Protection method for electrical collection system

Abstract

The present disclosure relates to a method for protecting an electrical power harvesting system comprising an electrical grid electrically coupled to an electrical branch comprising a plurality of switches for connecting or disconnecting the electrical branch at respective locations on the electrical branch, where a distributed energy resource is electrically coupled to nodes on the electrical branch. The method comprises: detecting a fault occurrence on an electrical branch based on a monitored voltage and / or current of the electrical branch; limiting power flow from the electrical branch to the grid based on the detected fault occurrence; adjusting the voltage and / or current on the electrical branch based on the detected fault occurrence; determining a fault location based on the adjusted voltage and / or current on the electrical branch; and disconnecting a portion of the electrical collection system based on the determined fault location. The invention further relates to a corresponding controller and system.

Description

Technical Field

[0001] This disclosure relates to a method for protecting an electrical collection system, a controller, and an electrical collection system. Background Technology

[0002] In power collection systems that deliver electricity from distributed energy resources (DERs) to the grid, faults cause numerous problems. A conventional solution for fault clearing is to install DC circuit breakers to block the path of power flow. However, such solutions not only increase power losses during operation but are also cost-inefficient.

[0003] Figure 1 a) illustrates a conventional medium-voltage DC (MVDC) system for wind farm applications. In Figure 1 a), electricity is delivered from the wind turbine to the grid via a power converter and bus electrically connected to the grid. Specifically, a grid AC / DC converter is electrically connected to the grid via a point of common coupling (PCC) and to the MVDC bus, and converts the power flow between the MVDC bus and the grid. Each wind turbine includes a generator and a current isolator. Such systems may alternatively or further include any other DERs, such as photovoltaic (PV) panels and battery energy storage (BES) devices, for smooth power output. Figure 1 b) illustrates a simplified block diagram of a conventional power harvesting system. In such MVDC systems, short-circuit faults cause numerous problems, and conventional fault clearing solutions increase power losses and are cost-inefficient.

[0004] Therefore, there is a need to improve a method, controller, and an electrical collection system for protecting electrical collection systems. Summary of the Invention

[0005] This disclosure relates to a method for protecting a power harvesting system, the power harvesting system including a power grid electrically connected to an electrical branch, the electrical branch including a plurality of switches for connecting or disconnecting the electrical branch at corresponding locations on the electrical branch, wherein distributed energy resources are electrically connected to nodes on the electrical branch, the method comprising: detecting the occurrence of a fault on the electrical branch based on a monitored voltage and / or current of the electrical branch; limiting the power flow from the electrical branch to the power grid based on the detected fault occurrence; adjusting the voltage and / or current on the electrical branch based on the detected fault occurrence; determining the fault location based on the adjusted voltage and / or current on the electrical branch; and disconnecting a portion of the power harvesting system based on the determined fault location.

[0006] In the embodiments, the limitation is or includes: limiting the power flow from the electrical branch to the power grid, particularly by controlling a bidirectional power valve that electrically connects the electrical branch to the power grid.

[0007] In an embodiment, the adjustment further includes: injecting a predetermined current into the electrical branch, specifically by controlling a current isolator that electrically connects the distributed energy resources to the node, and determining the fault location based on the adjusted current.

[0008] In an embodiment, the method further includes: limiting the power flow from the distributed energy resource to the node before disconnection, specifically by controlling the current isolator that electrically connects the distributed energy resource to the node.

[0009] In an embodiment, disconnection may include: disconnecting the at least two switches when the fault location is determined to be between at least two of a plurality of switches on a branch.

[0010] In an embodiment, at least two of the multiple switches are adjacent to each other, and in particular, there is a node located between the at least two switches.

[0011] In one embodiment, the two ends of the electrical branch are electrically connected to a bidirectional power valve, which is further electrically connected to the power grid, thereby forming a loop, and power flows from the distributed energy resource to the power grid.

[0012] In an embodiment, the method further includes: reoperating the power harvesting system by the following steps: enabling power flow from the grid to the distributed energy resource after disconnection, particularly by controlling a bidirectional power valve that connects the grid to the power branch.

[0013] This disclosure also relates to a controller for protecting a power harvesting system including a power grid electrically connected to an electrical branch, the electrical branch including a plurality of switches for connecting or disconnecting the electrical branch at corresponding locations on the branch, wherein distributed energy resources are electrically connected to nodes on the electrical branch, the controller being configured to: detect the occurrence of a fault on the electrical branch based on a monitored voltage and / or current of the electrical branch; limit the power flow from the electrical branch to the power grid based on the detected fault; adjust the voltage and / or current on the electrical branch based on the detected fault; determine the fault location based on the adjusted voltage and / or current on the electrical branch; and disconnect a portion of the electrical harvesting system based on the determined fault location.

[0014] In an embodiment, the controller is further configured to perform a method according to any of the embodiments disclosed herein.

[0015] This disclosure further relates to a power harvesting system comprising a power grid electrically connected to an electrical branch, the electrical branch including a plurality of switches for connecting or disconnecting the electrical branch at corresponding locations on the electrical branch, wherein distributed energy resources are electrically connected to nodes on the electrical branch.

[0016] In an embodiment, the power harvesting system further includes a controller according to any of the embodiments disclosed herein.

[0017] The methods according to any of the embodiments disclosed herein can advantageously monitor and / or estimate quantities of industrial assets, such as operational performance, operating status, or information about external conditions or adjacent systems. A specific quantity to be monitored and / or estimated is the health status of the industrial asset, which allows for understanding asset degradation, predicting its remaining useful life (RUL), and making decisions regarding operation, maintenance, and repair. The information thus obtained can be used to inform human operators, managers, or stakeholders to support their operational or other decisions or to partially or fully automate the operation of the asset.

[0018] Various exemplary embodiments of this disclosure are provided with features that will become readily apparent from the following description when understood in conjunction with the accompanying drawings. Exemplary systems, methods, and apparatuses are disclosed herein according to various embodiments. However, it should be understood that these embodiments are presented by way of example and not limitation, and that various modifications can be made to the disclosed embodiments by those skilled in the art who read this disclosure, while remaining within the scope of this disclosure.

[0019] Therefore, this disclosure is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, the specific order and / or hierarchy of steps in the methods disclosed herein are merely exemplary methods. The specific order or hierarchy of steps in the disclosed methods or processes may be rearranged based on design preferences while remaining within the scope of this disclosure. Therefore, those skilled in the art will understand that the methods and techniques disclosed herein present various steps or actions in a sample order, and unless expressly stated otherwise, this disclosure is not limited to the specific order or hierarchy presented.

[0020] In the following, exemplary embodiments of this disclosure will be described. It should be noted that, unless otherwise stated or obvious, some aspects of any of the described embodiments may also be found in some other embodiments. However, for the sake of understanding, each aspect will be described in detail only upon its first mention, and any repeated descriptions of the same aspect will be omitted.

[0021] The above and other aspects and their embodiments are described in more detail in the accompanying drawings, description and claims. Attached Figure Description

[0022] Figure 1 a) illustrates a conventional power grid.

[0023] Figure 1b) illustrates a simplified diagram of a conventional power grid.

[0024] Figure 2A flowchart illustrating a method according to an embodiment of the present disclosure is shown.

[0025] Figure 3 a) illustrates a power harvesting system according to an embodiment of the present disclosure under normal operating conditions.

[0026] Figure 3b) illustrates a power harvesting system according to an embodiment of the present disclosure under fault conditions.

[0027] Figure 3c) illustrates a power harvesting system according to an embodiment of the present disclosure under fault conditions.

[0028] Figure 3 d) illustrates a power harvesting system according to an embodiment of the present disclosure under fault conditions.

[0029] Figure 3e) illustrates a power harvesting system according to an embodiment of the present disclosure during a fault location process.

[0030] Figure 4 A flowchart illustrating a method according to an embodiment of the present disclosure is shown.

[0031] Figure 5 The illustration shows a flowchart of a fault location determination method according to an embodiment of the present disclosure.

[0032] Figure 6 a) illustrates a bidirectional power valve according to an embodiment of the present disclosure during a startup or restart process.

[0033] Figure 6b) illustrates a bidirectional power valve according to an embodiment of the present disclosure after a startup or restart process.

[0034] Figure 6c) illustrates a bidirectional power valve according to an embodiment of the present disclosure during normal operating conditions.

[0035] Figure 7 The illustration shows a power harvesting system according to an embodiment of the present disclosure.

[0036] Figure 8 a) illustrates a controller for a power harvesting system according to an embodiment of the present disclosure.

[0037] Figure 8b) illustrates a power harvesting system according to an embodiment of the present disclosure. Detailed Implementation

[0038] Figure 2 A flowchart of a method according to an embodiment of the present disclosure is illustrated. Specifically, the method is used to protect an electricity harvesting system comprising a power grid electrically connected to an electrical branch, the electrical branch including a plurality of switches for connecting or disconnecting the electrical branch at corresponding locations on the branch, wherein distributed energy resources are electrically connected to nodes on the electrical branch. The electricity harvesting system may be equivalently referred to as a power collection system.

[0039] At S201, a fault in the electrical branch is detected based on the monitored voltage and / or current of the branch. The monitored voltage and / or current can be measured at any location on the branch, particularly at any of the corresponding locations of multiple switches. The detection can be based on at least one of the voltage and / or current measured at any location on the branch, particularly at the corresponding locations of multiple switches. The detection can further be based on any other electrical or physical parameters of the electrical collection system and / or any components included therein.

[0040] At S202, the power flow from the electrical branch to the grid is limited based on the detected fault. Those skilled in the art will understand that the term 'limit' is semantically equivalent to other terms such as 'change,' 'reduce,' 'block,' 'cut off,' etc., and can therefore be used interchangeably with these other terms. In an embodiment, the limitation is or includes: controlling a bidirectional power valve, wherein the bidirectional power valve electrically connects the electrical branch to the grid. In an embodiment, the limitation is performed after S201 and / or before S203. The limitation can also be performed even when it has been determined that no fault has occurred, for example, when a fault detection produces a false negative response.

[0041] At S203, the voltage and / or current on the electrical branch are adjusted based on the detected fault. Those skilled in the art will understand that the term 'adjustment' is semantically equivalent to other terms such as 'setting,' 'controlling,' etc., and can therefore be used interchangeably with these other terms. In embodiments, adjustment is or includes: injecting a predetermined current into the electrical branch, particularly by controlling a current isolator, wherein the current isolator electrically connects a distributed energy resource (DER) to the node. The term 'distributed energy resource' refers to any decentralized power source, such as a generator or power storage device (e.g., a battery). In embodiments, adjustment is performed after S202 and / or before S204.

[0042] At S204, the fault location is determined based on the adjusted voltage and / or current on the electrical branch. The adjusted voltage and / or current can be measured at any location on the electrical branch, particularly at any of the corresponding locations of multiple switches. The fault location can be a fault range, where the fault lies within that range. In an embodiment, the fault range is determined by measuring the adjusted voltage and / or current at at least two different locations on the electrical branch, particularly at at least two different locations where two different switches of the multiple switches are respectively located, wherein the fault range lies between at least two different switches of the multiple switches. In an embodiment, the determination of the fault location is based on the current on the adjusted electrical branch.

[0043] At S205, a portion of the electrical collection system is disconnected based on the determined fault location. In an embodiment, disconnection is or includes: disconnecting at least two switches when the fault location is determined to be between at least two of a plurality of switches on a branch.

[0044] In an embodiment, the method further includes: limiting the power flow from the distributed energy resource to the node. The limiting may be performed after S203 and / or before S205. The limiting may be or include: controlling a current isolator, wherein the current isolator electrically connects the distributed energy resource to the node.

[0045] In one embodiment, the method further includes: reoperating the power harvesting system by enabling power flow from the grid to the distributed energy resource. Reoperation may be performed after S205. In another embodiment, enabling may include: controlling a bidirectional power valve that connects the grid to the power branch.

[0046] In an embodiment, at least two of the multiple switches are adjacent to each other, and in particular, there is a node located between the at least two switches.

[0047] In one embodiment, the two ends of the electrical branch are electrically connected to a bidirectional power valve to form a loop, wherein the bidirectional power valve is further electrically connected to the power grid via a power converter, and wherein power flows from the distributed energy resource to the power grid. The loop may be a ring mains unit.

[0048] In one embodiment, multiple switches are connected to the electrical branch at their respective locations, particularly under normal operating conditions. In another embodiment, at least one of the multiple switches is disconnected from the electrical branch at its respective location, particularly under normal operating conditions.

[0049] In this document, the term 'disconnecting switch' may be used interchangeably with the term 'switch'.

[0050] Figures 3a) through 3e) illustrate an electricity harvesting system according to an embodiment of the present disclosure, operating based on the exemplary methods disclosed herein. Specifically, the electricity harvesting system 300 includes a power grid 310 electrically connected to an electrical branch 330, wherein the electrical branch 330 includes a plurality of switches 331, 332, 333, 334, 335, and 336 for connecting or disconnecting the electrical branch 330 at corresponding locations on the electrical branch 330, and wherein a distributed energy resource (i.e., a generator 350 in Figures 3a) through 3e) is electrically connected to a node on the electrical branch 330. This node is located on the electrical branch between a second switch 331 and a third switch 332 among the plurality of switches 331, 332, 333, 334, 335, and 336. For readability, in Figures 3a) through 3e), only selected switches 331, 332, 333, 334, 335, and 336 are referred to by reference numerals, and the numbering begins at the upper portion of electrical branch 330 (one of its two ends is electrically connected to bus 321) and increases along the electrical branch toward the other end of the branch. Bus 321 can be any of electrical interconnects, electrical buses, electrical busbars, and PCCs. A set of two consecutive switches including nodes electrically connected to DER can be referred to as two consecutive switches. For example, second switch 331 and third switch 332 are two consecutive switches. Power converter 311 electrically connects grid 310 to bidirectional power valve 360, which is further electrically connected to bus 321, to which both ends of electrical branch 330 are electrically connected. SST 340 electrically connects DER to nodes of electrical branch 330.

[0051] Figure 3 a) illustrates a power harvesting system according to an embodiment of the present disclosure under normal operating conditions. The term 'normal operating conditions' refers to operating conditions without abnormalities and / or operating conditions after startup or restart. For example, an abnormality could be a fault in an electrical branch, such as a short-circuit fault. For example, an abnormality could be a fault in any electrical component included in the power harvesting system. Under normal operating conditions, multiple switches 331, 332, 333, 334, 335, and 336 are connected to electrical branch 330 at their respective locations. Under normal operating conditions, power generated by generator 350 is delivered to grid 310 via SST 340, bus 321, bidirectional power valve 360, and power 311. Under normal operating conditions, bidirectional power valve 360 ​​is controlled to act as a unidirectional power valve that only enables the power flow from electrical branch 330 to grid 310. Those skilled in the art will understand that the generated power may be delivered to another DER electrically connected to the electrical branch, such as BES. In an embodiment, BES is controlled to provide power to the electrical branch. Under normal operating conditions, fault occurrence in the electrical branch is detected based on the monitored voltage and / or current of the electrical branch 330. The above method can be an embodiment of S201. Such fault occurrence detection can be performed iteratively. Once a fault is detected in the electrical branch, the power harvesting system 300 executes the following method according to an embodiment of this disclosure, as illustrated in FIG3 b).

[0052] Figure 3b) illustrates a power harvesting system according to an embodiment of the present disclosure under fault conditions. When a fault occurs on an electrical branch between the third switch 332 and the fourth switch 333 among multiple switches 331, 332, 333, 334, 335, and 336 (illustrated with lightning in Figures 3b to 3e) and the fault is detected (e.g., according to S201), the power flow between the electrical branch 330 and the power grid 310 is limited by controlling the bidirectional power valve 360. It should be noted that at this stage, the exact location of the fault on the electrical branch may not be determined, but merely detecting the occurrence of the fault may be sufficient. The above method can be an embodiment of S202. Once the power flow between the electrical branch 330 and the power grid 310 is limited, the current on the electrical branch 330 can be adjusted by controlling SST 340 to inject a predetermined current into the electrical branch 330. The above method can be an embodiment of S203. Then, the fault location is determined based on the adjusted current on the electrical branch 330. The above method can be an embodiment of S204. In performing the above method, multiple switches 331, 332, 333, 334, 335, and 336 are connected to electrical branch 330 at their respective locations. Once the fault location is determined, the power harvesting system 300 performs the following method according to an embodiment of the present disclosure, as illustrated in FIG3 c).

[0053] Figure 3c) illustrates a power harvesting system according to an embodiment of the present disclosure under fault conditions. Once the fault location is determined to be between the second switch 331 and the third switch 332 among a plurality of switches 331, 332, 333, 334, 335, and 336, the power flow from the generator 350 to the electrical branch 330 is limited by controlling SST 340. In performing the above method, the plurality of switches 331, 332, 333, 334, 335, and 336 are connected to the electrical branch 330 at their respective locations. Then, as illustrated in Figure 3d), a fault point isolation method according to an embodiment of the present disclosure is executed.

[0054] Figure 3d) illustrates a power harvesting system according to an embodiment of the present disclosure under fault conditions. When a fault is determined to be located between the third switch 332 and the fourth switch 333 and the power flow from the generator 350 to the electrical branch 330 is controlled, a portion of the electrical branch is disconnected by disconnecting the third switch 332 and the fourth switch 333 (i.e., disconnecting the electrical branch 330 at the corresponding locations of the third switch 332 and the fourth switch 333). Those skilled in the art will understand that, for illustrative purposes, the two switches most adjacent to the fault location (i.e., the third switch 332 and the fourth switch 333) are disconnected to isolate the fault, but it is possible to achieve the same purpose by controlling any combination of at least two of the multiple switches 331, 332, 333, 334, 335, and 336, as long as the fault is located within a selected combination of at least two switches. For example, the third switch 332 and the seventh switch 334 may be controlled to disconnect a portion of the electrical branch therebetween. The above method may be an embodiment of S205.

[0055] Figure 3e) illustrates a power harvesting system according to an embodiment of the present disclosure during a fault location process. Specifically, Figure 3e) illustrates an embodiment of S204 or the method shown in Figure 3b). When the bidirectional power valve 360 ​​restricts the power flow between the electrical branch 330 and the power grid and adjusts the current in the electrical branch 330, the adjusted current in the electrical branch 330 flows toward the fault location between the third switch 332 and the fourth switch 333. Defining any current direction as a positive direction 380 allows the current direction to be observed at multiple measurement points (e.g., at corresponding locations of multiple switches 331, 332, 333, 334, 335, and 336). Furthermore, when the DER injects current into the electrical branch 330 at multiple locations along the conduction path, the current accumulates along the path from any location on the electrical branch toward the fault location. Therefore, the fault location can be identified between a first measurement point recording the maximum current along the positive current direction and a second measurement point recording the maximum current along the negative current direction. Figure 4 The method illustrated in the figure can be implemented in conjunction with the electrical collection system illustrated in Figures 3a) to 3e).

[0056] Figure 4 A flowchart of a method according to an embodiment of the present disclosure is illustrated. At S401, a periodic protection check is performed. At S402, an MVDC fault is determined. S402 may be equivalent to S201. At S403, further action is determined based on the occurrence of the fault determined at S402. When no fault is detected, the method jumps to another process (S404). In an embodiment, the other process of S404 may include the fault detection in S402. When a fault is detected, SST is controlled to output a preset current (S406) to adjust the current in the electrical branch. In an embodiment, prior to S406, the power flow between the power grid and the electrical branch is limited. Then, at S407, a fault location process is performed, wherein the fault point is iteratively checked until it is determined (S408). In an embodiment, after a predefined number of iterations or a predefined time period, the loop formed by the negative results of S407, S408, and S409 is interrupted and the method jumps to another block, such as S409. In the same embodiment, after a predefined number of iterations or a predefined time period, the fault point can be determined as a predefined location on the electrical branch. Blocks S405 to S408 can correspond to the method illustrated in the system diagram shown in Figure 3b). Once the fault location is determined, the controlled SST at S406 is blocked to limit the power flow between the grid and the node (S409). S409 can correspond to the method illustrated in the system diagram shown in Figure 3c). The fault point is then isolated by disconnecting adjacent switches (S410). S410 can correspond to the method illustrated in the system diagram shown in Figure 3d). At S411, the system enters a restart process. S411 can correspond to the method illustrated in the system diagram shown in Figure 3e). The terms 'restart' or 'reoperation' refer to the action of controlling the relevant components included in the system to return to normal operation, especially after applying protective measurements such as disconnecting a portion of the electrical branch.

[0057] Figure 5 The illustration shows a flowchart of a fault location determination method according to an embodiment of the present disclosure. Figure 5The method illustrated in Figure 3(e) can be an embodiment of the fault location determination in S407 or the method shown in Figure 3(e). When an MVDC fault is detected, the current in the electrical branch can be adjusted as illustrated in Figure 3(b). At S503, the adjusted current is measured at the corresponding positions of multiple switches on the electrical branch. Based on the current direction at S502, the measured adjusted current is classified into a first group of disconnecting switches (S504) where the current flows in a defined positive direction and a second group of disconnecting switches (S505) where the current flows in a defined negative direction. The numbers of the disconnecting switches (in counting order) are identified at S506 and S507, respectively, and these disconnecting switches record the maximum current value in the first and second groups. Then, at S508, the fault area is located based on the numbers of the two disconnecting switches with the maximum current. At S509, the fault area and the numbers of the two adjacent disconnecting switches are output for further processing or signal generation.

[0058] Figures 6a) through 6c) illustrate a power harvesting system according to an embodiment of the present disclosure during various processes and conditions. Power harvesting system 600 is a simplified diagram of power harvesting system 300 illustrated in Figures 3a) through 3e). That is, the power grid 610, power converter 620, bidirectional power valve 630, bus 640, electrical branch 650, SST 660, and generator 670 in Figures 6a) through 6c) correspond respectively to the power grid 310, power converter 311, power valve 360, bus 321, electrical branch 330, SST 340, and generator 350 illustrated in Figures 3a) through 3e). In embodiments, power converter 620 and / or SST 660 enable bidirectional power transfer. The bidirectional power valve 630 includes: a first branch including a first plurality of diodes; and a second branch including a second diode connected in antiparallel to the first plurality of diodes, wherein the second branch further includes a switch for connecting or disconnecting the second branch at a position following the second diode in the direction of current flow through the second diode when the second diode is forward biased. Those skilled in the art will understand that the first branch of the bidirectional power valve may include only one diode.

[0059] Figure 6a) illustrates a power harvesting system according to an embodiment of the present disclosure during a startup or restart process. During the startup or restart process, a switch included in the second branch closes to enable power flow from the grid 610 to the generator 670 through the second branch of the bidirectional power valve 630. After such a startup or restart process, power flows through the first branch, as shown in Figure 6b). Figure 6b) illustrates a power harvesting system according to an embodiment of the present disclosure after a startup or restart process. After such a startup or restart process, power is delivered from the generator 670 to the grid 610 through the first branch included in the bidirectional power valve 630. It should be noted that the switch in the second branch included in the bidirectional power valve 630 may still be connected to the second branch. Figure 6c) illustrates a power harvesting system according to an embodiment of the present disclosure during normal operating conditions. Under normal operating conditions, the switch in the second branch included in the bidirectional power valve 630 disconnects the second branch, and power is delivered from the generator 670 to the grid 610 through the first branch included in the bidirectional power valve 630.

[0060] Figure 7 The illustration depicts a power harvesting system according to an embodiment of the present disclosure. Specifically, the power harvesting system includes... Figure 3a The system illustrated in Figures 3 to 3e) further includes a controller and a plurality of intelligent electronic devices (IEDs). The controller is configured to perform a method according to any of the embodiments disclosed herein. The controller may be further configured to communicate with any of the components included in the system, particularly bidirectional communication. In embodiments, the controller receives or acquires measurements and / or signals, and generates control and / or communication signals based on the received or acquired measurements and / or signals. Each of the plurality of IEDs may be or includes a voltage and / or current sensor. Each of the plurality of IEDs may be located at a corresponding position of a plurality of switches included in an electrical branch for connecting and disconnecting the electrical branch at said corresponding position. Those skilled in the art will understand that the number of the plurality of IEDs may differ from the number of the plurality of switches. The controller may be configured to control the plurality of switches. The plurality of IEDs may be configured to control the plurality of switches. The grid AC / DC converter may be or includes a modular multilevel converter (MMC) with a full-bridge unit, such as Figure 7 As illustrated in the figure. An MMC may include m full-bridge units in a branch. In the embodiment, m is given as:

[0061] Where n is the number of all units in the electrical branch. It is a function that rounds the elements towards infinity to the nearest integer. It is the maximum voltage of the AC power grid, and It is the minimum voltage of the unit in operation (assuming that the voltage of all units is the same).

[0062] Figure 8a) illustrates a controller for a power harvesting system according to an embodiment of the present disclosure. The controller 810 may be... Figure 7 The controller is illustrated in the figure. In an embodiment, the controller 810 is further configured to perform a method according to any of the embodiments disclosed herein. The controller 810 is a controller for protecting a power harvesting system 800, the power harvesting system including a power grid 820 electrically connected 823 to an electrical branch 830, the electrical branch 830 including a plurality of switches 840 for connecting or disconnecting the electrical branch 830 at corresponding locations on the electrical branch 830, wherein a distributed energy resource 850 is electrically connected 835 to nodes on the electrical branch 830, the controller being configured to: detect the occurrence of a fault on the electrical branch 830 based on a monitored voltage and / or current of the electrical branch 830; based on the detection of a fault, limit the power flow from the electrical branch 830 to the power grid 820; based on the detection of a fault, adjust the voltage and / or current on the electrical branch 830; determine the fault location based on the adjusted voltage and / or current on the electrical branch 830; and disconnect a portion of the power harvesting system 800 based on the determined fault location.

[0063] Figure 8b) illustrates a power harvesting system according to an embodiment of the present disclosure. The power harvesting system 800 is a power harvesting system including a power grid 820 electrically connected 823 to an electrical branch 830, the electrical branch 830 including a plurality of switches 840 for connecting or disconnecting the electrical branch 830 at corresponding locations on the electrical branch 830, wherein a distributed energy resource 850 is electrically connected to a node on the electrical branch 830, and the power harvesting system 800 further includes a controller according to any of the embodiments disclosed herein.

[0064] While various embodiments of this disclosure have been described above, it should be understood that they are presented by way of example only and not by way of limitation. Similarly, various figures may depict exemplary architectures or configurations, provided to enable those skilled in the art to understand the exemplary features and functionality of this disclosure. However, such persons will understand that this disclosure is not limited to the illustrated exemplary architectures or configurations, but can be implemented using various alternative architectures and configurations. Additionally, as those skilled in the art will understand, one or more features of one embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of this disclosure should not be limited to any of the exemplary embodiments described above.

[0065] It should also be understood that any reference to elements in this document using names such as "first," "second," etc., generally does not restrict the number or order of those elements. Rather, these names may be used herein as a convenient means of distinguishing between two or more elements or instances of elements. Therefore, references to the first element and the second element do not imply that only two elements may be used, or that the first element must somehow precede the second element.

[0066] Additionally, those skilled in the art will understand that information and signals can be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, and symbols, as referenced in the above description, can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0067] Those skilled in the art will further understand that any of the various illustrated logic blocks, units, processors, devices, circuits, methods, and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of both), firmware, various forms of program or design code in conjunction with instructions (which may be referred to herein as “software” or “software unit” for convenience), or any combination of these technologies.

[0068] To clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative components, blocks, units, circuits, and steps have generally been described above in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software, or a combination of these technologies, depends on the specific application and the design constraints imposed on the system as a whole. Those skilled in the art can implement the described functionality in various ways for each specific application, but such implementation decisions will not depart from the scope of this disclosure. According to various embodiments, processors, devices, components, circuits, structures, machines, units, etc., may be configured to perform one or more of the functions described herein. As used herein with respect to a specified operation or function, the terms "configured to" or "configured for" mean a processor, device, component, circuit, structure, machine, unit, etc., physically constructed, programmed, and / or arranged to perform that specified operation or function.

[0069] Furthermore, those skilled in the art will understand that the various illustrative methods, logic blocks, units, devices, components, and circuits described herein can be implemented within or executed by an integrated circuit (IC), which may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, or any combination thereof. Logic blocks, units, and circuits may further include antennas and / or transceivers for communication with various components within a network or device. A general-purpose processor may be a microprocessor; however, alternatively, the processor may be any conventional processor, controller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other suitable configuration to perform the functions described herein. If implemented in software, the functions may be stored as one or more instructions or code on a computer-readable medium. Therefore, the steps of the methods or algorithms disclosed herein can be implemented as software stored on a computer-readable medium.

[0070] Computer-readable media include both computer storage media and communication media. Communication media includes any media that can be enabled to transfer computer programs or code from one place to another. Storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disc storage devices, magnetic disk storage devices or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0071] Additionally, memory or other storage devices and communication components may be employed in embodiments of this disclosure. It will be understood that, for clarity, embodiments of this disclosure have been described above with reference to various functional units and processors. However, it will be apparent that any suitable set of functions may be used across different functional units, processing logic elements, or domains without diminishing the scope of this disclosure. For example, functions illustrated as being performed by separate processing logic elements or controllers may be performed by the same processing logic element or controller. Therefore, references to specific functional units are merely references to appropriate means for providing the described functions and do not indicate a strict logical or physical structure or organization.

[0072] Various modifications to the embodiments described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the embodiments shown herein, but is to be endowed with the widest scope consistent with the novel features and principles disclosed herein, as set forth in the appended claims.

Claims

1. A method for protecting a power harvesting system, the power harvesting system comprising a power grid electrically connected to an electrical branch, the electrical branch including a plurality of switches for connecting or disconnecting the electrical branch at corresponding locations on the electrical branch, wherein, The method of electrically connecting distributed energy resources to nodes on the electrical branch includes: The occurrence of faults in the electrical branch is detected based on the monitored voltage and / or current of the electrical branch; Based on the detection of a fault, the power flow from the electrical branch to the power grid is restricted; Based on the detection of a fault, the voltage and / or current on the electrical branch are adjusted; The fault location is determined based on the adjusted voltage and / or current on the aforementioned electrical branch; and A portion of the electrical collection system is disconnected based on the identified fault location.

2. The method according to claim 1, wherein, The restriction is or includes: restricting the power flow from the electrical branch to the power grid, particularly by controlling a bidirectional power valve that electrically connects the electrical branch to the power grid.

3. The method according to claim 1 or 2, wherein, The adjustment further includes: injecting a predetermined current into the electrical branch, specifically by controlling the current isolator that electrically connects the distributed energy resource to the node, and The location of the fault is determined based on the adjusted current.

4. The method according to any one of claims 1 to 3, further comprising: Prior to the disconnection, the power flow from the distributed energy resource to the node is limited, specifically by controlling the current isolator that electrically connects the distributed energy resource to the node.

5. The method according to any one of claims 1 to 4, wherein, The disconnection includes, or may include, disconnecting the at least two switches when the fault location is determined to be between at least two of the plurality of switches on the branch.

6. The method according to claim 5, wherein, At least two of the plurality of switches are adjacent to each other, and in particular, there is a node located between the at least two switches.

7. The method according to any one of claims 1 to 6, wherein, The two ends of the electrical branch are electrically connected to a bidirectional power valve, thereby forming a loop. The bidirectional power valve is further electrically connected to the power grid, and Electricity flows from the distributed energy resources to the power grid.

8. The method according to any one of claims 1 to 7, further comprising: Re-operate the power harvesting system by following these steps: Following the disconnection, power flow from the grid to the distributed energy resource is enabled, specifically by controlling a bidirectional power valve that connects the grid to the power branch.

9. A controller for protecting a power harvesting system, the power harvesting system comprising a power grid electrically connected to an electrical branch, the electrical branch including a plurality of switches for connecting or disconnecting the electrical branch at corresponding locations on the electrical branch, wherein, The distributed energy resource is electrically connected to a node on the electrical branch, and the controller is configured to: The occurrence of faults in the electrical branch is detected based on the monitored voltage and / or current of the electrical branch; Based on the detection of a fault, the power flow from the electrical branch to the power grid is restricted; Based on the detection of a fault, the voltage and / or current on the electrical branch are adjusted; The fault location is determined based on the adjusted voltage and / or current on the electrical branch. as well as A portion of the electrical collection system is disconnected based on the identified fault location.

10. The controller according to claim 9, wherein, The processor is further configured to perform the method according to any one of claims 2 to 8.

11. A power harvesting system comprising a power grid electrically connected to an electrical branch, the electrical branch including a plurality of switches for connecting or disconnecting the electrical branch at corresponding locations on the electrical branch, wherein, The distributed energy resource is electrically connected to a node on the electrical branch, and the power harvesting system further includes a controller according to claim 9 or 10.

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