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© OMICRON Process Bus and Sampled Process Bus and Sampled Values Based Applications Values Based Applications Dr. Alexander Apostolov Los Angeles, CA
© OMICRON
Process Bus and Sampled Process Bus and Sampled Values Based ApplicationsValues Based Applications
Dr. Alexander ApostolovLos Angeles, CA
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Analog Signal Processing in ISDAnalog Signal Processing in ISD
AnalogInput
Module
MultifunctionISD
OptoInput
Module
RelaInput
Module
FunctionModule
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Analog Signal Processing in ISDAnalog Signal Processing in ISD
Multiplexer
A/D Converter
Data Bus
AnalogInput
Module
FunctionModule
Analog Filters
Analog Filters
Analog Filters
Input X-er
Input X-er
Input X-er
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Distributed FunctionsDistributed Functions
BayComputer
Distributed function
P...
Protection IED
R…
P…
LogicalConnection 1
LogicalConnection 2
Protection IED
R…
P…
Interface 8
Interface 8
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Merging UnitMerging Unit
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Merging Unit DelayMerging Unit Delay
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• Time synchronization is essential to any event analysis system
• There are two common ways of synchronizing various devices to the same clock source:
• Synchronization over direct connection• Network synchronization
Time synchronizationTime synchronization
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• Accomplished using SNTP Simple Network Time Protocol
• SNTP is in essence a subset of NTP (Network Time Protocol). NTP uses UTC (Universal Time Coordinated, Temps Universel Coordonné) as reference time.
• UTC is an official standard for the current time and evolved from the former GMT (Greenwich Mean Time).
IEC 61850 Time SynchronizationIEC 61850 Time Synchronization
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• The UTC second has been defined by the 13th General Conference of Weights and Measures in 1967 as "The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom."
IEC 61850 Time SynchronizationIEC 61850 Time Synchronization
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• SNTP accuracy is not sufficient for SAV time synchronization
• IEEE 1588 is the future standard
Time synchronizationTime synchronization
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Distributed Analog FunctionsDistributed Analog Functions
Protection Device
Distributedanalog function
IF 4 LC1
RDRE
TCTR
LC2AnalogInterface
Unit
IF 4 AnalogInterface
Unit
TVTRTCTR
TVTR
TCTR
LCn
IF 4
TVTR
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Logical InterfacesLogical InterfacesTechnical ServicesRemote control (NCC)
CONTR. PROT.
FCT. A FCT. B
PROT. CONTR.
Sensors Actuators
BAY/UNIT LEVEL
STATION LEVEL
PROCESS LEVEL
HV Equipment
Remote protection
Process Interface
1,6
3 3
9
8
1,6
2 2
4,54,5
710
Remote protection
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61850-9-1/2
Waveform Recording Based on Waveform Recording Based on Sampled Measured ValuesSampled Measured Values
SAVWaveformRecordingFunction
Recording IED
TCTR
TVTRMerging Unit
Data Set andSAV
Formatting
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Sampled Measured ValuesSampled Measured Values
DOcf-attrdc-attr
MX attr
DOcf-attrdc-attr
MX attr
Publisher
ACSI
SVC
DATA:SAVcf-attrdc-attr
MX attr
Trans-missionBuffer
ControlBuffer
Sample.req
DATA-SET
Local issue
SendSMVMessage(Communicationmapping specific)
Member
Member
Member
FCDA1
FCDA2
FCDA3
MemberReference( = Functionallyconstraint DATA-ATTRIBUTE)
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Recording IEDRecording IED
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Distributed Recording SystemDistributed Recording System
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RDRE Logical Node Data RDRE Logical Node Data ObjectsObjects
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Object Model MappingObject Model Mapping
RDRE
RADR
RBDR
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Distributed Recording SystemDistributed Recording System
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IntroductionIntroduction
• IEC 61850 is now an approved international standard
• It allows the development of a new generation of distributed applications
• Distributed analogue values applications are analysed in this paper
• Devices conforming with the new communications standard are available from multiple vendors
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Ethernet FrameEthernet FramePre SFD DA SA Length
TypeMAC Data + Pad FCS
7 1 6 6 2 46-1500bytes 4
• Pre: The Preamble is an alternating pattern (7 bytes) of 1 and 0 that tells receiving stations that a frame is coming
• SFD: Start-of-frame delimiter (1 byte: 10101011) indicating that the next bit is the left-most bit in the left-most byte of the destination address.
• DA: Destination address (6 bytes) identifies which station(s) should receive the frame
• SA: Source addresses (6 bytes) identifies the sending station
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Ethernet FrameEthernet FramePre SFD DA SA Length
TypeMAC Data + Pad FCS
7 1 6 6 2 46-1500bytes 4
• Length Type: Number of MAC-client data bytes that are contained in the data field of the frame
• MAC Client Data: A sequence of n bytes (46=< n =<1500) of any value. (The total frame minimum is 64 bytes). The Pad contains (if necessary) extra data bytes in order to bring the frame length up to its minimum size. A minimum Ethernet frame size is 64 bytes from the Destination MAC Address field through the Frame Check Sequence.
• FCS: The Frame Check Sequence is a 32-bit cyclic redundancy check (CRC) value
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Addressing ModesAddressing Modes
• Unicast communication takes place over the network between a single sending IED and a single receiving IED. The Destination Address identifies a unique device that will receive the Ethernet frame.
• Multicast is the addressing mode in which a given frame is targeted to a group of logically related IEDs. In this case the Destination Address is the Multicast Address, also called a "group" address.
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Addressing ModesAddressing Modes
• Broadcast is the mode when an IED is sending a frame to all devices connected to the substation network.
• The Destination Address in this case is a Broadcast Address - a multicast address identifying the group of all devices on a network - all 1 bits.
• The Broadcast Domain includes all network segments joined together by bridges.
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Logical InterfacesLogical Interfaces
• IF1: protection-data exchange between bay and station level
• IF2: protection-data exchange between bay level and remote protection
• IF3: data exchange within bay level• IF4: CT and VT instantaneous data
exchange (especially samples) between process and bay level
• IF5: control-data exchange between process and bay level
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Logical InterfacesLogical Interfaces
• IF6: control-data exchange between bay and station level
• IF7: data exchange between substation (level) and a remote engineer’s workplace
• IF8: direct data exchange between the bays especially for fast functions like interlocking
• IF9: data exchange within station level• IF10: control-data exchange between
substation (devices) and a remote control center
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Optical CT InterfaceOptical CT Interface
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Transmission of Sampled Transmission of Sampled ValuesValues
• The transmission of sampled values requires special attention with regard to the time constraints.
• The model provides transmission of sampled values in an organized and time controlled way so that the combined jitter of sampling and transmission is minimized to a degree that an unambiguous allocation of the samples, times, and sequence is provided.
• The model applies to the exchange of values of a DATA-SET (DATA of the common data class SAV).
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Transmission of Sampled Transmission of Sampled ValuesValues
• The information exchange shall be based on a publisher/subscriber mechanism.
• The publisher shall write the values in a local buffer at the sending side.
• The subscriber shall read the values from a local buffer at the receiving side.
• A time stamp shall be added to the values, so that the subscriber can check the timeliness of the values.
• A sampled value control (SVC) in the publisher shall be used to control the communication procedure.
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Sampled Measured Values Sampled Measured Values Based ModelBased Model
SMVProtection
LN
RelayOutput Module
Protection ISD
TCTR
TVTR
MMXU
Merging Unit
Data Set andSMV
Formatting
61850-9-1/2
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Sampled Measured ValuesSampled Measured Values
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Transmission of Sampled Transmission of Sampled ValuesValues
• The transmission of sampled values using multicast (MULTICAST-SAMPLE-VALUE CONTROL- BLOCK – MSVCB) shall be based on configuration in the publishing device.
• To support self-descriptive capabilities, any client may read the attributes of the sampled value control instance.
• Authorized clients may modify attributes of the sampled value control.
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Transmission of Sampled Transmission of Sampled ValuesValues
• The data exchange shall be based on the multicast application association.
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Transmission of Sampled Transmission of Sampled ValuesValues
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Transmission of Sampled Transmission of Sampled ValuesValues
• The transmission of sampled values using unicast(UNICAST-SAMPLE-VALUE- CONTROL- BLOCK –MSVCB) shall be based on two-party application associations.
• The subscriber shall establish the association with the producer.
• The subscriber may then configure the class and enable the transmission of the sampled values with the attribute SvEna.
• When the association is released, the transmission of the sampled values shall stop and the instance of the control class shall be released.
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Distributed Analog FunctionsDistributed Analog Functions
Protection Device
Distributed analogfunction
PDIF
Analog Interface Unit
TCTR
TVTR
LogicalConnection 1
LogicalConnection 2
Analog Interface Unit
TCTR
TVTR
Analog Interface Unit
TCTR
TVTRLogicalConnection n
Interface 4
Interface 4
Interface 4
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Disturbance RecordingDisturbance Recording
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Transmission systems Transmission systems --waveform recordwaveform record
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SAV Waveform Recording SAV Waveform Recording Object ModelObject Model
TCTR
TVTR
RDRE
RADR
RBDRXCBR
Pxxx
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RDRE Logical Node Data ObjectsRDRE Logical Node Data Objects
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Object Model MappingObject Model Mapping
RDRE
RADR
RBDR
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CT SaturationCT Saturation
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CCVT 3rd HarmonicCCVT 3rd Harmonic
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NonNon--conventional Sensor Interfaceconventional Sensor Interface
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Optical CTOptical CT
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Protection Applications Based Protection Applications Based on SAVon SAV
ProcessControl
Process
Protection ISD
Interface Module
Function Module
Outputs Module
Process
Process
Merging Unit
Control Interface Unit
Analog Sensor
Status Sensor
Sensor Module
Input Module
Interface Module
Interface Module
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Interoperability Demo at CIGRE Interoperability Demo at CIGRE 20042004
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Interoperability Demo at CIGRE Interoperability Demo at CIGRE 20042004
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Mapping to IEC 61850 9Mapping to IEC 61850 9--2:2:
• The mapping provides the capability to concatenate more than one ASDU into one APDU before the APDU is posted into the transmission buffer.
• The numbers of ASDUs which will be concatenated into one APDU are configurable and related to the sample rate.
ASDU’s(Application – Service Data Unit)
Tag Length ASDU 1 ASDU 2 ASDU nNo. of ASDUs (UI16)
APCI(Application – Protocol Control Information)
IEC 098/04APDU (Application – Protocol Data Unit)
