APPLICATION CASE

Lamifil nv

Frederic Sheidlaan B-2620 Hemiksem, Belgium www.lamifil.be Tel. +32 (0)3 870 06 11 VAT - BE - 0422 050 265 FORTIS Bank: (BE49) 220-0035440-71 BIC : GEBABEBB Fax +32 (0)3 870 06 74 RPR Antwerp ING Bank: (BE62) 320-0027054-61 BIC : BBRUBEBB

doubling the load transfer capacity – ACCC conductor

In 2007, Elia was informed that an industrial plant was going to commission a new 400MVA production

unit and deliver power to the Belgian transmission network by 2010. A small coal fired production unit

some 20 km further down was going to be shut down around the same time. Load flow studies examining

system reliability at N-1 showed that a 20km long double-circuit 150 kV connection would be overloaded

under certain conditions.

The two circuits were strung with ACSR 298mm² conductors having a diameter of 22.4 mm and had a

maximum load transfer capability of 162 MVA each. The maximum operating temperature was 75 °C as

specified by Belgian legislation. The challenge Elia faced was to increase the load capacity of each circuit

from 162 MVA to 360 MVA without important reinforcement of the tower-foundation system and with

minimal environmental impact. Each circuit had to be upgraded while the second stayed in operation.

The solution

All technical solutions were considered before deciding that reconductoring was the best option. Circuit

reconductoring did not require the existing towers and foundations to be reinforced and it was the only

solution that enabled Elia to complete the project within a reasonable time-scale.

The sag of the new conductor at its maximum operating temperature could not exceed the sag of the

existing ACSR 298mm² at 75°C. The outer diameter of the new conductor and the forces on the existing

towers had to be less or equal than with the ACSR 298mm² conductor. At 75°C the load transfer capacity

of the new conductor had to be some 22% higher than previously. Several new or existing technologies

were examined to check whether they could meet the requirements: ACSS, GZTACSR, ACCR and the

most recent technology, ACCC.

After comparing all solutions on the table, Elia went for the ACCC Lisbon 325mm², which offered several

advantages:

• doubled load transfer capacity with a conductor of the same size

APPLICATION CASE

Lamifil nv

Frederic Sheidlaan B-2620 Hemiksem, Belgium www.lamifil.be Tel. +32 (0)3 870 06 11 VAT - BE - 0422 050 265 FORTIS Bank: (BE49) 220-0035440-71 BIC : GEBABEBB Fax +32 (0)3 870 06 74 RPR Antwerp ING Bank: (BE62) 320-0027054-61 BIC : BBRUBEBB

• no significant modifications to the towers,

limited expenditure for reinforcements

• lower sag helps reducing magnetic field

level at the annual mean current

• reduced time for reconductoring existing

circuits resulting in the lowest overall cost

compared to other technical solutions.

• the ACCC Lisbon 325mm² has the lowest

line losses

Replacing the ACSR 298mm² conductor with ACCC Lisbon 325mm² conductor for this line doubled the

ampacity and should save an estimated 64,500 MWh of losses over a 30 year economic life. It should

also reduce generation capacity requirements by 600kW and save the emission of over 40,000 metric

tons of carbon dioxide over that 30 year period.

During installation, Lamifil and CTC Cable monitored the conductor stringing

procedure, the installation of the accessories and controlled the quality of the

work. All conductor compressions were subject to a visual inspection by Elia

Grid Services prior to commissioning and immediately after commissioning; the

transmission line was checked with thermo-vision. To secure the knowledge

and expertise with respect to ACCC technology, Elia trained a full crew of their

Grid Services - Power Links division.

The possibility to make compressions on dead-end clamps on the towers with

a light 60-ton press was considered to be a major advantage for safety and

comfortable working conditions.

Conclusion

Elia, the Belgian TSO successfully completed its first project involving ACCC

conductor. The installation of some 125km of ACCC conductor ran smoothly

and was completed ahead of schedule. The 150kV double circuit transmission

line is back into normal operation since the end of November 2009, and is now

offering ample current carrying capacity at a temperature up to 75°C and has a

long term spare capacity for working under N-1 conditions.

previous present

ACSR 298mm² ACCC Lisbon conductor

22,4mm 21,78mm diameter

662A 1380A nominal current

double circuit vertical

super-bundle low-reactance circuit configuration

75°C 180°C max. operating temperature

150kV nominal voltage

20km circuit length