Andrea Bonetti - Relay product manager
The new IEC 61850-8-1 test equipment from Megger, called GOOSER™, has been designed to be a very simple piece of equipment:
1) It is able to convert one GOOSE message into a binary electrical signal (Binary Output). The GOOSER is equipped with ten binary outputs, so it is able to receive (subscribe to) 10 GOOSE messages at the same time.
2) It is able to convert one electrical signal (energisation of a GOOSER binary input) into a GOOSE message. The GOOSER is equipped with ten binary inputs, so it is able to send (publish) 10 GOOSE messages at the same time.
The GOOSER Test Instrument
The GOOSER is a new test instrument designed by Megger with consideration of all these issues. The GOOSER is a patent pending product.
IEC 61850 Relay testing
The GOOSER can be interfaced with any test set of any manufacturer for relay application with IEC 61850 GOOSE messages. With the GOOSER, the upgrade of relay test sets is not technically necessary anymore. It is enough to connect the GOOSER to the IEC 61850 station bus, program it to receive the trip GOOSE message from the tested IED and connect the binary output of the GOOSER to the binary input of the test set. The tester will be stopped by the electrical signal generated by the GOOSER. The signal follows the digital value of the trip GOOSE message (GOOSER output closed TRIP = 1; GOOSER output open TRIP = 0).
Since the delay time requested to convert a GOOSE message into binary output is typically less than 0.5 ms, the GOOSER does not introduce any noticeable time delay in the reported trip time for the tested IED.
At the last IEC 61850 interoperability training organized by STRI (www.stri.se), the 61850 relays have been tested with the help of a SVERKER, connected to the GOOSER of course!
Control engineers will have a benefit in the correct use of GOOSER, as it does not require any relay and/or test equipment competence in order to be used and does not need to be connected to any relay test set for its use in control applications.
The GOOSER binary outputs are strong enough to drive external electromechanical relays, that can represent the circuit breaker, disconnector or any desired interlocking logic. It is possible to receive one or several GOOSE messages, with their statuses driving some electrical relays that are connected to binary inputs of the GOOSER sending other GOOSE messages depending on the logic described by the externally connected mechanical relays.
The GOOSER solves the security problem as no PC is required to be connected to the substation Ethernet bus in order to be run.
The GOOSER is equipped with two separate Ethernet ports. The first port (so called IEC 61850 sensor) is the “IEC 61850-8-1 port”, and is the port that is connected to the IEC 61850 substation bus.
The GOOSE messages are routed from the GOOSER to the second Ethernet port, which is the so called “PC port”.
Fig.1 – testing an IEC 61850 IED with a conventional test set by using the GOOSER.
Fig.2 – The GOOSER inserted in an electromechanical interlocking system used to verify GOOSE interlocking. High electrical capability of the GOOSER binary outputs!
Fig.3 – The GOOSER connected to the station bus via the “IEC-61850-8-1 port” and connected to the PC via the “PC Port”
A PC Application will show the detected GOOSE messages (sniffed GOOSE messages) and will allow to map the GOOSE messages to the different binary input outputs of the GOOSER.
The mapping information are sent to the GOOSER through the PC Ethernet port and the GOOSER will start to work as requested, without any further interaction with the PC.
Because of this solution, it is possible to use the GOOSER as a GOOSE firewall. The IEC 61850-8-1 Ethernet port is permanently connected to the PC bus. A PC with GOOSER installed acts as a network analyzer when connected to the GOOSER unit via the PC Ethernet port. Then network traffic can be analyzed from the PC. An IP message from PC cannot reach the substation bus because the data flow is only in one direction: from the “sensor port” to the “PC port”. This is the meaning of the diode shown in Figure 3.
PC GOOSER – The PC Application
The PC application designed together with the GOOSER has other benefits that will be covered in the next issue. IEC 61850 is growing and the GOOSER will grow with it!