JP7461492B2 - Method and apparatus for switching transmit branches to alleviate overload - Patents.com - Google Patents

Description

The subject matter of the present invention relates to the field of power systems. More particularly, the subject matter of the present invention relates to switching of transmission branches for overload alleviation in power systems.

A power grid is comprised of multiple transmission and distribution lines and power generation sources (eg, generators). There may be scenarios in a power grid where one or more transmission branches or generation sources fail. This causes system overload. Overloads can occur in real time within a power grid network. Overloads cause power generation and distribution problems within the power grid and therefore there is a need to alleviate overloads.

Existing systems to alleviate overload on power grid networks require adjusting the schedule of generation sources. Adjusting the schedule involves resending power from a power generation source, such as a generator. However, such costly retransmission of power from the generating source involves operational costs. Therefore, there is a need in the art to find new approaches to reduce the overload of power grid networks.

Additionally, current systems for mitigating overloads do not take into account scenarios in which overloads may occur at future points in time. For example, a scenario may arise where the power system fails again after a transmission branch switchover has been implemented. Therefore, there is a need for a power system that checks the possibility that overloads will occur in the future and prepares accordingly for such overloads.

In one embodiment, the present invention relates to a method and system for selecting a transmission branch from multiple transmission branches in a power system. At least one overload in the power system is detected. At least one radial branch and a critical branch are excluded from the plurality of transmit branches to obtain the first set of transmit branches. At least one pair of analog and digital parameters for each of the plurality of transmit branches are calculated and compared to one or more thresholds and the plurality of transmission lines are sorted to obtain a second set of transmit branches. An outage is simulated in the power system, and stability of the power system is checked based on one or more dynamic constraints to identify and eliminate the weakest branch from the second set of transmission branches. The ranks of the second set of transmission branches are reconfigured and a transmission branch to switch to is selected.

The above summary is illustrative only and is not intended to be limiting in any way. In addition to the exemplary aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent with reference to the drawings and the detailed description below.

The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate example embodiments and, together with the description, serve to explain the principles of the disclosure. In the drawings, the left-most digit of a reference number identifies the drawing in which the reference number first appears. The same numbers are used throughout the drawings to refer to similar features and components. Some embodiments of systems and/or methods according to embodiments of the present subject matter are described below, by way of example only, with reference to the accompanying drawings.
1 is a diagram illustrating an example environment according to some embodiments of the present disclosure. FIG. 1 is a diagram illustrating a power grid according to some embodiments of the present disclosure. FIG. 1 is a flowchart illustrating a method according to some embodiments of the present disclosure. 1 is a flowchart illustrating a method according to some embodiments of the present disclosure. FIG. 3 is a diagram illustrating calculation of a Thevenin equivalent circuit according to some embodiments of the present disclosure. FIG. 3 is a diagram illustrating a graph plot according to some embodiments of the present disclosure. 1 is a block diagram illustrating a computing device according to some embodiments of the present disclosure. FIG.

It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual illustrations of example systems embodying the principles of the present subject matter. Similarly, it is recognized that any flowcharts, flow diagrams, state diagrams, pseudo code, etc. are substantially representative of various processes that may be represented on a computer-readable medium and executed by a computer or processor. will be done.

In this document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will be described in detail below. However, there is no intention to limit this disclosure to the form disclosed, but on the contrary, this disclosure is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure. should be understood.

The terms "comprises", "comprising", or any other variations thereof, are intended to cover non-exclusive inclusions, such that a setup, device, or method comprising a series of components or steps does not include only those components or steps, but may also include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements of a system or apparatus preceding "comprises" does not, without further constraints, exclude other or additional elements from being present in the system or method.

The terms "comprise", "comprising", or any other variation thereof, are intended to cover non-exclusive inclusions, such that a set-up, device, or method that includes a series of components or steps does not include only those components or steps, but may also include other components or steps that are not expressly listed or that are inherent to such set-up or device or method. In other words, one or more elements of a system or apparatus preceding "comprises" does not, without further constraints, exclude other or additional elements from being present in the system or method.

In the following detailed description of embodiments of the disclosure, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration certain embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is understood that other embodiments may be utilized and that changes may be made without departing from the scope of the disclosure. It should be understood that Therefore, the following description shall not be considered in a limiting sense.

The various terms used in this invention are as follows:

Power system: A power system may be defined as a network that includes at least one transmission line and a power generation source.
Transmission Branch: A transmission branch may be defined as an electrical wire that connects two nodes.
Node: A node is an interconnection point or junction between one or more power system components. A node can be defined as an endpoint of a sending branch. A node may be connected to one or more power generation sources and/or loads. The power generation source can include, for example, a generator. Examples of nodes may include loads, compensation devices, or general power system equipment.
Overload: Overload can be defined as a situation where the capacity of the equipment present in the power system is compromised.
Outage: An outage in a power system may be defined as a scenario in which one or more network elements (eg, a transmission line or one or more power generation sources) fail. Therefore, overload is a result of outage.
Weakest Node: A weakest node is a node that has a tendency to violate at least one of transient stability constraints, isotopic stability, voltage stability, and frequency stability.
Angular stability: Node with few short defective MVA.
Voltage stability: The generator with the least reactive power margin and the load with the greatest change in nodal reactive power losses within the zone.
Frequency Stability: Nodes with low inertia or high rate of change in frequency in response to small/large disturbances.
Static Limits: During steady state operation, each node/equipment becomes subject to operating constraints, expressed as minimum and maximum limits per planning criteria or by the system operator at some time. These are the limits of a network that can survive a breach lasting from seconds to minutes. Calculating such limits takes a shorter time frame, for example a few milliseconds. For example, a 400 kV node with a voltage variation of ±5% is possible.
Dynamic constraints: These are constraints that should be checked in transient conditions. These are network limitations that need to be checked and defined within a time frame of a few milliseconds. Calculation of such limits takes a longer time frame, eg seconds/minutes. For example, if the fault clearance is less than 120 milliseconds, the angular stability at the node will be stable, otherwise the system will be unstable.

The present invention will be described below with reference to the drawings.

Referring to FIG. 1, a power system 100 is disclosed according to one embodiment. FIG. 1 discloses the system 100 including a power grid 103, a communication network 102, and a computing device 105. The power grid 103 may be in communication with the computing device 105 via the communication network 102.

Power grid 103 may include multiple transmission lines and one or more power generation sources. A transmission line connected between two nodes is called a transmission branch. A node may be connected to one or more power generation sources and/or loads. Power grid 103 is illustrated in FIG. As shown in FIG. 2, the transmit branches are connected between nodes 204, 206, 210, 212, 214, 220, 222, 226, 230.

Some transmission branches among the plurality of transmission branches in power system 100 may be classified as critical branches and radial branches. The critical branch is necessary for the operation of the power system 100, and without it, the power system 100 may not function properly. In one embodiment, critical branches are predefined by the system operator. A radial transmission branch may be defined as a transmission branch that may be directly connected to a node. For example, as shown in FIG. 2, the transmission branches connected between nodes 226 and 230, 204 and 206, 212 and 214 are radial lines because they are directly connected to the generator (G).

Referring to FIG. 2, a scenario may arise in which the transmitting branch connected between 210 and 212 fails, for example due to a power failure. Therefore, overloading may occur between the transmit branches connected between 210 and 226. To reduce overload, switching of transmit branches is required. This disclosure proposes a novel approach for switching power from one transmitting branch to another. Switching requires selecting the transmit branch to switch to with minimal computation.

Referring to FIG. 1, computing device 105 is any general purpose computing device comprising a processor 110 and a memory 112 coupled to processor 110 and configured to store instructions executed by processor 110. There may be. Computing device 105 is described in more detail below.

Referring to FIG. 3, a method for selecting one transmission branch from multiple transmission branches in a power system is described.

At step 302, the method includes detecting at least one overload in the power system. The processor 110 may detect one or more overloads occurring in the power system 100. The one or more overloads may be caused by a failure of one or more transmission branches in the power grid 103. In one embodiment, the one or more overloads may be caused by a change in load in the power system. In yet another embodiment, the one or more overloads may be caused by intermittent renewable energy generation. For example, as described above with respect to FIG. 2, an outage may occur in a transmission branch connected between 210 and 212, which may cause an overload between 210 and 226. In one embodiment, the computing device 105 may include an overload detection module (not shown). The overload detection module may detect one or more overloads occurring in the power system 100.

In step 304, the method includes eliminating at least one radial branch and at least one critical branch from the plurality of transmitting branches to obtain a first set of transmitting branches. As described above, the critical branch is predefined by the system operator. Furthermore, the radial line may be directly connected to one or more generating sources and/or one or more loads in the power system. The processor 110 is configured to eliminate the number of radial branches and critical branches from the total number of transmitting branches present in the power grid. The set of remaining branches obtained after eliminating the critical branches and radial branches is referred to as a first set of transmitting branches. The at least one critical branch and the at least one radial branch may not be considered for switching when switching the transmitting branches in case of a power failure. Thus, for example, in a power grid, there may be 100 transmitting branches, of which 10 may be critical branches and another 10 may be radial branches. Therefore, the first set of transmitting branches may include 80 transmitting branches, i.e., excluding 20 branches (10 radial branches and 10 critical branches) from a total of 100 transmitting branches. The remaining 80 transmitting branches may be further processed to select a transmitting branch to switch sources when an overload occurs in the power system 100.

At step 306, the method includes calculating at least one pair of analog and digital parameters for each of the second set of transmit branches. The processor is configured to obtain analog and digital parameters for each of the first set of transmission branches obtained in the above step. For example, analog and digital parameters may be obtained for all 80 transmit branches (as in the example above).

To obtain the analog and digital parameters of the transmitting branches, a Thevenin equivalent circuit is obtained for each transmitting branch. FIG. 4 illustrates a Thevenin equivalent circuit obtained for any one transmitting branch connected between two nodes. The calculation of the Thevenin equivalent is known in the art, and the description of the calculation of the Thevenin equivalent is omitted in this specification. Using the Thevenin equivalent circuit, one or more analog and digital parameters are obtained. The one or more analog and digital parameters include one or more of the following: voltage, impedance, angle, voltage deviation, impedance deviation, angle deviation, switchgear state (ON/OFF). The switchgear state may include a current breaker state (ON/OFF), an isolator state (ON/OFF).

From the Thévenin equivalent circuit in Figure 4,

式中、
Ｖ_ｓは、送信端（送信ブランチの一方の側）におけるベクトル、電圧、および位相、
Ｖ_ｒは、受信端（送信ブランチの他方の側）におけるベクトル、電圧、および位相である。

During the ceremony,
V _s is the vector, voltage and phase at the sending end (one side of the sending branch),
V _r are the vector, voltage, and phase at the receiving end (on the other side of the transmitting branch).

Ｚは、Ｚｂｕｓ行列からの線路の複素インピーダンス／ブランチの移動、
Ｉは、電流ベクトルである。

Z is the complex impedance of the line/branch transfer from the Zbus matrix;
I is the current vector.

The complex AC power transmitted to the receiving end of the transmitting branch can be calculated as follows.

The branch model can be more realistic due to the resistive component of the impedance. Therefore, the power transfer between both ends of the line is

Ｐ＝線路の両端間における実際の電力
Ｑ＝線路の両端間における無効電力
δ＝電力角度
θ＝インピーダンス角度

P = Actual power across the line Q = Reactive power across the line δ = Power angle θ = Impedance angle

Using the power transfer equations above, the angle and voltage thresholds may be calculated based on the "available transfer capacity" (ATC) and known variables of transfer impedance and voltage.
The ATC may be defined as follows:
ATC = branch rating - branch power flow = P _rating - P _flow
where ATC is the maximum allowable power in the branch.

Similarly, the simplest form of the power flow equations can be expressed if the resistance and capacitance of the branches are neglected and the line is represented as lossless.

The power flow equation described above can be used for the calculated ATC value.

The method then proceeds to step 308. At step 308, the method includes comparing the calculated at least one pair of analog and digital parameters to one or more threshold values.

At step 310, the method includes sorting the first set of transmission branches based on the comparison to obtain a second set of transmission branches.

Steps 308 and 310 may be performed by computing device 105 by plotting a graph. Graphs may be plotted between one or more analog and/or digital parameters. For example, graphs may be plotted between analog and analog parameters, between digital and digital parameters, or between analog and digital parameters.

Figure 5 discloses a plot of a graph between the parameter angle and voltage. The angle and voltage parameters are obtained from the Thévenin equivalent circuit. The plotted angle and voltage parameters are further compared to a threshold value. The threshold value is defined by the system operator of the power system 100 or by calculating based on static limits and available transmission capacity (ATC) using one or more power flow equations as described above. As shown in Figure 5, the bold lines define the stable operating range boundary, i.e. the threshold value. The angle and voltage parameter values that are outside the operating range boundary are excluded. This means that the transmitting branches having analog and digital parameter values that are outside the operating range boundary are excluded from further screening. The remaining transmitting branches thus obtained are referred to as a second set of transmitting branches. Figure 5 also shows a dotted line. This dotted line may be referred to as a safety margin and may be defined by the system operator.

As an example, a graph is plotted for all 80 transmission branches present in the power grid (ie the transmission branches obtained after excluding the radial and critical transmission branches). The analog and digital parameters of each of the 80 transmit branches are compared to one or more thresholds, and transmit branches with analog and digital parameters outside the thresholds are eliminated. Thus, in this example, there may be 50 branches that may be eliminated according to the method described. Therefore, the second set of transmission lines may be equal to 30 (total of 80 lines minus 50 branches whose analog and digital parameters are outside the threshold).

At step 314, the method includes ranking each of the second set of transmitting branches based on one or more objective functions. The processor is configured to rank each of the second set of transmitting branches based on one or more objective functions. Thus, considering the above example, the 30 transmitting branches obtained as the second set of transmission lines are ranked by the processor. The one or more objective functions include, for example, minimum loss, minimum generation cost, minimum angle deviation, minimum voltage deviation. In one embodiment, the one or more objective functions are solved using one or more optimization methods. In one embodiment, the objective function is defined by a system operator of the power system. For example, the system operator may define "minimum loss" as one of the objective functions that may be used to rank the transmitting branches. The system operator may define that the power system should have minimum loss by selecting "minimum loss" as one of the objective functions. Once the objective parameters are selected, the processor ranks the transmitting branches by reducing or eliminating overloads in the branches. The ranking is done such that losses in the power system are minimal. For example, using the transmission branch ranked "1" is predicted to have the least loss, followed by the other ranked transmission branches.

At step 316, the method includes simulating an outage in the power system to reconfigure the ranking of each of the second set of transmission branches. Outages may be simulated to check the possibility of future failures in the power system. A future failure may occur, for example, when a transmission branch is selected to switch from the second set of transmission branches, and an outage will occur in the future as a result of an overload in the power system 100. Therefore, to future-proof the power system, the power system is checked for one more outage in the system 100. Yet another type of outage is a forced outage performed by simulation techniques known in the art. This ensures that, if a power outage occurs in the power system in the future, the power system 100 is prepared for the outage.

At step 318, the method includes checking power system stability based on one or more dynamic constraints. When an outage is simulated in the power system, processor 110 is configured to check the stability of the power system in the simulated environment. A system operator at computing device 105 may simulate power system 100 in a simulated environment, and the stability of the power system after an outage is checked for a predetermined period of time. Checking the stability of the system includes checking the stability of one or more transmission branches and nodes in the power grid 103. Stability may include how stable the power system is after an outage occurs. This includes checking whether another outage/overload occurs in the power system after a predetermined period of time. In one embodiment, computing device 105 may include a stability analysis module (not shown) that checks the stability of power system 100.

The stability of the power system includes at least one of transient stability, voltage stability, frequency stability, and angular stability of the power system. In one embodiment, stability may include checking if there is a violation in any of the dynamic constraints of the power system. Dynamic constraints may include angle, voltage, and frequency. However, dynamic constraints need not be limited to those defined herein. Therefore, in the simulated environment, the processor 110 is configured to check if there is any change in any of the dynamic constraints of each transmitting branch, ie angle, voltage, or frequency. If there are no violations of the dynamic constraints, processor 110 is configured to determine that the power system is stable. Alternatively, if there is a violation of the dynamic constraint, the processor 110 is configured to identify the transmitting branch (from the first set of transmitting branches) violating the dynamic constraint as the weakest branch/node of the power system. configured.

At step 320, the method includes identifying one or more weakest transmitting branches from the second set of transmitting branches in the power system based on the power system stability results. The weakest transmitting branch may include a transmitting branch of the second set of transmitting branches that has the greatest change in dynamic constraints. For example, the transmitting branch ranked first may have the greatest change in angle or voltage value when simulated for a predetermined amount of time. Thus, the transmitting branch ranked first may be identified as the weakest node.

At step 322, the method includes eliminating one or more identified weakest transmission branches from the second set of transmission branches. The processor is configured to exclude the identified one or more weakest transmission branches from the second set of transmission branches. Therefore, the second set of transmission branches may be updated by eliminating the weakest transmission branch.

At step 324, the method includes reconfiguring the ranks of the second set of transmission branches after eliminating the one or more identified weakest transmission branches. When the second set of transmit branches is updated, the processor is configured to reconfigure the ranks of the second set of transmit branches. For example, as discussed above, the transmitting branch with rank "1" may be identified as the weakest transmitting branch. Therefore, the rank '1' transmit branch may be eliminated (as it is the weakest branch) and the rank '2' transmit branch may then become the rank '1' transmit branch. Accordingly, the processor updates the second set of transmit branches to obtain the reconstructed ranks of the remaining transmit branches among the second set of transmit branches.

In step 326, the method includes selecting a transmit branch from the second set of transmit branches based on the reconfigured rank. The processor may select a transmit branch based on the reconfigured rank of the transmit branches present in the second set of transmit branches. For example, a transmit branch with rank "1" may be selected for switching. The selected transmit branch may be used for branch switching to alleviate an overload occurring in the power system 100.

In one embodiment, steps 316-326 may be eliminated. Accordingly, after the second set of transmission branches are ranked, a transmission branch is selected based on the ranking to reduce or eliminate overload occurring in power system 100.

The order in which method 300 is described is not to be construed as limiting, and any number of the described method blocks may be combined in any order to implement the method. Additionally, individual blocks may be deleted from the method without departing from the scope of the subject matter described herein. Furthermore, the method may be implemented in any suitable hardware, software, firmware, or a combination thereof.

Computing Device FIG. 6 depicts a block diagram of an exemplary computing device 105 implementing embodiments consistent with this disclosure. Computing device 105 may include a central processing unit (“CPU” or “processor”) 110. Processor 110 may include special purpose processing units such as an integrated system (bus) controller, memory management controller, floating point arithmetic unit, graphics processing unit, digital signal processing unit, and the like. Processor 110 may be arranged in communication with one or more input/output (I/O) devices 609 and 610 via I/O interface 601 . Computing device 105 may also include a stability analysis module and an overload detection module.

The I/O interface 601 may employ communication protocols/methods such as, but not limited to, audio, analog, digital, mono, RCA, stereo, IEEE-1394, serial bus, Universal Serial Bus (USB), infrared, PS/2, BNC, coaxial, component, composite, Digital Visual Interface (DVI), High Definition Multimedia Interface (HDMI), RF antenna, S-Video, VGA, IEEE 802.n/b/g/n/x, Bluetooth, cellular (e.g., Code Division Multiple Access (CDMA), High Speed Packet Access (HSPA+), Global System for Mobile Communications (GSM), Long Term Evolution (LTE), WiMax, etc.).

Using the I/O interface 601, the computing device 105 may communicate with one or more I/O devices 609 and 610. For example, the input device 609 may be an antenna, keyboard, mouse, joystick, (infrared) remote control, camera, card reader, fax machine, dongle, biometric reader, microphone, touch screen, touch pad, trackball, stylus, scanner, storage device, transceiver, video device/source, etc. The output device 610 may be a printer, fax machine, video display (e.g., cathode ray tube (CRT), liquid crystal display (LCD), light emitting diode (LED), plasma, plasma display panel (PDP), organic light emitting diode display (OLED), etc.), audio speaker, etc.

In some embodiments, the processor 110 may be disposed in communication with the communications network 102 via a network interface 603. The network interface 603 may communicate with the communications network 611. The network interface 603 may employ a connection protocol, including, but not limited to, a direct connection, Ethernet (e.g., twisted pair 10/100/1000 Base T), Transmission Control Protocol/Internet Protocol (TCP/IP), Token Ring, IEEE 802.11a/b/g/n/x, and the like. The communications network 611 may include, but is not limited to, a direct interconnect, a local area network (LAN), a wide area network (WAN), a wireless network (e.g., using a wireless application protocol), the Internet, and the like. Using the network interface 603 and the communications network 611, the computing device 105 may communicate with the power grid 612 to screen for contingencies in the power grid 612. The network interface 603 may employ a connection protocol including, but not limited to, direct connection, Ethernet (e.g., twisted pair 10/100/1000 Base T), Transmission Control Protocol/Internet Protocol (TCP/IP), Token Ring, IEEE 802.11a/b/g/n/x, etc.

Communication network 611 may include a direct interconnection, an e-commerce network, a peer-to-peer (P2P) network, a local area network (LAN), a wide area network (WAN), a wireless network (e.g., using a wireless application protocol), the Internet, Wi-Fi. including but not limited to. The first network and the second network communicate with each other using various protocols, such as Hypertext Transfer Protocol (HTTP), Transmission Control Protocol/Internet Protocol (TCP/IP), Wireless Application Protocol (WAP), etc. It can be either a dedicated network or a shared network, representing an association of different types of networks. Further, the first network and the second network may include various network devices, including routers, bridges, servers, computing devices, storage devices, and the like.

In some embodiments, the processor 110 may be disposed in communication with the memory 112 (e.g., RAM, ROM, etc., not shown in FIG. 6) via a storage interface 604. The storage interface 604 may connect to the memory 112, including, but not limited to, memory drives, removable disk drives, etc., employing connection protocols such as Serial Advanced Technology Attachment (SATA), Integrated Drive Electronics (IDE), IEEE-1394, Universal Serial Bus (USB), Fibre Channel, Small Computer System Interface (SCSI), etc. The memory drives may further include drum, magnetic disk drives, magnetic optical drives, optical drives, redundant arrays, redundant arrays of independent disks (RAID), solid state memory devices, solid state drives, etc.

Memory 112 may store a collection of programs or database components, including, but not limited to, a user interface 606, an operating system 607, and the like. In some embodiments, computing device 105 may store user/application data 606, such as data, variables, records, etc., as described in this disclosure. Such a database may be implemented as a fault-tolerant, relational, scalable, and secure database, such as Oracle or Sybase.

Operating system 607 may facilitate resource management and operation of computing device 105. Examples of operating systems include, but are not limited to, Apple Macintosh OS X, Unix, Unix-like system distributions (e.g., Berkeley Software Distribution (BSD), FreeBSD, NetBSD, OpenBSD, etc.), Linux distributions (e.g., Red Hat, Ubuntu, Kubuntu, etc.), IBM OS/2, Microsoft Windows (XP, Vista/7/8, etc.), Apple iOS, Google Android, BlackBerry OS, etc.

Additionally, as used herein, the term module refers to an application specific integrated circuit (ASIC), an electronic circuit, a field programmable gate array (FPGA), a programmable system on a chip (PSoC), a combinational logic circuit, and/or Refers to other suitable components that provide the described functionality. When a module is configured with the functionality defined in this disclosure, it becomes novel hardware.

Additionally, one or more computer-readable storage media may be used in implementing embodiments consistent with this disclosure. Computer-readable storage medium refers to any type of physical memory that may store information or data that is readable by a processor. Accordingly, a computer-readable storage medium may store instructions for execution by one or more processors, including instructions for causing a processor to perform steps or stages consistent with embodiments described herein. good. It is to be understood that the term "computer-readable medium" includes tangible items and excludes carrier waves and transient signals, ie, non-transitory. Examples include random access memory (RAM), read-only memory (ROM), volatile memory, non-volatile memory, hard drives, CD ROMs, DVDs, flash drives, disks, and any other known physical storage media. can be mentioned.

Furthermore, the code implementing the described operations may be embodied in a "transmission signal," which may propagate through space or through a transmission medium such as optical fiber, copper wire, etc. The transmission signal encoded with the code or logic may further include radio signals, satellite transmissions, radio waves, infrared signals, Bluetooth, etc. The transmission signal encoded with the code or logic may be transmitted by a transmitting station and received by a receiving station, and the code or logic encoded in the transmission signal may be decoded at the receiving station and the transmitting station or device and stored in hardware or a non-transitory computer readable medium.

Where a single device or article is described herein, it will be readily apparent that more than one device/article (whether in conjunction with or not) may be used in place of the single device/article. Similarly, where more than one device or article is described herein (whether in conjunction with or not), it will be readily apparent that a single device/article may be used in place of the more than one device or article, or a different number of devices/articles may be used in place of the number of devices or articles shown. The functionality and/or features of a device may alternatively be embodied by one or more other devices not expressly described as having such functionality/features. Thus, other embodiments of the present invention need not include the device itself.

Finally, the language used herein has been selected primarily for readability and instructional purposes, and may not have been selected to delineate or limit the subject matter of the invention. Accordingly, the scope of the invention is intended to be limited not by this detailed description, but rather by any claims of an application based thereon. Accordingly, the disclosure of embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

Although various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are intended to be illustrative and not limiting, with the true scope and spirit being indicated by the following claims.

100 Power system 102 Communication network 103 Power grid 105 Computing device 202-232 Node 110 Processor 112 Memory 300 Method 302-326 Method steps 601 I/O interface 603 Network interface 604 Storage interface 606 User interface 607 Operating system 608 Web server 609 Input device 610 Output device

Claims (22)

A method (300) of selecting a transmitting branch from a plurality of transmitting branches in a power system (100), the method comprising:
detecting (302) at least one overload in the power system;
eliminating (304) at least one radial branch and at least one critical branch from the plurality of transmit branches to obtain a first set of transmit branches;
calculating (306) at least one pair of analog and digital parameters for each of the first set of transmit branches;
comparing the calculated at least one pair of analog and digital parameters to one or more threshold values (308);
culling (310) the plurality of transmit branches based on the comparison to obtain a second set of transmit branches;
ranking (312) each of the second set of transmission branches based on one or more objective functions;
simulating an outage in the power system to reconfigure the ranking of each of the second set of transmission branches (314);
checking (316) the stability of the power system based on one or more dynamic constraints;
identifying (320) one or more weakest transmission branches from the second set of transmission branches in the power system based on the stability results of the power system;
eliminating (322) the identified one or more weakest transmission branches from the second set of transmission branches;
reconfiguring (324) the ranks of the second set of transmission branches after eliminating the identified one or more weakest transmission branches;
selecting (326) one transmission branch from the second set of transmission branches based on the reconstructed rank. 2. After the step of ranking each of the second set of transmission branches, the method further comprises selecting one transmission branch based on the ranking of the second set of transmission branches. the method of. 2. The method of claim 1, wherein the step of calculating one or more analog and digital parameters for each of the plurality of transmit branches comprises calculating a Thevenin equivalent for each of the plurality of transmit branches. Method. The method of claim 1, wherein the analog and digital parameters include one or more of the following: voltage, impedance, angle, voltage deviation, impedance deviation, angle deviation, switchgear state. The method of claim 1, wherein the threshold is defined by a system operator of the power grid or by calculation based on static limits and available transmission capacity (ATC) using one or more power flow equations. the one or more objective functions are solved using one or more optimization methods;
The one or more objective functions are
minimum loss,
minimum power generation cost,
minimum angular deviation,
2. The method of claim 1, comprising a minimum voltage deviation. 2. The method of claim 1, wherein the step of checking stability of the power system includes checking behavior of the power system over a period of time. The method of claim 1, wherein the step of checking the stability of the power system includes checking the stability of the plurality of transmitting branches and at least one node in the power system, each transmitting branch being connected between two nodes. 2. The method of claim 1, wherein the stability of the power system includes at least one of transient stability, voltage stability, frequency stability, and angular stability of the power system. The method of claim 1, wherein the one or more dynamic constraints of the power system include angle, voltage, and frequency. The method of claim 1, wherein the at least one critical branch is defined by a system operator. A computing device (105) for selecting a transmission branch from a plurality of transmission branches in a power system (100), comprising:
A processor (110);
a memory (112) communicatively coupled to the processor (110);
The memory (112) stores processor-executable instructions that, when executed, cause the processor to:
detecting at least one overload in the power system;
eliminating at least one radial branch and at least one critical branch from the plurality of transmitting branches to obtain a first set of transmitting branches;
calculating at least one pair of analog and digital parameters for each of the first set of transmit branches;
comparing the calculated at least one pair of analog and digital parameters to one or more thresholds;
sorting the plurality of transmitting branches based on the comparing to obtain a second set of transmitting branches;
ranking each of the second set of transmitting branches based on one or more objective functions;
simulating an outage in the power system to reconfigure the ranking of each of the second set of transmitting branches;
checking the stability of the power system based on one or more dynamic constraints;
identifying one or more weakest transmitting branches from the second set of transmitting branches in the power system based on the stability result of the power system;
removing the identified weakest transmitting branch or branches from the second set of transmitting branches;
reconfiguring the ranks of the second set of transmitting branches after eliminating the identified one or more weakest transmitting branches;
A computing device causes a transmitting branch to be selected from the second set of transmitting branches based on the reconfigured rank. The processor,
13. The computing device of claim 12, configured to: rank each of the second set of transmitting branches based on one or more objective functions, and then select one transmitting branch based on the ranking of the second set of transmitting branches. The computing device of claim 12, wherein the processor is configured such that calculating one or more analog and digital parameters for each of the plurality of transmit branches includes calculating a Thevenin equivalent for each of the plurality of transmit branches. 13. The computing device of claim 12, wherein the analog and digital parameters include one or more of voltage, impedance, angle, voltage deviation, impedance deviation, angular deviation, switchgear condition. The computing device of claim 12, wherein the threshold is defined by a system operator of the power grid or by calculation based on static limits and available transmission capacity (ATC) using one or more power flow equations. the one or more objective functions are solved using one or more optimization methods;
The one or more objective functions:
Minimum loss,
Minimum generation cost,
Minimum angle deviation,
The computing device of claim 12 comprising a minimum voltage deviation. 13. The computing device of claim 12, wherein the processor is configured to check behavior of the power system over a period of time. 13. The computer of claim 12, wherein the processor is configured to check the stability of the plurality of transmitting branches and at least one node in the power system, each transmitting branch being connected between two nodes. ing device. The computing device of claim 12, wherein the stability of the power system includes at least one of transient stability, voltage stability, frequency stability, and angle stability of the power system. 13. The computing device of claim 12, wherein the one or more dynamic constraints of the power system include angle, voltage, and frequency. The computing device of claim 12, wherein the at least one critical branch is defined by a system operator.

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