Screen Shot 2014-11-19 at 12.57.11 PMThe second generation Giga-Transceiver Network Communication Card,or GTNETx2, provides a real time communication link to and from the simulator via Ethernet. Different protocols are used with the GTNETx2 depending on the application. The different protocols, described below in detail, accommodate MODBUS, TCP/UDP socket communication, IEEE C37.118 data output streams, IEC 61850 GSE binary messaging, IEC 61850-9-2 sampled values, DNP3 communication, IEC 60870-5-104 protocol and playback of large data files stored on a PC hard disk.

In previous generation rack-based systems, the GTNETx2 card is rack-mounted, residing within the RTDS card cage. In NovaCor-based systems, the GTNETx2 card may reside in a specially designed chassis that can be mounted within the NovaCor cubicle. Each GTNET chassis can hold up to 3 GTNETx2 or GTNET cards.

The GTNETx2 communicates with the simulation through the GT optical port which is connected to a NovaCor chassis or PB5 card.

Each GTNETx2 card has two modules. Each module has one Ethernet port, which may be equipped for one of three connection options: 100/1000 Copper, 100BASE-FX, or 1000BASE-SX.

Licensing and available protocols

Each of the 2 GTNETx2 modules can have 1 active network protocol at any given time, which means each GTNETx2 card can operate a total of 2 network protocols simultaneously. This is a significant enhancement over the previous GTNET card, which could operate a maximum of 1 protocol at any given time.

When a firmware is purchased, the license is specific to a module on the GTNETx2 card. The user can install as many of the presently available network protocols on the GTNETx2 card modules as they desire. Of all the installed protocols on a given GTNETx2 card module, the user can select 1 to be active at any given time.

Included with the purchase of each GTNETx2 card are 2 firmwares – the new Socket (“GTNET-SKT”) firmware, which is detailed below, and one additional user-selected firmware.


The new Socket firmware, which is included with every GTNETx2 card, is used to interface with external software and physical equipment over a Local or Wide Area Network connection using Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) sockets.

The communication is bidirectional and asynchronous. GTNET-SKT is capable of sending up to 300 data points per packet, with each point defined over 4 bytes. The data transmitted can be of either integer or floating-point (IEEE 754) type.


The MODBUS firmware, available for the GTNETx2 card only, provides Modbus communication over TCP/IP networks using the GTNETx2 hardware. The component supports Modbus TCP, Modbus RTU over TCP, and Modbus ASCII over TCP.

GTNET-MODBUS operates as a Modbus server (slave) communicating to a Modbus master station through the GTNETx2’s Ethernet port. This master station can be either an IED on dedicated hardware or a computer workstation running a Modbus master API.


Testing of Phasor Measurement Units (PMU devices) is necessary for any PMU application, be it a simple visualization and archiving system or a more complex set of real-time system operations tools. PMUs are available from virtually every manufacturer of protection and monitoring equipment. PMUs can be an embedded function within relays or disturbance recorders or alternatively they can be standalone products. RTDS simulations can now include PMUs allowing the PMU data to be used for, but not limited to, the monitoring of oscillations, angle difference, system frequency and voltage stability. Other ideas for PMU data include situational awareness, alarm and operational limit settings, state estimation and congestion management to name a few.

The PMU firmware option for the GTNETx2 provides P class or M class synchrophasor output data streams according to the IEEE Std C37.118.1aTM-2014. Two PMU streaming options are available for GTNET-PMU.

Using the first option, a single GTNET-PMU can represent and provide output for up to eight (8) PMU’s with symmetrical component information related to 3-phase sets of voltage and current using UDP or TCP connections. The reporting rate of each PMU can be set individually between 1 and 60 frames per second. Reporting rates as high as 240 frames per second are supported, but require the number of PMU’s represented by one firmware to be a maximum eight. Note M class reporting rates are limited to 10 frame per second.

Using the second option, a single GTNET-PMU can represent and provide output for up to twenty four (24) PMU’s containing only positive sequence data. Frame rates up to the system frequency (50/60 Hz) are supported.

The GTNET-PMU component output is synchronized to an external 1PPS, IRIG-B or IEEE 1588 signal via the GTSYNC card.


The GTNET-GSE firmware option can be used to model 1-4 individual IEDs (Intelligent Electronic Devices). Each model is capable of sending and receiving up to 64 points (or 32 points with associated quality bitmap). For each GSE firmware installed, GOOSE messages can be received from a total of 16 unique external IEDs. The GTNET GOOSE configuration is done via an SCD file. RSCAD contains a built in SCD editor which helps the user to easily and conveniently configure the publication and subscription of GOOSE messages

IEC GOOSE fields such as the Test mode, Needs Commissioning and individual Quality bitmaps can be dynamically changed and monitored for both transmit and receive messages during a simulation to allow many scenarios to be thoroughly tested and verified.


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 GTNETx2 via a BNC coax connection or fibre optical port. Alternatively, the GTNETx2 can provide the master 1PPS signal to the IED(s) being tested.

One installed SV firmware, without using the GTSYNC 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 GTNETx2 at a rate of 80 samples per cycle.

The new GTNET_SV9_v5 component is able to transmit up to two data streams for up to 4 current and 4 voltage channels at a rate of 80 samples per cycle, or one stream at 256 samples per cycle. The new component can also be configured to receive sampled data from one Merging Unit (4 x V and 4 x I) at either 80 or 256 samples per cycle. There must be a GTSYNC card present to synchronize the simulation timestep to an external time source to make use of the GTNET_SV9_v5 component.

In non-9.2LE mode, based on IEC 61869-9 and the Chinese National Standard for SV merging units, one GTNET-SV can publish 1 data stream for up to 24 voltages or currents at a rate of 80 samples per cycle, with < 10 μs jitter between samples as is required by the standard.


The DNP3 firmware option allows the GTNETx2 to act as a DNP slave using the DNP 3.0 protocol. DNP3 is a SCADA protocol commonly used in substations.

For each DNP3 protocol operating, the GTNETx2 can communicate with one DNP3 master and accommodate the following maximum communication capacity:

  • 1024 binary simulation status points (i.e. breaker position) at scan rate of 1000 Hz
  • 512 binary simulation control points (i.e. breaker commands) at scan rate of 1000 Hz
  • 500 analogue status points (i.e. output from simulator) at scan rate of 10 Hz
  • 100 analogue control (i.e. input to simulator) at scan rate of 10 Hz


The 104 firmware option allows the GTNETx2 to act as a slave using the IEC 60870-5-104 protocol. IEC 60870-5-104 is a commonly used SCADA communication protocol.

For each 104 protocol operating, the GTNETx2 can accommodate the following maximum communication capacity:

  • 1024 binary simulation status points (i.e. breaker position) at scan rate of 1000 Hz
  • 512 binary simulation control points (i.e. breaker commands) at scan rate of 1000 Hz
  • 500 analogue status points (i.e. output from simulator) at scan rate of 10 Hz
  • 100 analogue control (i.e. input to simulator) at scan rate of 10 Hz


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 Playback firmware option, namely rtds_risc_ctl_GTNETCOMTRADE and rtds_risc_ctl_GTNETPLAYBACK.

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 GB can be handled easily. The component also allows for independent pre and post fault looping.

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 a real time 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.

Hardware Exchange Program:

Customers who participate in our Hardware Extended Warranty Program are eligible for the hardware exchange program. The GTNETx2 card is included in our hardware exchange program. This means that customers can exchange a GTNET card to receive a 50% reduction in the purchase price of a GTNETx2 card. Several of our other hardware items are also included in this program.


Download the GTNETx2 product information sheet.