Software: Microsoft Office

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.

 


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