Claims:We claim:
1. A bay control unit (BCU) (100) for substation automation system, comprising:
one or more sensing modules (104, 108, 110, 112) to sense field input data; and
a processor module (102) comprising a data acquisition module (202), coupled to the one or more sensing modules (104, 108, 110, 112), to:
receive the sensed field input data from the one or more sensing modules (104, 108, 110, 112);
process the received field input data for communicating to an International Electrotechnical Commission (IEC) 61850 compliant supervisory control and data acquisition (SCADA) system (204) and to a local graphical user interface (GUI) (116);
transmit the processed field input data to the IEC 61850 complaint SCADA system (204) and the local GUI (116);
receive commands from at least one of the SCADA system (204) and the GUI (116); and
transmit digital outputs corresponding to the received commands to a digital output module (106), coupled to the data acquisition module (202).
2. The BCU (100) as claimed in claim 1, wherein the processor module (102) processes the received field input data by:
amplifying and phase correcting the field input data;
extracting fundamental component from the amplified and phased corrected field input data using Discrete Fourier Transform (DFT) technique; and
mapping a computed value of the extracted fundamental component with IEC 61850 substation automation protocols for communication with the IEC 61850 compliant SCADA system (204) and the local GUI (116).
3. The BCU (100) as claimed in claim 1, wherein the one or more sensing modules (104, 108, 110, 112) comprising:
a CT/PT module (112) comprising an instrument transformer to sense input analog signals corresponding to the phase voltages/currents, wherein the instrument transformer is one of a current transformer (CT) and a potential transformer (PT); and
a filter module (110), coupled to the instrument transformer, to perform band limiting and amplitude scaling to the input analog signals before the input analog signals are digitized for submission to the data acquisition module (202).
4. The BCU (100) as claimed in claim 1, wherein the one or more sensing modules (104, 108, 110, 112) comprising an isolator module (108) to sense and provide a 4-20 mA sensor signal to the data acquisition module (202).
5. The BCU (100) as claimed in claim 1, wherein the one or more sensing modules (104, 108, 110, 112) comprising a digital input module (104) for providing a status signal from a switchgear in the form of binary data.
6. The BCU (100) as claimed in claim 1, further comprising a power supply module (114) to supply power to all the modules of the BCU (100) from a single source.
7. The BCU (100) as claimed in claim 5, wherein the one or more sensing modules (104, 108, 110, 112) are coupled to the processor module (102) through Flat Ribbon Cable (FRC), and wherein the power supply module (114) supplies the power separately through a power cable to one or more sensing modules (104, 108, 110, 112) and the processor module (102).
8. The BCU (100) as claimed in claim 1, wherein the processor module (102) periodically provides output data which is sought by an IEC 61850 compliant external client device.
9. The BCU (100) as claimed in claim 1, wherein the BCU (100) facilitates Generic Object Oriented Substation Event (GOOSE) messaging between bay level and process level Intelligent Electronic Devices (IEDs).
10. The BCU (100) as claimed in claim 1, wherein all of the modules (102, 104, 106, 108, 110, 112, 114) are housed in a single rack compliant with electromagnetic-interference (EMI) / electromagnetic-compatibility (EMC).
11. A method for implementing bay control unit (BCU) (100) for substation automation systems, the method comprising:
acquiring analog and digital field input data using one or more sensing modules (104, 108, 110, 112);
receiving, at a processor module (102), the acquired analog and digital field input data from the one or more sensing modules (104, 108, 110, 112);
processing, at the processor module (102), the acquired analog and digital field data by:
amplifying and phase correcting the field input data;
extracting fundamental component from the amplified and phased corrected field input data using Discrete Fourier Transform (DFT) technique; and
mapping a computed value of the extracted fundamental component with International Electrotechnical Commission (IEC) 61850 substation automation protocols;
communicating, by the processor module (102), the processed analog and digital field input data to the IEC 61850 compliant supervisory control and data acquisition (SCADA) system (204) and a local graphical user interface (GUI) (116); and
receiving, at the processor module (102), control commands from the SCADA system (204) over an IEC 61850 communication protocol based network.
12. The method as claimed in claim 11, further comprising:
mapping, at the processor module (102), the control command received from the SCADA system (204) to actual switchgear devices for operation; and
forwarding the mapped control commands to a digital output module (106) communicatively coupled to the processor module (102).
, Description:BAY CONTROL UNIT FOR SUBSTATION AUTOMATION SYSTEM
TECHNICAL FIELD
[0001] The present disclosure, in general, relates to a bay control unit (BCU) for substation automation system (SAS) and, in particular, relates to methods to implement the BCU for the SAS using International Electrotechnical Commission (IEC) communication protocol based communication network.
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 systems for supplying electric power to households, factories, or buildings include an electric power plant for producing electric power, one or more transmission lines for transmitting electric power, one or more substations for transforming the amplitude of electric power into a desired amplitude, and one or more distribution lines for distributing electric power to respective areas that require electric power.
[0004] A substation of the electric power systems generally includes electric power equipment, such as a transformer, bus, line, and circuit breaker. The transformer is to transform the amplitude of voltage to be transmitted, the bus is to connect transmission lines, and a circuit breaker is to open and close the electric power flow through the transmission lines. Apart from these electric power equipment, intelligent electronic devices (IEDs) are installed in the substation and are configured to monitor, control, and protect various types of electric power equipment. However, in case a fault occurs in such an IED, it is difficult to properly monitor, control, and protect the electric power equipment, and thus it is difficult to smoothly supply electric power.
[0005] In conventional substations, respective IEDs are directly connected to electric power equipment and independently operated. However, recently, a substation automation system (SAS) in which respective IEDs share information with each other has been adopted.
[0006] IEC 61850 is an international standard for substation automation communication architecture that was proposed in order to implement effective communication between heterogeneous IEDs installed in a substation. IEC 61850 has been established as the only international standard for substation automation, and all IEDs are expected to follow this international standard. In 2012, the second edition of IEC 61850 was released in order to cover new applications and improve interoperability.
[0007] Efforts have been made in state of the art to implement the communication standard IEC 61850 to the SAS. For example, EP Patent number EP 2203754 B1 concerns the operation of substations in which protection, control and measurement devices (IEDs) exchange operational data over a data network, for instance, according to IEC standard 61850.
[0008] Another US Patent number US 9136697 B2 describes that internal communication of a substation can be implemented as defined in IEC 61850 for medium-voltage substations, for example, according to section 5 of IEC 61850 which defines the communication that takes place inside a substation.
[0009] Yet another US Patent number US 8923993 B2 provides substation automation system based on IEC 61850. The system includes components, such as Protection and Control (P&C) IEDs, SA Process Controllers IEDs, each of the IEDs with their own Local Human Machine Interfaces (LHMI), Substation Level Human Machine Interface, and Substation (to Control Centre) Gateway.
[0010] Yet another US Patent Publication number US 2014 0025321 A1 describes that the IED can implement the IEC 61850 communication protocol to allow external IEC 61850 clients to make data and information requests to the IED regarding power usage and power quality for any metered point within a power distribution system. Also, the IED supports IEC 61850 GOOSE, which is a server/client model and is called publisher/subscriber for fast exchange of information.
[0011] Yet another US Patent number US 8532944 B2 describes a substation automation testing tool for IEC 61850 compliant substations is disclosed. The testing tool verifies the configuration of a first Intelligent Electronic Device (IED) that is part of substation automation (SA) system and initially configured to perform the measurement, protection and/or control functions in accordance with a substation configuration specification.
[0012] Yet another EP Patent number EP 2264967 B1 describes interfacing description or structure of an inter-bay substation automation application. IEC 61850 substation configuration description (SCD) file is used to generate a formal description of the interfaces of the inter-bay substation automation application.
[0013] Yet another US Patent number US 8327049 B2 describes that the electrical process interface device has a structuring of its own functionality according to the IEC 61850 communication standard and also communicates over the computer communication network in accordance with this standard.
[0014] Yet another US Patent number US 9478973 B2 describes methods and systems for coordinated transfer of control in a substation system having IED or logical devices/servers using Generic Object Oriented Substation Event (GOOSE) messages with preconfigured data models with logical nodes containing one or more data objects including private data objects (DO) connected in the substation communication network.
[0015] Although this method of utilizing the communication standard IEC 61850 has multiple advantages, the existing substation automation systems are still having a decentralized bay oriented architecture. Such architecture may require separate processing of data and sometimes may result in data loss and data inaccuracy.
[0016] Therefore, there is a need for a system or a method for providing centralized bay architecture utilizing the advantages of the communication standard IEC 61850.
OBJECTS OF THE DISCLOSURE
[0017] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed herein below.
[0018] It is an object of the present disclosure to provide a system and a method for implementing a centralized bay architecture.
[0019] It is another object of the present disclosure to develop interfacing of the data acquisition cards with a processor module, where the processor module may act as an interface for data exchange between data acquisition cards and field communication.
[0020] It is another object of the present disclosure to provide a system and a method to convey the information regarding the techniques involved in the implementation of the information exchange between two elements in the substation automation systems employing the IEC 61850 protocol.
[0021] It is another object of the present disclosure to implement the facility of tracking the existence of a communication either between two intelligent electronic devices (IEDs) at the bay level or between bay and process level.
SUMMARY
[0022] This summary is provided to introduce concepts related to the architecture of bay control unit for substation automation systems. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0023] In an embodiment, a bay control unit (BCU) for substation automation system is described. The BCU includes one or more sensing modules to sense field input data and includes a processor module having a data acquisition module coupled to the one or more sensing modules. The data acquisition module is to receive the field input data from the one or more sensing modules. The received field input data is then processed by the processor module for communicating to an International Electrotechnical Commission (IEC) 61850 compliant supervisory control and data acquisition (SCADA) system as well as to a local graphical user interface (GUI) device. Following the processing, the processor module transmits the processed field input data to the IEC 61850 complaint SCADA system and the local GUI device. In response to the transmission, the processor module receives commands from at least one of the SCADA system and the GUI device. Based on the received command, the data acquisition module of the processor module transmits digital outputs to a digital output/relay module.
[0024] In an aspect of the embodiment, the processor module processes the input filed data by: amplifying and phase correcting the field input data; extracting fundamental component from the amplified and phased corrected field input data using Discrete Fourier Transform (DFT) technique; and mapping a computed value of the extracted fundamental component with IEC 61850 substation automation protocols for communication with the IEC 61850 compliant SCADA system and the local GUI device.
[0025] In a further embodiment, a method for implementing a bay control unit (BCU) for substation automation system is described. In an implementation, the method begins with acquiring analog and digital field data using one or more sensing modules. Following this, the acquired analog and digital field data are transmitted to a processor module from the one or more sensing modules. At the processor module, the acquired analog and digital field data are processed by amplifying and phase correcting the field data; extracting fundamental component from the amplified and phased corrected field data using Discrete Fourier Transform (DFT) technique; and mapping a computed value of the extracted fundamental component with International Electrotechnical Commission (IEC) 61850 substation automation protocols. The processed analog and digital field data are then communicated to the IEC 61850 compliant supervisory control and data acquisition (SCADA) system and a local graphical user interface (GUI) device. In response to the communication, the processor module receives control commands from the SCADA system over the IEC 61850 communication protocol based network.
[0026] In an aspect of the further embodiment, after receiving the control commands from the SCADA system, the processor module maps the control commands received from the SCADA system to actual switchgear devices for operation and forwards the mapped control commands to a digital output module communicatively coupled to the processor module for controlling the operation.
[0027] Thus, with the present subject matter, a centralized bay architecture of bay control unit having one processor module (microprocessor) and a number of data acquisition modules (sensing modules) can be implemented. In such architecture, there would be no data losses and at the same time accuracies would be increased, as all the data processing is performed by a single processor module.
[0028] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:
[0030] FIG. 1 illustrates an exemplary arrangement of various modules housed in a single rack compliant with electromagnetic-interference (EMI) / electromagnetic-compatibility (EMC), in accordance with an exemplary embodiment of the present disclosure;
[0031] FIG. 2 illustrates an exemplary architecture of a bay control unit along with field input(s)/output(s) and supervisory control and data acquisition (SCADA) system, in accordance with an exemplary embodiment of the present disclosure;
[0032] FIG. 3 illustrates an exemplary block diagram of an initialization routine, in accordance with an exemplary embodiment of the present disclosure;
[0033] FIG. 4 illustrates an exemplary block diagram of IEC 61850 server, in accordance with an exemplary embodiment of the present disclosure;
[0034] FIG. 5 illustrates an exemplary block diagram of Generic Object Oriented Substation Event (GOOSE) publisher, in accordance with an exemplary embodiment of the present disclosure;
[0035] FIG. 6 illustrates an exemplary block diagram of Generic Object Oriented Substation Event (GOOSE) subscriber, in accordance with an exemplary embodiment of the present disclosure;
[0036] FIG. 7 illustrates an exemplary block diagram of sampled value subscriber, in accordance with an exemplary embodiment of the present disclosure;
[0037] FIG. 8 illustrates an exemplary block diagram of tracking services, in accordance with an exemplary embodiment of the present disclosure;
[0038] FIG. 9 illustrates an exemplary flow diagram illustrating a method of implementing a base control unit for (BCU) for substation automation systems, in accordance with an exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION
[0039] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; 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.
[0040] 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.
[0041] 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.
[0042] 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 groups used in the appended claims.
Non-Limiting Definitions
[0043] Definitions of one or more terms that will be used in this disclosure are described below without limitations. For a person skilled in the art, it is understood that the definitions are provided just for the sake of clarity, and are intended to include more examples than just provided below.
[0044] The term “bay control unit” means a control unit used for control, protection, and monitoring of bay/feeder equipment in electrical substations. It is applicable to all types of busbar and switchgear arrangement in both gas and air-insulated substations. It is suitable for use in the highest voltage level substations in which very high reliability is required, but can also be applied for industrial substation and automation substations due to its flexible settings and functions. The bay control unit facilitates the controlling remotely through the communication network/bus or locally from a graphical human-machine interface (HMI) on the front panel of the unit.
[0045] The term “substation automation system” refers to a system using data from intelligent electronic devices (IED) and control commands from remote users/devices to control and automate power-system devices of a substation.
[0046] The term “intelligent electronic devices (IEDs)” is used in the electric power industry to describe microprocessor-based controllers of power system equipment, such as circuit breakers, transformers, and capacitor bank. The IEDs are generally responsible for the protection, control, and monitoring of the primary devices of a substation.
[0047] 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.
Overview:
[0048] Exemplary embodiments of the present disclosure provide a bay control unit for substation automation system which performs protection functions for a bay of an electrical power distribution substation, for example, a high and medium power substation, without at least some of the disadvantages of known techniques. For instance, exemplary embodiments of the present disclosure provide a centralized architecture of the bay control unit having one processor module and a number of sensing modules, which provide for failing protection functions, without the costs associated with duplication of the hardware devices which execute the protection functions.
[0049] In an exemplary embodiment, a bay control unit (BCU) for substation automation system is described herein. The BCU includes one or more sensing modules to sense field input data and includes a processor module having a data acquisition module coupled to the one or more sensing modules. The data acquisition module is to receive the field input data from the one or more sensing modules. The received field input data is then processed by the processor module for communicating to an International Electrotechnical Commission (IEC) 61850 compliant supervisory control and data acquisition (SCADA) system as well as to a local graphical user interface (GUI) device. Following the processing, the processor module transmits the processed field input data to the IEC 61850 complaint SCADA system and the local GUI device. In response to the transmission, the processor module receives commands from at least one of the SCADA system and the GUI device. Based on the received command, the data acquisition module of the processor module transmits digital outputs to a digital output/relay module.
[0050] In an aspect of the embodiment, the processor module processes the field input data by: amplifying and phase correcting the field input data; extracting fundamental component from the amplified and phased corrected field input data using Discrete Fourier Transform (DFT) technique; and mapping a computed value of the extracted fundamental component with IEC 61850 substation automation protocols for communication with the IEC 61850 compliant SCADA system and the local GUI device. Those skilled in the art can appreciate that although the communication protocol is described for the communication standard IEC 61850, the present disclosure is not restricted to IEC 61850. In an exemplary implementation, the recent versions of IEC 61850 can be implemented in the present subject matter without deviating from the scope of the present disclosure.
[0051] Thus, with the present subject matter, a centralized bay architecture of bay control unit having one processor module (microprocessor) and a number of data acquisition modules (sensing modules) can be implemented. In such architecture, there would be no data losses and at the same time accuracies would be increased, as all the data processing is performed by a single processor module. Also, as the single processor module is handling all the functions, there are no data transfer delays, in addition to better accuracies and no dependencies.
[0052] Further, in an aspect of the embodiment, the one or more sensing modules include a CT/PT module and a filter module. The CT/PT module includes an instrument transformer to sense input analog signals corresponding to the phase voltages/currents. In an example, the instrument transformer can be one of a current transformer (CT) and a potential transformer (PT). The filter module is to perform band limiting and amplitude scaling to the input analog signals before the input analog signals is digitized for submission to the data acquisition module of the processor module.
[0053] In an aspect of the embodiment, the one or more sensing modules further includes an isolator module to sense and provide a 4-20 mA sensor signal to the data acquisition module.
[0054] In an aspect of the embodiment, the one or more sensing modules further includes a digital input module for providing a status signal from a switchgear in the form of binary data.
[0055] Accordingly, the analog sensing modules will acquire the analog field data and send it to processor module for further communication. Similarly, digital sensing module will acquire the digital field data and sent it to the processor module for further communication. Such fixed functionality modules are advantageous from the point of view of fault diagnosis and easy maintenance. Further, in an example, the analog sensing modules and digital sensing modules can be configured using a configuration tool known in the art.
[0056] In an aspect of the embodiment, the BCU includes a power supply module to supply power to all the modules of the BCU from a single power source.
[0057] In an aspect of the embodiment, the one or more sensing modules are coupled to the processor module through Flat Ribbon Cable (FRC), while the power supply module supplies the power separately through a power cable to one or more sensing modules and the processor module. The separation of power cable and data cable (FRC) provides less interference to the data signals and improve the reliability.
[0058] In an aspect of the embodiment, all the modules of the BCU are housed in a single rack compliant with electromagnetic-interference (EMI) / electromagnetic-compatibility (EMC), and a common power supply is used to power all the modules. Further, as there is no differentiation in the modules for medium voltage and low voltage, the modules are generic and can be used interchangeably. Such configuration of the modules provides modularity and ease of maintenance.
[0059] In a further aspect of the embodiment, the processor module periodically provides output data which is sought by an IEC 61850 compliant external client device.
[0060] In a yet further aspect of the embodiment, the BCU facilitates Generic Object Oriented Substation Event (GOOSE) messaging between bay level and process level Intelligent Electronic Devices (IEDs).
Exemplary Embodiments:
[0061] Various embodiments are further described herein with reference to the accompanying figures. It should be noted that the description and figures relate to exemplary embodiments, and should not be construed as a limitation to the subject matter of the present disclosure. It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the subject matter of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the subject matter of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof. Yet further, for the sake of brevity, operation or working principles pertaining to the technical material that is known in the technical field of the present disclosure have not been described in detail so as not to unnecessarily obscure the present disclosure.
[0062] FIG. 1 illustrates an exemplary arrangement of all modules of a bay control unit (BCU) 100 in a single rack compliant with electromagnetic-interference (EMI) / electromagnetic-compatibility (EMC), in accordance with an exemplary embodiment of the present disclosure.
[0063] As can be seen from FIG. 1, the single rack includes a single processor module 102, four digital input modules 104, two digital output modules 106, one isolator module 108, one filter module 110, two CT/PT module 112, and a power supply module 114. Apart from these documents, the front panel of the rack provides a local human machine interface (HMI) / graphical user interface (GUI) 116 for local supervision or controlling of substation devices.
[0064] The details of the BCU 100 are described with reference to FIG. 2. FIG. 2 illustrates a centralized architecture of the BCU 100 in accordance with an exemplary embodiment of the present disclosure.
[0065] FIG. 2 illustrates various components of a proposed BCU 100. In an example, the BCU 100 may be implemented in a computing device which can communicate with other computing devices through a communication network. The communication network may be implemented as one of the different types of networks, such as Local Area Network (LAN), serial (RS232 and RS485) and the like. The communication network may either be a dedicated network or a shared network. Further, the communication network may include a variety of network devices, including routers, bridges, servers, computing devices, storage devices, and the like.
[0066] In an example implementation, the BCU 100 may include a processor module 102. The processor module 102 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, logic circuitries, and/or any devices that manipulate data based on operational instructions. Among other capabilities, the processor module 102 is configured to fetch and execute computer-readable instructions stored in a memory (not shown) of the processor module 102. The memory may store one or more computer-readable instructions or routines, which may be fetched and executed to acquire or share the field data over a network service. The memory may include any non-transitory storage device including, for example, volatile memory such as RAM, or non-volatile memory such as EPROM, flash memory, and the like.
[0001] The processor module 102 may also include an interface(s) (not shown in figures). The interface(s) may include a variety of interfaces, for example, interfaces for data input and output devices referred to as I/O devices, storage devices, and the like. The interface(s) may facilitate communication of the processor module 102 with various devices coupled to the processor module 102. The interface(s) may also provide a communication pathway for one or more components of the processor module 102. Examples of such components include, but are not limited to, the data acquisition module 202.
[0002] The data acquisition module 202 may be implemented as a combination of hardware and programming (for example, programmable instructions) to implement one or more functionalities of the data acquisition module 202. In examples described herein, such combinations of hardware and programming may be implemented in several different ways. For example, the programming for the data acquisition module 202 may be processor executable instructions stored on a non-transitory machine-readable storage medium and the hardware for the data acquisition module 202 may include a processing resource (for example, one or more processors), to execute such instructions. In the present examples, the machine-readable storage medium may store instructions that, when executed by the processing resource, implement the data acquisition module 202. In such examples, the processor module 102 may include the machine-readable storage medium storing the instructions and the processing resource to execute the instructions or the machine-readable storage medium may be separate but accessible to the processor module 102 and the processing resource. In other examples, the data acquisition module 202 may be implemented by electronic circuitry.
[0003] Further, the processor module 102 is communicatively coupled to an International Electrotechnical Commission (IEC) 61850 compliant supervisory control and data acquisition (SCADA) system 204 as well as to a local graphical user interface (GUI) / HMI 116.
[0067] In operation, one or more sensing modules (data acquisition modules) periodically acquire analog and digital field input data.
[0068] For acquiring analog field input data, the one or more sensing modules include the CT/PT module 112 and the filter module 110. The CT/PT module 112 may include an instrument transformer (not shown in figures) to sense input analog signals corresponding to the phase voltages/currents in electrical devices. In an example, the instrument transformer can be one of a current transformer (CT) and a potential transformer (PT). The filter module 110 is to perform band limiting and amplitude scaling to the input analog signals before the input analog signals is digitized for submission to the data acquisition module 202 of the processor module 102. Also, in an aspect, the one or more sensing modules further includes an isolator module to sense and provide a 4-20 mA sensor signal to the data acquisition module 202.
[0069] For acquiring digital field input data, the one or more sensing modules include a digital input module 104 for providing a status signal, from switchgear, in the form of binary data to the data acquisition module 202.
[0070] In an exemplary implementation, all the inputs from the field are subjected to required signal conditioning before digitizing.
[0071] Once the analog and digital field input data is acquired, the processor module 102 processes the field data by: amplifying and phase correcting the field data; extracting fundamental component from the amplified and phased corrected field data using Discrete Fourier Transform (DFT) technique; and mapping a computed value of the extracted fundamental component with IEC 61850 substation automation protocols for communication with the IEC 61850 compliant SCADA system 204 and the local GUI/HMI 116. Those skilled in the art can appreciate that although the communication protocol is described for the communication standard IEC 61850, the present disclosure is not restricted to IEC 61850. In an exemplary implementation, the recent versions of IEC 61850 can be implemented in the present subject matter without deviating from the scope of the present disclosure.
[0072] In an exemplary implementation, all the modules of the BCU 100 are powered with a 24V DC which is derived from a universal input supply module 114.
[0073] Continuing with the present disclosure, following the processing, the processor module transmits the processed field input data to the IEC 61850 complaint SCADA system 204 and the local GUI/HMI 116. In response to the transmission, the processor module 102 receives commands from at least one of the SCADA system 204 and the GUI/HMI 116. Based on the received command, the data acquisition module 202 of the processor module 102 transmits digital outputs to a digital output/relay module 106. In an exemplary implementation, each digital module 106 caters 16 digital outputs.
[0074] In an exemplary implementation, the BCU 100 may utilize a communication module having 4 number of RS232, 2 number of RS485 and 2 number of LAN ports for communicating with low-end energy meters and high-end SCADA system 204.
Exemplary Implementations:
[0075] Further, the BCU 100 for substation automation systems may be implemented using application code developed in C language in Real-Time Operating System (RTOS) environment, as RTOS provides greater timing accuracy. Herein, the application is designed as multiple processes with multiple threads. Each thread is designed to perform a particular task. For an application, algorithms have been developed for analog and digital data acquisition, measurement, sequence of events (SOE) recording, alarms recording, and data transfer over IEC 61850 substation protocol.
[0076] In an exemplary implementation, the entire implementation of IEC 61850 in the proposed architecture is divided into the following subsystems:
i. IEC 61850 Server module: This module provides all IEC 61850 communication as well as data model of IED for external IEC 618S0 clients. When client requests for any of the IEC 61850 services, this module facilitates all the validation and provides accession of data through IEC 61850 data models configured via Substation Configuration Language (SCL) eXtensible Markup Language (XML) file. All IEC 61850 client requests are addressed via pre-registered leaf functions. This module passes the logical control to IED interface module whenever it needs access to IED data. This is the first threaded module of IEC 61850 server implementation.
ii. IEC Generic Object Oriented Substation Event (GOOSE) Publisher: This module facilitates the publishing of multi-cast GOOSE packets to media access control (MAC) addresses according to SCL definitions. Hence, it provides GOOSE data to external IEC GOOSE subscribers via IEC GOOSE communication. Whenever there is any change in GOOSE data from IED, this module facilitates all the validation and provides publication of data through IEC GOOSE publisher control blocks configured via SCL XML (SCD) file. This module uses shared memory data copy to identify the changes in GOOSE data. This is the second threaded module of IEC 61850 server implementation.
iii. IEC Generic Object Oriented Substation Event GOOSE Subscriber: This module facilitates subscribing of multicast GOOSE packets from MAC addresses according to the External Reference in SCL definitions. Hence, it provides GOOSE data from external IEC GOOSE publishers to the defined IED. Whenever there is any changed GOOSE data from the subscriber module, it informs the IED via the shared memory. This is the third threaded module of IEC 61850 server implementation.
iv. Sampled Value Subscriber: This module facilitates the subscribing of multi-cast sampled value packets from MAC addresses according to the External Reference in SCL definitions. Hence, it provides sampled value data from the External Sampled Value publishers to IED. Whenever it receives Sampled Value data from subscriber module, it informs the defined IED via the shared memory. This is the fourth threaded module of Sampled Value driver implementation.
[0077] The technique of implementing the service-tracking facility as per the edition 2 of IEC 61850 had been implemented which can be employed in the above-mentioned modules to allow the client to track the services in a communication.
Initialization Module
[0078] FIG. 3 shows a block diagram of an initialization routine/module which describes the basic flow of initialization sequences of IEC 61850 server driver. As can be seen from Fig. 3, SCD file 302 is the main configuration file. BCU-IEC Map file 303 is a configuration file concerned with IED application and IEC 61850 application put in a configuration text file consisting of shared memory type (IN & OUT data types) and shared memory index for each of the IEC 61850 data in the IED section of the SCD file 302. IEC 61850 application internally loads the configuration file 303 at start-up and reads-and-writes shared memory data according to the configuration.
[0079] Further, a StartUp.cfg file 301 is provided to the IED user to facilitate the parsing of SCD file 302 using SCL parser 305 compliant with IEC 61850 Edition 2.0 SCL schema for this user’s IED.
[0080] Yet further, the IED Data Mapping module 308 is using the configuration file 303 provided by the IED User to identify the mapping information related to the IED and IEC 61850 data objects. The IED Data Mapping module 308 fills the IEC 61850 server index and shared memory address and type information to the respective IEC 61850 data structures 313. At runtime, this information is used by IED Data Mapping module 308 to feed data from the IED shared memory to IEC 61850 server database.
[0081] Yet further, a dynamic object creator takes the IEC 61850 - MMS (Multimedia Messaging Service) configuration file as an input to initialize the MMS connections as well as the MMS global objects 304. The MMS global objects 304 also configure the logging and initialize a memory subsystem.
[0082] Yet further, the SCD file 302 gets parsed further to decode the type information details. Also, logical device instance(s) 309 are created along with the logical node instances 310 using SCL data type information 307.
[0083] Control blocks 311, such as buffered report control blocks, un-buffered report control blocks, setting group control blocks, SV (Sampled Value), and GOOSE control blocks, service tracking 314 are initialized further by supervisory LN objects 315.
[0084] After creating the base objects, the corresponding functions are attached to each of the leaf variables in the form of leaf functions 312. This information is used at run-time for reading/write operations. The initialization of IEC 61850 server structures helps in the entire implementation module for easy and fast access to IEC 61850 and IED data at runtime.
IEC 61850 Server
[0085] FIG. 4 shows a block diagram of IEC 61850 server routine which describes the basic operation of IEC 61850 server functionality. As can be seen from FIG. 4, IEC 61850 server module handles all the IEC 61850 operations. The operations include servicing client requests 401 with client specific responses 408, validation of client requests 401, and passing read-write indications 402, 403 to internal data structures 404, 405. The other important operation or functionality of this IEC 61850 server module is to handle control blocks 406 according to client specified parameters. This handling includes handling of buffered and un-buffered report control blocks, setting group control blocks, and log control blocks.
[0086] Providing data information into IEC 61850 server module is done by the data structures 404, 405. Hence, these structures 404, 405 are referred dynamically by the IEC 61850 server module for any transactions with external clients.
[0087] There are specific functions for handling report data and log data. Such specific functions are performed by report servicing module 407. Log file recycling of entire system, limiting of maximum size and acting as a circular file is managed by this report servicing module 407. This functionality helps entire system to not use disk capacity in an unlimited manner.
IEC GOOSE Publisher
[0088] FIG. 5 shows a block diagram of the GOOSE publisher which describes IEC 61850 GOOSE publisher functionality. As can be seen from FIG. 5, the IEC GOOSE publisher module 501 handles all the GOOSE data publishing operations and enable/disable of GOOSE control blocks by any external clients. This IEC GOOSE publisher module 501 detects the data changes 503 in GOOSE dataset variables and trigger new GOOSE publishing 504 for that specific GOOSE control block. Retransmission 505 of the triggered GOOSE, packets are handled by a separate function which takes care of fast and slow publishing of GOOSE packets into subnet interface 506.
[0089] GOOSE module demands more performance than IEC 61850 server in terms of its functionality of putting packets to Ethernet interface bypassing many intermediate MMS layers. This makes GOOSE a connectionless protocol, which in turn demands retransmissions. This ensures the receiving of GOOSE packets at the other end even if there is any packet loss. Subscribers who are interested in BCU’s GOOSE packets will be receiving the same in an efficient manner because of this retransmission mechanism of IEC GOOSE module.
[0090] Further, in accordance with an exemplary implementation, a fixed number of GOOSE control blocks are dedicated for GOOSE publishing. Accordingly, the user can assign any dataset to these GOOSE control blocks while creating ICD / CID files. The user can also create new dynamic datasets for these publisher GOOSE control blocks.
IEC GOOSE Subscriber
[0091] FIG. 6 shows a block diagram of GOOSE subscriber which describes IEC 61850 GOOSE Subscriber functionality. With reference to FIG. 6, IEC GOOSE subscriber module 601 handles all the GOOSE data receiving operations and enable/disable of GOOSE control blocks by any external client. The IEC GOOSE subscriber module 601 detects the data changes in GOOSE dataset variables received and updates the same to pre-configured shared memory data structure blocks 604. This IEC GOOSE subscriber module 601 also simultaneously updates the status in a GOOSE supervision logical node module 605 for any client to monitor the status.
[0092] In an implementation, subnet interface module 605 is registered to receive GOOSE packets only for the required MAC addresses. The IEC GOOSE subscriber module 601 demands more performance than IEC 61850 server in terms of its function of receiving packets from Ethernet interface by avoiding many intermediate MMS layers. The configuration of subscriber GOOSE control blocks are handled in the following manner:
i. External inputs section in the SCD File 302 provides information of remote data attributes that may come from remote Publishers.
ii. During the creation of an SCD file 302, the SCL user should know about the details of all remote GOOSE control blocks and their respective datasets, to which the IED is going to subscribe.
iii. As per Edition 2 of IEC 61850, the remote IED details should be present in the SCD file 302.
iv. The dataset elements in the subscribed GOOSE datasets are mapped to digital output values of the shared memory using BCU - IEC 61850 map file 303.
Sampled Value Subscriber
[0093] FIG. 7 shows a block diagram of the Sampled Value subscriber which describes IEC 61850 Sampled Value subscriber functionality. With reference to FIG. 7, it is understood that the Sampled Value Subscriber module 701 handles reception of analog data from Ethernet which are sent by Sampled Value Publishers. This Sampled Value Subscriber module 701 only fetches the sampled values (SV) from the Ethernet network and filters sampled values packets (702) and dumps the same to the corresponding shared memory 704 using the data mapping and writing module 703.
[0094] This Sampled Value Subscriber module 701 also simultaneously updates the status in the sampled value supervision logical node module 705 for any client to monitor the status. There is no periodicity for the operations because the reception is handled by consecutive Ethernet read functions. Subnet interface 706 is registered to receive sampled value packets only for the required MAC addresses. The configuration of Subscriber Sampled Value Control Blocks (SVCB) is handled in the following manner:
a. External Inputs section in SCD File 302 provides information of remote data attributes from remote Sampled Value Publishers. The binding of external signals defined by “Inputs” tags. This section allows binding of an external signal to an IED internal address.
b. During the creation of an SCD file 302, the SCL user should know about the details of all remote SV control blocks and their respective datasets, to which the IED is going to subscribe. Data mapping should be done using the SCL Tool accordingly.
c. As per the Edition 2, the remote IED details should be present in the SCD file.
[0095] The dataset elements in the subscribed SV packets are mapped to ANALOG output for SV quality and FLOAT output for SV data of the shared memory using the BCU - IEC 61850 Map file 303.
Service Tracking:
[0096] FIG. 8 shows a block diagram of the tracking services in which the tracking details are updated by the respective modules when changing the configuration or runtime values. With reference to FIG. 8, it is understood that the tracking details are updated by the respective modules (801-804) when changing configuration or runtime values. These values are sent to the client (408), whenever the client requests (401) for an indication from the server side. The following tracking services are implemented as per the IEC 61850 Edition 2 standard:
a. Continuously monitors the current BRCB (Buffered Report control Block) values of the module (801) and the old BRCB values and updates the data to BRCB tracking node of the module (805).
b. Continuously monitors the current URCB (Un-Buffered Report Control Block) values of the module (801) and the old URCB values and updates the data to URCB tracking node of the module (805).
c. Continuously monitors the current GOCB (GOOSE Control Block) values of the module (802) and the old GOCB values and updates the data to GOCB tracking node of the module (805).
d. Tracks the select operation in the module (803) and updates the data according to the single point or double point control of module (805).
e. Tracks the cancel operation in the module (803) and updates the data to according to the single point or double point control cancellation of the module (805).
f. Tracks the select with value and operation in the module (803) and updates the data according to the single point or double point control of module (805).
g. Tracks the SGCB (Setting Group Control Block) parameters in the module (804) and updates the data to SGCB tracking node of the module (805).
[0097] FIG. 9 illustrates example method 900 for implementing bay control unit (BCU) 100 for substation automation system. The order in which the method 900 is described is not intended to be construed as a limitation, and any number of the described method blocks may be combined in any order to implement the method 900, or an alternative method. Furthermore, method 900 may be implemented by processing resource or computing device(s) through any suitable hardware, non-transitory machine-readable instructions, or combination thereof.
[0098] It may also be understood that methods 900 may be performed by programmed computing devices, such as computing device(s) or processor module 102 as depicted in FIGS. 1-2. Furthermore, the method 900 may be executed based on instructions stored in a non-transitory computer-readable medium, as will be readily understood. The non-transitory computer-readable medium may include, for example, digital memories, magnetic storage media, such as one or more magnetic disks and magnetic tapes, hard drives, or optically readable digital data storage media. The method 900 is described below with reference to the processor module 102 and the BCU 100 as described above; other suitable systems/devices for the execution of the method 900 may also be utilized. Additionally, implementation of the method 900 is not limited to such examples.
[0099] At block 902, analog and digital field input data are obtained using one or more sensing modules. In an example, the analog field input data may be obtained using modules including, but not limited to, CT/PT module 112, filter module 110, and isolator module 108, while the digital field input data may be obtained using modules including, but not limited to, digital input modules 104.
[00100] At block 904, the acquired analog and digital field input data are transmitted from the one or more sensing modules to a processor module.
[00101] At block 906, the processor module processes the received field input data by amplifying and phase correcting the field input data; extracting fundamental component from the amplified and phased corrected field input data using Discrete Fourier Transform (DFT) technique; and mapping a computed value of the extracted fundamental component with International Electrotechnical Commission (IEC) 61850 substation automation protocols.
[00102] At block 908, the processor module communicates the processed analog and digital field input data to the IEC 61850 compliant supervisory control and data acquisition (SCADA) system and a local graphical user interface (GUI) / Human Machine Interface (HMI).
[00103] At block 910, the processor module receives control commands from the SCADA system over the IEC 61850 communication protocol based network, for controlling the operations of one or more electrical devices of the substation.
[00104] Thus, with the present subject matter, a centralized bay architecture of bay control unit having one processor module (microprocessor) and a number of data acquisition modules (sensing modules) can be implemented. In such architecture, there would be no data losses and at the same time accuracies would be increased, as all the data processing is performed by a single processor module. Also, as the single processor module is handling all the functions, there are no data transfer delays, in addition to better accuracies and no dependencies.
[00105] The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[00106] Note that throughout the following discussion, numerous references may be made regarding servers, services, engines, modules, interfaces, portals, platforms, or other systems formed from computing devices. It should be appreciated that the use of such terms are deemed to represent one or more computing devices having at least one processor configured to or programmed to execute software instructions stored on a computer-readable tangible, non-transitory medium or also referred to as a processor-readable medium. For example, a server can include one or more computers operating as a web server, database server, or another type of computer server in a manner to fulfill described roles, responsibilities, or functions. Within the context of this document, the disclosed devices or systems are also deemed to comprise computing devices having a processor and a non-transitory memory storing instructions executable by the processor that cause the device to control, manage, or otherwise manipulate the features of the devices or systems.
[00107] It should be understood, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, as apparent from the discussion herein, it is appreciated that throughout the description, discussions utilizing terms such as “acquiring” or “receiving” or “communicating” or “processing” or the like, refer to the action and processes of a computing machine, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.
[00108] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[00109] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[00110] 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.