1 / 17

Communication Delays in Wide Area Measurement Systems (WAMS)

Communication Delays in Wide Area Measurement Systems (WAMS). Biju Naduvathuparambil, Matthew C. Valenti, and Ali Feliachi Lane Department of Comp. Sci. & Elect. Eng. West Virginia University. Preview of Talk.

quilla
Download Presentation

Communication Delays in Wide Area Measurement Systems (WAMS)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Communication Delays in Wide Area Measurement Systems (WAMS) Biju Naduvathuparambil, Matthew C. Valenti, and Ali Feliachi Lane Department of Comp. Sci. & Elect. Eng. West Virginia University

  2. Preview of Talk Idea: Communication delays in WAMS due to the usage of phasor measurement units (PMUs). Motivation: The use of innovative techniques like PMUs in wide area protection systems in a deregulated power industry. Technique: PMU processing time, PMU data format (IEEE 1344) length, and communication link involved.

  3. Wide Area Protection • Technical Advantage: • Wide area protection (WAP) systems (with the help of Phasor Measurement Units) enhance system reliability by early detection and immediate avoidance of possible catastrophic events. • Economics: • WAP is an appropriate system for business support in an unbundled and open-access utility environment. • WAP is designed for an open-access market where production and transmission patterns will more often change than in a closed market. • WAP creates maximum profitability by reducing downtime and by optimizing system performance.

  4. System Setup of WAMS

  5. Phasor Measurement Units

  6. PMU Facts • PMU uses discrete Fourier transform (DFT) to obtain the fundamental frequency components of voltage / current. • Data samples are taken over one cycle / multiple cycles. • Currently, sampling is done at 12 samples/cycle (IEEE C37.111 Std.). • Resolution of the A / D converter is 16 bits.

  7. Technique behind PMU Samples are used to calculate the fundamental frequency component – phasor magnitude and phasor angle. X = phasor, N = total number of samples, xk= waveform sample The positive sequence phasor is then calculated as:

  8. Applications of PMUs • State estimation • Instability prediction • Adaptive relaying • Improved control of power systems

  9. PMU Data Communication • PMU communicates using the IEEE 1344 data format. • IEEE 1344 • Data frame • Information regarding phasor data • Header frame • Identification information about the PMU • Configuration frame • Number of phasors and digital channels

  10. IEEE 1344

  11. Communication Options • Telephone lines • Fiber-optic cables • Satellites • Power lines • Microwave links

  12. Communication Delay Causes • Transducer delays • Window size of the DFT • Processing time • Data size of the PMU output • Multiplexing and transitions • Communication link involved • Data concentrators

  13. Delay Calculations • The total delay can be expressed as: fixed delay link propagation delay L amount of data transmitted R data rate of the link associated random delay jitter

  14. Delay Calculations…… • Fixed delay • Delay due to processing, DFT, multiplexing and data concentration • Independent of communication medium used • Estimated to be around 75 ms • Propagation delay • Function of the communication link and physical separation • Ranges from 25 ms in case of fiber-optic cables to 200 ms in case of low earth orbiting (LEO) satellites

  15. Delay Calculations…… • The data length L of the PMU message is assumed to be around 3640 bits (including data, header and configuration frames) • The data rate R is assumed to be around 33.6 kbps for telephone lines and power lines. The data rate R, for fiber-optic cables and microwave links, is considered to be infinity for all practical purposes

  16. Delay Calculation Table

  17. Conclusion • Communication delays play an important role in determining the effectiveness of control procedures • Delay parameters presented can be integrated with power systems design and analysis. • Distributed control with outdated measurements.

More Related