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UPLC Universal Power-Line Carrier

Universal Power-Line Carrier


The most economical medium for protective relay communications!

As with our previous power-line carrier designs, UPLC requires no hardware modifications for most required configurations. UPLC is frequency programmable across the entire power-line carrier spectrum (30 to 500 kHz) without changing any hardware components. UPLC can be software configured either as an ON/OFF or frequency-shift keyed (FSK) power-line carrier unit without changing any hardware components. This  flexibility makes each UPLC universally suited for any directional comparison blocking, permissive, phase comparison or transfer trip protective relay application.

In addition, UPLC is fully programmable using a simple-to-use web browser interface, which offers many benefits for the user. First, a web browser is often installed on a personal computer when the operating system is installed. This removes the need to have administrative rights to install proprietary interface software. Secondly, since the web browser is used for other applications, the user is familiar with browser functionality. Lastly, the web browser screens are dynamically updated to reflect status of the unit.

Since UPLC is fully programmable, the settings can be uploaded via any of the communication ports. Setting files are in the Extensible Markup Language (XML) format, which can be easily modified if desired. With the XML format, the unit will be compatible with future intelligent electronic devices (IEDs). Settings may also be applied from the factory defaults which are stored in the unit. The user has choices for the most commonly used types of protection systems.

In the AM mode, there is Directional Comparison Blocking or Phase Comparison Blocking for line relaying. In the FSK mode, there is Directional Comparison Unblocking (DCU)/Permissive Overreaching Transfer Trip (POTT) for line relaying. Direct Transfer Trip is also offered for equipment protection in the FSK mode. A combination of DTT and DCU/POTT is available with the 3 frequency setting in the FSK mode.

A new feature of the UPLC is the 4-Frequency Logic. Similar to the 3-Frequency option, this provides for 2 functions over one channel. This new feature allows two independent inputs to key independently or simultaneously to produce received outputs for a command A trip, a command B trip or a command A & B trip. Four frequencies are transmitted within the one channel, a guard frequency, a command A frequency, a command B frequency and a fourth frequency that represents command A & B.

Self-calibration provides for ease of installation and maintenance. Pulsar was the first to introduce a self-calibrating receiver. Now the UPLC incorporates this plus a self-calibrating transmitter. No longer are instruments needed to calibrate an individual transmitter/receiver. Accurate measurements for the transmitter output and the received signal level are displayed on the front of the UPLC and on the web page.

Reflected power measurement is included on the UPLC. While this cannot take the place of a reflected power meter when tuning the high voltage equipment, it will provide information for the user to track changes in the tuning efficiency of the line. Reflected power readings are available on the front of the unit, through the test function or on the home web page of the UPLC.


  • Programmable for either FSK or ON-OFF Applications
  • Fully Frequency Programmable from 30 to 535 kHz in 0.01 kHz Increments
  • Bandwidths and Frequency Shifts Selectable
  • FSK Units Settable for 2 or 3-Frequency Applications
  • All Software Configurable Items are set via Standard Web Browser
  • Integrated HMI with Front Keypad and 4x20 Character Plasma Display
  • Unit can be programmed to match any narrowband PLC at remote end, excluding voice or checkback functions.
  • Front Panel Transmit and Receive Level Readouts
  • Automatic Receiver Sensitivity Settings
  • Transmitter Reflected Power Monitor
  • Sequence of Events, Time-Tagged with 1-ms Accuracy for most Events
  • IRIG-B Input (Both Modulated and TTL)
  • 48/60 Vdc or 110/250 Vdc Powered
  • 5 Keying Inputs, High Threshold and Optically Isolated Design
  • Outputs: 7 Programmable Solid State, 3 Programmable Contacts
  • Standard 19 Inch Chassis Mounting, 3 Rack Units
  • Meets or Exceeds All Applicable IEC and ANSI Standards