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10 Communication
are the same report according to the timestamps. Clock synchronization error of the IED may lead
to report loss/redundancy.
As a conclusion:
In mode 2, it's difficult to realize seamless switchover between dual nets;
In mode 3, the IED may be unable to provide enough report instances if too many clients are
applied on site.
For the consideration of client treatment and IED implementation, mode 1 (Dual -net full duplex
mode sharing the same report instance) is recommended for MMS communication network
deployment.
10.4.4 Server Data Organization
IEC61850 defines an object-oriented approach to data and services. An IEC61850 physical device
can contain one or more logical device(s) (for proxy). Each logical device can contain many logical
nodes. Each logical node can contain many data objects. Each data object is composed of data
attributes and data attribute components. Services are available at each level for performing
various functions, such as reading, writing, control commands, and reporting.
Each IED represents one IEC61850 physical device. The physical device contains one logical
device, and the logical device contains many logical nodes. The logical node LPHD contains
information about the IED physical device. The logical node LLN0 contains information about the
IED logical device.
10.4.4.1 Digital Status Values
The GGIO logical node is available in the PCS-9600 series relays to provide access to digital
status points (including general I/O inputs and warnings) and associated timestamps and quality
flags. The data content must be configured before the data can be used. GGIO provides digital
status points for access by clients. It is intended that clients use GGIO in order to access digital
status values from the PCS-9600 series relays. Clients can utilize the IEC61850 buffered reporting
features available from GGIO in order to build sequence of events (SOE) logs and HMI display
screens. Buffered reporting should generally be used for SOE logs since the buffering capability
reduces the chances of missing data state changes. All needed status data objects are transmitted
to HMI clients via buffered reporting, and the corresponding buffered reporting control block
(BRCB) is defined in LLN0.
10.4.4.2 Analog Values
Most of the analog measured values are available through the MMXU logical nodes, and metering
values in MMTR, the others in MMXN, MSQI and so on. Each MMXU logical node provides data
from an IED current/voltage "source". There is one MMXU available for each configurable source.
MMXU1 provides data from CT/VT source 1 (usually for protection purpose), and MMXU2
provides data from CT/VT source 2 (usually for monitor and display purpose). All these analog
data objects are transmitted to HMI clients via unbuffered reporting periodically, and the
corresponding unbuffered reporting control block (URCB) is defined in LLN0. MMXUx logical
nodes provide the following data for each source:
10-12
PCS-9611 Feeder Relay
Date: 2014-04-08
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