resistors in the voltage divider network. This ensures that the transmitter electronics are protected from higher voltages without impeding the flow of the tracking signal. This coupling implementation thus provides an efficient and safe method for transmitting tracking signals even in high-voltage environments.

[0174] While the subject matter has been described in detail with respect to various specific example embodiments, each example is provided by way of explanation rather than limitation. Modifications, variations, and equivalents to such embodiments will readily arise for those skilled in the art upon acquiring the foregoing understanding. Therefore, this disclosure does not exclude such modifications, variations, and / or additions to the subject matter that will be readily apparent to those skilled in the art. For example, a feature partially illustrated or described as one embodiment may be used with another embodiment to produce yet another further embodiment. Therefore, this disclosure is intended to cover such modifications, variations, and equivalents.

[0175] A system of one or more computers can be configured to perform a specific operation or action by means of software, firmware, hardware, or a combination thereof installed on the system that causes the system to perform actions during operation. One or more computer programs can be configured to perform a specific operation or action by means of instructions that, when executed by a data processing device, cause the device to perform actions.

[0176] One general aspect includes a transmitter for efficient location of ground faults in a photovoltaic circuit, which may include one or more photovoltaic panels acting as an active voltage source. The transmitter also includes at least two connection terminals, which may include: a first connection terminal configured to be electrically coupled to a first connection location in the photovoltaic circuit; and a second connection terminal configured to be electrically coupled to an electrical ground. The transmitter also includes at least one signal generation circuit, which may include a load that can be selectively connected between the first and second connection terminals. The transmitter also includes a controller configured to: detect an active voltage source within the photovoltaic circuit; and, in response to detecting an active voltage source within the photovoltaic circuit, selectively connect the load between the first and second connection terminals to draw current from the active voltage source and generate a tracking signal on the photovoltaic circuit detectable by a proximity-based signal detector. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, all configured to perform the actions of the method.

[0177] Example implementations may include any combination of one or more of the following features: A transmitter, wherein the transmitter is configured to generate a tracking signal having a frequency of at least 50 Hz. The transmitter may be configured to generate a tracking signal having a frequency of at least 1 kHz. The photovoltaic circuit may include an ungrounded photovoltaic circuit. The transmitter may include an interface and protection circuitry electrically located between the signal generation circuitry and a first terminal of the transmitter electrically coupled to a first connection location, the interface and protection circuitry being configured to limit voltage reaching the signal generation circuitry or limit current passing through the signal generation circuitry. The transmitter may be operable in multiple operating modes associated with at least two different tracking signals, wherein the transmitter is switchable between multiple operating modes, and wherein the at least two different tracking signals are different due to at least one of amplitude, frequency, or phase. The transmitter may measure the voltage between the connection terminals to determine the presence of a fault within the photovoltaic circuitry and communicate with a proximity-based signal detector to provide continuous indication of the presence of a fault. The transmitter may also include a third connection terminal configured to be electrically coupled to a second connection location of the photovoltaic circuitry, wherein the first connection location may include a negative terminal of the photovoltaic circuitry and the second connection location may include a positive terminal of the photovoltaic circuitry.

[0178] One general aspect includes a method for efficiently locating ground faults in an electrical circuit. The method includes: electrically coupling a transmitter to a system ground and a first connection point within the electrical circuit, wherein the electrical circuit may include one or more energized electrical circuit branches, and the one or more energized electrical circuit branches may include one or more active voltage sources. The method further includes: causing the transmitter to generate a tracking signal that circulates as a current within a portion of the electrical circuit between the system ground and the first connection point. The method further includes: using a proximity-based signal detector to track the tracking signal through the electrical circuit to identify locations where one or more characteristics of the tracking signal change, wherein the locations where one or more characteristics of the tracking signal change indicate the location of a ground fault within the electrical circuit. Other embodiments of this aspect include corresponding computer systems, apparatuses, and computer programs recorded on one or more computer storage devices, all configured to perform the actions of the method.

[0179] Example implementations may include any combination of one or more of the following features: A method where the location of one or more characteristics of the tracking signal changes may include the location where the frequency, amplitude, phase, or polarity of the tracking signal changes. One or more voltage sources may include one or more DC voltage sources. The electrical circuit may include an ungrounded electrical circuit. The electrical circuit may include a battery storage device, which may include multiple batteries interconnected with each other. The electrical circuit may include a photovoltaic array comprising multiple photovoltaic panels, and wherein the electrical circuit may include at least one photovoltaic string, which may include at least two of a plurality of photovoltaic panels connected in series. Generating a tracking signal within the electrical circuit by a transmitter may include: having the tracking signal present between one side of the photovoltaic panel string and a ground fault; the method may also include: disconnecting the photovoltaic panel string from any other parallel string; and tracking the tracking signal through the electrical circuit using a proximity-based signal detector to identify the location where one or more characteristics of the tracking signal change may include: tracking the tracking signal from one side of the photovoltaic panel string to the location where one or more characteristics of the tracking signal change. The electrical circuit may include a photovoltaic array, which may include multiple photovoltaic panels arranged in one or more string groups, and each of the one or more string groups may include two or more strings of photovoltaic panels connected in parallel at a branch connection point. Sending a tracking signal into the electrical circuit via a transmitter may include: having the tracking signal present between one side of a branch connection point of a first string group and a ground fault; the method may further include: disconnecting all parallel strings in the first string group except the first string from one side of the branch connection point; and tracking the tracking signal through the electrical circuit using a proximity-based signal detector to identify locations where one or more characteristics of the tracking signal change may include: tracking the tracking signal along the first string to the locations where one or more characteristics of the tracking signal change. Generating a tracking signal within an electrical circuit using a transmitter may include: having the tracking signal present between one side of a branch connection point of a first string group and a ground fault in one or more string groups; the method may further include: disconnecting each of the parallel strings in the first string group from the other side of the branch connection point of the first string group; and tracking the tracking signal through the electrical circuit using a proximity-based signal detector to identify the location where one or more characteristics of the tracking signal change may include: tracking the tracking signal from one side of the first string group to the location where one or more characteristics of the tracking signal change.Sending a tracking signal through an electrical circuit via a transmitter may include: having the tracking signal present on either side of a branch connection point of a first string group in one or more string groups between the tracking signal and a ground fault; the method may also include: having more than one of the parallel strings in the first string group connected to both sides of a branch connection point of the first string group; and using a proximity-based signal detector to track the tracking signal through the electrical circuit to identify the location where one or more characteristics of the tracking signal change may include: collecting multiple measurements of the tracking signal from multiple strings respectively; and comparing the multiple measurements to identify the location of the ground fault. One or more string groups may include multiple string groups electrically connected to a common bus at an inverter or combiner; sending a tracking signal through an electrical circuit via a transmitter may include: having the tracking signal present on one side of the common bus between the tracking signal and a ground fault; the method may also include: disconnecting each of the multiple string groups from the other side of the common bus; and using a proximity-based signal detector to track the tracking signal through the electrical circuit to identify the location where one or more characteristics of the tracking signal change may include: analyzing which combined branch exhibits the maximum tracking signal to identify which combined branch the ground fault is located on. Implementations of the described techniques may include hardware, methods or processes, or computer software on a computer-accessible medium.

[0180] One general aspect includes a system for efficient location of ground faults in electrical circuits, which may include one or more active voltage sources. The system includes a transmitter that may include at least two connection terminals, which may include a first connection terminal configured to be electrically coupled to a first connection location in the electrical circuit; and a second connection terminal configured to be electrically coupled to an electrical ground. The transmitter also includes at least one signal generation circuit, which may include a load that can be selectively connected between the first and second connection terminals. The transmitter further includes a controller configured to selectively connect the load between the first and second connection terminals to draw current from the active voltage source and generate a tracking signal on a photovoltaic circuit. The system also includes a handheld proximity-based signal detector configured to detect one or more characteristics of the tracking signal at different locations in the electrical circuit to indicate the location of a ground fault within the electrical circuit. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices.

[0181] Example implementations may include any combination of one or more of the following features: A system in which a proximity-based signal detector is operable in multiple operating modes, which may include a proximity-based signal detection mode and a clamp-based signal detection mode. The proximity-based signal detector may include one or more magnetic field detectors, and the one or more magnetic field detectors may include inductive coils, fluxgates, or other magnetic sensors. A tracking signal is generated as an AC signal having a frequency greater than 1 kHz and detectable by the proximity-based magnetic field sensor. The signal detector utilizes one or more current clamps as additional sensor devices to detect the tracking signal on the wiring and determine one or more characteristics of the tracking signal. The signal detector may be used for residual current detection to compare the amplitude of the tracking signal flowing through the positive and negative sides of a first circuit branch with the amplitude of the tracking signal flowing through the positive and negative sides of at least one other circuit branch; and wherein the circuit branch with the largest current difference between the positive and negative sides is identified as a faulty branch. Communication and control may be provided between the signal detector and a transmitter, wherein communication and control are performed wirelessly or via coupling through electrical circuitry. The transmitter can generate a tracking signal by injecting voltage into one or more terminals; or by loading an electrical circuit and drawing current from one or more active voltage sources within the circuit. Implementations of the described techniques may include hardware, methods or processes, or computer software on a computer-accessible medium.

Claims

1. A transmitter for efficient location of ground faults in a photovoltaic circuit, the photovoltaic circuit including one or more photovoltaic panels acting as an active voltage source, the transmitter comprising: At least two connection terminals, the at least two connection terminals including: a first connection terminal configured to be electrically coupled to a first connection location of the photovoltaic circuit; and a second connection terminal configured to be electrically coupled to electrical ground; At least one signal generation circuit includes: a load that can be selectively connected between a first connection terminal and a second connection terminal; and The controller is configured as follows: Detecting the active voltage source within the photovoltaic circuit; and In response to the detection of an active voltage source within the photovoltaic circuit, a load is selectively connected between the first and second connection terminals to draw current from the active voltage source and generate a tracking signal on the photovoltaic circuit that can be detected by a proximity-based signal detector.

2. The transmitter of claim 1, wherein the transmitter is configured to generate a tracking signal having a frequency of at least 50 Hz.

3. The transmitter of claim 1, wherein the transmitter is configured to generate a tracking signal having a frequency of at least 1 kHz.

4. The transmitter of claim 1, wherein the photovoltaic circuit includes an ungrounded photovoltaic circuit.

5. The transmitter of claim 1, further comprising an interface and protection circuitry electrically positioned between the signal generation circuitry and a first terminal of the transmitter electrically coupled to the first connection location, the interface and protection circuitry being configured to limit voltage reaching the signal generation circuitry or limit current passing through the signal generation circuitry.

6. The transmitter of claim 1, wherein the transmitter is operable in a plurality of operating modes associated with at least two different tracking signals, wherein the transmitter is switchable between the plurality of operating modes, and wherein the at least two different tracking signals are different due to at least one of amplitude, frequency, or phase.

7. The transmitter of claim 1, wherein the transmitter measures the voltage between connection terminals to determine whether a fault exists in the photovoltaic circuit, and communicates with a proximity-based signal detector to provide continuous indication of the presence of a fault.

8. The transmitter of claim 1, wherein the transmitter further comprises a third connection terminal configured to be electrically coupled to a second connection location of the photovoltaic circuit, and wherein the first connection location includes a negative terminal of the photovoltaic circuit and the second connection location includes a positive terminal of the photovoltaic circuit.

9. A method for efficiently locating grounding faults in electrical circuits, the method comprising: The transmitter is electrically coupled to a first connection point within the system ground and electrical circuitry, wherein the electrical circuitry includes one or more energized electrical circuit branches, and the one or more energized electrical circuit branches include one or more active voltage sources; The transmitter generates a tracking signal, which circulates as current within the portion of the electrical circuit between the system ground and the first connection position. A proximity-based signal detector is used to track a tracking signal passing through an electrical circuit to identify the location where one or more characteristics of the tracking signal change, wherein the location where one or more characteristics of the tracking signal change indicates the location of a ground fault within the electrical circuit.

10. The method of claim 9, wherein the location where one or more characteristics of the tracked signal change includes the location where the frequency, amplitude, phase, or polarity of the tracked signal changes.

11. The method of claim 9, wherein one or more voltage sources comprise one or more DC voltage sources.

12. The method of claim 9, wherein the electrical circuit includes an ungrounded electrical circuit.

13. The method of claim 9, wherein the electrical circuitry includes a battery storage container, the battery storage container comprising a plurality of batteries interconnected with each other.

14. The method of claim 9, wherein the electrical circuit includes a photovoltaic array, the photovoltaic array includes a plurality of photovoltaic panels, and wherein the electrical circuit includes at least one photovoltaic string, the at least one photovoltaic string including at least two of the plurality of photovoltaic panels connected in series.

15. The method of claim 14, wherein: The process of enabling the transmitter to generate a tracking signal within the electrical circuit includes: ensuring that the tracking signal exists between one side of the photovoltaic string and the ground fault; The method further includes: disconnecting the photovoltaic panel string from any other parallel string; and Using a proximity-based signal detector to track a tracking signal through an electrical circuit to identify the location where one or more characteristics of the tracking signal change includes: tracking the tracking signal from one side of a photovoltaic string to the location where one or more characteristics of the tracking signal change.

16. The method of claim 9, wherein the electrical circuit includes a photovoltaic array comprising a plurality of photovoltaic panels, wherein the plurality of photovoltaic panels are arranged in one or more string groups, and wherein each of the one or more string groups includes two or more photovoltaic panel strings connected in parallel at a branch connection point.

17. The method of claim 16, wherein: Sending a tracking signal from the transmitter to the electrical circuitry includes: ensuring that the tracking signal is present on one side of a branch connection point of the first string group in the one or more string groups and between the ground fault; The method further includes: disconnecting all parallel strings in the first string group except the first string from one side of the branch connection point; and Using a proximity-based signal detector to track a tracking signal through an electrical circuit to identify the location where one or more characteristics of the tracking signal change includes: tracking the tracking signal along a first string to the location where one or more characteristics of the tracking signal change.

18. The method of claim 16, wherein: Generating a tracking signal within the electrical circuitry for the transmitter includes: ensuring that the tracking signal is present on one side of a branch connection point of the first string group in the one or more string groups and between the ground fault; The method further includes: disconnecting each of the parallel strings in the first string group from the other side of the branch connection point; and Using a proximity-based signal detector to track a tracking signal through an electrical circuit to identify the location where one or more characteristics of the tracking signal change includes: tracking the tracking signal from one side of a first string group to the location where one or more characteristics of the tracking signal change.

19. The method of claim 16, wherein: Sending a tracking signal from the transmitter to the electrical circuit includes: ensuring that the tracking signal is present on either side of a branch connection point of the first string group in the one or more string groups between the ground fault; The method further includes: connecting more than one branch connection point in the parallel strings of the first string group to both sides of the first string group; and Using a proximity-based signal detector to track a tracking signal through an electrical circuit to identify locations where one or more characteristics of the tracking signal change includes: Multiple measurements of the tracking signal are collected from the plurality of strings, respectively; and The multiple measurements are compared to identify the location of the ground fault.

20. The method of claim 16, wherein: The one or more string groups include multiple string groups electrically connected to a common bus at the inverter or compositer; The process of enabling the transmitter to send a tracking signal into the electrical circuit includes: ensuring that the tracking signal exists between one side of the common bus and the ground fault; The method further includes: disconnecting each of the plurality of string groups from the other side of the public bus; and Using proximity-based signal detectors to track trace signals through electrical circuits to identify the location where one or more characteristics of the trace signal change includes: analyzing which combined branch exhibits the maximum trace signal to identify which combined branch a ground fault is located on.

21. A system for efficient location of ground faults in an electrical circuit including one or more active voltage sources, the system comprising: Transmitter, including: At least two connection terminals, the at least two connection terminals including: a first connection terminal configured to be electrically coupled to a first connection position of an electrical circuit; and a second connection terminal configured to be electrically coupled to an electrical ground; At least one signal generation circuit includes: a load that can be selectively connected between a first connection terminal and a second connection terminal; and The controller is configured to selectively connect a load between a first connection terminal and a second connection terminal to draw current from an active voltage source and generate a tracking signal on the photovoltaic circuit. A handheld proximity-based signal detector is configured to detect one or more characteristics of a tracking signal at different locations within an electrical circuit to indicate the location of a ground fault within the electrical circuit.

22. The system of claim 21, wherein the proximity-based signal detector is operable in multiple operating modes, the multiple operating modes including a proximity-based signal detection mode and a clamp-based signal detection mode.

23. The system of claim 21, wherein the proximity-based signal detector comprises one or more magnetic field detectors, and wherein the one or more magnetic field detectors comprise an inductive coil, a fluxgate, or other magnetic sensor.

24. The system of claim 21, wherein the generated tracking signal is an AC signal having a frequency greater than 1 kHz and detectable by a proximity-based magnetic field sensor.

25. The system of claim 21, wherein the signal detector utilizes one or more current clamps as additional sensor devices to detect the tracking signal on the wiring and determine the one or more characteristics of the tracking signal.

26. The system of claim 21, wherein a signal detector is used for residual current detection to compare the amplitude of a tracking signal flowing through the positive and negative sides of a first circuit branch with the amplitude of a tracking signal flowing through the positive and negative sides of at least one other circuit branch; and wherein the circuit branch having the maximum current difference between the positive and negative sides is identified as the faulty branch.

27. The system of claim 21, wherein communication and control are provided between the signal detector and the transmitter, wherein communication and control are performed wirelessly or via coupling through electrical circuitry.

28. The system of claim 21, wherein the transmitter generates the tracking signal by: injecting voltage into one or more terminals; or loading electrical circuitry and drawing current from the one or more active voltage sources within the circuitry.

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