ELECTRONIC DEVICES

[0001] The invention relates generally to the field of substation automation, and more specifically to the intelligent electronic devices deployed in the substations.

BACKGROUND

[0002] An electrical or power substation involves electricity transmission and distribution systems where voltage is transformed from high to low or the reverse using transformers. Electric power may flow through several substations between generating plant and consumer, and may be changed in voltage in several steps.

[0003] The substations generally include one or more transformers, and switching, protection, control, metering and grounding equipment. Appropriate equipments are selected for these functions depending on whether the substation is a transmission, sub-transmission, or distribution substation. Currently different types of Intelligent Electronic Devices (IEDs) are used in the substation to cater to different substation functions. The IEDs are microprocessor-based controllers of power system equipment, such as circuit breakers, generators, transformers, power lines, power cables, reactors, motors, capacitor banks etc. Typically, the IEDs receive data from sensors and power equipment, and can issue control commands, such as tripping circuit breakers if they sense voltage, current, or frequency anomalies, or raise/lower voltage levels in order to maintain the desired level. Common' types of IEDs include protective relaying devices, load tap changer controllers, circuit breaker controllers,, recloser controllers, voltage regulators, etc. These are advantageous because, with the available microprocessor technology a single unit can perform several protection, metering, monitoring and control functions concurrently.

[0004] Substation automation forms an important and complex aspect for maintenance and control of different equipments involved in different processes within the substation. Multiple protocols exist for substation automation, which include many proprietary protocols with custom communication links. However, interoperation of devices from different vendors is highly desired for simplicity in implementation and use of substation automation devices.

[0005] The IEC61850 standard from International Electrotechnical Commission (IEC) advocates interoperability amongst Intelligent Electronic Devices (IEDs) from various manufacturers using common engineering models, data formats and communication protocol. Recent IEDs are therefore designed to support the IEC61850 standard for substation automation, which provides interoperability and advanced communications capabilities.

[0006] IEC 61850 features include data modeling where complete functionality of the substation is modeled into various IEC61850 compliant logical nodes that are grouped and arranged under different logical devices. Logical nodes are the smallest part of a function that exchanges data and these logical nodes are objects defined by its data and methods. Logical devices are virtual devices that exist to enable aggregation of logical nodes and data sets for communication purposes.

[0007] There are logical nodes for data/functions related to the logical device (LD) and physical device (LPHD). The data can emanate from an IED through various schemes like GOOSE (Generic Object Oriented Substation Events) events, reports, Sampled and Measured Values (SMVs). An IED can receive the commands from a client or peer IEC 61850 system. Regarding data storage, a SCL (Substation Configuration Language) is defined for complete storage of configured data of the substation in a specific format.

[0008] The abstract data models defined in IEC61850 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), SMV (Sample Measured Values), and soon to Web Services. These protocols can run over TCP/IP networks and/or substation LANs (local area networks) using high speed switched ethernet to obtain the necessary response times of less than four minutes for protective relaying.

[0009] The IEC61850 standard also makes the provision for addressing of data within an IED that is generally, addressed by respective IED engineering/configuration tools. The addressing concepts are adapted to suit the philosophies that are applicable for any internal variables' data being communicated between the IED 's hardware components.

[0010] The IEC61850 standard supports two different attributes for addressing, depending on whether data emanates from the IED or in other words is published from the IED, using GOOSE/SMV/MMS profile or whether the IED receives data from other peer IEDs, using the GOOSE/MMS communication profiles. The information terminating into the IED via GOOSE always needs to be flexible as one does not know the number of signals being subscribed by the IED from other peer IEDs apriori, when the IED engineering is started. [0011] For. IEDs that support a predefined or fixed super set of configurations, the internal addressing is generally constant. The IED tool, based on the selected configuration, generates the needed ICD/CID file (IED configuration description file/Configured IED Description file) for publishing information. However, for IEDs like Process Controllers or 'Intelligent' Remote I/O systems or 'I/O configurable' Protection and Control relays, that allow partial or completely flexible arbitrary configurations, a constant addressing scheme limits the functionality. Unless the address scheme is a flexible one, the information that needs to be published from the mentioned IED types (Process Controllers or 'Intelligent' Remote I/O systems or 'I/O configurable' Protection and Control relays) to other recipient IEDs may not be unique.

[0012] Hence there is a need to develop a flexible addressing technique that utilizes the ability of the IEDs to be configured as per the user or substation requirement.

BRIEF DESCRIPTION

[0013] According to one aspect, a method for publishing data emanating from an intelligent electronic device (IED) is provided. The method includes assigning an identifier to one or more data field, where the one or more data field is associated with a short address attribute in the data emanating from the intelligent electronic device.

[0014] According to another aspect, a substation automation apparatus for controlling and monitoring operations at the substation is provided. The substation automation system includes intelligent electronic devices (IEDs), each of the IEDs have a distinct capability and the distinct capability is represented as a list of functions. Each function from the list of functions is represented as a logical node; and each logical node contains one or more data objects, where one or more data objects employ a flexible addressing scheme for publishing data emanating from the IED. The system further includes an application configuration tool, for configuring a subset of functions from the list of functions provided by the IED based on requirements of the substation; where the application configuration tool is configured to dynamically update one or more data objects using the flexible addressing scheme.

[0015] In yet another aspect, an intelligent electronic device (IED) for monitoring and control of operations in a substation is disclosed. The IED includes a list of functions; (each function being represented as a logical node; and each logical node contains one or more data objects); and a flexible addressing scheme for configuring the data objects and publishing data from the IED. DRAWINGS

[0016] These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0017] FIG. 1 is a block diagram representation of Intelligent Electronic Devices (IEDs) along with their functions, data and a configuration tool;

[0018] FIG.2 is flow chart representation of exemplary steps for a method of publishing data from the IED;

[0019] FIG. 3 is a snapshot depicting a use of flexible addressing scheme for publishing data from the IED in one exemplary embodiment of a Distributed Control System (DCS) Process Controller;

[0020] FIG. 4 is a snapshot representation depicting a use of flexible addressing scheme for publishing data from the IED in another exemplary embodiment of a Protection and Control Relay as a switching object;

[0021] FIG. 5 is a snapshot representation depicting a use of flexible addressing scheme for publishing data from the IED in another exemplary embodiment of a Protection and Control Relay as a switching object;

[0022] FIG. 6 is a snapshot representation depicting a use of flexible addressing scheme for publishing data from the IED in another exemplary embodiment of a Protection and Control Relay as a switching object;

[0023] FIG. 7 is a snapshot representation depicting a use of flexible addressing scheme for publishing data from the IED in another exemplary embodiment of a Protection and Control Relay as a switching object;

[0024] FIG. 8 is a snapshot representation depicting a use of flexible addressing scheme for publishing data from the IED in another exemplary embodiment of a Protection and Control Relay as a generic Input Output; and [0025] FIG. 9 is a snapshot representation depicting a use of flexible addressing scheme for publishing data from the IED in another exemplary embodiment of an Intelligent Distributed Input /Output system.

DETAILED DESCRIPTION

[0026] A method and system for publishing data from intelligent electronic devices (IEDs) using a flexible addressing concept is disclosed that functions to dynamically populate the addressing fields in the data or information published by the IED operating in an IEC 61850 environment. This fiinctionality is implemented in the respective IED configuration tools. Flexibility being referred in this context amounts to having a unique identifier, for the emanating data out of IED (published from the IED) and data subscribed into the IED.

[0027] Referring now to FIG. 1, a substation automation system is shown generally by reference numeral 12. The system 12 includes several intelligent electronic devices (IEDs) shown by reference numerals 14, 14', 14"...14 ^{n l} . The IED is represented as a physical device which includes several logical devices. Each of the IEDs have a distinct capability, the distinct capability is typically represented as a list of functions, shown as fi f _n indicated by reference numeral 16. Some examples of these functions include power system equipment protection (based on over or under current, over or under voltage, over or under frequency, power, impedance etc.), control, metering and monitoring. Each function from this list of functions is represented as a Logical Node (LN), shown as Li... L _n indicated by reference numeral 18. Each Logical Node further contains several 'Data Objects Instantiated' (DOI) 20, shown as DOIi.... DOI _n . According to aspects of the present technique one or more Data Objects employ a flexible addressing scheme for publishing data (data emanating) from the IED shown generally by reference numeral 22. As would be known to one skilled in the art, a short address attribute (sAddr) is defined with every DOI associated with a Logical Node that represents the functionality implemented in the IED. The representation of this short address attribute varies from IED to IED depending on the internal addressing schemes, prevalent in the IED. The flexible addressing scheme as described herein includes assigning an identifier to the one or more DOIs providing flexibility in addressing the DOIs and for proper mapping of published information from the IED over MMS/GOOSE/SMV.

[0028] The system 12 also includes sensors 28 to collect field data that is communicated as SMVs (Sampled Measure Value), depicted by reference numeral 30 to one or more IEDs. It will be appreciated by those skilled in the art that the sensors could also be IEDs. The different IEDs communicate with each other as shown by reference numeral 26 using GOOSE/MMS and the IEDs also publish data to be sent to a user display monitor or IED configuration tool 24 as described herein below using MMS as depicted by reference numeral 22.

[0029] The system 12 includes an IED configuration tool 24 as shown in FIG. 1, for configuring a subset of functions from the list of functions provided by the IED as described hereinabove, based on requirements of the substation. As would be apparent to one skilled in the art, a user can configure the IED by "mixing and matching different functions according to the final application needed at the substation using the IED configuration tool 24. Further, according to aspects of the present technique, the IED configuration tool 24 is used to dynamically ('on the fly' , without any prior type definitions in the configuration tool or user intervention) update the one or more DOIs by updating the identifier using the flexible addressing scheme. The short address attribute as described hereinabove is dynamically updated by the IED configuration tool based on the configured information. The updation of configured information may be based on a user specific configuration data or automatic configuration data from the application configuration tool or in response to virtual (calculated) signals received from application logic of the IED.

[0030] Besides this, additional attributes like LN prefixes (LN prefix gives more information on the application for which the LN is modeled) and instance numbers (the instances of such a LN

Type) can also be dynamically updated based on user/automatic configuration according to aspects of present technique. An example illustrating the above is given below using IEC61850 -

Substation Configuration Language (SCL):

<LN prefix="xyz" inst="abc" lnClass="GGIO" lnType="GGIO_xyz" desc="Generic I/O function">

<DOI name="Alm" desc="Start">

<DAI sAddr="xxxxxxxxxxxxxx" name="general" valKind="Set" />

<DAI name="d" valKind="Set">

<Val>GGIO_ALM</Val> </DAI>

</DOI>

</LN>

[0031] The above is an example of a Generic I/O function based Logical Node. The Application function in the IED that generates an Alarm condition (based on some process condition) that needs to be published on the IEC61850. This function is mapped to a GGIO LN. The Alarm condition output information is mapped to a DOI 'Aim' under the GGIO LN node. As will be appreciated by those skilled in the art, the 'Aim' DOI comprises of at least two Data Attributes. One of the 'Data Attributes Instantiated' (DAI) is the short address that needs to be updated with dynamic value according to the internal addressing rules in the host IED. The update of the short address is based on select conditions that include the data type which is the IED 's internal reference with respect to a register communication address register or a reference to its internal application logic etc. Other information that could be included in the short address definitions could be the data handling criteria like minimum and, maximum values, deadbands etcetera.

[0032] FIG. 2 is an exemplary flowchart 32 describing exemplary steps for a method for publishing data emanating from an IED. The method includes at step 34 assigning an identifier to one or more data fields, where the one or more data field is associated with a short address attribute in the data emanating from the intelligent electronic device. At step 36 the identifier is dynamically updated using the configured data information from a user specific configuration data or automatic configuration data. And at step 38 the data is published by the IED.

[0033] As would be appreciated by one skilled in the art, the method described herein provides a flexible way to configure a IEC 61850 configuration file when the number of Inputs/Outputs (I/Os), or functions are unknown for an application. This technique is especially advantageous for generic I/Os, power control applications that work on varied number of I/Os. The number of such I/Os are usually cannot be predetermined during the supply of IEDs to a user or customer. Thus using the identifier based flexible addressing scheme the user can implicitly and easily configure a 61850 configuration file using the application configuration tool.

[0034] FIG. 3 is a computer screen snapshot 40 where the identifier is associated with a channel of a virtual output card in the intelligent electronic device to implement a Process Controller, for example a Distributed Control System (DCS) Processor Controller. The DCS Process Controller, referred in this document, is a real time embedded device that is used in implementation of power automation functions and is IEC61850 compliant.

[0035] The snapshot 40 was created by using a process controller configuration tool. Reference numeral 42 indicates a Process Controller configuration tool tree view, created after importing an SCD file, with focus on a 'Virtual Output' module PC GAPC. Reference numeral 44 is an editor view of the Process Controller configuration tool corresponding to PC GAPC with a channel 'Str' (start) indicated by reference numeral 46. Reference numeral 48 is an SCL file view integrated with Process Controller configuration tool, showing the corresponding Logical Node LN PCGAPC at reference numeral 50 and DOI 'Str' at reference numeral 52 A view of a SCL file in a standard XML editor is depicted by reference numeral 54.

[0036] It will be appreciated by those skilled in the art that the creation of the Process Controller configuration tool tree view as shown herein above is completely dependent on the content of the SCD file that in turn is dependent on process logic running in the Controller. Hence, the content in the tree is completely flexible. In such a scenario, it is advantageous if the short addressing is adaptive as well, as described herein below.

[0037] It can be seen from FIG. 3 at reference numeral 44, the ' Str' channel id is 1.1.3.1. The IED tool converts this into a hex equivalent of 01010301, whose decimal equivalent is 16843521 as shown at reference numeral 56. This address or identifier 56 is assigned to all attributes under the 'Str' DOI. As would be appreciated by skilled in the art, the identifier may be employed to indicate a general attribute or a quality and timestamp.

[0038] In the DCS process controller described herein, the dynamically created 'Virtual Output' units are related to Logical Nodes. The Virtual Output units or cards are created using the identifier that is updated based on the configured functionality in the Controller like voltage control, synchronisation, load shedding etc (as is done in the Analog or Digital Output cards). These Virtual Output units have channels that are co-related to DOIs. The channel identifier or address is updated as a part of short address attribute based on the data type of the variable.

[0039] FIG. 4 is a computer screen snapshot 58 where the identifier is associated with an Input/Output (I/O) node of the intelligent electronic device to implement a Protection and Control

Relay. A switching object refers to a primary equipment like a circuit breaker CB, shown by reference numeral 60, is controlled from the IED. Here, the I/O configurable protection is based on user configuration data, besides the information based on actual signal assignments for that data point. The short address is updated with both the above aspects. As shown above in FIG. 4 a circuit breaker CBl indicated by reference numeral 62 indicated as switching object at 64 is configured with a signal assignment '9' indicated by reference numeral 66 with additional information from a user interface indicated by 68 results in the output as described herein below. [0040] Referring again to FIG. 4, a Logical Node CILO, associated with a Switching Object 2-2, is indicated by reference numeral 70, with LN instance '9', is updated with the prefix as per object type and CB designation in the description, as described hereinabove. Similarly Logical Nodes CSWI and XCBR indicated by reference numerals 72 and 74 respectively, are also updated. Further updation aspects with respect to 70, 72, and 74 are described in more detail in reference to FIG. 5-7.

[0041] Referring now to FIG. 5, the snapshot 76, LN CILO as described in reference to FIG. 3 has two DOIs; EnaOpn indicated by reference numeral 78 and EnaCls as indicated by reference numeral 80 whose short addresses are updated with the same data as the signal assignment indicated by reference numeral 82 and event numbers 84, 86 respectively for spontaneous transmission.

[0042] In another example, as shown in FIG. 6, a snapshot 88 for the Logical Node CSWI (shown also in FIG. 4), with LN instance 9 indicated by reference numeral 82, updated as shown at reference numeral 90 with the prefix as per object type and CB designation in the description.

[0043] In another example, as shown in FIG. 7, a snapshot 92 for a Logical Node XCBR (shown also in FIG. 4), with LN instance 9 indicated by reference numeral 82, updated with the prefix as per object type and CB designation in the description as shown by reference numerals 94, 96, and 100.

[0044] In another example, a snapshot 102 for a generic input and output is shown at in FIG. 8. A combined binary output and input functionality indicated by reference numeral 104 is updated, each configured from a user interface with additional IEC61850 definitions and results in a GGIO LN with following co-relations. The signal assignments T and '2', indicated by reference numerals 106 and 108 respectively, are updated as LN/DOI short address attributes and as DO description attributes as indicated by reference numerals 110, 112, 114 and 116. The signal descriptions are updated as DO (SPCSO) 'd' attribute value as shown in the snapshot 118. It can be seen that the OpCnt, Pos, BlkOpn and BlkCls DOI 's short address fields are updated with the same data as the signal assignment. Also, the Pos DOI's short address fields are updated with the same data as the signal assignment.

[0045] FIG. 9 is a computer screen snapshot 120 of another example, where the identifier is associated with a position and a channel number of an Analog/Digital Input board, where the Analog/Digital Input board is configured using an application configuration tool to implement a Intelligent Distributed I/O IED. Depending on the position of the module and the channel number, the short address attribute is updated. For example a 5 ^th channel indicated by reference numeral 122 of the digital input board 124 at position '3' indicated by reference numeral 126 is configured as an alarm as indicated by reference numeral 128. The LN instance associated with above is 3 as indicated byieference numeral 130. The updated profile is shown generally by reference numeral 132 and the updated attributes are shown by reference numerals 134-142.

[0046] The field data collected by the Analog/Digital Input boards could be sent to other IEDs using the GOOSE/SMV/MMS communication profiles. Similarly, another channel in the same board can be configured as an event by mapping it as an 'Ind' DOI. Data collected by an Analog Input board could be mapped as MV or SAV DOIs.

[0047] Thus according to the aspects of present technique, the configurable/modular devices can be addressed in a flexible manner using signals from field or virtual signals from application logic emanating out of the IED. The short address using the identifier can be used to fetch the data from the IED and can also be used to verify the actual hardware configuration, before the configuration file is accepted by the IED. Thus the method described herein also provides a way to verify

(through the IED Configuration Tool in the case of but not limited to online configuration mechanism or through the IED in the case of offline configuration mechanism) the IEC61850 configuration file (ICD/CID) with respect to actual device configuration/device capability. The verification step is an added feature to ensure correctness of configuration. Also, based on the application, the allocation of functions and logical nodes can be grouped and the data model can be arranged to map the actual product.

[0048] . It may also be noted here that though the description refers to IEC 61850 standard, the above described methods and systems may also be translated to other standards, and the IEC 61850 standard is an exemplary non-limiting implementation of the above referred technique and systems.

[0049] While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.