DESC:TECHNICAL FIELD
[0001] The present disclosure generally relates to electrical power generation and distribution systems, and in particular to systems and methods for managing communication between devices in an electric power generation and delivery system.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Electric power delivery systems may include electric power generation, transmission, and distribution equipment and loads that consume the electric power. For example, such systems include various types of equipment such as generators, transformers, circuit breakers, switches, distribution lines, transmission lines, buses, capacitor banks, reactors, loads, and the like. The purpose of electric power delivery systems is to generate and deliver usable electric power to an end user or load. Often, the generation sites are located at great distances from an end user or load. Generated electric power is typically at a relatively low voltage, but is transformed into a relatively high voltage before entering a transmission system. The voltage is again reduced for the distribution system, and often reduced yet again before ultimate delivery to the end user or load. The electric power may be monitored and controlled at various stages in the delivery system. Intelligent electronic devices (IEDs) are often used to collect electric power system information, make control and/or protection decisions, take control, automation, and/or protection actions, and/or monitor the electric power delivery system. The IEDs and various ways they can communicate together can form substation automation systems (SAS).
[0004] IEDs within an electric power delivery system may be interconnected by a variety of technologies and may utilize various communication protocols. To promote high inter-operability between systems and IEDs from different vendors, IEC 61850 standard has been developed. The objectives of the standard include development of a single protocol for complete substation considering modelling of different data required for substation; definition of basic services required to transfer data so that the entire mapping to communication protocol can be made future proof, promotion of high inter-operability between systems from different vendors, a common method/format for storing complete data and definition of complete testing required for the equipment which conforms to the standard.
[0005] The IEC 61850 standard is receiving acceptance worldwide to deploy Ethernet Local Area Networks (LANs) for electrical substations in a smart grid environment. While originally designed for the integration of electric utility substation devices, it has now been extended for use in wind power plant, hydro power generation and for the management of distributed energy resources (DER) and provides Indication, command, Measurement, Time sync, fault record, Inter-Operability, Process bus and Engineering Support. The abstract data models defined in IEC 61850 can be mapped to a number of protocols. Current mappings in the standard are to MMS (Manufacturing Message Specification), GOOSE (Generic Object Oriented Substation Event) and SMV (Sampled Measured Values).
[0006] IEC61850 based Generic Object Oriented Substation Events (GOOSE) is a controlled model mechanism in which any format of data (status, value) is grouped into a data set and transmitted within a time period of 4 milliseconds. GOOSE data is directly embedded into Ethernet data packets and works on publisher-subscriber mechanism on multicast or broadcast MAC addresses. Using this protocol, addition or removal of IEDs is very easy as compared to other protocols. Being a real object oriented protocol it is easily portable for new domains, has very less configuration time compared to other protocols and has fast communication with single or redundant 100 MB/s.
[0007] While MMS and GOOSE service implemented with Ethernet link drive a new trend in substation automation systems (SAS) for short distances , they have inherent difficulties and shortcomings over long distances of about 20-25 kilometres. The network implementation becomes very complex and costly when such connectivity is to be achieved and maintained over such distances. In case multiple substations are to be connected using IEC 61850 GOOSE protocol over such distances, they need to be connected with a main Ethernet hub and a number of repeaters further increasing the installation cost and complexity. Besides, maintenance costs of an Ethernet network over such distances, involving underground cables and repeaters are very high.
[0008] Hence there is a need in the artfor a system and method that, while retaining the advantages of IEC 61850 GOOSE protocol, overcomes one or more of the abovementioned limitations to enjoy widespread practical use.
[0009] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in mean incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply
[0010] In some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0011] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0012] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0013] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

OBJECTS OF THE INVENTION
[0014] It is an object of the present disclosure to provide for a system for GOOSE message communication over Cellular networks that can provide lower rates of message dropping and can avoid wiring leading to substantial cost reduction.
[0015] It is an object of the present disclosure to provide for a system of wireless cellular technologies that can be used in point-to-point backhaul trunk with the capacity of transmission over 60-240 Kbps and can cover a about 20-25 kilometres.
[0016] It is an object of the present disclosure to provide for a system that can also be used for other multimedia applications such as Video conferencing.
[0017] It is an object of the present disclosure to provide for a system that is a very fast wireless oriented device to multi-device scheme.
[0018] It is an object of the present disclosure to provide for a system can be used for event driven transmission on change of state of any of the connected IEDs.
[0019] It is an object of the present disclosure to provide for a system can enable connection of any device to nodes that have IEC 61850 enabled.
[0020] It is an object of the present disclosure to provide for a system that can enable data reception from a serial interface or Ethernet interface and can transmit data on a second interface using cellular network, thereby enabling normally wired components to become wireless.
[0021] It is an object of the present disclosure to provide for a system that can, using 3G/4G cellular technology, offer very fast data rate and high Quality of Service (QoS).
[0022] It is an object of the present disclosure to provide for a system that can operate in a frequency spectrum range of 824-894MHz/1900MHz and so can be designed for an optimum balance amongst different system factors such as number of sites, geography, coverage needed, size of antennas etc. Higher frequency ranges require larger number of cell sites but can make do with smaller antennas. On the other hand, lower frequency ranges provide for better transmission without attenuation but require bigger antennas.
[0023] It is an object of the present disclosure to provide for a system that can have a very high area coverage depending upon availability of cellular services in the areas sought to be covered.
[0024] It is an object of the present disclosure to provide for a system that can use a cellular topology that can consist of cells, each formed by low power transmitters and can use movement of mobile devices having cellular modems to hand over transmission of data, thereby facilitating uninterrupted data flow amongst the various IEDs of the substation automation system.
[0025] It is an object of the present disclosure to provide for a system that can also use existing infrastructure to some extent and existing IEDs.
[0026] It is an object of the present disclosure to provide for a system that can be effective over a long range of up to 25 kilometres using existing wireless cellular 3G/4G networks, that has low installation as well as maintenance costs, is not complex and does not involve large quantity of underground cables, repeaters and Ethernet hubs etc.

SUMMARY
[0027] The present disclosure generally relates to electrical power generation and distribution systems, and in particular to systems and methods for managing communication between devices in an electric power generation and delivery system.
[0028] In an aspect, the present disclosure relates to a system is configured to enable substation based communication, wherein the system can include at least a first intelligent electric device (IED) having a IEC-61850 stack; and at least a second intelligent electric device (IED) having a IEC-61850 stack, wherein the first IED communicates at least one GOOSE message employing IEC 61850 with the second IED through cellular communication.
[0029] In an aspect, the first IED can be a relay or a communication/protection device. The first IED can be configured at a first electrical network, and the second IED can be configured at a second electrical network, wherein each of the first and second electrical networks comprise a plurality of IEDs. In an aspect, the plurality of IEDs can be operatively coupled with each other through any or a combination of a LAN, WAN, or Internet connection. In another aspect, the IEDs that form part of the first network can be connected to a first Ethernet switch. In another aspect, the first Ethernet switch can be operatively coupled with a cellular base station. In another aspect, the IEDs that form part of the second network can be connected to a second Ethernet switch, and wherein the second Ethernet switch can be operatively coupled with a cellular subscriber unit, and wherein the cellular subscriber unit can communicate with the cellular base station.
[0030] In an aspect, the GOOSE message can be communicated based on a substation configuration description (SCD) file, wherein the SCD file maps logical nodes that form part of the system. In yet another aspect, the GOOSE message can be encoded and transmitted from the first IED to the second IED over cellular network, wherein the GOOSE message employing IEC 61850 can be made compliant with IEEE 802.21 standard. In another aspect, the first IED can be validated before transmission of the GOOSE message to the second IED.

BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 illustrates an exemplary representation of the IEC 61850 protocol stack layers as used in the system in accordance with embodiments of the present disclosure.
[0032] FIG. 2 illustrates a high level system block diagram, in accordance with an exemplary embodiment of the present disclosure.
[0033] FIG. 3 illustrates, using a flow chart, a method for message transmitting in accordance with an exemplary embodiment of the present disclosure.
[0034] FIG. 4 illustrates, using a flow chart, a method for message receiving in accordance with an exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION
[0035] The following is a detailed description of embodiment of the disclosure depicted in the accompanying drawing. The embodiment is in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiment; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0036] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0037] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0038] The present disclosure generally relates to electrical power generation and distribution systems and in particular to systems and methods for managing communication between devices in an electric power generation and delivery system.
[0039] In an aspect, the present disclosure relates to a system is configured to enable substation based communication, wherein the system can include at least a first intelligent electric device (IED) having a IEC-61850 stack; and at least a second intelligent electric device (IED) having a IEC-61850 stack, wherein the first IED communicates at least one GOOSE message employing IEC 61850 with the second IED through cellular communication.
[0040] In an aspect, the first IED can be a relay or a communication/protection device. The first IED can be configured at a first electrical network, and the second IED can be configured at a second electrical network, wherein each of the first and second electrical networks comprise a plurality of IEDs. In an aspect, the plurality of IEDs can be operatively coupled with each other through any or a combination of a LAN, WAN, or Internet connection. In another aspect, the IEDs that form part of the first network can be connected to a first Ethernet switch. In anther aspect, the first Ethernet switch can be operatively coupled with a cellular base station. In another aspect, the IEDs that form part of the second network can be connected to a second Ethernet switch, and wherein the second Ethernet switch can be operatively coupled with a cellular subscriber unit, and wherein the cellular subscriber unit can communicate with the cellular base station.
[0041] In an aspect, the GOOSE message can be communicated based on a substation configuration description (SCD) file, wherein the SCD file maps logical nodes that form part of the system. In yet another aspect, the GOOSE message can be encoded and transmitted from the first IED to the second IED over cellular network, wherein the GOOSE message employing IEC 61850 can be made compliant with IEEE 802.21 standard. In another aspect, the first IED can be validated before transmission of the GOOSE message to the second IED.
[0042] The disclosure generally relates to electrical power generation and distribution systems and in particular to systems and methods for managing communication between devices in an electric power generation and delivery system.
[0043] Figure 1 illustrates an exemplary representation of the IEC 61850 protocol stack layers as used in the system in accordance with embodiments of the present disclosure. As illustrated, Table as shown in Figure 1 presents the IEC 61850 protocol stack layers of functionality, which provide flexibility in advancement of communication technology, its relationship with the Open Systems Interconnection (OSI) model and the respective protocol specification for each type of communication stack.
[0044] Figure 2 illustrates a high level system block diagram, in accordance with an exemplary embodiment of the present disclosure. The system, in accordance with the embodiments of the present disclosure, can include a plurality of Intelligent Electric Devices (IEDs), one of which can be IED-1 (206a) that can be an intelligent electric device having IEC-61850 stack in the application layer manufacturing Message Specification (MMS). In an aspect, IED-1 (206a) can be any relay or communication/protection device that supports IEC61850. The network can have plurality of IEDs shown as 206a, 206b…206(n) that can have different applications. In an embodiment, these devices can perform protection of different feeders using relays.
[0045] In an embodiment, the plurality of IEDs can be connected in a single LAN network using Ethernet to form a local network. In an embodiment, the different IEDs forming local LAN network can be connected by an Ethernet switch 204 that in turn can be connected via an ethernet cable as physical media to exchange data between the ethernet switch 204 and a cellular base station 202. The cellular base station 202 can be used to transmit data with high speed and range up to 25 kilometres. In essence, the system can include a LAN network shown as 200 that can include devices (e.g. relays) shown as 206a, 206b..206n that can all be IEC 61850 enabled, connected to an ethernet switch (hub) 204 that is in turn can be connected to a cellular device 202 that can be a cellular base station.
[0046] In an embodiment, the system can further include a cellular subscriber (receiver) unit 208 placed within a range of 25 kilometres from the cellular base station 202.The cellular subscriber unit 208 can in turn be connected via ethernet cable to an ethernet switch 210 that can in turn be configured to pass data received from cellular base station 202 to a particular node of LAN network that the ethernet switch 210 is connected to, depending upon the MAC address and/or IED number of the IED. The cellular subscriber unit 208 can also include plurality of devices shown as 212a, 212b…212m connected to the Ethernet switch (hub) 210.In this way, data can then be transferred between different networks using cellular technology.
[0047] Substation Configuration description Language (SCL) is the language and representation format specified by IEC 61850 for the configuration of electrical substation devices. This can include representation of modelled data and communication services specified by IEC 61850– 7 –X standard documents. The complete SCL representation and its details are specified in IEC 61850-6 standard document. It can include data representation for substation device entities; its associated functions represented as logical nodes, communication systems and capabilities. The complete representation of data as SCL can enhance the different devices of a substation to exchange the SCL files and to have complete interoperability. The types of SCL files can include System Specification Description (SSD) file and Substation Configuration Description (SCD) file. The System Specification Description (SSD) file can include complete specification of a substation automation system including single line diagram for the substation and its functionalities (logical nodes). This can have Substation part, Data type templates and logical node type definitions but need not have IED section. The System Specification Description (SCD)file can describe complete substation detail. It can include substation, communication, IED and Data type template sections. An .SSD file and different .ICD files contribute in making an SCD file.
[0048] Figure 3 illustrates using a flow chart, a method for message transmission in accordance with embodiments of the present disclosure. In an embodiment, method can include, at step 302, mapping address of logical node in an SCD file. IEC61850 application can have an SCD (substation configuration description) file in which all Logical Nodes can be mapped and accordingly, all node addresses can be mapped in datamap.cfg file. Step 304 can include configuring the SCD file with IEC 61850 code. Step 306 can include executing IEC 61850 stack code or run it i.e. executing IEC61850 application with mapped SCD and data map file. Step 308 can include setting comp logic for CPU card. Step 310 can include setting comp logic for which IED one need to generate goose. Step 312 can include encoding and transmitting the GOOSE message over cellular network. Step 312 includes setting command to generate goose application and transmit it through cellular device. The cellular device can encode the received message and transmit it.
[0049] FIG. 4 illustrates, using a flow chart, a method for receiving message in accordance with embodiments of the present disclosure. In an embodiment, the method can include, at step 402, waiting for GOOSE message. The cellular subscriber unit can act as a receiver over cellular technology. It can continuously search for incoming messages. Step 404 can include decoding GOOSE message by cellular subscriber (Receiver) unit. Step 406 can include validating IP address of IED in LAN. The Ethernet switch can validate the IP address of IED and can pass the validated IP address to that IED if that IED in its Local Network. Step 408 can include address mapping. The Received message can be mapped by IEC61850 Application layer as per the SCD file and datamap.cfg file. Step 410 can include the IED doing the necessary operation i.e.as per the received data, IEC61850 will copy the data in particular address as per the Memory Map. Step 412 can include displaying/indicating IED operation. The Relay or Device can perform the necessary Operation as per new data received.
[0050] The GOOSE message service employing IEC 61850 can be made compliant with IEE 802.21 standard making it extremely efficient/high-speed and long distance communicating and fault information system and method, resulting in a high speed distributed intelligence system. The system, in accordance with embodiments of the present disclosure, can effectively extend the substation LAN into the distribution network and can enable fast detection, isolation and recovery from faults on the instrumented feeders. Further, the system, realized in accordance with embodiments of the present disclosure, can use latest industry standards that can allow for expansion into the future without technological obsolescence and can provide for ability for multiple vendors and devices to coexist on the same communication network. Due to this interoperability, a customer can at any time, select the best in class devices for its Smart Grid.
[0051] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0052] The present disclosure provides for a system for GOOSE message communication over Cellular networks that can provide lower rates of message dropping and can avoid wiring leading to substantial cost reduction.
[0053] The present disclosure provides for a system of wireless cellular technologies that can be used in point-to-point backhaul trunk with the capacity of transmission over 60-240 Kbps and can cover a range of up to25 kilometres.
[0054] The present disclosure provides for a system that can also be used for other multimedia applications such as Video conferencing.
[0055] The present disclosure provides for a system that is a very fast wireless oriented device to multi-device scheme.
[0056] The present disclosure provides for a system that can be used for event driven transmission on change of state of any of the connected IEDs.
[0057] The present disclosure provides for a system that can enable connection of any device to nodes that have IEC 61850 enabled.
[0058] The present disclosure provides for a system that can enable data reception from a serial interface or Ethernet interface and can transmit data on a second interface using cellular network, thereby enabling normally wired components to become wireless.
[0059] The present disclosure provides for a system that can, using 3G/4G cellular technology, offer very fast data rate and high Quality of Service (QoS).
[0060] The present disclosure provides for a system that can operate in a frequency spectrum range of 824-894MHz/1900MHz and so can be designed for an optimum balance amongst different system factors such as number of sites, geography, coverage needed, size of antennas etc. Higher frequency ranges require larger number of cell sites but can make do with smaller antennas. On the other hand, lower frequency ranges provide for better transmission without attenuation but require bigger antennas.
[0061] The present disclosure provides for a system that can have a very high area coverage depending upon availability of cellular services in the areas sought to be covered.
[0062] The present disclosure provides for a system that can use a cellular topology that can consist of cells, each formed by low power transmitters and can use movement of mobile devices having cellular modems to hand over transmission of data, thereby facilitating uninterrupted data flow amongst the various IEDs of the substation automation system.
[0063] The present disclosure provides for a system that can also use existing infrastructure to some extent and existing IEDs.
[0064] The present disclosure provides for a system that can be effective over a long range of up to25 kilometres using existing wireless cellular 3G/4G networks, that has low installation as well as maintenance costs, is not complex and does not involve large quantity of underground cables, repeaters and Ethernet hubs etc.

,CLAIMS:1. A system configured to enable substation based communication comprising:
at least a first intelligent electric device (IED) having a IEC-61850 stack; and
at least a second intelligent electric device (IED) having a IEC-61850 stack, wherein the first IED communicates at least one GOOSE message employing IEC 61850 with the second IED through cellular communication.
2. The system of claim 1, wherein the first IED is a relay or a communication/protection device.
3. The system of claim 1, wherein the first IED is configured at a first electrical network, and the second IED is configured at a second electrical network, wherein each of the first and second electrical networks comprise a plurality of IEDs.
4. The system of claim 3, wherein the plurality of IEDs are operatively coupled with each other through any or a combination of a LAN, WAN, or Internet connection.
5. The system of claim 3, wherein IEDs that form part of the first network are connected to a first Ethernet switch.
6. The system of claim 5, wherein the first Ethernet switch is operatively coupled with a cellular base station.
7. The system of claim 6, wherein the IEDs that form part of the second network are connected to a second Ethernet switch, and wherein the second Ethernet switch is operatively coupled with a cellular subscriber unit, and wherein the cellular subscriber unit communicates with the cellular base station.
8. The system of claim 1, wherein the GOOSE message is communicated based on a substation configuration description (SCD) file, wherein the SCD file maps logical nodes that form part of the system.
9. The system of claim 1, wherein the GOOSE message is encoded and transmitted from the first IED to the second IED over cellular network, and wherein the GOOSE message employing IEC 61850 is made compliant with IEEE 802.21 standard.
10. The system of claim 1, wherein the first IED is validated before transmission of the GOOSE message to the second IED.