SATEC PMU230 Phasor Measurement Unit User Guide

IEEE C37.118.2 Data Communications
The PMU PRO supports various reporting rates at different system frequencies. Each data stream can be configured independently to match the desired reporting rate.

Commanded Unicast UDP and TCP Data Transmission
To initiate commanded unicast data transfer, the client sends commands over a TCP or UDP connection to the PMU’s local port. Configuration and header frames are sent to the originating IP address, while data frames are sent to the IP address from which the start command was initiated.
TCP Connection Timeouts: The PMU PRO utilizes TCP keepalive probes to monitor idle connections and prevent resource leaks. A keepalive is sent if the connection remains idle for more than 20 seconds.
Spontaneous UDP Data Transmission
For broadcasting within the local network, set the host part of the network address to 255. To expand beyond the local network, use a routable broadcast address.

IEEE C37.118.2 Message Frames

Data Frames
Data frames contain synchrophasor data in binary format.

Configuration Frames
Configuration frames provide information about the data stream and support CFG-1, CFG-2, and CFG-3 formats as specified by IEEE C37.118.2 2011 standards.
- Channel Names: Phasor, analog data, and digital status channels can be user-configured with names up to 16 characters long.
- Floating-Point Format: If data is in floating-point format, a 24-bit value represents a unity scale factor and should be disregarded.
- Spontaneous Configuration Frames: CFG-2 or CFG-3 frames can be sent periodically without explicit client commands in spontaneous UDP transmission mode.

Frequently Asked Questions (FAQ)

How often are configuration frames sent in spontaneous UDP data transmission mode?
Configuration frames are sent periodically every 30 seconds in spontaneous UDP data transmission mode.

INTRODUCTION

Every effort has been made to ensure that the material herein is complete and accurate. However, the manufacturer is not responsible for any mistakes in printing or faulty instructions contained in this book. Notification of any errors or misprints will be received with appreciation.

For further information regarding a particular installation, operation or maintenance of equipment, contact the manufacturer or your local representative or distributor.

General

This document describes protocol implementation features and configuring of the IEEE C37.118.2 synchrophasor data transfer protocol in the PMU PRO phasor measurement unit (PMU).

The PMU PRO provides commanded client-server UDP and TCP data transmission and spontaneous UDP data transmission over IP protocol.
Streaming of synchrophasor data is also available over Ethernet via the IEC 61850 protocol by mapping the IEEE C37.118.2 synchrophasor data stream to IEC 61850-9-2 sampled values service (see the PMU PRO IEC 61850 Reference Guide for more information).

Reference documents:
- IEEE Std C37.118.1-2011, IEEE Standard for Synchrophasor Measurements for Power Systems
- IEEE Std C37.118.1a-2014, IEEE Standard for Synchrophasor Measurements for Power Systems, Amendment 1: Modification of Selected Performance Requirements
- IEEE Std C37.118.2-2011, IEEE Standard for Synchrophasor Data Transfer for Power Systems
- IEC/IEEE 60255-118-1:2018, Measuring relays and protection equipment – Part 118-1: Synchrophasor for power systems – Measurements
- IEEE Std 1588-2008, IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems
- IEEE Std C37.238-2017, IEEE Standard Profile for Use of IEEE 1588 Precision Time Protocol in Power System Applications
  NOTE
  The PMU PRO comes with a Telnet server that can be used to monitor or check the current status and operations of the device. Run a Telnet client on your PC, log into the device with your user password and enter a command from the suggested list.

Protocol Implementation

The PMU PRO IEEE C37.118.2 features are user-configurable, allowing it to be easily adapted for use in a variety of installations. To keep maximum interoperability with phasor data concentrators (PDC) and controlling stations, the PMU PRO supports all standard frame types for synchrophasor data interrogation and streaming.
The PAS configuration software supplied with the PMU PRO provides all the necessary tools for the remote configuration of the device.

See Chapter 3 for instructions on how to configure IEEE C37.118.2 options in the device for your particular installation.
See the PMU PRO Installation and Operation Manual for more information on configuring the device via PAS.
The protocol implementation details are explained in the following sections.

IEEE C37.118.2 Data Communications

The PMU PRO provides commanded unicast client-server UDP and TCP data transmission and spontaneous multicast or unicast UDP data transmission using two data streams with programmable data rates. The data stream ID number assigned to PMU streams uniquely identifies each data stream. Only requests with matching data stream ID numbers are responded by the PMU.
The synchrophasor measurement data reporting rate can be configured in submultiples or multiples of the nominal power line frequency from 1 to 240 frames per second.
PMU reporting rates at 50 Hz system frequency:

Reporting rates (frames/s) 1 2 5 10 25 50 100 200
PMU reporting rates at 60 Hz system frequency:

Reporting rates (frames/s) 1 2 3 4 5 6 10 12 15 20 30 60 120 240
Each data stream can be individually configured to any data rate that is submultiple of the PMU reporting rate.

Commanded Unicast UDP and TCP Data Transmission

Commanded unicast data transfer is controlled by commands sent by the client over a unicast TCP or UDP connection to the PMU’s local TCP or UDP port, respectively.
Configuration and header frames are always sent to the IP address and port from which the corresponding command was received, while data frames are sent to the IP address and port from which the start command was sent. This does not necessarily have to be the same port.
Streaming Data Slots
- The PMU PRO provides up to 5 simultaneous unicast TCP and/or UDP connections for streaming synchrophasor data at a user-programmable data rate using one of two commanded data streams. The transmission start command should indicate the selected stream identifier.
- The stream data rate must be a submultiple of the PMU reporting rate. If it is not, the device will set it to the PMU reporting rate.
- Although the UDP server responds to commands from an unlimited number of UDP clients and the TCP server can support more client connections, commands to turn on data transmission for new connections after all 5 data streams have started will be ignored.
TCP Connection Timeouts
- The PMU PRO uses the TCP keepalive probes to detect dead connections and prevent resource leaks. If the connection is idle for longer than 20 seconds, the device sends a keepalive request to check if the connection is alive. If no response is received after 5 successive keepalive retransmissions, the connection is considered dead and will be closed.
- The client connection idle timeout can be used to terminate a connection if it has been inactive for too long. The idle timeout can be configured from 30 to 300 seconds or set to 0 to disable it via the device Network Setup (see the PMU PRO Installation and Operation Manual for details). It is disabled by default, and when enabled will be automatically deactivated while streaming data.
Uncontrollable UDP Data Flow
- In case of the commanded UDP transmission, IEEE C37.118.2 does not provide tools for probing whether a client who initiated transmission is still alive and listening to the synchrophasor data stream.
- Abnormal termination of client operations without explicitly turning off the data transmission may leave the streaming slot active forever and thus limit the number of slots available for new data streams.
- The PMU PRO provides a command you can send to the device via the IEEE C37.118.2 setup dialog (see Section 3) that stops all active commanded UDP streams and releases the corresponding data streaming slots.
- You can check which data streams are currently active via Telnet using the “188” command as shown in the following picture.

Spontaneous UDP Data Transmission

Unlike commanded data transfer, spontaneous data frames are sent to a user-configured IP address and destination port. The PMU PRO provides two data streams for the simultaneous transmission of synchrophasor data frames to two different destinations at user-programmable data rates.

Spontaneous data transfer must be enabled or disabled explicitly by the user through the IEEE C37.118.2 settings (see Section 3 for details) or over an alternative client-server TCP or UDP connection to a local PMU TCP or UDP port, respectively, by referring to the appropriate spontaneous data stream identifier. Regardless of how the data stream is enabled, its state is stored in non-volatile memory, so that if it is enabled, data transfer is automatically started after the device reboots.
Configuration and header frames can be requested and received over an alternate TCP or UDP connection by referencing the appropriate data stream identifier, just as in a regular client-server connection. Configuration frames can also be sent spontaneously to a user-configured destination port without an explicit command like spontaneous data frames are sent (see Spontaneous Configuration Frames below).
Spontaneous UDP data transmission can operate in unicast, multicast,or broadcast mode depending on the destination IP address the user specified. If the UDP clients have the ability to join a multicast group, you can select one from the multicast address range of 225.0.0.0 through 239.255.255.255.

For broadcast transmission within your local network, set the host part of the network address to 255. Use a routable broadcast address to expand the broadcast transmission beyond your local network.

IEEE C37.118.2 Message Frames

Data Frames

Synchrophasor data frames transmit a time-stamped set of measurements that include phasor estimates, frequency deviation from the nominal power line frequency or actual frequency, and the rate of change of frequency. In addition, the data frame can be expanded to contain analog data (total active, reactive and apparent power, and power factor) and digital input status information.

Phasor components can include three voltage and three current phasors, positive sequence voltage and current phasors, negative sequence voltage and current phasors, or all of them in one frame.
Complex phasor values can be sent in a rectangular coordinates format (real and imaginary) or in polar coordinates (magnitude and angle). Phasor and frequency data can be represented in 32-bit IEEE floating-point format or as 16-bit scaled integer numbers. When using the integer format, the data conversion factors are provided in IEEE C37.118.2 configuration frames.
See Section 3 for information on configuring IEEE C37.118.2 data frames.

Configuration Frames

IEEE C37.118.2 configuration frames provide information about the synchrophasor data stream in binary format. The PMU PRO supports CFG-1, CFG-2 and CFG-3 configuration frames.
The configuration frame contents correspond to the specification given by IEEE C37.118.2-2011. In CFG-3 frames, the PMU GUID is not supported and is transmitted as a null string.

Channel Names
The names of the phasor, analog data and digital status channels are user-configurable. The channel name can be up to 16 characters long.
Conversion Factors
- When transmitting data in 16-bit integer format, the conversion factors for phasor channels in CFG-2 frames are represented as an unsigned 24-bit word in 10–5 volts or amperes per bit
  to scale.
- Conversion factors for analog channels in CFG-2 frames are represented as an unsigned 24-bit word in 10–3 per bit to scale. Power readings are transmitted in kW/kvar/kVA units.
- If transmitted data is in floating-point format, this 24-bit value will represent a unity scale factor and shall be ignored.
Spontaneous Configuration Frames
In spontaneous UDP data transmission mode, CFG-2 or CFG-3 configuration frames can be sent spontaneously without an explicit client command. When enabled, a configuration frame is sent periodically every 30 seconds.

Header Frame
A header frame gives information about a synchrophasor data stream in human-readable format. An example header frame for positive sequence phasor data is shown below.

UTC Time Synchronization

The PMU PRO clock must be synchronized to UTC time using an external IRIG-B timecode source or from an IEEE 1588 PTPv2 master clock.
NOTE: The warning LED on the front panel of the PMU PRO flashes red ones a second when the PMU clock is not synchronized with the UTC time source.

You can check the clock status and time accuracy via Telnet using the “time” command as shown in the following picture.
You can also see the clock status in the status bar on the PMU PRO front display and check the time quality on the Monitor/Clock Status page (see the PMU PRO Installation and Operation Manual).

IRIG-B Time Synchronization

Connect the IRIG-B signal wires to the PMU PRO IRIG-B terminals.
To enable the IRIG-B port as a UTC source, select the IRIG-B time synchronization option in the IEEE C37.118.2 setup (see Section 3 for details) or in the Local Settings setup (see the PMU PRO Installation and Operation Manual).

The PMU PRO IRIG-B port uses an unmodulated (pulse-width coded) timecode signal (unbalanced 5V level) according to the IRIG 200-04 standard. It supports B004/B005 timecode formats with time code extensions specified for the IRIG-B profile in Annex D of IEEE Std C37.118.1-2011.
The PMU IRIG-B port can synchronize to the IRIG-B timecode source with sub-microsecond accuracy.

IEEE 1588 PTP Time Synchronization

The PMU PRO Ethernet port must be connected to an IEEE 1588 grandmaster clock through a 1588 PTPv2 peer-to-peer transparent clock switch compliant with IEEE Std 1588-2008.
To enable the IEEE 1588 port as a UTC source, select the IEEE 1588 time synchronization option in the IEEE C37.118.2 setup (see Section 3 for details) or in the Local Settings setup (see the PMU PRO Installation and Operation Manual).
Both PMU PRO Ethernet ports can be connected to the same or two different 1588 switches. The device will obtain UTC time from one of the available sources and automatically switch to the other port whenever the signal is lost for any reason.

Each PMU PRO port implements the ordinary PTPv2 clock, complying with the IEEE Std 1588-2008 standard, and uses the following PTP profile:
1. PTP version 2.
2. PTP transport over Layer 2 Ethernet (IEEE 802.3), IEEE 1588-2008, Annex F.
3. Multicast addressing.
4. Peer-to-peer (P2P) path delay measurement mechanism.
5. Capable of working with one-step and two-step master clocks.
6. Responds to peer path delay requests with two-step peer delay responses (Pdelay_Resp, Pdelay_Resp_Follow_Up messages).
The IEEE 1588 PMU port can synchronize to the PTP grandmaster clock with sub-microsecond accuracy, which can be degraded by network topology, PTP switch accuracy, or transmission media asymmetry.
To troubleshoot connectivity issues with 1588 switches, you can monitor the PTP clock status and time accuracy via Telnet using the “ptp” command, as shown in the following picture.

Configuring IEEE C37.118.2

Use the PAS configuration software provided with your device to configure IEEE C37.118.2 options. See the PMU PRO Operation Manual for more information on installation and operating PAS on your computer.
To configure IEEE C37.118.2 options:
1. Make sure that the selected connection protocol for communication with your device is set to Modbus RTU or Modbus ASCII.
2. Select Communications Setup from the Meter Setup menu and then click on the IEEE C37.118.2 tab.
3. Select the desired PMU and data frame parameters. See the table below for the available options and their explanations.
4. To change the default phasor, analog or digital channel names, click the corresponding Tags button on the right, enter custom channel names, and click OK. The channel name can be up to 16 characters long.
5. Click the TCP/UDP Communication button to configure IEEE C37.118.2 data streams.
6. Configure device’s local TCP and UDP port numbers for client connections, and the destination addresses and ports for spontaneous transmission as desired. The default port numbers are set to the values recommended by IEEE C37.118.2.
7. Configure the data stream parameters as required for your application. Avoid assigning the same identifier to multiple streams, as this will make streams following the first one unavailable to client commands.
8. Click Save as… to store your setup in the device site database, and click Send to send the setup to the device.

The following table provides information on the available options.

Parameter	Options	Default	Description
IEEE C37.118.2 Setup
Station Name	Up to 16 ASCII characters	station_name	Identifies the station
PMU Latitude, degrees	-90.00000 to 90.00000	0.00000	PMU latitude (WGS84)
PMU Longitude, degrees	-180.00000 to 180.00000	0.00000	PMU longitude (WGS84)
Phasor Type	Vabc/Iabc, V1/I1, V2/I2 in any combination	Vabc/Iabc	Phasor components: Vabc/Iabc – voltage and current phasors V1/I1 – positive sequence V2/I2 – negative sequence
Phasor Coordinate Format	Rectangular (Re/Im) Polar (Mag/Ang)	Rectangular	Vector data format: Rectangular – real and imaginary, Polar – magnitude and angle
Phasor/Frequency Data Format	16-bit integer, 32-bit floating point, 32-bit floating point (actual FREQ)	32-bit floating point with actual frequency	Data type for phasor and frequency data 1
Analog Data Format	16-bit integer, 32-bit floating point	32-bit floating point	Data type for analog data
Analog Data	None, ‘P,Q,S,PF’, P, S, ‘P,Q’, ‘P,Q,S’, ‘P,Q,PF’	None	Analog values to be included in data frames
Digital Data	None, 16 DI, 32 DI	None	Digital status words to be included in data frames
Reporting Rate, frames/s	1-6,10,12,15,20, 25,30,50,60,100, 120,200,240	10	Synchrophasor measurement rate 2
Service Class	P, M	P	PMU performance class
Time Synchronization	IRIG-B, IEEE 1588 (PTPv2)	IRIG-B	UTC time source
Spontaneous CFG Frames	NO, CFG-2, CFG-3	CFG-3	Enables spontaneous configuration frames
Configuration Change Count	0-65535	0	Maintained by the device
Client-server UDP/TCP Transmission
Data Stream ID 1	1-65534	7000	Commanded data stream 1 ID number
Data Rate 1, frames/s	Submultiple of the PMU reporting rate	10	Commanded data stream 1 transmission rate
Data Stream ID 2	1-65534	7001	Commanded data stream 2 ID number
Data Rate 2, frames/s	Submultiple of the PMU reporting rate	10	Commanded data stream 2 transmission rate
Local UDP Port	1024-49151	4713	Device UDP port number for client-server connections
Local TCP Port	1024-49151	4712	Device TCP port number for client-server connections

Stop UDP Streams	NO, YES	NO	Stops all active controlled UDP streams
Spontaneous UDP Transmission
Transmission Enabled 1	Disabled, Enabled	Disabled	Enables spontaneous data stream 1 transmission
Data Stream ID 1	1-65534	7002	Spontaneous data stream 1 ID number
Data Rate 1, frames/s	Submultiple of the PMU reporting rate	10	Spontaneous data stream 1 transmission rate
Destination UDP Port 1	1024-49151	4713	Destination port number for spontaneous data stream 1 transmission
Destination IP Address 1 (unicast/multicast)		225.100.100.1	Destination IP address for spontaneous data stream 1 transmission
Transmission Enabled 2	Disabled, Enabled	Disabled	Enables spontaneous data stream 2 transmission
Data Stream ID 2	1-65534	7003	Spontaneous data stream 2 ID number
Data Rate 2, frames/s	Submultiple of the PMU reporting rate	10	Spontaneous data stream 2 transmission rate
Destination UDP Port 2	1024-49151	4713	Destination port number for spontaneous data stream 2 transmission
Destination IP Address 2 (unicast/multicast)		225.100.100.2	Destination IP address for spontaneous data stream 2 transmission

NOTES:

When 32-bit floating point phasor/frequency format with actual frequency is selected, the measured frequency is transmitted as the actual frequency, otherwise it is transmitted as the deviation from the nominal frequency.
The selected PMU reporting rate is automatically rounded up to the nearest submultiple or multiple of the nominal frequency. In case of using both IEEE C37.118.2 and IEC 61850 synchrophasor data communications, the new reporting rate is applied to both protocols.

A stream data rate must be a submultiple of the PMU reporting rate, otherwise it will be automatically set to the PMU reporting rate.
Configure the synchrophasor data frame properties and local port settings before turning on the data transmission. Changing either invalidates all active data streams and stops data transmission in progress.
Changing the local TCP port causes closing all active connections and restarting the network services. If you make changes via an Internet connection, wait a couple of seconds until the network is ready for operation before sending a new connection request.

Changing the synchrophasor data frame properties advances the configuration change count. You can set it to any desired number by explicit writing the count value.

Documents / Resources

SATEC PMU230 Phasor Measurement Unit [pdf] User Guide
PMU230, PMU-PRO-IEEE-C37.118.2, PMU230 Phasor Measurement Unit, PMU230, Phasor Measurement Unit, Measurement Unit, Unit

References

User Manual

SATEC PMU230 Phasor Measurement Unit

Product Information

Product Usage Instructions

Protocol Implementation

Frequently Asked Questions (FAQ)

INTRODUCTION

General

Protocol Implementation

IEEE C37.118.2 Data Communications

IEEE C37.118.2 Message Frames

UTC Time Synchronization

Configuring IEEE C37.118.2

Documents / Resources

References

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