Description

This section explains how to instantiate a C37.118 slave driver to report configured phasors, analogs and digitals data, as well as frequency deviation from nominal, frequency rate of change and timestamp to a C37.118 master.

The C37.118 communication protocol has been implemented according to the IEEE Std C37.118.2-2011 standard. However, some features are not supported for the moment. Please refer to the Limitations section for more information.

Three communication protocols are supported: TCP only, UDP only or TCP/UDP. It is the user's responsibility to select the communication protocol that matches their requirements.

More details can be found in Annex F of the IEEE Std C37.118-2-2011 document.

If a precise timestamping is required, an external synchronization source can be connected to the driver.

See additional details in the Configuration and Connections sections.

Supported Features

The following is a list of the features supported by the driver:

• IEEE Std C37.118.2-2011 compliant

Supports all of the following:

• Internal timestamping for quick testing and supports external synchronization for very accurate timestamping
• Having the time quality indicator for each synchrophasor; the indicator code can change in accordance with section 6.2.2 of the IEEE Std C37.118.2™-201 standard
• Rounding the timestamp in order to simulate being perfectly aligned on the UTC time
• Fast configuration of multiple slaves, each slave has its own configuration
• TCP only, UDP only or TCP and UDP
• IP aliasing

Configurable for:

• TCP and/or UDP ports
• nominal frequency (50 Hz or 60 Hz)
• data rate (10 to 240 frames per second) or custom data rate up to 512 frames per second
• phasor representation (polar or rectangular)
• data format (INT16 or FLOAT)
• header frame
• Driver's internal queues can be monitored to evaluate performances

Configuration

The driver is entirely configurable via the RT-LAB GUI. It is possible to easily add, delete and duplicate C37.118 slaves, phasors, analogs, and digitals in order to quickly obtain the desired configuration.

General configuration

The first parameters to be configured are found below:

Slave configuration

By default, the driver is configured with one slave that contains 2 phasors, 2 analogs, and 2 digitals.

Each slave has multiple parameters:

When using TCP or TCP and UDP protocols, the combination of the IP address and TCP port has to be unique for each slave.

There are 3 possible cases:

• the same IP address for all slaves with a unique TCP port
• unique IP address for each slave using the IP aliasing with the same TCP port
• both IP address (using the IP aliasing) and TCP port are unique for each slave

The same considerations apply for UDP port when using UDP or TCP and UDP protocols.
When using TCP and UDP protocol, TCP is used to receive commands and UDP is used to send data.

Both ports must be different from one another.

Each slave will have its own IP alias (i.e. eth0:0, eth0:1 ...) and they should appear in the list displayed by the Linux command ifconfig.

Note: If the C37.118 master driver is used to connect to the slave running on the same target, the localhost address (127.0.0.1) must be used as well as the loopback network interface lo.

 *Following the standard, a scaling factor will be automatically applied. See  Phasor Configuration > Phasor unit for more information. 

**Following the standard, a scaling factor will be automatically applied. See Slave Connectable Points > Frequency Rate Of Change for more information. 

Phasor Configuration

Each slave contains a list of phasors to be configured depending on the desired name, type, and unit.

Each phasor has three parameters:

For example, if the signal connected to the phasor input has a magnitude of 11 000 and the specified unit for this phasor is 100, the value will be interpreted as (11 000 * 100 * 10^-5) = 11 by the C37.118 master.

This scaling feature is defined by the standard. If the data format is FLOAT, this scaling does not apply.

Analog configuration

Each slave contains a list of analogs that are to be configured depending on the desired name, type, and unit.

Each analog has three parameters:

Digital configuration

Each slave contains a list of digitals that are to be configured depending on the desired name and unit.

Each digital has two parameters:

• The first word is used to indicate the normal status of the digital input by returning a 0 on a logic (XOR) with the corresponding digital input (also referred to as status word).
• The second word indicates the current valid inputs to the PMU by setting the bit in the binary position corresponding to the digital input to 1 and all other bits to 0.
• If the digital status words are used for something different than a Boolean status indication, the use of masks is left to the user, such as min or max settings.

Connections

Once the driver has been configured as desired, the user will have to connect points in the model to points in the driver by using the designated RT-LAB GUI. This connection panel will show all the driver's and model's connectable points, once the model has been compiled. It is also possible to make connections to Dashboards panels.

The driver's connectable points depend on the number of slaves and on the number of phasors, analogs, and digitals of each slave. Saving the configuration will automatically update the list of connections available. 

The following lists the driver connectable points for the monitoring queues, a slave, a phasor, an analog, a digital and the external clock signals.

Monitoring Queues Connectable Points

Slave Connectable Points

Phasor Connectable Points

If the phasor representation is POLAR, the phasor connectable points are:

*Note regarding the angle: if the phasor format is INT16, the driver will automatically apply a scaling factor of 10⁴. For example, if the signal connected to the phasor input has a an angle of 3.1222 radians and the phasor format is INT16, the value sent will be (3.1222 * 10⁴) = 31222. Most third party tools (such as PMU Connection Tester and Wireshark) automatically apply the inverse factor and convert to degrees. 

This scaling feature is defined by the standard. If the data format is FLOAT, this scaling does not apply.

If the phasor representation is RECTANGULAR, the phasor connectable points are:

Analog and Digital Connectable Points

Each analog and digital has only one connectable point. The connectable point's name is the same as the configured analog's or phasor's name and its value is coming from the model.

Clock Connectable Points

If the general parameter Use external clock is set to true and Auto-connect to external synchronization if present is set to false, additional connectable points appear:

The example model provided with RT-LAB is already packaged with connections between the driver and the model. It can be used to understand how the connections between the model and the driver should be done.

Limitations

The following is a list of the limitations of the driver:

• A configuration containing 100 slaves streaming 16 phasors each at a data rate of 60 frames per second has been tested and validated
• Other functional configurations can be created by modifying the number of slaves, phasors, the data rate, etc...
• Custom data rate value must be between 1 and 512 frames per second
• Statistic word is not supported and will be 0 within all reported packets
• Time quality leap second information is not implemented and will be 0 within all reported packets
• Configuration reported by the C37.118 slave following a CFG-1 or CFG-2 command is the same
• Configuration frame #3 is not supported
• Fraction of second (FRACSEC) value of the data frames is reported in microseconds
• External synchronization has been fully tested using Spectracom TSync-PCIe and Oregano syn1588 PCIe NIC cards.
• On 32bit OPAL-RTLinux (x86-based) platforms (such as RedHat 5.2), a maximum of 2000 PMUs can be handled by one I/O interface instance. If more are required, it is recommended to use an extra interface instance for every 2000 PMUs needed. This limitation is not present on OPAL-RTLinux (x64-based) platforms.