Impact of Sun Storms on GPS based devices

The impact of sun storms on electric power grids has been subject to many papers, articles and reports during the last two decades.
System disturbances caused by solar activity can disrupt complex power grids due to the geomagnetically induced currents (GIC) resulting from the interaction of the Earth's magnetic field and ionized particles carried by the solar wind. Severe magnetic storms induce electric fields in the Earth that create potential differences in voltage between grounding points and causes GICs to flow through transformers, power system lines, and grounding points.
The appearance of a spot (an area of highly organized magnetic activity) on the surface of the Sun that produced two solar blasts in January 2008 signaled to scientists around the world the beginning of a new solar cycle - 'Cycle 24'. Each solar cycle lasts an average of 11.1 years. This cycle is expected to build gradually, with the number of sunspots and solar storms reaching a maximum by 2011 or 2012. However, intense solar activity can occur at any time. More information on this new cycle is available at: http://www.esa.int/esaCP/SEMT1J3MDAF_index_0.html
Composite Sun Flare Image: courtesy of NASA
 
The impact of solar activity on the power grid is not the only concern for protection specialists. The last few years have seen a significant increase in the interest and use of synchrophasors. The wide acceptance of IEC 61850 and the benefits of process bus will lead to the replacement of copper analog circuits with fiber cables transmitting sampled analog values. Both technologies require time synchronization with accuracy better than 1 microsecond. Time synchronization of different intelligent electronic devices (IEDs) in substations is based on GPS signals. The concern regarding the impact of solar activity on time synchronization of substation devices is based on the fact that a solar flare creates radio bursts that traveled to the Earth, covering a broad frequency range, affecting GPS and other navigational systems. The radio waves act as noise over these frequencies, including those used by GPS and other navigational systems that can degrade a signal. Several major events of such nature have already occurred. For example the satellite-based GPS was seriously disrupted in December 2006 by a solar storm. The unexpected solar radio burst on December 6 affected nearly all GPS receivers on the lighted half of the Earth.
The impact of GPS systems failure on the performance of critical electric power systems protection and control functions needs to be studied and well understood in order to determine if any changes in the design of devices with time synchronization are required.
 
Artist Interpretation of GPS satellite
See: http://www.noaanews.noaa.gov/stories2007/s2831.htm.

 

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