GE Multilin B30 Bus Differential System C-7APPENDIX C C.4 GENERIC SUBSTATION EVENT SERVICES: GSSE AND GOOSECC.4GENERIC SUBSTATION EVENT SERVICES: GSSE AND GOOSE C.4.1 OVERVIEWIEC 61850 specifies two types of peer-to-peer data transfer services: Generic Substation State Events (GSSE) and GenericObject Oriented Substation Events (GOOSE). GSSE services are compatible with UCA 2.0 GOOSE. IEC 61850 GOOSEservices provide virtual LAN (VLAN) support, Ethernet priority tagging, and Ethertype Application ID configuration. The sup-port for VLANs and priority tagging allows for the optimization of Ethernet network traffic. GOOSE messages can be givena higher priority than standard Ethernet traffic, and they can be separated onto specific VLANs. Because of the additionalfeatures of GOOSE services versus GSSE services, it is recommended that GOOSE be used wherever backwards com-patibility with GSSE (or UCA 2.0 GOOSE) is not required.Devices that transmit GSSE and/or GOOSE messages also function as servers. Each GSSE publisher contains a “GSSEcontrol block” to configure and control the transmission. Each GOOSE publisher contains a “GOOSE control block” to con-figure and control the transmission. The transmission is also controlled via device settings. These settings can be seen inthe ICD and/or SCD files, or in the device configuration software or files.IEC 61850 recommends a default priority value of 4 for GOOSE. Ethernet traffic that does not contain a priority tag has adefault priority of 1. More details are specified in IEC 61850 part 8-1.IEC 61850 recommends that the Ethertype Application ID number be configured according to the GOOSE source. In theB30, the transmitted GOOSE Application ID number must match the configured receive Application ID number in thereceiver. A common number may be used for all GOOSE transmitters in a system. More details are specified in IEC 61850part 8-1.C.4.2 GSSE CONFIGURATIONIEC 61850 Generic Substation Status Event (GSSE) communication is compatible with UCA GOOSE communication.GSSE messages contain a number of double point status data items. These items are transmitted in two pre-defined datastructures named DNA and UserSt. Each DNA and UserSt item is referred to as a ‘bit pair’. GSSE messages are transmit-ted in response to state changes in any of the data points contained in the message. GSSE messages always contain thesame number of DNA and UserSt bit pairs. Depending the on the configuration, only some of these bit pairs may have val-ues that are of interest to receiving devices.The GSSE FUNCTION, GSSE ID, and GSSE DESTINATION MAC ADDRESS settings are used to configure GSSE transmission.GSSE FUNCTION is set to “Enabled” to enable the transmission. If a valid multicast Ethernet MAC address is entered for theGSSE DESTINATION MAC ADDRESS setting, this address will be used as the destination MAC address for GSSE messages. Ifa valid multicast Ethernet MAC address is not entered (for example, 00 00 00 00 00 00), the B30 will use the source Ether-net MAC address as the destination, with the multicast bit set.C.4.3 FIXED GOOSEThe B30 supports two types of IEC 61850 Generic Object Oriented Substation Event (GOOSE) communication: fixedGOOSE and configurable GOOSE. All GOOSE messages contain IEC 61850 data collected into a dataset. It is this datasetthat is transferred using GOOSE message services. The dataset transferred using the B30 fixed GOOSE is the same datathat is transferred using the GSSE feature; that is, the DNA and UserSt bit pairs. The FlexLogic operands that determinethe state of the DNA and UserSt bit pairs are configurable via settings, but the fixed GOOSE dataset always contains thesame DNA/UserSt data structure. Upgrading from GSSE to GOOSE services is simply a matter of enabling fixed GOOSEand disabling GSSE. The remote inputs and outputs are configured in the same manner for both GSSE and fixed GOOSE.It is recommended that the fixed GOOSE be used for implementations that require GOOSE data transfer between UR-series IEDs. Configurable GOOSE may be used for implementations that require GOOSE data transfer between UR-seriesIEDs and devices from other manufacturers.C.4.4 CONFIGURABLE GOOSEThe configurable GOOSE feature allows for the configuration of the datasets to be transmitted or received from the B30.The B30 supports the configuration of eight (8) transmission and reception datasets, allowing for the optimization of datatransfer between devices.