GE D90 Plus Instruction Manual page 131

CHAPTER 6: COMMUNICATIONS
Remote devices
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Dataset Item 1, Dataset Item 2, Dataset Item 3,..., Dataset Item 64
Range: all valid MMS data item references for transmitted data
Default: 0
These settings are used to select an MMS data item for each configurable GOOSE
dataset item.
Remote inputs and outputs provide a means to exchange digital state information
between Ethernet-connected devices. The IEC 61850 Generic Substation State Event (GSSE)
and Generic Object Oriented Substation Event (GOOSE) standards are used for this
purpose.
The sharing of digital point state information between GSSE/GOOSE equipped relays is
essentially an extension of FlexLogic, allowing for distributed FlexLogic by making
operands available to and from devices on a common communications network. In
addition to digital point states, GSSE/GOOSE messages identify the originator of the
message and provide other information required by the communication specification. All
devices listen to network messages and capture data only from messages that have
originated in selected devices.
IEC 61850 GSSE messages are compatible with UCA GOOSE messages and contain a fixed
set of digital points. IEC 61850 GOOSE messages can, in general, contain any configurable
data items. When used by the remote inputs and outputs feature, IEC 61850 GOOSE
messages contain the same data as GSSE messages.
Both GSSE and GOOSE messages are designed to be short, reliable, and have high priority.
GOOSE messages have additional advantages over GSSE messages due to their support of
virtual LAN (VLAN) and Ethernet priority tagging functionality. The GSSE message structure
contains space for 128 bit pairs representing digital point state information. The IEC 61850
specification provides 32 DNA bit pairs that represent the state of two pre-defined events
and 30 user-defined events. All remaining bit pairs are UserSt bit pairs, which are status
bits representing user-definable events. The D90
available UserSt bit pairs.
The IEC 61850 specification includes features that are used to cope with the loss of
communication between transmitting and receiving devices. Each transmitting device
sends a GSSE/GOOSE message upon successful power-up, when the state of any included
point changes, or after a specified interval (the default update time) if a change-of-state
has not occurred. The transmitting device also sends a hold time that is the GSSE
equivalent of "time to live" in IEC GOOSE messages.
Receiving devices constantly monitor the communications network for required messages,
as recognized by the identification of the originating device carried in the message.
Messages received from remote devices include the message time allowed to live. The
receiving relay sets a timer assigned to the originating device to this time interval, and if it
has not received another message from this device at time-out, the remote device is
declared to be non-communicating, so it uses the programmed default state for all points
from that specific remote device. If a message is received from a remote device before the
time allowed to live expires, all points for that device are updated to the states contained in
the message and the hold timer restarts. The status of a remote device, where "Offline"
indicates non-communicating, can be displayed.
Plus
The D90 provides for 64 remote inputs and 64 remote outputs.
Plus
In a UR -series IED, the device ID that identifies the originator of the message is
programmed in the
IED Name
Select the Settings > Communications > IEC 61850 > GSSE/GOOSE Configuration >
Inputs/Outputs > Remote Devices menu to open the remote devices configuration
window.
Plus
implementation provides 32 of the 96
setting.
IEC 61850 COMMUNICATIONS
121