Swedish
Institute of Space Physics
Real-Time Forecast Service for
Geomagnetically Induced Currents,
GIC
Pilot Project for Space Weather Applications
ESTEC/Contract No.
16953/02/NL/LvH
Monthly Progress Report
GIC-MR-24-05
Period: 2005-03-01--03-31
Author: Lars Eliasson
1.
Progress status
In the frame of the COST 724 Action, Risto
Pirjola made a visit to IRF Lund on March 16 to 22. The main objective of the
visit, which was also achieved, was to intensively work with Magnus Wik in
order to implement computations of GIC in the (southern) Swedish high-voltage
power system by applying Swedish power grid data to MatLab computer programs
developed at FMI. The timing of Risto's visit was perfect as IRF had received
the data from the Swedish power company just a
few days earlier. The data were given
in the form of EXCEL tables, which included station coordinates (in a special
Swedish coordinate system), resistances of each parallel transformer at the
stations considered, transmission line resistances and station earthing
resistances. Information about autotransformers between the 400 kV and 130 kV
grids was also provided.
As discussed within the SDA earlier, GIC
calculations are limited to the 400 kV system in the present SDA and special
attention is paid to a station located at the eastern coast of Sweden, at which
GIC is continuously recorded as well. The data given by the power company were
also limited to the part of the entire grid that is necessary for calculating
GIC at the station.
As usual, the power grid data required
some interpretation and pre-calculations (e.g., the determination of total
resistances of parallel transformers) before they were available for FMI's GIC
computation routines. For example, the most applicable routines read station
latitudes and longitudes instead of the coordinates provided by the power
company. Anyway, the grid modeled now was small enough to be easily manageable
(14 stations and 17 lines), and Magnus and Risto decided to neglect voltages
lower than 400 kV totally. This is not exactly right at stations with
autotransformers, and tests in which the (effective) earthing resistance is
artificially decreased at these stations will be
made later.
To ensure that there were no typing errors
etc in the power system input data, Magnus and Risto used two different GIC
computation Matlab codes together with a uniform-geoelectric-field assumption
and found that both of them gave the same results. Other test-type calculations
concerned the rotation of a uniform field to identify at each station the field
direction that gives the largest GIC there, and the relative magnitudes of
these largest GIC were also obtained. As expected, the tests showed the
well-known "corner effect", i.e. the largest GIC were observed at
corners and ends of the system.
Real large space weather events (in
September 1998, April 2000, May 2000 and July 2000) were also considered by
first calculating the geoelectric field from geomagnetic data by using a
layered Earth conductivity model. The agreement with GIC measurements at the
"eastern station" was satisfactory after the computed GIC was scaled
to compensate shortcomings of the Earth's conductivity model (which has been
observed to be necessary in other GIC studies as well).
In conclusion, the GIC calculation program
was obtained into an operational stage for the southern Swedish 400 kV grid
during Risto's visit to IRF Lund. The next steps in the SDA should include
feedback, comments and advice from the Swedish power industry and a coupling of
the GIC calculation to geoelectromagnetic predictions belonging to the work in
the SDA. During the visit, Magnus and Risto also discussed geoelectric
calculations, in particular Earth conductivity
modeling for GIC purposes.
A paper submitted to Annales Geophysicae in December 2004 with the title
"Study of the solar wind coupling to the time difference horizontal
geomagnetic field" has been updated based on comments from referees
and re-submitted.
WP 100 User
requirements
The URD has been accepted. It can be found at
http://www.lund.irf.se/gicpilot/gicpilotinternal/wp/100/urd_1_5.pdf
(2003-12-18).
WP200 Database
Solar wind data have been collected.
GIC data from south Sweden have been collected.
A database with geomagnetic data, solar wind data, and GIC data exists.
The Technical Note has been updated in Sep and Oct
2004 based on a preliminary review made by ESTEC. The TN version 0.3 can be
found at http://www.lund.irf.se/gicpilot/gicpilotinternal/wp/200/.
It contains four parts: the solar wind, the magnetic field, GIC-data, and data
about the power grid.
WP201 Solar
wind and GIC datasets
The solar wind and GIC datasets have been
selected for the project and input given to the
Technical Note (WP200). Statistical analysis of solar wind and GIC
data are included in the TN300 and TN400.
Ground magnetic field in a dense grid has been
calculated. The 400 kV power net is used. The 220 kV power net will not be
used.
WP202 Dataset with computed geomagnetic data
in a dense grid
Model event set has been constructed and
selected.
Data for the geomagnetic database have
been collected.
Ionospheric currents have been calculated.
Data set with geomagnetic data
grid ready and input given to the Technical Note (WP200).
WP300 Model for computation of GIC from
geomagnetic field
Software package
is constructed.
A draft of the Technical Note for WP300
describing the calculation of the geoelectric
field in general can be found at http://www.lund.irf.se/gicpilot/gicpilotinternal/wp/300/.
WP301 Model for computation of geoelectric
field from geomagnetic field
Software applicable to the computation of
geoelectric field from geomagnetic field has been prepared.
Input to draft Technical Note
WP300 has been delivered.
WP302 Model for computation of GIC from
geoelectric field
FMI has prepared software applicable to the
computation of GIC from geoelectric field.
Adjustment of the model and
the final validation will be performed.
WP400 Forecasting model of GIC from solar
wind data
A list of interesting events (WP400) to be used for analysis and
testing has been identified. It is available at http://www.lund.irf.se/gicpilot/gicpilotinternal/wp/200/201/eventList.html
Java software for the neural network has been
developed.
Draft Technical Note is ready.
http://www.lund.irf.se/gicpilot/gicpilotinternal/wp/400/
WP401 Forecasting model of geomagnetical
grid from solar wind data
Datasets for training, validation, and
testing have been generated.
Neural network architectures have been identified.
Neural networks have been developed and validated.
Optimal neural network for implementation has been
identified.
Java software has been developed. Input to draft
Technical Note WP400 has been delivered.
WP402 Forecasting model of observed GIC from
solar wind
Datasets for training, validation, and
testing have been generated.
Neural network architecture has been identified and linear filter
constructed.
Optimal forecasting model for
implementation has been identified.
Software has been developed. Input to draft Technical Note
WP400 has been delivered.
WP500 Service
implemention
Work with implementing services is in progress. A fluxgate magnetometer is being installed close to
V”xj–.
Software requirements document is being
prepared. Draft showing preliminary content can be found at http://www.lund.irf.se/gicpilot/gicpilotinternal/wp/500/
Prototype
software system is ready.
System manual
will be written in
html-format
User manual will
be provided on-line.
Test report is
being prepared.
WP600
Cost-benefit analysis
Work on cost benefit analysis has started in
close collaboration with the costumer and some material has been delivered from
them.
Forecast service has been running since early
September 2004
GIC events are being monitored and one
important event identified that gave good
possibilities to test the
service.
Cost benefit
report ready at T0 + 24
WP700 Management
Business plan
ready at T0 + 24
2. Problem areas/reasons
for slippages
Power system data were delivered in March 2005.
This delay will not cause any problems to the project since the final report is
supposed to be delivered during fall 2005.
3. Events anticipated to be
accomplished during next reporting period
SDA meeting in Vienna.
4. Status report on all
long lead or critical delivery items
None
5.
Action items
No open
6.
Milestone payment status
Progress payment
has been received.
7. Expected dates for major
schedule items
Date for the next Progress Meeting is Spring
2005.
Swedish Institute of Space
Physics
PO Box 812
SE-981 28 Kiruna, Sweden
|
+46 980
790 00 |
|
|
Fax |
+
46 980 790 50 |
|
internet |