WG C4.112 Power Quality Monitoring in Flexible Power Networks


There has been noticeable increase in the amount of power quality monitoring taking place in electric power systems in recent years. Monitoring of voltages and currents gives the network operator information about the performance of their network, both for the system as a whole and for individual locations and customers. There is also pressure from the customers and the regulatory agencies to provide information on the actual power quality level. Developments in enabling technology (monitoring equipment, communication technology, data storage and processing) have made it possible to monitor at a large scale and to record virtually any parameter of interest. The change in types of loads connected to the network and proliferation of nonconventional, power electronic interface connected, generators as well as envisaged further increase in non-conventional types of loads/storage (e.g., electric vehicles) puts additional pressure on network operators to monitor and document various aspects of network performance. While many network operators are installing monitoring equipment and while more and more manufacturers have monitors available, there is a lack of knowledge and agreement on a number of aspects of the monitoring process and in particular on processing the recorded data. The end users of the data, be it network operators or their customers, are increasingly asking for useful information rather than just large amounts of data to be provided by installed monitors and supporting software. In order to resolve some of the issues highlighted above, this WG will address in particular the application aspects of power-quality monitoring, including the following:

  1. Guidelines for choosing locations to install monitoring equipment and for the number of monitors needed to get a sufficiently-accurate picture of the power quality. Trade-off between costs of monitoring and amount of information provided, including the practical value of additional information gained by adding more monitors against the complexity of data extraction and classification. Possibility and potential advantages of installing a monitoring function in a large number of the metering devices and/or protection relays. Methods for reliable estimation of relevant power quality indices at non-monitored locations.
  2. Which parameters should be recorded and at what sampling rate/resolution? This will include a discussion about appropriate data averaging window (3 seconds, 1 minute or 10 minutes) and viability of inclusion of waveform data. How and where should the monitoring results be stored (locally or centrally)? If the data are to be transmitted to central location should raw data (which may be constrained by communication channels/bandwidths) or processed/compressed data be transmitted. The recommendations will not only cover existing practice (like reporting to regulatory agencies) but will also include possible future applications, including  customer requests for past-performance at a certain site, and the need for future research and development in for example data capture and processing.
  3. How to present the results of monitoring? It is neither possible, nor desirable, to have one way of reporting for all applications. Different ways of presenting the results of monitoring are needed for different types of application and decision making. This recommendation will address the way of presenting statistical/probabilistic results over the whole or a large part of the service area; statistical/probabilistic results for individual customers over one or more years; and results for individual events or over a short period of time.

The results from earlier CIGRE working group as well as other working groups and research activities will be used as basis for the work.

  1. A CIGRE report/guidelines for monitoring power quality in contemporary and future power networks addressing each of the points specified above.
  2. Electra publication summarising major conclusions and recommendations and technical papers reporting intermediate results
Convener: J. Milanovic (UK)

Progress Report 2013 (pdf, 85kB)