Phasor identification via synchronous messaging

Abstract

A node in a power distribution system is described. The node includes an electrical connection to a single-phase power signal from an AC main power source, a wireless communication interface configured to receive a first phase synchronization message, and a controller. The controller is configured to determine whether the first phase synchronization message is acceptable and, in response to determining that the first phase synchronization message is acceptable, detect a zero-crossing event on the single-phase power signal after receiving the first phase synchronization message. The controller is further configured to calculate a time difference between receipt of the first phase synchronization signal and the detected zero-crossing event, determine a local phase angle based on the time difference, and establish an identity of the single-phase power signal based on the local phase angle.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to U.S. Provisional Patent Application No. 63 / 053,189, filed July 17, 2020, the contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments disclosed herein relate to phase determination within a power distribution network. Background Technology

[0004] In a power distribution network with multiphase power supplied to multiple distribution locations, it may be difficult to accurately determine which phase a device is connected to. Summary of the Invention

[0005] According to one embodiment, a node in a power distribution system is described. The node includes an electrical connection to a single-phase power signal from a mains AC power supply, a wireless communication interface configured to receive a first phase synchronization message, and a controller. The controller is configured to determine whether the first phase synchronization message is acceptable, and in response to determining that the first phase synchronization message is acceptable, detect a zero-crossing event on the single-phase power signal after receiving the first phase synchronization message. The controller is further configured to calculate the time difference between the reception of the first phase synchronization signal and the detected zero-crossing event, determine a local phase angle based on the time difference, and establish an identifier for the single-phase power signal based on the local phase angle.

[0006] In one aspect, the node is embedded in the electricity utility meter.

[0007] In another aspect, the first phase synchronization message includes the node's tier value, the node's determined phase angle, the frequency of the single-phase power signal, and the node's communication address.

[0008] In another aspect, the first phase synchronization message is determined to be acceptable based on the fact that the layer value within the first phase synchronization message is higher than the layer value of the node.

[0009] In the other case, the tier value represents the distance from the AC mains power source, where a higher tier value indicates a shorter distance to the AC mains power source compared to a lower tier value.

[0010] In another aspect, the controller is further configured to transmit a second phase synchronization message in response to the establishment of an identifier for a single-phase power signal, wherein the second phase synchronization message includes at least the node's layer value, the determined local phase angle, and the identifier for the single-phase power signal.

[0011] In another aspect, the controller is further configured to determine whether the phase identifier of the single-phase power signal is known and to transmit a request message, wherein the request message is a request for one or more requested phase synchronization messages.

[0012] In another embodiment, a method for determining the phase identifier of a node device coupled to a phase of a multiphase AC distribution system is described. The method includes receiving a first phase synchronization message, determining whether the first phase synchronization message is acceptable, and, in response to determining that the first phase synchronization message is acceptable, detecting a zero-crossing event on the phase after receiving the first phase synchronization message. The method further includes calculating a time difference between the reception of the first phase synchronization message and the detected zero-crossing event, determining a local phase angle based on the time difference, and establishing a phase identifier based on the local phase angle.

[0013] In one aspect, the first phase synchronization message includes a layer value, the determined phase angle of the node, the frequency of the single-phase power signal, and the communication address of the node.

[0014] In one aspect, the method further includes determining the layer value of a node by incrementing the layer value of the first synchronization message by one.

[0015] In another scenario, the first phase synchronization message is determined to be acceptable if the layer value of the first phase synchronization message is higher than the determined layer value of the node.

[0016] In the other case, the tier value represents the distance from the AC mains power source, where a higher tier value indicates a shorter distance to the AC mains power source compared to a lower tier value.

[0017] In another aspect, the method further includes transmitting a second phase synchronization message in response to establishing an identifier for a single-phase power signal, wherein the second phase synchronization message includes at least the layer value of the node, the determined local phase angle, and the identifier of the single-phase power signal.

[0018] In another aspect, the method further includes determining whether the phase identifier of the single-phase power signal is known, and transmitting a request message, wherein the request message is a request for one or more requested phase synchronization messages.

[0019] In another embodiment, a monitoring system for a power distribution network is described. The system includes a first node coupled to a first phase of the power distribution network. The first node is configured to determine whether an identifier of the first phase is known, and to generate a first phase synchronization message in response to determining that the identifier of the first phase is known. The first node is further configured to monitor the first phase for zero-crossing events, and to transmit the first phase synchronization message in response to detecting a zero-crossing event.

[0020] In one aspect, the system further includes a second node coupled to a second phase of the distribution network. The second node is configured to receive a first phase synchronization message, determine whether the first phase synchronization message is acceptable, and detect a zero-crossing event on the second phase after receiving the first phase synchronization message. The second node is further configured to calculate the time difference between the reception of the first phase synchronization message and the detected zero-crossing event, determine a local phase angle based on the time difference, and establish an identifier for the second phase based on the local phase angle.

[0021] In another aspect, the second node is further configured to transmit a second phase synchronization message in response to an identifier for establishing a second phase, wherein the second phase synchronization message includes at least the layer value of the second node, the determined local phase angle, and the identifier of the second phase.

[0022] In another aspect, the second node is also configured to determine its layer value by incrementing the layer value of the first synchronization message by one.

[0023] In another aspect, the first phase synchronization message includes the layer value of the first node, the determined phase angle of the first node, the frequency of the first phase, and the communication address of the first node.

[0024] In another scenario, the first phase synchronization message is determined to be acceptable based on the fact that the layer value of the first node is higher than that of the second node.

[0025] Other aspects of this technology will become apparent upon consideration of the detailed description and accompanying drawings. Attached Figure Description

[0026] Figure 1 It is a schematic diagram of the hierarchical structure of nodes and node equipment in a power distribution system.

[0027] Figure 2 This is a block diagram showing the functional components of a node in a power distribution system.

[0028] Figure 3 This is a network diagram illustrating an exemplary embodiment of a phase determination system according to some embodiments.

[0029] Figure 4 This is a flowchart illustrating an exemplary embodiment of a method for processing phase synchronization signals.

[0030] Figure 5 This is a flowchart illustrating an exemplary embodiment of a method for generating a phase synchronization signal.

[0031] Figure 6 This is a flowchart illustrating an exemplary embodiment of a method for requesting a phase synchronization signal.

[0032] Figure 7 This is a flowchart illustrating an exemplary embodiment of a method for responding to a request for a phase synchronization signal. Detailed Implementation

[0033] Before explaining any embodiment of this application in detail, it should be understood that this application, in its application, is not limited to the details of the construction and arrangement of the components set forth in the following description or shown in the following figures. This application can be implemented or carried out in other embodiments and in various ways.

[0034] Furthermore, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered restrictive. The use of “comprising,” “including,” or “having,” and variations thereof is intended to include items listed herein and their equivalents, as well as additional items. Unless otherwise specified or limited, the terms “installed,” “connected,” “supported,” and “coupled,” and variations thereof, are used broadly and include both direct and indirect installation, connection, support, and coupling. The word “or” as used in this document may mean either inclusion or. As a non-restrictive example, if the example statement in this document “item Z may include element A or B,” this may be interpreted as disclosing an item Z that includes only element A, an item Z that includes only element B, and an item Z that includes both elements A and B.

[0035] As used in this article, "node" can refer to a data concentrator unit (DCU), an endpoint, a terminal device, a power grid sensor with communication capabilities, a utility meter (such as an electricity meter), or a handheld or heat-adhesive installation tool or device used by a lineman.

[0036] Figure 1An example of a phase determination system 100 according to an embodiment of the present disclosure is shown. The phase determination system 100 includes a power distribution network 104 and one or more nodes 106. In one embodiment, a node 106 may be a metering device, such as an electrical metering device (residential, commercial, industrial, etc.). In other embodiments, a node 106 is coupled to a metering device or other device within the power distribution network. Node 106 may be mechanically, electrically, and / or communicatively connected to aspects of the power distribution network 104. The system 100 may further include one or more data collection units (“DCUs”) 108. In some examples, the DCU 108 is a node device 106 with enhanced communication capabilities, such as longer transmission and / or reception range, additional communication bandwidth, additional communication modes (e.g., digital, analog, cellular, etc.), etc. For example, the DCU 108 may be a node device 106 coupled to a more capable antenna that can provide additional communication capabilities. Furthermore, the DCU 108 may have a more powerful transmitter to allow for a greater transmission range. DCU 108 can also be called a regional node or supervisor node because they are capable of communicating over greater distances.

[0037] like Figure 1 As shown, node 106 can be connected to transformer 109 (e.g., a distribution transformer that steps down a medium-voltage circuit to a low-voltage circuit). Node 106 can also communicate electronically with one or more other nodes 106 to facilitate communication between nodes 106. For example, node 106 can be connected to one or more other nodes 106 using wireless protocols such as cellular (e.g., 3G, 4G, LTE, CDMA, etc.), RF, ZigBee, Bluetooth, Wi-Fi, Wi-Max, LoRa, or other applicable wireless protocols. Node 106 can further communicate with central controller 110. Node 106 can communicate with central controller 110 via wireless communication protocols such as those described above. In some examples, node 106 can communicate with central controller 110 via a wired connection such as a wired internet connection. However, other wired connections, such as power line communication (“PLC”), are also contemplated. Central controller 110 can be a server-based controller, a cloud-based controller, or other centralized computing systems configured to perform the various operations described herein. In some examples, one of the nodes 106 can be configured to act as the central controller 110.

[0038] In one embodiment, the distribution network 104 includes distribution lines, each adapted to transmit power. Each distribution line may be connected to one phase of a multiphase distribution system. For example, distribution line 104-A may be adapted to transmit power having phase A to one or more node devices 106-A, distribution line 104-B may be adapted to transmit power having phase B to one or more node devices 106-B, and distribution line 104-C may be adapted to transmit power having phase C to one or more node devices 106-C. In one embodiment, the distribution lines of the distribution network 104 may transmit power having a combination of phases A, B, and / or C to node devices 106. For example, when the system includes Δ-Y and / or Y-Δ transformers, the output phases of these transformers will not be purely phase A, phase B, or phase C, but may instead be a combination of phases A, phase B, and / or phase C.

[0039] Node 106 can be placed at an end of the distribution network 104. However, in other embodiments, node 106 can be placed at an intermediate location within the distribution network 104, such as in a commercial, residential, or industrial substation. In some embodiments, node 106 can be installed on utility poles at specified intervals to ensure adequate coverage. In some embodiments, node 106 is placed at multiple locations within system 100 to facilitate communication between node 106 and / or other devices as needed. For example, node 106 can be placed every 5–10 miles to ensure that communication between nodes 106 can be maintained. In other embodiments, node 106 can be positioned such that one or more nodes 106 can facilitate communication between themselves and other devices within system 100. The distance between nodes can vary based on factors such as communication protocols and geography.

[0040] In some systems, accurately determining the phase connection of node 106 can be difficult because the location of node 106 increases with distance from the AC mains power supply 120. For example, the installer may not be able to directly trace the distribution line back to a specific phase output from transformer 109 or other distribution equipment. Conversely, the phase connection of node 106 near the AC mains power supply or distribution equipment (such as transformer 109) can usually be easily and quickly verified, at least due to the ability to directly trace the distribution line back to the source.

[0041] In some embodiments, nodes 106 can be organized according to a hierarchy relating to the AC main power supply 120 (such as a substation). Figure 1In the example shown, there is a first layer 111 of node 106, a second layer 112 of node 106, and a third layer 113 of node 106. Layers 111, 112, and 113 represent levels removed from the AC mains power supply 120 used for the distribution network 104. In one embodiment, one or more of nodes 106 may be reference nodes. A reference node may be a node device 106 that is very close to the AC mains power supply 120, such as in a substation, and may be verified to be coupled to a specific phase of the distribution network 104. Furthermore, a reference node may be selected due to its proximity to the AC mains power supply 120 to reduce the likelihood that it (e.g., during load balancing operations) may be coupled to a different phase over time. In some embodiments, the distribution network 104 may include only a single reference node. However, in other embodiments, the distribution network 104 may have more than one reference node, such as one reference node for each phase. In the case of multiple reference nodes, all reference nodes should generally be within communication range of each other to verify each other's transmissions and / or messages. As the connection phase of the reference node is verified, the reference node is configured to generate and transmit phase synchronization messages as described herein. In some cases, there may be no technical device differences between the reference node and other nodes 106. The designation of a “reference node” simply implies that the node 106 so designated has a verified phase connection. In one example, the reference node is designated as such during installation. As will be described in more detail, node 106 includes one or more circuits to determine or collect samples of voltage waveforms used for phase coupling. In some examples, node 106 includes circuitry for detecting zero-crossings of a sinusoidal waveform. Because the reference node can determine the zero-crossings of a sinusoidal waveform and has a verified phase connection, the reference node can be configured to calculate the timing of zero-crossings of other phasor voltages.

[0042] As described above, among other factors, nodes 106 can be segmented into various layers based on their location. Layers 111, 112, and 113 can be established within the power distribution network 104 via the wireless transmission and reception of phase synchronization messages. For example, the reference node 106 closest to the AC mains power supply 120 can broadcast information about its phase angle and layer via phase synchronization messages, allowing nodes 106 further away from the AC mains power supply 120 to determine their own layer and local phase angle based on the information received via the phase synchronization messages. As will be described in more detail below, a node 106 receiving a phase synchronization message can determine its own layer within the system 100 based on receiving the phase synchronization message from a node 106 at a higher layer (e.g., closer to the AC mains power supply 120) and incrementing the layer value contained in the phase synchronization message. Alternatively, if a node 106 receives a broadcast from a node 106 at an equal or lower layer, the node 106 can simply discard the phase synchronization message. The capabilities of node 106 and this wireless communication and phase connection identification process are described in further detail below.

[0043] Turn now Figure 2 The diagram illustrates a block diagram of node 106 according to some embodiments. Node 106 may be a standalone device or part of one or more devices, such as a power meter, switch cabinet, etc. Figure 2 As shown, node 106 includes processing circuitry 202, a communication interface 204, an input / output (I / O) interface 214, and one or more sensors 216. Processing circuitry 202 includes an electronic processor 208 and a memory 210. Processing circuitry 202 can be communicatively connected to one or more of the communication interface 204 and I / O interface 214. Electronic processor 208 can be implemented as a programmable microprocessor, an application-specific integrated circuit (ASIC), one or more field-programmable gate arrays (FPGAs), a processing unit group, or implemented together with other suitable electronic processing units.

[0044] Memory 210 (e.g., a non-transitory, computer-readable medium) includes one or more devices (e.g., RAM, ROM, flash memory, hard disk storage, etc.) for storing data and / or computer code for performing or facilitating the various processes, layers, and modules described herein. Memory 210 may include database components, object code components, script components, or other types of code and information for supporting the various activities and information structures described herein. According to one example, memory 210 is communicatively connected to electronic processor 208 via processing circuitry 202 and may include computer code for performing (e.g., via processing circuitry 202 and / or electronic processor 208) one or more processes described herein.

[0045] Communication interface 204 is configured to facilitate communication between node 106 and one or more external devices or systems, central controller 110, and / or one or more other nodes 106. Communication interface 204 may be or include a wireless communication interface (e.g., an antenna, transmitter, receiver, transceiver, etc.) for data communication between node 106 and one or more external devices (such as another node 106 or central controller 110). In some embodiments, communication interface 204 utilizes a proprietary protocol for communicating with other nodes 106 or central controller 110. For example, the proprietary protocol may be an RF-based protocol configured to provide efficient and effective communication between node 106 and other devices. In other embodiments, other wireless communication protocols may also be used, such as cellular (3G, 4G, 5G, LTE, CDMA, etc.), Wi-Fi, LoRa, LoRaWAN, Z-wave, Thread, and / or any other suitable wireless communication protocol.

[0046] I / O interface 214 can be configured to directly interface with one or more devices, such as power supplies, power monitors, etc. In one embodiment, I / O interface 214 may utilize general-purpose I / O (GPIO) ports, analog inputs, digital inputs, etc. Sensor 216 may include one or more sensors configured to monitor one or more aspects of the power distribution line coupled to node 106. For example, sensor 216 may include voltage sensors, current sensors, temperature sensors, and other sensors required for a given application. In some embodiments, sensor 216 includes one or more connections between node 106 and the connected power distribution line. In other examples, sensor 216 may be connected to the power distribution line using I / O interface 214.

[0047] As described above, memory 210 can be configured to store various processes, layers, and modules, which can be executed by electronic processor 208 and / or processing circuitry 202. In one embodiment, memory 210 includes phase synchronization message generation circuitry 212. Phase synchronization message generation circuitry 212 is configured to cooperate with electronic processor 208 to generate phase synchronization messages for establishing a common phase reference between nodes 106 in different layers. In one embodiment, communication interface 204 is used to transmit phase synchronization messages, such as by using the wireless communication protocol described above.

[0048] The memory 210 may also include phase synchronization message processing circuitry 218. Phase synchronization message processing circuitry 218 may be configured to receive phase synchronization messages from reference node 106, predict or detect zero-crossings of the power signal coupled to the power line of node 106, and / or determine the time difference between the reception of the phase synchronization message and the detected zero-crossing. This process will be described in more detail below. In some examples, phase synchronization message processing circuitry 218 may communicate with sensor 216 to detect zero-crossings of the power signal. The memory may further include message request circuitry 220, which is configured to transmit request messages to request phase synchronization messages, as described in more detail below.

[0049] Turn now Figure 3 According to some embodiments, a network diagram illustrates a network 300 of hierarchical nodes. Network 300 includes multiple first-layer nodes 302, 304, 306, 308, multiple second-layer nodes 310, 312, 314, and multiple third-layer nodes 316, 318, 320, 322. First-layer nodes 302, 304, 306, 308 may be designated as reference nodes, as described above. Each node may have an associated wireless communication coverage area. A wireless communication coverage area represents the area on which a node can receive and / or transmit various wireless communication messages (such as phase synchronization messages). Figure 3 As shown, wireless communication regions 311, 313, and 315 are associated with nodes 310, 312, and 314, respectively. In some embodiments, nodes may also have combined wireless coverage areas. In one embodiment, the combined wireless coverage area relates to the range of wireless communication at a specific layer of the node. For example, each of the first-layer nodes 302, 304, 306, and 308 may have its own coverage area as well as overlapping coverage areas. Figure 3 As shown, first-layer nodes 302, 304, 306, and 308 have overlapping first-layer coverage areas 324. Similarly, third-layer nodes have overlapping third-layer coverage areas 326. Other layers, including second-layer nodes, or layers beyond the third layer, may also have overlapping coverage areas as well as individual coverage areas.

[0050] like Figure 3As shown, one or more nodes (e.g., node devices, DCUs, endpoints, or terminal devices) 310, 312, 314 can be within the coverage area of ​​at least one higher-level node. For example, a second-level node 312 is located within the coverage area 324 of a first-level node 302, and node 312 can therefore receive phase synchronization messages from the first-level node 302. Similarly, a third-level node 322 is located within the coverage area 313 of the second-level node 312, and can therefore receive phase synchronization messages from the second-level node 312. The second-level node 312 is also within the overlapping coverage area 326 of the third-level node 322, and communication can therefore occur bidirectionally between the second-level node 312 and the third-level node 322. A second-level node 314 is located within the overlapping coverage area 324 of the first-level nodes 302, 304, 306, and 308. Such overlapping coverage can increase the ability of upper-level nodes to communicate with lower-level nodes, despite various conditions affecting RF signals, such as distance, weather, obstacles, atmospheric conditions, etc.

[0051] In some embodiments, one or more nodes may be configured to communicate with other networks or other components within network 300, such as other nodes, a central controller (such as central controller 110), or other applicable devices within network 300 where the node is local or where node 106 is not local. For example, second-layer nodes 310, 312, 314 and first-layer nodes 302, 304, 306, 308 may be configured to communicate with each other in a mesh network, such that second-layer nodes 310, 312, 314 and first-layer nodes 302, 304, 306, 308 can provide communication between all devices within the mesh network. Each of nodes 302, 304, 306, 308 may be configured to communicate with each other to create a mesh network. In yet another example, nodes 310, 312, 314 may be configured to communicate with each other and / or with nodes 302, 304, 306, 308 to facilitate communication between all devices within network 300.

[0052] In one embodiment, first-layer nodes 302, 304, 306, and 308 are directly connected to substation 301 of network 300. In this way, the phase connection of each of the first-layer nodes 302, 304, 306, and 308 can be known with a high confidence level, as described above. Some of the first-layer nodes 302, 304, 306, and 308 can be connected to different phases of substation 301. For example, first-layer nodes 302 and 308 can be connected to phase A of substation 301, while first-layer node 304 can be connected to phase B, and first-layer node 306 can be connected to phase C. First-layer nodes 302 and 308 connected to the same phase of substation 301 can be within each other's wireless communication range and can therefore verify each other's phase synchronization message broadcasts. Verification may include ensuring that phase synchronization messages are received within wireless range.

[0053] Each of the first-layer nodes 302, 304, 306, and 308 is configured to issue (e.g., broadcast) one or more phase synchronization messages, which can be received by second-layer nodes 310, 312, and 316 for determining their own phase. In one embodiment, the first-layer nodes 302, 304, 306, and 308 broadcast the phase synchronization message after detecting a zero-crossing event (e.g., a zero-crossing of the AC voltage associated with the respective first-layer node 302, 304, 306, and 308). The phase synchronization message may include a measured phase angle value, a phase name associated with the transmitting node, the transmitting node layer number, the local line frequency, the address of the transmitting node (e.g., a communication address), and transmitting node authentication information. The first-layer nodes 302, 304, 306, and 308 may issue the phase synchronization message to all nodes within coverage area 324 (e.g., to second-layer nodes 310, 312, and 314). Second-layer nodes 310, 312, and 314 receive the message and then determine the time increment between the reception of the phase synchronization message and the subsequent zero-crossing of the AC power signal associated with each corresponding second-layer node 310, 312, and 314. Second-layer nodes 310, 312, and 314 are further configured to determine their local phase angles based on the time increment and the known phase angle in the phase synchronization message.

[0054] Once the second-layer nodes 310, 312, and 314 determine the time period between message reception and the corresponding zero crossing, they can determine their own phase connections (e.g., determine the phases they are connected to, such as A, B, C, etc.) according to a method described in more detail below, and store this information in memory 210. The second-layer nodes 310 and 312 can also transmit this information to a central controller, such as central controller 110. In some embodiments, central controller 110 may be one or more of the first-layer nodes 302, 304, 306, and 308. In one embodiment, the second-layer nodes 310, 312, and 314 may be configured to determine their own layer based on the layer of the node from which they receive the phase synchronization message.

[0055] Layer 2 nodes 310 and 312 can also be configured to transmit phase synchronization messages. For example, if the phase of Layer 2 node 310 is known to Layer 2 node 310, Layer 2 node 310 can broadcast a phase synchronization message that includes the known phase as a declared phase angle, the local line frequency, the layer value of Layer 2 node 310, authentication information, and the address of Layer 2 node 310. The phase synchronization message broadcast by Layer 2 node 310 can be received by one or more Layer 3 nodes, such as Layer 3 nodes 316 and 318. After receiving the phase synchronization message from Layer 2 node 310, Layer 3 nodes 316 and 318 can broadcast their own phase synchronization messages as described above. The phase synchronization messages broadcast by Layer 3 nodes 316 and 318 can be based on the declared phase angle of Layer 2 node 310, the time of receiving the phase synchronization message from Layer 2 node 310, and the local zero-crossing time predicted at the receiving Layer 3 nodes 316 and 318.

[0056] Similarly, since the second-layer node 312 is located within the coverage area 324, its phase can be determined based on the phase synchronization message received from the first-layer node. After the phase of node 312 is determined, subsequent phase synchronization messages can be broadcast by node 312, which can be used to determine the phases of other second-layer or third-layer nodes within the coverage area 324. This can continue for other nodes with overlapping coverage areas, thus allowing the determination of the phases of additional lower-layer nodes. Furthermore, the phases of lower-layer nodes can be determined based on the known phase of node 312, as described in further detail below.

[0057] Turn now Figure 4According to some embodiments, a process 400 for processing a received phase synchronization message is described. In one embodiment, process 400 is performed by a node (such as node 106 described above). Although process 400 is described as being performed by node 106, it is contemplated that one or more other components described herein may be configured to perform process 400. In one embodiment, process 400 may be performed by phase synchronization processing circuitry 218, as described above. At process block 402, node 106 receives a phase synchronization message from a transmitting node. In one embodiment, the transmitting node may be another node such as node 106. As described above, the phase synchronization message may include various data such as the transmitting node layer number, the declared phase angle of the transmitting node, the local line frequency measured at the transmitting node, the transmitting node authentication information, the transmitting node address, etc. This information may be used by node 106 to determine its own layer value and phase, as described in detail below.

[0058] At process block 404, node 106 determines whether the phase synchronization message should be accepted or discarded based on information within the phase synchronization message (such as the transmitting node's layer value). If node 106 does not yet have a verified layer value, or if the transmitting node's layer value is higher than node 106's known layer value, the phase synchronization message is accepted. However, if the transmitting node's layer value is equal to or lower than node 106's known layer value, node 106 rejects the received phase synchronization message at process block 405.

[0059] At process block 406, the layer value of node 106 is established and stored in memory 210. If the layer value of node 106 is known, it can be verified based on the layer of the transmitting node. If node 106 does not know its layer value before receiving a phase synchronization message, node 106 sets its layer value to the transmitting node's layer value plus one. For example, if the transmitting node's layer value is N, node 106 determines and stores its own layer value as N+1 in memory 210.

[0060] At process block 408, node 106 predicts and / or detects the first zero-crossing event after receiving the phase synchronization message. The zero-crossing event is the zero-crossing of a sinusoidal AC voltage on the power line associated with node 106. In one embodiment, sensor 216 may be configured to detect the zero-crossing event. At process block 410, node 106 calculates the time difference (increment) between the reception of the phase synchronization message and the predicted or detected zero-crossing. As the wirelessly transmitted phase synchronization message travels at a very high speed (i.e., approximately the speed of light), there is little or no time delay between the transmission of the phase synchronization message from the transmitting node and its reception by node 106. Therefore, the phase synchronization message transmitted at the rising zero-voltage cross at the transmitting node (as described above and in more detail below) can be precisely correlated at the receiving node with the timing of the rising zero-voltage cross at the transmitting node. Therefore, the phase delay time δ is calculated using the following Equation 1 to predict the rising zero-voltage cross at the receiving node:

[0061] δ=(360°×VCD / VCP-PDProductNullingOffset+360)mod 360 Equation 1 Where VCP is the known voltage cross periodicity of the AC main voltage source, VCD is the local delay before the predicted voltage cross, and PDProductNullingOffset is a fixed value representing the delay between the actual sinusoidal electrical signal and the representative square wave signal of the analog used for analysis. In some embodiments, PDProductNullingOffset is 12 ms. However, values ​​greater than or less than 12 ms are also contemplated. In some cases, the timing of the most recently detected rising zero-crossing voltage at the receiving node can be correlated, rather than the delay of the predicted voltage cross (VCD). For example, sensor 216 can detect the rising zero-crossing voltage after receiving a phase synchronization message. In some cases, the rising zero-crossing voltage is detected by sensor 216 and stored in memory 210 along with a timestamp, thereby allowing the node to determine whether the rising zero-crossing voltage occurred simultaneously with the rising zero-crossing voltage event at the transmitting node.

[0062] At process block 410, the determined phase delay time is then correlated with the declared phase angle provided in the received phase synchronization message to produce a local phasor angle in degrees as shown in Equation 2:

[0063]

[0064] As used in Equation 2, DeclaredPhaseAngle is the value presented in the received phase synchronization message, representing the phase angle of the transmitting node relative to the reference node. For example, if the transmitting node and the reference node are perfectly synchronized (e.g., have the same phase), the angle will be zero. If the transmitting nodes are one phasor apart, the value can be 30° or 330°.

[0065] This local phasor angle is sometimes referred to herein as local phase, phase angle, or local phase connection. In response to determining the local phase angle, the phase name (e.g., phase A, phase B, phase C, etc.) of node 106 can be determined at process block 414. In one embodiment, a table (such as Table 1 below) can be used to determine the phase name of node 106. In one embodiment, node 106 can make this determination at process block 414. In other embodiments, another device (such as central controller 110) can determine the phase name of node 106.

[0066]

[0067] Table 1

[0068] Then, at process block 416, node 106 broadcasts the local phasor angle in a new phase synchronization message. As described above, the new phase synchronization message may include various data, such as the transport node layer number, the declared phase angle of the transport node, the local line frequency measured at the transport node, the transport node authentication information, the transport node address, etc. In one embodiment, node 106 transmits the phase angle or phase synchronization message to at least one other node, such as the transport node. In other embodiments, node 106 may transmit the phasor angle or phase synchronization message to a central controller, such as the central controller 110 described above. In some examples, node 106 may generate a message containing the phase difference between the declared phase of the received phase synchronization message and a predicted or detected zero crossing. This message may further include information such as the node's layer number, the declared phase, sender information, authentication information, local line frequency, node identifier, identifier of the device transmitting the synchronization message, etc. In some embodiments, the message may include a known phase associated with the node (if known).

[0069] Turn now Figure 5According to some embodiments, a process 500 for generating and transmitting phase synchronization messages by a node (such as node 106) is described. At process block 502, node 106 monitors one or more parameters of the phase of the power distribution system associated with node 106. In one embodiment, the monitored parameter is voltage. However, other parameters such as current, temperature, etc., may also be monitored. At process block 504, node 106, such as via processing circuitry 202, determines whether node 106 knows which phase it is coupled to in the power distribution system. In some examples, node 106 may be a reference node as described above and will therefore be configured to know the phase it is coupled to. In other embodiments, node 106 may have previously used a process similar to process 400 described above to determine the associated phase. In response to determining an identifier that node 106 does not know the phase to which node 106 is coupled, node 106 continues monitoring one or more parameters of the phase of the power distribution system at process block 502.

[0070] In response to determining that node 106 knows the identifier of the phase to which node 106 is coupled, node 106 generates a phase synchronization message at process block 506. In one embodiment, phase synchronization message generation circuit 212 generates the phase synchronization message. As described above, the phase synchronization message may include declared phase information (e.g., phase identifier / name), measured phase angle, layer value, address of node 106, time data, other monitored parameter data, location data, etc. In one embodiment, the generated phase synchronization message may be stored in the memory 210 of node 106.

[0071] At process block 508, node 106 monitors for zero-crossing events on the phase associated with node 106. At process block 510, node 106 determines whether a zero-crossing event has been detected. In response to determining that no zero-crossing event has occurred, node 106 continues to monitor the phase associated with node 106 for the zero-crossing event at process block 508. In response to determining that a zero-crossing event has occurred, node 106 transmits the generated phase synchronization message at process block 512. By transmitting during a zero-crossing event, the local phasor angle equivalent to node 106's declared phase angle is transmitted.

[0072] In some embodiments, in process block 512, nodes 106 may broadcast a declared phase with adjusted timing based on their own determined phase and known zero crossings. Sometimes, node 106 determines that a spectrum (e.g., an available transmit frequency allocated to node 106) should converge at a specific timing where its normal broadcast declared phase angle is equal to its own local phasor angle. In this case, node 106 may broadcast a declared phase angle not equal to its own by selecting a random number between 0 and 11, or any equivalent selection procedure. Each of the 12 optional numbers can be used as an index for different phase angles. For example, 0 may correspond to 30°, 1 to 60°, 3 to 90°, and so on. By randomly or intentionally selecting a declared phase angle other than its own phase angle, node 106 can determine the relevant broadcast time for an appropriate phase synchronization message by calculating the transmission delay, as shown in Equation 3 below.

[0073]

[0074] SelfPhaseNumber is the index number that was randomly or intentionally selected above. Node 106 then adds the transmission delay TXD to the current time to generate a future time at which the phase synchronization message containing the modified statement should be transmitted. Node 106 can then transmit the phase synchronization message at that future time.

[0075] In some cases, node 106 may be battery-powered or powered by renewable energy and may simply act as a "store-and-forward" device that receives phase synchronization messages, stores them, and attempts to retransmit them. In this case, the phase synchronization messages may include LineFreq measurements to account for the slew rate error in the local clock when performing the aforementioned calculations. These battery-powered or renewable energy-powered nodes 106 may be transient, as they may only be powered for a finite amount of time. Nevertheless, this type of node 106 can be useful for increasing the range of reference node 106.

[0076] In some cases, the power distribution network 104 may be tampered with or modified, causing a phase change in some nodes 106. In this case, node 106 may determine that its own phase has changed while identifying its own phase via conventional wireless communication, and alert the central controller 110 to the detected phase change via wired or wireless communication.

[0077] In some cases, a node 106 may be equipped with a GPS receiver, which, after determining its own phase according to the methods disclosed herein, can transmit its phase and GPS data to the central controller 110. Furthermore, node 106 may be equipped with sensors to monitor its local power signal and phase. This type of node 106 can also transmit any monitored data to the central controller 110.

[0078] In some embodiments, when node 106 is unaware of the phase it is connected to, node 106 can request information, such as phase synchronization messages, from other devices within the power distribution system. For example, in a new installation or after a power loss event, node 106 may be unaware of the phase it is connected to or have lost knowledge of that phase. In the case of a power loss event, node 106 may have previously known the phase it was connected to, but after the power loss event, it may not be able to know the phase with any degree of certainty because node 106 may have been moved to a different phase, etc. Therefore, node 106 may wish to actively determine its phase rather than waiting to receive a broadcast phase synchronization message.

[0079] Turn now Figure 6 According to some embodiments, a process 600 for requesting a phase synchronization message is illustrated. In one embodiment, process 600 is performed by a node, such as node 106. However, one or more other devices described herein may perform process 600. In one embodiment, message request circuitry 220 is responsible for performing process 600 in conjunction with processing circuitry 202.

[0080] At process block 602, node 106 is initialized. This initialization can occur during the initial setup and installation of the node and / or after a power loss event. At process block 604, node 106 determines whether it knows which phase of the distribution system it is connected to. As noted above, after a power loss or during initial installation, node 106 may not know with any certainty which phase it is connected to, even if the node previously knew its associated phase. However, in some cases, the user can set a flag or provide a definitive indication of the phase to which node 106 is coupled. For example, if node 106 is a reference node, the phase can be set within node 106. In response to determining that the phase of node 106 is known, node 106 operates normally at process block 606. In response to determining that the phase of node 106 is unknown, node 106 transmits a request for phase data (such as the phase synchronization message described above). In one example, the request is transmitted via communication interface 204. In some examples, a request for phase data may include the address of node 106, the time the request was sent, the layer value of node 106 (if known), etc.

[0081] In some examples, the request is configured to be received by other devices, such as a DCU. However, in other embodiments, other nodes, such as a reference node, may be configured to receive the request. In some examples, if a supervisory device, such as a DCU, receives the request, it may subsequently send follow-up messages to any node within its communication range to request phase synchronization messages from higher-level nodes (or nodes that know their associated phases).

[0082] Turn now Figure 7 According to some embodiments, a process 700 for transmitting a phase synchronization message in response to receiving a transmission request is illustrated. In one embodiment, message request circuitry 220, in conjunction with processing circuitry 202, executes process 700. At process block 702, node 106 monitors the transmission request. In some examples, the transmission request may be as described above with respect to process 600. In some embodiments, the request may be a subsequent message transmitted by a monitoring device (such as a DCU). The request may be received via communication interface 204.

[0083] At process block 704, node 106 determines whether the request has been received. In response to determining that the request has not been received, node 106 continues monitoring the request at process block 702. In response to determining that the request has been received, the node at process block 706 determines whether the phase of the node 106 receiving the request is known. In response to determining that the phase of the node 106 receiving the request is unknown, node 106 continues monitoring the received request at process block 702. In response to determining that the phase is known, node 106 transmits a phase synchronization message at process block 708. In one embodiment, node 106 transmits the phase synchronization message as described above with respect to process 500. One or more nodes 106 (including the node that transmitted the request) can then receive the transmitted phase synchronization message, as described above.

[0084] In addition to determining whether the phase associated with node 106 is known, node 106 can also determine whether the layer value is higher than the layer value of the transmitting node (e.g., closer to the AC power supply). In response to determining that the layer value is not higher than the transmitting node, node 106 may not transmit the phase synchronization message at process block 708.

[0085] The various features and advantages of the present invention are set forth in the following claims.

Claims

1. A node in a power distribution system, comprising: Electrical connection to a single-phase power signal from the AC mains power supply; A wireless communication interface configured to receive a first phase synchronization message; as well as The controller is configured as follows: Determine whether the first phase synchronization message is acceptable; In response to determining that the first phase synchronization message is acceptable, a zero-crossing event on the single-phase power signal is detected after receiving the first phase synchronization message; Calculate the time difference between the reception of the first phase synchronization message and the detected zero-crossing event; The local phase angle is determined based on the time difference; and The identifier of the single-phase power signal is established based on the local phase angle. The first phase synchronization message includes a layer value, and Wherein, the first phase synchronization message is determined to be acceptable if the layer value of the first phase synchronization message is higher than the layer value of the node, and wherein, the higher layer value indicates a shorter distance to the AC main power supply compared to the lower layer value.

2. The node according to claim 1, wherein, The node is embedded in the electricity utility meter.

3. The node according to claim 1, wherein, The first phase synchronization message also includes the determined phase angle of the node, the frequency of the single-phase power signal, and the communication address of the node.

4. The node according to claim 1, wherein, The controller is further configured to transmit a second phase synchronization message in response to establishing an identifier for the single-phase power signal, wherein the second phase synchronization message includes at least the layer value of the node, the determined local phase angle, and the identifier of the single-phase power signal.

5. The node according to claim 1, wherein, The controller is further configured to: Determine whether the phase identifier of the single-phase power signal is known; and Transmit a request message, wherein the request message is a request for one or more requested phase synchronization messages.

6. A method for determining the phase identifier of a node device, the node device being coupled to the phase of a single-phase power signal of a main power supply of a multiphase AC distribution system, the method comprising: Receive the first phase synchronization message; Determine whether the first phase synchronization message is acceptable; In response to determining that the first phase synchronization message is acceptable, a zero-crossing event on the phase is detected after the first phase synchronization message is received; Calculate the time difference between the reception of the first phase synchronization message and the detected zero-crossing event; The local phase angle is determined based on the time difference; as well as The phase identifier is established based on the local phase angle. The first phase synchronization message includes a layer value, and Wherein, the first phase synchronization message is determined to be acceptable if the layer value of the first phase synchronization message is higher than the layer value of the node, and wherein, the higher layer value indicates a shorter distance to the AC main power supply compared to the lower layer value.

7. The method according to claim 6, wherein, The first phase synchronization message also includes the determined phase angle of the node, the frequency of the single-phase power signal, and the communication address of the node.

8. The method of claim 7, further comprising determining the layer value of the node by incrementing the layer value of the first phase synchronization message by one.

9. The method of claim 6, further comprising transmitting a second phase synchronization message in response to establishing an identifier for the single-phase power signal, wherein, The second phase synchronization message includes at least the layer value of the node, the determined local phase angle, and the identifier of the single-phase power signal.

10. The method of claim 6, further comprising: Determine whether the phase identifier of the single-phase power signal is known; as well as Transmit a request message, wherein the request message is a request for one or more requested phase synchronization messages.

11. A monitoring system for a power distribution network, the system comprising: A first node coupled to a first phase of the power distribution network, wherein the first node is configured as follows: Determine whether the identifier of the first phase is known; A first phase synchronization message is generated in response to determining that the identifier of the first phase is known; Monitor the first phase for zero-crossing events; In response to detecting the zero-crossing event, the first phase synchronization message is transmitted; A second node coupled to a second phase of the power distribution network, wherein the second node is configured as follows: Receive the first phase synchronization message; Determine whether the first phase synchronization message is acceptable; After receiving the first phase synchronization message, detect the zero-crossing event on the second phase; Calculate the time difference between the reception of the first phase synchronization message and the detected zero-crossing event; The local phase angle is determined based on the time difference calculated from the time; and The identifier of the second phase is established based on the local phase angle. The first phase synchronization message includes a layer value, and Wherein, the first phase synchronization message is determined to be acceptable if the layer value of the first phase synchronization message is higher than the layer value of the node, and wherein, the higher layer value indicates a shorter distance to the AC main power supply compared to the lower layer value.

12. The system according to claim 11, wherein, The second node is further configured to transmit a second phase synchronization message in response to establishing an identifier for the second phase, wherein the second phase synchronization message includes at least the layer value of the second node, the determined local phase angle, and the identifier for the second phase.

13. The system according to claim 11, wherein, The second node is further configured to determine the layer value of the second node by incrementing the layer value of the first phase synchronization message by one.

14. The system according to claim 11, wherein, The first phase synchronization message also includes the determined phase angle of the first node, the frequency of the first phase, and the communication address of the first node.

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