US20090129376A1 - Power distribution system communication system and method - Google Patents

Abstract

A power distribution system may incorporate a network communication capability. The network communication capability may be configured or may be configurable as a multi-tiered, mesh network. The network may have two tiers of fixed node meshes (tier2 and tier3) and one tier of mobile nodes mesh (tier1). Each tier and each node of each tier has distinct characteristics relative to application, type of routing, transmit power control, physical configuration and message priorities. The configuration and the characteristics of the network change based upon varying application and communication needs of the network.

Description

• This application claims the benefit of U.S. Provisional Application No. 60/844,782 filed Sep. 15, 2006.
TECHNICAL FIELD
• This patent relates to power distribution systems, and more particularly, this patent relates to communication systems and methods providing communication within power distribution systems.
BACKGROUND
• Power distribution systems include technology to couple sources of power to loads while protecting the distribution infrastructure and maintaining service via circuit protection, fault isolation, circuit reconfiguration (typically for restoration of service to stranded, load-side customers) and system return-to-normal functions. For example, the power distribution system may include circuit switching and fault protection devices including: source protection devices, such as circuit breakers, load protection devices, such as fuses, and fault protection devices, such as fault interrupters, sectionalizers, reclosers and the like, that segment a distribution line and permit fault isolation. While various strategies may be employed to manage the power distribution system to maintain service and to protect the power distribution system, typically the fault protection devices should operate in a coordinated manner to optimize performance of the power distribution system and to minimize the scope and duration of service interruptions. That is, to isolate a fault at the fault protection device nearest the fault to protect the source and to preserve service to loads between the source and the fault protection device.
• At the same time, the power distribution system should be manageable, recoverable and operable at a high level of performance with reduced burden. These goals become difficult to obtain as the distribution system becomes heavily populated with distributed, intelligent devices that allow an operator to manage and control the distribution of power and protect the distribution infrastructure.
• Wide area communication systems have been employed for several decades as a means to enhance the automation of electric power distribution systems to provide management, improved operation and system recovery. These systems are responsible for controlling the distribution of power from sources/substations out over medium voltage feeders/distribution lines to consumers and are typically radio based due to the high cost of providing fiber or other fixed communication media over a wide geographic area. An example of commercial communication products include the Utilinet radio, sold by Schlumberger, Inc. Most of these products are used in conjunction with SCADA systems, or other low to medium-speed communication applications such as the IntelliTEAM® circuit reconfiguration system, available from S&C Electric Company, Chicago, Ill.
• Many aspects of the management and control and particularly the fault protection of the power distribution system, on the other hand, require high speed (low latency) and high reliability communications. Such systems are again preferably radio-based to take advantage of the ease and low cost of installation. An example of such a system includes the HRDS system available from S&C Electric Company. These systems utilize dedicated point-to-point links and dedicated communication channels for each pair of communicating devices. A company called Freewave Communications offers a radio-based off-the-shelf product for use in conjunction with the Schweitzer Engineering Laboratories, Inc. (SEL) mirrored-bits communication protocol. With these two technologies, digital status points can be conveyed between two interconnected distribution automation control devices over radio-based communication infrastructure.
• There remain various drawbacks to radio-based, dedicated point-to-point systems:
• 1) Each point-to-point link requires dedicated infrastructure including dedicated channels and often dedicated radio pairs and repeaters. This makes the cost prohibitive and the installation and maintenance process cumbersome.
• 2) In grid-style power distribution topologies, it may take many of these point-to-point links to provide comprehensive coordination of protective devices.
• 3) If the communication link fails, no other communication path can be created “on-the-fly” to restore the communication link.
• 4) The links cannot be used to exchange other communication traffic because this could compromise the low-latency message delivery requirements of protection applications.
• Mesh-topology communication systems or communication systems based upon the Internet's Ad-Hoc Routing methodology and spread-spectrum radios address several of the foregoing concerns, but not all. Bandwidth and/or latency-related issues remain, particularly when the systems are allowed to carry other competing communication traffic. For example, mesh network architecture requires that most nodes in the network have at a minimum communication links to two different nodes to provide alternate routing. Wired networks, e.g., copper or fiber optic, contain communication energy within the communication links between the node and its neighbor nodes. Wireless networks, one the other hand, have traditionally employed broadcast capability, i.e., omni antenna, and the energy utilized to affect a communication is not contained. Nodes not intended to be part of the communication path receive this energy and are thus forced to delay their own transmissions until the spectrum is clear leading to inefficient bandwidth usage and potential latency issues.
• What is needed is a communication system that can efficiently manage routine radio communication traffic and that responds quickly, effectively and reliably to prioritized or emergency communication traffic. Such a system may respond to more than one priority of message traffic, and may do so without losing or seriously disrupting lower priority traffic. The communication system may also recognize the presence of prioritized or emergency traffic and respond to that traffic in an effective manner. The communication system may also support complex interconnectivity and alternate communication paths to provide consistent, reliable high speed radio-based communication. The system should do so without requiring complex, time-consuming configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a graphic illustration of power distribution grid incorporating network communication architecture in accordance with the herein described embodiments;
• FIG. 2 is a block diagram of a distributed power distribution device including network architecture communication capability in accordance with the herein described embodiments;
• FIG. 3 is graphic depicting a multi-tier network communication architecture that may be employed in power distribution systems, such as that illustrated inFIG. 1;
• FIG. 4 is a graphic depicting a communication protocol under which the multi-tier network ofFIG. 3 may be operated;
• FIG. 5 is a graphic depicting establishment of node family members in accordance with the herein described protocol;
• FIG. 6 is a graphic depicting establishment of node family members in accordance with the herein described protocol silent segment configuration;
• FIG. 7 is a graphic depiction of a multi-tier mesh network in accordance with the herein described embodiments;
• FIG. 8 is a graphic depiction of the network ofFIG. 7 and further illustrating adaptive link route establishment;
• FIG. 9 is a graphic depiction of the network ofFIG. 7 and further illustrating edge node affect on adaptive link route establishment;
• FIG. 10 is a graphic depiction of the network ofFIG. 7 and further illustrating edge node route convergence;
• FIG. 11 is a graphic depiction of the network ofFIG. 7 and further illustrating route edge node redirecting route;
• FIG. 12 is graphic depiction of the network ofFIG. 7 and further illustrating priority route configuration and power binding;
• FIG. 13 is a graphic depiction of the network ofFIG. 7 and further illustrating the multi-tier route configuration;
• FIG. 14 is a graphic depiction of the network ofFIG. 7 and further illustrating the multi-tier routing configuration;
• FIGS. 15-19 are flow charts depicting node operation in accordance with embodiments of the herein described protocol.
DETAILED DESCRIPTION
• A power distribution system may incorporate a network communication capability. The network communication capability may be configured or may be configurable as a multi-tiered, mesh network (“network”). For example, the network may have two tiers of fixed node meshes (tier2 and tier3) and one tier of mobile nodes mesh (tier1), although alternate structures incorporating additional or fewer tiers. Each tier and the nodes of each tier have distinct characteristics relative to application, type of routing; transmit power control, physical configuration and message priorities. The configuration and the characteristics of the network change based upon varying application and communication needs of the network. Configuration changes may be implemented through spectrum management, power control and node awareness in the multi-tiered and multi-dimensional network.
• Adopting a dynamically configurable network communication capability for the power distribution system provides a robust, self-healing network that can make available multiple permutations of network topography for virtually any given source or destination route. A meshed system for any given communication session is, in reality, a serial path between the source and destination that is connected via one or more nodes/routes in tandem acting as repeaters. A well designed mesh network allows multiple sessions to be simultaneously accommodated within the network at any given time.
• FIG. 1 illustrates an example open loop or radialelectrical distribution system100 that may incorporate the communication architecture, systems and methods, i.e., a communication network, in accordance with one or more of the herein described embodiments. It should be understood that while various communication technology, techniques and methodologies will be described in connection with the various herein described embodiments of the communication network, the system components and structures, techniques and methodologies may well be interchangeable in various actual implementations. Thus, one of ordinary skill in the art will appreciate that while each element, structure, feature or technique may not be described in connection with every embodiment they are variously combinable in implementations not specifically described herein; however, such combination are contemplated within this disclosure. Furthermore, while the communication architecture, systems and methodologies are described primarily in connection with power distribution systems, these architectures, systems and methodologies may be employed with various other systems such as petroleum processing and distribution systems, emergency services and first responder communication systems and the like.
• The electricalpower distribution system100 illustrates a typical electrical power distribution structure and how such a system operates. Thesystem100 may incorporate one or more substations or sources of supply (S1-n)102 that provide electricity for distribution via thesystem100. The solidstraight lines104 illustrate distribution lines or conductors that connect between thesources102 and closed switches (X1-n)106 and open switches (O1-n)108. Eachline104 typically represents a three-phase distribution feeder, which may or may not contain a fourth ground conductor depending on the type of distribution. The dashedstraight lines110 indicate connections to adjacent feeders or adjacent substations (not depicted). The curved dashedlines112 indicate portions (or segments)114 of thedistribution system100 bounded byswitches106/108. This description of thedistribution system100 is consistent with the architecture of the IntelliTEAM-II circuit reconfiguration system where theswitches106/108 associated with each of thesesegments114 is known collectively as a “team” (T1-n). The optionally provided repeaters/routers (R1-n)116 represent repeating radios that may form a portion of a network as described in further detail below.
• FIG. 2 illustrates a typical switching or fault protection device,device200 that may provide the function of theswitches106/108 of thesystem100. Thedevice200 may include acontrol204 that couples to a circuit interrupting or switchingdevice206, such as a circuit breaker, vacuum fault interrupter or the like. Thecontrol204 may include internal memory or may couple to memory (not depicted) wherein is stored a control program and operating parameters used by thecontrol204 to affect operation of thedevice200. Thedevice200 may further include a power supply, which may be provided by an external source, a storage source, a distribution line tap, or any other suitable power source, (not depicted).
• Thedevice200 couples to an associatedcommunication device202 that operates in accordance with a communication architecture and communication protocol consistent with the herein described network embodiments. Alternatively, thecommunication device202 may be incorporated within thedevice200. Onepossible communication device202 is a Nova Engineering Inc. NovaRoam EH900 frequency hopping spread spectrum radio. Thecommunication device202 may connect to thecontrol204 via a 10/100MBS Ethernet connection208, and seamlessly creates what appears to thecontrol204 to be an Internet Protocol (IP) wide area network. Thecommunication device202 may provide layers1-3 of an OSI-compliant TCP/IP communication protocol stack, and may allow messages to be intelligently routed within thesystem100 using the herein described routing protocols. In this regard, thecommunication device202 may include acontroller212 coupled to a memory orcache214. The memory may store electronically, optically or otherwise a control program used by the communication device to affect generation, transmission, receipt and/or routing of route configuration messages, data containing messages, system overhead messages, mapping and discovery messages, system maintenance messages, and the like. Thecontroller212 is further coupled to a transmitting device that couples to anantenna210 to affect transmission of the various messages.
• Each of the devices, e.g., sources/destinations102,switches106/108, loads (not depicted) andrepeaters116 within thesystem100 form points or nodes of the communication network and as such incorporate a communication capability such as thecommunication device202 described in connection with thedevice200 or any other suitable communication capability. The communication system may incorporate stationary stand alone communication devices, e.g.,repeaters116, and may furthermore incorporate mobile communication devices,mobile units122, such as communication devices, wireless enabled computing devices, handheld computing devices, cellular data-enabled communication devices and the like associated with mobile service personnel that may include a communication capability, memory and process capability in order to operate to affect generation, transmission, receipt and/or routing of route configuration messages, data containing messages, system overhead messages, mapping and discovery messages, system maintenance messages, and the like. Still further, communication devices that are not associated with the system may be incorporated into the network. These devices may include public or private wireless access points, wireless enabled computing devices, handheld computing devices, cellular data-enabled communication devices, and the like that may be made to communicate in a manner compatible with the herein described communicate network and protocol.
• FIG. 3 illustrates a multi-tiered structure for acommunication network300 that may be associated withsystem100 and its associated devices.Mobile devices122 form a first tier orTier1 of thenetwork300. A portion of the stationary devices, such assources102,switches106/108, andrepeaters116 form a second tier orTier2 of thenetwork300. The remainingstationary devices301 form a third tier orTier3 of thenetwork300. As will be described, characteristics of each of the devices determined whether the device is ultimately associated withTier1,Tier2 orTier3. Furthermore, the dynamic nature of thecommunication network300 may see devices being associated at times with one of the tiers and at other times with another tier. While thenetwork300 incorporates three tiers as illustrated inFIG. 3, implementations using more or fewer than three tiers are possible. An optionalcentral control302 may exist apart from the tiers and may be coupled to thenetwork300, as will also be described.
• Thecommunication network300 may implement a protocol that can change the characteristics of the network allowing multiple applications access to thenetwork300. The protocol automatically accommodates the various applications such as transporting emergency messages, improving latency when required, providing a higher percentage access to the network capacity, reliably improving connectivity, providing scalability and providing spectrum utilization or reuse. Furthermore, thenetwork300 may operate without a central server or management system and is in essence an independent intelligent wireless ad-hoc network; however, one that implements a Transmit Power Control with Adaptive Link Routing (TPC/ALR) configuration capability.
• FIG. 4 illustrates the TPC/ALR protocol400 providing link routing between anapplications layer402 and a physical,wireless communication layer404. Thetransport layer406 incorporatesrouting layer408 and aaccess protocol410, such as carrier sense multiple access (CSMA) operating in conjunction withadaptive routing412 andpower control414. The TPC/ALR protocol400 dictates thenetwork topography416 based on the current application using the network for transport via transmit power control and link routing based upon a three dimensional geometric (tier, compass location) relationship of a node to all other nodes within the three tieredmeshed network300.
• The TPC/ALR protocol400 may specifically provide for interlink to mobile/fixed backhaul wireless networks (not depicted). Theprotocol400 is furthermore be made cognizant of the structure of thenetwork300, i.e., node type, node density, node location and route azimuth including calculated or provided node-to-node distance and tier elevation. Theprotocol400 utilizes this information to control node transmit power, provide “smart” antenna control and radio branching, transmit unicast route request messages (RREQ), and with embedded location segment identifier information when to ignore, respond to or retransmit a RREQ. As will be described, theprotocol400 provides for routing around obstacles such as buildings, mountains, inoperable/congested nodes and dead end routes. Themulti-tier network structure300 in conjunction with theprotocol400 furthermore allows routing of data traffic in a leap-frog manner between tiers in order to meet latency and capacity loads.
• Theprotocol400 is operable to control the transmit power of each communication device innetwork300, and in this regard is capable to control the transmit power of both RREQ and route reply (RREP) messages and corresponding data sessions. In this manner, theprotocol400 provides for extensive reuse of RF spectrum substantially increasing available bandwidth by minimizing impact of CSMA, which in systems that are not dynamic can take up to 50% of the networks capacity as well as increase latency and decrease connectivity.
• Although theprotocol400 can be utilized in systems wherein the communication devices transmit primarily via omni-directional antenna, particular benefits are seen where the protocol is used in conjunction with communication devices having “smart” or directional antenna capability. Smart antenna technology is well known to the person having ordinary skill in the art. A smart antenna and communication device using a smart antenna, i.e., a node, as used herein at least means that the communication device can transmit messages in an omni mode, i.e., with a 360° radiation pattern or selectively transmit to one or more sectors or radial segments, e.g., 22°, 45°, 90°, 180°, etc. The particular technology for implementing smart antenna capability in the nodes is not critical to the operation of theprotocol400 or its benefits. Nor does the use of the term smart antenna herein imply that additional smart antenna technologies not specifically related to segment transmit capability.
• In accordance with theprotocol400, as may be required, nodes may broadcast signals in all directions or transmit unicast signals within particular sectors/segments corresponding to a route/destination node direction. Smart antenna capability allows an increase in multiple routing sessions as well as an increase in spatial reuse.
• Theprotocol400 uses smart antennas in combination with power control to maintain a high level of connectivity and overall network communication capacity. In most instances, the protocol provides for node transmission at a lowest possible power setting (P1) consistent with latency requirements. Transmitting at a low power level increases the number of nodes involved in the route and hence increases latency. For standard transmissions, this is not of concern, and maintaining low transmit power levels helps to achieve the goal of increasing RF spectrum utilization. For certain messages, such as emergency/priority messages and other latency sensitive messages, e.g., VoIP associated messages, theprotocol400 provides for message type detection and automatic power increase (e.g., P2, P3, PX-max) thereby reducing the number of nodes for message transport. This is done in a scalable fashion with the destination node responding to a RREQ-P with its own RERR-L (routes err due to latency). The source node will then send a route request message indicating a need for reduced latency (RREQ-Pn) at a next higher power level, this RREQ-Pn will be received by a repeater node which responsive thereto will also up its power when it transmits its RREQ-Pn, and this process is repeated until the latency goal is achieved or maximum power (PX) is reached. For example, for VoIP messaging, power increase and latency reduction is established as part of the session connection process so that upon actual data transmission, i.e., dialogue, the latency goals are achieved.
• Message routes are determined dynamically responsive to a RREQ and generally are not maintained. Routine message routes are dropped after a period of time of the route becoming inactive, e.g., the route may be dropped after N seconds where the value of N may be selected based upon network usage data, history data, operator selection or combinations thereof. Instead of storing routes, theprotocol400 provides that each node caches network node density and location information and neighboring nodes IP addresses and associated geographical relationship relative to its own location to facilitate route establishment using the smart antenna capability and lowest power level settings achieving latency requirements. For example, the nodes may cache IP addresses and quadrant information, e.g.,geographic locations 1°-90°, 91°-180°, 181°-270° and 271°-360° compass directions relative to the node. Priority message and emergency message routes may be established using a “Fire Drill” or other similar procedure. Priority message and emergency message routes are maintained in accordance with the Fire Drill procedure.
• In the described embodiments and as illustrated inFIG. 3, thenetwork300 is a multi-tiered mesh network consisting ofTier1,Tier2 andTier3 nodes each with their own distinct characteristics. BecauseTier1 nodes are mobile in nature they typically do not associate themselves as family with nodes inTier2. However in certain priority communication situations and emergency or first responder communications applications, e.g., example emergency situations, an otherwise mobile node inTier1 that is stationary may be automatically accepted intoTier2 and allowed to establish its location in the mesh. This is designed into theprotocol400 to accommodate temporary nodes having to act as command posts for disaster recovery or other similar applications. Although not associated withTier2 nodes,Tier1 nodes may link to Tier2 nodes in order to affect communications, and in particular, backhaul type voice and data communications from aTier1 node to thecentral location302.
• Theprotocol400 furthermore provides rudimentary hand-off of aTier1 mobile node betweenmultiple Tier2 nodes. This is accomplished by automatically increasing the quantity of hello beacons corresponding to the mobile node's increase in speed. In this application while a route is being usedclose proximity Tier2 nodes in essence track theTier1 node. This enables theTier1 mobile node to move betweenTier2 nodes while a route is being used. During this transition betweenTier2 nodes new and closer nodes,Tier2 or otherwise, (stronger RF signal) become available for new routing. Data and/or voice interruption is minimized (less then 50 msec) due to the fact that the previous routing is maintained active long enough for the new route to converge with the original route.
• Thenetwork300 will generally havefewer Tier3nodes301 thanTier1122 or2nodes102/106/108/116. TheTier3 nodes are intended to and serve primarily as a transport layer betweenTier2 clusters or to act as a backhaul forTier1 andTier2 traffic destined for thecentral point302 or other destinations.Tier3 nodes will generally have a higher above ground level (AGL) antenna centerline than the other surrounding nodes.Tier3 nodes will furthermore re-transmit (unicast) a RREQ to a node in a destination sector, even if theTier3 node was not in the destination sector from the original source/repeater node.
• Fixed nodes especially in high density networks will tend to cluster especially in peer-to-peer systems where each application layer based peer is constantly checking in with its peer group. Such clusters will be typical inTier2, and less so inTier1 andTier3, butTier1 orTier3 nodes are not prohibited from clustering. The large amount of local traffic typically generated within a cluster can hinder intra-cluster routes. In these instances should a unicast RREQ be delayed too long, the next RREQ to be generated may include a code that will be recognized by one ormore Tier3 nodes and unicast toother Tier3 nodes that are closest to the destination nodes location thus bypassing the cluster that was delaying or blocking the RREQ. Nodes inTier3 can also be utilized by a source node to link to a destination node that is beyond an established node count for RREQ life expectancy or for latency requirements using only same tier nodes. UnlikeTier2nodes Tier3 nodes are not constrained to route direction and may re-transmit a RREQ even if it is not in the quadrant of the proposed route.Tier3 nodes can decide whether to re-transmit the data as aTier2 message or as aTier3 message to anotherTier3 node.Tier2 nodes that may inadvertently receive aTier3 message may be configured to simply ignore the transmission, or depending on the message type and content to respond accordingly to the message.
• Depending onTier2 node densities aTier3 node may have a nest of nodes tied to a sectored/directional or a single node connected to a smart antenna at one location. For multiple sectored/directional antennas configuration theprotocol400 allows interaction with RF branching networks such that the nest is able to process a RREQ and data at the link level versus going down to the IP level for retransmission.
• Thenetwork300 operating in accordance with theprotocol400 provides for each node establishing a relationship with nearby/family nodes. The relationship at least defines the geographic location of the nearby nodes relative to itself allowing unicast messaging via the use of smart antennas. The nodes are able to establish tables containing network node density information both within it's transmit power reach and beyond (overall network configuration data). Transmit power is also controlled to provide route establishment meeting latency goals, and transmit power may further define the family relationship. As described, the communication device forming each node includes a memory and processor capable of learning the family nodes, the network node density and caching this data for message transmission usage.
• The following describes configuration of a network of nodes to have the structure of thenetwork300 and to operate in accordance with theprotocol400. For example, on initialization, a node, such as aTier2 node, sets its transmit power to the lowest setting and learns its physical location, either by global positioning system (GPS) or other similar positioning technology, by network operator configuration or other suitable means. TheTier2 node then initializes a process to learn family nodes.
• FIG. 5 illustrates aTier2node502 surrounded by a plurality of potential family nodes. Thenode502 attempts to establish a link to a closest family member in each segment/sector504,506,508 and510, although more or fewer segments/sectors may be used. Family members may be defined as follows:
• Sibling node: is a node that has sufficient received signal strength (RSL) to provide reliable connectivity with another node using minimum transmit (TX) power (<+10 dBm);
• 1^stCousin Node: is a node that has sufficient RSL to provide reliable connectivity with another node using medium TX power (+11 dBm to +20 dBm);
• 2^ndCousin Node: is a node that has sufficient RSL to provide reliable connectivity with another node using medium to maximum TX power (+21 dBm to +30 dBm); and
• DTS node: is a node that does not have sufficient RSL to provide reliable connectivity with another node using maximum TX power (>+30 dBm) and is subject to grey code blockade.
• Of course, fewer or more levels of association may be defined.
• Family discovery process dictates thatnode502 sends an HELLO with its geographic/tier location imbedded in turn it listens for other nodes HELLO beacon that contains that nodes geographic location. Upon receipt of the Hello a node caches the nodes embedded family information. This process is repeated for various power levels (P1, P2, P3, . . . , Pn, PX), the number and power of each level potentially being user configurable, until thenode502 is able to learn and retain in its cache itssibling512, 1^stcousin 514 and 2^ndcousin nodes516. Nodes that do not meet these criteria are DTS, and are not retained in the cache as a family member.
• Nodes controls transmit power (TX) under unicast conditions and are configured to try to obtain a substantially common RSL from all of its family members. This is accomplished in that the transmitting nodes bind their power to keep within a predetermined, e.g., N, direct links after identifying closest family members (sibling, 1^stcousins, and if necessary, 2^ndcousins). The transmitting node may exceed its bound transmit power for emergency/priority message transmission, latency sensitive messages or for various other configurable purposes. Nodes may be configured to periodically verify and update the family member table retained in its cache. In one embodiment, a node may update its family member table everyn time. Thus, if nodes become inoperable, congested or otherwise unavailable, a revised family table is generated with reliable, active links.
• Common RSL for all node family members is a goal. However, a node also attempts to meet the requirement to have a family member node in each quadrant criteria. Thenode602 illustrated inFIG. 6 is only able to meet the “n_direct_links” requirement for three quadrants,606,608 and610, viafamily members603 with themissing quadrant604. In this instance, thenode602 will attempt to link to family nodes in each segment up to its maximum transmit power “PX”. As shown inFIG. 6, the node may link to nodes closest to the silent sectors, in thiscase family node616 in the610 quadrant. If it is unable to meet this goal, thenode602 may be adapted to assume an edge node configuration and does not pursue the location of a node in the silent sector(s). However, upon hearing a newborn node in the silent sector, thenode602 will attempt to establish a family relationship. Furthermore, whenever thenode602 receives a RREQ with imbedded geographic/tier information, thenode602 updates its cache with this information so that it is constantly updating is knowledge of the network configuration and nodes within the network structure.
• The configuration, operational features and advantages of systems structured to include networks similar to thenetwork300 are illustrated byFIGS. 7-14 and the following discussion.
• FIG. 7 illustrates amesh network700 consisting of 33Tier2 nodes, one of which is identified asnode702, positioned around twogeographic obstructions704 and706. Arrangement of themesh network700 is substantially as described in connection with thenetwork300 illustrated inFIG. 3. As described, eachnode702 employs a discovery/mapping function allowing it to learn its physical location and the locations of its family members (sibling, 1^stcousin, 2^ndcousin, etc.) in relation to it as well as the nodes that form themesh708 defining thenetwork700.
• InFIG. 8, the mesh representation shown inFIG. 7 is removed from the drawing to add discussion of the routing of a message from asource node710 to adestination node712 via aroute714. The message is assembled in accordance with virtually any suitable packet data transport protocol such as TCP/IP, UDP, or the like. The message is further adapted in accordance with theprotocol400.
• To send the message, thesource node710 initiates a RREQ by first looking at its cache to determine a direction and an estimated link number to thedestination node712. Thesource node708 adds the direction to the destination node address, e.g. (N/E 172.40.68.21) where the term “N/E” represents the direction, e.g., north east, of thedestination node710 relative to thesource node708 while the term “172.40.68.21” is the address identifier of thedestination node710. Various direction indicators may be used, such as the compass rose indicators: N, N/E, E, S/E, S, S/W, W, N/W; longitude/latitude indicators, or any other suitable directional indicators. The source node may furthermore add a life expectancy or latency token to the message. Because thesource node710 knows the relative direction of thedestination node712, it may utilize smart antenna capability to unicast the RREQ into a segment or segments appropriate to reach thedestination node712. A family member node ofnode710, e.g.,node716, receives the RREQ; thenode716 being along the route direction relative to the bearing of thedestination node712. Thenode716 similarly determines a segment or segment appropriate to reach thedestination node712 and unicasts/repeats the message into that segment reaching thenode718, which similarly unicasts/repeats the message into a segment to reach thedestination node712. At each node, the node may update the direction information contained in the message such that the directional information continues to correspond to a direction appropriate to reach the destination node.
• In a RREQ implementation,nodes719 that are not in the segments or direction of714 may receive the RREQ. Nodes receiving a RREQ but that are not on theroute714 to thedestination node712 may be configured to ignore the message and not to repeat the message.
• Nodes of thenetwork700 furthermore may be required to use a full or limited broadcast capability as opposed to the preferred unicast technique.FIG. 9 illustrates thenetwork700 and anode720 attempting to message thenode712. However thenode720 is an edge node as result of its proximity to theobstruction706. That is, thenode720 does not have family nodes in each segment and in particular lacks a family node in the segment directed toward thedestination node712. Ordinarily family nodes to thenode720, e.g.,nodes722 and724, not in segments supporting the route to thedestination node712 upon receiving the RREQ from thenode720 would ignore it since the node is not in a segment supporting a route to the destination. However, as a result of the discovery/mapping process, thenode720 knows that it is an edge node and furthermore knows that it does not have family members in segments supporting a route to thedestination node712. Therefore, thenode720 attaches an edge node indicator to the RREQ along with the destination node address and directional indication. Upon receipt of the RREQ including the edge node indicator, thefamily nodes722 and724 respond to the RREQ. In a first response technique, thenodes722 or724 service segments supporting a route to thedestination node712. Each of thenodes722 or724 unicast/repeat the RREQ into appropriate segments to establish routes to thedestination node712. If thenodes722 or724 are edge nodes or otherwise do not include segments supporting a route to thedestination node712, they may implement the multicast process further attaching an edge node indicator to the RREQ.
• As shown inFIG. 9, each of thenodes722 and724 support a segment to establish a route to thedestination node712, and thus tworoutes728 and730 are established. However, afternode732,routes728 and730 pass through the same nodes to reach thedestination node712. Theroutes728 and730 may be converged into asingle route728′ (FIG. 10). Route convergence may be based upon a latency measures, node count indicators or other similar techniques.
• Thenetwork700 operating in accordance with theprotocol400 is operable to detect potential dead end routes or to otherwise direct messages around obstructions, such asobstructions704,705 and706. Anode734 attempting to send a message to thedestination node712 initiates a RREQ, and in accordance with theprotocol400 attaches to the RREQ both the destination node address and a direction indicator. Thedestination node712 is northwest of thenode734 and therefore the direction indicator is N/E.The resulting route736 encounters thenode720, which as discussed above is an edge node and does not support a segment supporting a route directly to the destination node712 (FIG. 11). Upon receipt of the RREQ with the N/E direction indicator along with thenode712 address, thenode720 therefore implements the foregoing described multicast technique to enlistnodes722 and724 to complete theroute736 to thedestination node712. As described, the route from thenode720 to thedestination node712 converges into theroute728′, and hence theroute736 formed includes theroute728′ from thenode720 to thedestination node712.
• It may happen that upon initiating or repeating a RREQ a node will not receive a response from a family node within the latency/life expectancy requirements of the RREQ. In this instance, the node may resend the RREQ this time including an edge node indicator to enlist additional nodes to provide a response. Failing a response to the second request, the node may further resend the RREQ, this time, however, deleting the directional indicator and using a broadcast technique. A node receiving the broadcast message will attempt to implement theprotocol400 to unicast the message into an appropriate segment supporting a route to the destination node, relying on either edge node techniques or broadcast techniques when the unicast technique fails.
• In accordance with theprotocol400, routes are dynamically established and are not saved beyond a predetermined period of time of route inactivity. Subsequent routes results in contemporaneous route generation. Priority/emergency messages may enjoy preferred or preestablished routes that are saved as part of a “Fire Drill” process of the network discovery/mapping process. The desire to utilize lowest unicast power settings to establish a route is retained, and the source node initiates a RREQ as previously described, unicasting the RREQ to sibling nodes but also to 1^stcousin nodes using medium unicast power. The receiving family members repeat/unicast the RREQ. If the latency requirement for the priority message is not met, the destination node replies with a RERR (L), route request error due to latency, the source node increases power and provides an indication in the RREQ for receiving family nodes to likewise increase power. Increasing unicast power has the affect of reducing the number of nodes required to support the route from the source node to the destination node, and hence reduces latency. When the destination node receives the RREQ within the required latency, the destination responds with a RREP. Moreover, these priority routes and corresponding power settings are maintained within each node cache as part of the initial network discovery/mapping.
• Each node forming a priority route knows the direction of the priority route from the node (N, N/E, E, S/E, S, S/W, W, N/W). Because of potential increased power settings for priority routes, nodes in segments supporting the priority route may hear the priority message RREQ, but not being part of the priority route, e.g., due to latency issues, such nodes only listen to the RREQ and do not respond. These nodes do bind their power and instruct their family members in segments supporting the route to similarly bind their power. A node not in a segment of the priority route hearing the message will likewise bind its power. This node will also instruct its family members to similarly bind their power. The effect is to create a region740 (FIG. 12) that is free of competing communications to the priority message. Aregion742 outside the bounds of theregion740 remains available for communications, provided the transmit power is bound such that it does not interfere with and/or is subject to collision/interference requirements of the priority route. Theregion742 is substantially populated by family members of nodes adjacent the priority route but not within segments supporting the priority route.
• The foregoing discussion relates generally toTier2 node operation.Tier3 nodes generally have a higher above ground level antenna centerline than any of the surrounding nodes, e.g.,Tier2 andTier1 nodes.FIG. 13 illustrates anetwork700′. Thenetwork700′ is substantially themesh network700 described above further including theTier3nodes750,752 and754. Positioned substantially above theTier2 andTier1 nodes, e.g., on theobstructions704,705 and706, theTier3nodes750,752 and754 see nodes that theTier2 orTier1 nodes cannot see. Upon receiving a RREQ, aTier3 node, e.g.,node752 will unicast the RREQ to afamily member756 in the destination segment even if theTier3 node is not in the destination segment of theoriginal source node758. This allows establishment of aroute770 over theobstruction704 as opposed to around it usingTier2 andTier1 nodes, e.g.,764, reducing latency. This arrangement furthermore supports cluster-to-cluster communication from afirst cluster766 ofTier2 nodes to asecond cluster768 ofTier2 nodes.
• TheTier3nodes750,752 and754 furthermore support backhaul communication, communicate to a central point and reduced latency by reducing the number of route forming nodes. Referring toFIG. 14, a RREQ to adestination node774 initiated aTier2node772 is received byTier3node750. Thenode750 unicasts the RREQ to Tier3node752, which in turn, unicasts the RREQ to Tier3node754. Thenode754 unicasts the RREQ to thedestination node774. Upon unicast betweennodes750 and752 and betweennodes752 and754, thenodes756 and754 attach aTier3 node identifier to the RREQ, signifying toTier2 andTier1 nodes that listen and can hear the RREQ not to respond to the RREQ.
• The flowcharts ofFIGS. 15-19 depict the operation of the nodes in a multi-tier mesh network structure according to an operating protocol, such as the network and operating protocol described above.FIG. 15 depicts source node RREQ initiation. At1502 the address of the destination node is identified, and at1504, the source node looks into its cache to determine the location indicator to be attached to the destination node address in the RREQ. If the destination nodes location indicator is not contained in the cache,1506, the source node attaches itscoordinates 1508 and the RREQ is sent,1510. If the destination location indicator is contained in the cache, the source node checks whether this is a retry to send the RREQ,1512. A RREQ retry is an indication that a family node did not respond to the original RREQ. To expand the number of family nodes hearing the RREQ that may respond, an edge node identifier may be attached to the RREQ,1514, allowing multicast of the RREQ and broader response. Such is also the case it if determined that the destination segment is a silent sector,1518.
• The response of a node receiving the RREQ is depicted in the flowchart ofFIG. 16. The node waits,1602, to receive a RREQ. Upon receipt of a RREQ,1604, the node determines first if the route is a priority route,1606, which is handled in accordance with the flowchart ofFIG. 19. If it is not a priority route the receiving node caches the route source/destination node address and coordinates,1608. Next, the node checks the destination node location indicator,1610, and if not present, which may result is the source node has not included the destination location indicator because of a failed RREQ, the local node address and location indicator is added to the RREQ,1612, and the RREQ is resent,1614. Otherwise, the received RREQ is checked for an edge node indicator,1616. If an edge node indicator is present, and the RREQ was previously sent, the node returns to waiting to receive a RREQ,1618. Otherwise, the node checks if the route is in a silent segment,1620. If the route is not to a silent sector the local node address and location indicator is added,1612, and the RREQ is resent,1614. Otherwise, an edge node indicator is added,1622, before adding the local node address and location and resending the RREQ. Lacking an edge indicator, the node checks the RREQ to determine if it is aTier3 RREQ,1624, and if so, the node returns to waiting to receive an RREQ,1602. If the RREQ is not aTier3 RREQ and the node is in a segment supporting the route,1626, the silent sector check is performed,1620, before adding an edge node indicator,1622, if appropriate, and the local node address andlocation indicator1612 before resending theRREQ1614.
• FIG. 17 illustrates in flowchart form similar response to receipt of a RREQ by aTier3 node. The node waits,1702, to receive a RREQ. Upon receipt of a RREQ,1704, the node determines first if the route is a priority route,1706. If it is not a priority route the receiving node caches the route source/destination node address and coordinates,1708. Next, the node checks whether destination node location indicator,1710, and if not present, the node location indicator is added to the RREQ,1712, and the RREQ is resent,1714. Otherwise, the received RREQ is checked for an edge node indicator,1716. If an edge node indicator is present, and the RREQ was previously sent,1718, the node returns to waiting to receive a RREQ,1702. Otherwise, the node checks if the route is in a silent segment,1720. If the route is in a silent segment, an edge node indicator is added,1722, the node location is added to the RREQ,1712, and the RREQ is resent,1714. Otherwise, the node checks the RREQ to determine if it is aTier3 RREQ,1724, and if so, the node adds theTier3 indicator,1726, the node location is added to the RREQ,1712, and the RREQ is resent,1714.
• FIG. 18 illustrates priority route processing after a determination that the RREQ refers to a priority route, as depicted inFIGS. 16 and 17. Upon receipt of a RREQ,1802, and confirmation that it is associated with a priority route,1804, the node checks the RREQ power level,1806. If it the power level is lowest (P1), the latency is checked,1808, and a RREP-P1 or a RERR-L1,1810 and1812, respectively, is sent. If the power level is a medium power level (P2, P3, , , , Pn),1814, the latency is checked,1816, and a RREP-Pn or a RERR-Ln,1818 and1820, respectively, is sent. If the power level is maximum power level (PX),1822, the latency is checked,1824, and a RREP-PX is sent if latency is ok,1826. If latency is not ok, best latency reply, RREP (PX) is sent,1828 and a latency alert is generated,1830.
• The action of the source node to the RREP/RERR messages is depicted inFIG. 19. Upon receiving either an RREP or RERR, 1902, the priority status of the route is checked, 1904, and if it is not a priority route, for the RERR message, 1906, the RREQ is resent, 1908. Otherwise, the data is sent via the route, 1910. Confirming the priority status of the route, RERR(L1)/RREP(P1) messages are checked, 1912. If there is a latency error, the RREQ is sent at the next power level, 1914. If there is no latency error at the power level P1, and there is a route reply (RREP(P1)), 1916, the data is sent, 1910. If there is neither a RREP(P1) or RERR(L1), RERR(L2)/RREP(P2) messages are checked,1918. If there is a latency error, the RREQ is sent at the next power level, 1920. If there is no latency error at a medium power level (P2, P3, . . . , Pn), and there is a route reply at medium power level (RREP(Pn)), 1922, the data is sent, 1910. If there is neither a RREP(P2) or RERR(L2), RREP(P3)/RREP(PX) messages are checked,1924. If there is a RREP(PX) message, 1926, the transmit power level is set to max (PX), 1928, the data is sent,1910 and a latency alert is generated, 1930. Otherwise, based upon the RREP(Pn), the data is sent, 1910.
• A multi-tier mesh network and an operating protocol as herein described will find numerous applications. In the primary embodiment described herein, the network and protocol find application in a power distribution system having distributed source, switching/control and load elements with communication capability. New technology in this field requires a communication capability to recognize and transport priority messages and decrease latency. This is necessary to allow peer-to-peer switching devices to react quickly enough to detect, protect and restore the power grid that may cover 5 to 10 square miles of infrastructure. Multiple nodes must detect, react and transport high priority messages in mille-seconds to prevent circuit overloads and protect expensive utility infrastructure. At the same time nodes not directly involved in the emergency session need to quickly bind their power to minimize interference for the priority messages to be transported.
• Another application of the herein described network structure and protocol is in commodity processing and/or distribution systems such as petroleum processing and distribution systems. Similar to power distribution systems, petroleum processing and distribution requires a system that can automatically/remotely detect and isolate faulty valves, broken pipes and vandalism/terrorist attacks. In this application the 2^ndTier nodes generally have the mission critical responsibility and are the core infrastructure relative to the 1 and 3^rdTier nodes. Infrastructure protection is the primary mission of the 2^ndtier mesh in this applications as the need for emergency communications is required less then 5% of the time for a given grid section. Thus, the communication network and protocol may be used for SCADA, telemetry, meter reading, video surveillance, vehicle and voice for the majority of the time. The herein described network and protocol can quickly change applications automatically from routine communications to emergency communications and in a timely manner. The network and protocol according to the herein described embodiments is further adept at providing for the 2^ndtier nodes to accommodate androute 1^sttier voice and data from mobile units to the 3^rdtier nodes for backhaul without loosing sight of its original mission to protect the infrastructure.
• Yet another application relates primarily to emergency/local communication/first responder services. The herein described networks and protocol are well suited for providing a reliable network for emergency communications because of the capability to react to priority messages, vehicle/node location and video surveillance. The networks and protocol furthermore allow for a migration path to convergent technology. In this application the 15′ tier nodes have the mission critical responsibility and forms the core of the infrastructure relative to the 2^ndand 3^rdtier nodes. In this case the 2^ndtier fixed nodes are predominantly utilized as repeaters (occasionally video surveillance nodes) between 1^stand 3^rdtier node backhaul and provide an RF footprint to the geographical area (similar to cell sites) for 1^sttier node connectivity. Priority messages are generated by the 1^sttier mobile nodes and transported via 2^ndand 3^rdtiers nodes to central command/dispatch.
• While the invention is described in terms of several preferred embodiments of power distribution protection and recovery systems and corresponding methods, it will be appreciated that the invention is not limited to such systems and methods. The inventive concepts may be employed in connection with any number of systems, devices and methods for providing coordinated distribution system protection.
• While the present disclosure is susceptible to various modifications and alternative forms, certain embodiments are shown by way of example in the drawings and the herein described embodiments. It will be understood, however, that this disclosure is not intended to limit the invention to the particular forms described, but to the contrary, the invention is intended to cover all modifications, alternatives, and equivalents defined by the appended claims.
• It should also be understood that, unless a term is expressly defined in this patent using the sentence “As used herein, the term ‘______’ is hereby defined to mean . . . ” or a similar sentence, there is no intent to limit the meaning of that term, either expressly or by implication, beyond its plain or ordinary meaning, and such term should not be interpreted to be limited in scope based on any statement made in any section of this patent (other than the language of the claims). To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term by limited, by implication or otherwise, to that single meaning. Unless a claim element is defined by reciting the word “means” and a function without the recital of any structure, it is not intended that the scope of any claim element be interpreted based on the application of 35 U.S.C. §112, sixth paragraph.

Claims (29)

1. In a power distribution system having distributed source, switching and load components, hereinafter nodes, each node having communication capability, a communication protocol associated therewith for affecting message communication between the nodes, the protocol comprising:

determining relative to each node family nodes, wherein the designation for each family node includes an address and a location indicator;

initiating a route request from a source node to a destination node, the route request including the address of the destination node and the location indicator for the destination node; and

unicasting the route request to a family node of the source node based upon the location indicator.

2. The protocol ofclaim 1, wherein each node is associated with one of a first tier or a second tier based upon at least one characteristic of the node.

3. The protocol ofclaim 2, wherein the characteristic comprises: mobility, physical relationship or node function.

4. The protocol ofclaim 3, wherein physical relationship comprises relative elevation of the node with respect to the remaining nodes.

5. The protocol ofclaim 1, wherein one or more of the nodes is designated as an edge node based upon not having family nodes in each of a set of segments extending about the node.

6. The protocol ofclaim 5, wherein the edge node is configured to either unicast or broadcast the route request responsive to the existence and location of family nodes associated with the edge node.

7. The protocol ofclaim 1, wherein a node disassociated from the route bearing location indicator is configured to no respond to the route request.

8. The protocol ofclaim 1, the source node being operable to broadcast the route request responsive a failure to receive a route reply to the unicast of the route request.

9. The protocol ofclaim 1, wherein the family nodes are further designated based upon a power level value required for the node to communicate with the family node.

10. The protocol ofclaim 1, wherein the nodes are physically dispersed over a geographic area in three dimensions, and wherein each nodes is associated with one of a first tier and a second tier based upon the characteristics of the physical location of the node.

11. The protocol ofclaim 10, the second tier nodes having a higher physical elevation with respect to the first tier nodes, the second tier nodes.

12. The protocol ofclaim 10, the second tier nodes are configured to respond to a route request regardless of its locational relationship to the destination node.

13. The protocol ofclaim 10, the second tier nodes configured to attach a second tier node indicator to the route request to provide a revised route request, the second tier nodes are configured to respond to the revised route request while first tier nodes are configured to ignore the revised route request.

14. The protocol ofclaim 1, wherein the route request is related to a priority message and a priority route, the priority route being defined by a set of the nodes.

15. The protocol ofclaim 14, wherein family nodes of the set of the nodes defining the priority route have bound power during communication of the priority message.

16. The protocol ofclaim 1, the route request including a latency requirement indication, and wherein the destination node is responsive to receipt of the route request and the latency requirement indication to provide a route reply message or a route error message, the source node being responsive to the route reply message to begin data communication and further being responsive to the route error message to resend the route request.

17. The protocol ofclaim 16, wherein the source node is responsive to the route error message to resend the route request message at an increased power level.

18. The protocol ofclaim 16, wherein the source node is responsive to the route error message to resend the route request message as a broadcast route request.

19. The protocol ofclaim 1, comprising responsive to the route request a route between the source node and the destination node, the route including an intermediary node, the intermediary node being associated with the location indicator.

20. The protocol ofclaim 19, comprising responsive to the route request two routes between the source node and the destination node.

21. The protocol ofclaim 20, wherein the route comprises a convergence of the two route.

22. A communication protocol for affecting message communication between the nodes of a communication network, the protocol comprising:

determining relative to each node family nodes, wherein the designation for each family node includes an address and a location indicator;

initiating a route request from a source node to a destination node, the route request including the address of the destination node and the location indicator for the destination node; and

unicasting the route request to a family node of the source node based upon the location indicator.

23. The protocol ofclaim 22, wherein each node is associated with one of a first tier or a second tier based upon at least one characteristic of the node.

24. The protocol ofclaim 23, wherein the characteristic comprises: mobility, physical relationship or node function.

25. The protocol ofclaim 22, wherein the nodes are physically dispersed over a geographic area in three dimensions, and wherein each nodes is associated with one of a first tier and a second tier based upon the characteristics of the physical location of the node.

26. The protocol ofclaim 25, the second tier nodes are configured to respond to a route request regardless of its locational relationship to the destination node.

27. The protocol ofclaim 22, the route request including a latency requirement indication, and wherein the destination node is responsive to receipt of the route request and the latency requirement indication to provide a route reply message or a route error message, the source node being responsive to the route reply message to begin data communication and further being responsive to the route error message to resend the route request.

28. The protocol ofclaim 27, wherein the source node is responsive to the route error message to resend the route request message at an increased power level.

29. In a commodity processing and/or distribution system having distributed network components, hereinafter nodes, each node having communication capability, a communication protocol associated therewith for affecting message communication between the nodes, the protocol comprising:

determining relative to each node family nodes, wherein the designation for each family node includes an address and a location indicator;

initiating a route request from a source node to a destination node, the route request including the address of the destination node and the location indicator for the destination node; and

unicasting the route request to a family node of the source node based upon the location indicator.

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