Giga-Transceiver Network Communication Card

The GTNET card occupies a single slot of an RTDS Simulator rack and draws power from the backplane. The card transmits and receives signals from a GPC processor through one of the GT ports on the rear of the GPC card. Other GT-I/O cards can be connected in daisy chain to the GTNET through the same GPC port.

The Ethernet connection to the GTNET is provided by a 100Base-TX RJ45 port located on the rear of the unit.

The GTNET is equipped a BNC coax connector that can accept or provide a 1PPS timing signal.

The GSE firmware option for the GTNET allows a maximum of 32 binary input and 32 binary output signals to be exchanged between the RTDS Simulator and up to five IEC 61850 compliant IED's. Both GSSE (UCA GOOSE) and GOOSE formatted messaging are supported, but cannot be provided simultaneously from one GTNET.

The SV firmware option provides IEC 61850-9-2 sampled value messaging for power system voltages and currents. In order to timestamp the sampled values, a one pulse per second (1PPS) signal can be input to the GTNET via a BNC connection. Alternatively, the GTNET can provide master 1PPS signal to the IED(s) being tested.

One GTNET card can provide sampled values for a maximum of eight signals (e.g. 4 x V and 4 x I) simultaneously. The sampled values are sent out from the GTNET at a rate of 80 samples per cycle.

The Playback firmware option is used to read large data files stored on a PC hard drive and allow them to be played back in an RTDS simulation. Sampling frequencies as high as 20 kHz can be maintained in a true real time simulation.

Two components can be used with the GTNET Playback firmware option, namely rtds_risc_ctl_GTNETCOMTRADE and rtds_risc_ctl_GTNETPLAYBACK.

rtds_risc_ctl_GTNETCOMTRADE
The rtds_risc_ctl_GTNETCOMTRADE component allows COMTRADE files with up to 8 channels to be played back on the RTDS Simulator. Because the COMTRADE data file is stored remotely on a PC, file sizes of several hundred MB can be handled easily. The component also allows for independent pre and post fault looping.

rtds_risc_ctl_GTNETPLAYBACK
The primary application of the rtds_risc_ctl_GTNETPLAYBACK component has been to inject currents recorded at an actual installation (e.g. arc furnace or rolling mill) in an RTDS simulation. It is very difficult to accurately simulate the behavior of such installations so the recorded waveforms are often the best representation of the on site dynamics. By injecting the recorded current into the plant simulation, the performance of compensation equipment (e.g. SVC or STATCOM) can be accurately evaluated for the expected operating conditions. Simulation/playback times in excess of 30 minutes allow even the flicker (PST) reduction factor to be observed.

The DNP firmware option allows the GTNET to act as a DNP slave using the DNP 3.0 protocol. DNP is a SCADA protocol commonly used in substations.

Using the DNP protocol, the GTNET can communicate with one DNP master and accommodate the following maximum communication capacity:

• Binary simulation status (i.e. breaker position), 1024 (scan rate 1000 Hz)
• Binary simulation control (i.e. breaker commands), 512 (scan rate 1000 Hz)
• Analogue status (i.e. output from simulator), 500 (scan rate 4 Hz)
• Analogue control (i.e. input to simulator), 100 (scan rate 4 Hz)