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WG C4.502 Power system technical performance issues related to the application of long HVAC cables

 

Due to the increasing public resistance against erection of new overhead lines, transmission utilities have to consider installation of large number of HV/EHV AC cable lines in their networks. Some of these cable lines are of very long length, even in the range of 100 km. Such long cables most likely require installation of reactive power compensating stations along the cable line.

Network planners, network operators and equipment suppliers do not have much experience with the performance of transmission systems with large share of (very long) HV/EHV AC cables. Currently, the longest EHV AC cable lines (2x 500 kV, 40 km) are operated inJapan. A 100km-long cable is being installed inDenmark; it is the 150 kV AC connection of offshore wind farm Horns Rev 2.

As a result of an increasing share of AC cable lines in the Danish transmission network Energinet.dk for some time has been carrying out studies related to issues that can be described as performance of transmission system with very long HV/EHV AC cable lines. Some of the studies resulted in a number of questions that require further analyses.

WG B1.05 has studied maximum lightning overvoltages along long cables. Their report recommended forming a WG that should study switching transients in long AC cables.

JWG 21/33 was evaluating the influence of transient overvoltages on AC cable insulation design. Their report recommends further studies especially for cables with extruded insulation. Additionally it advises further studies using numerical simulation techniques for various network configurations in order to establish guidelines concerning how to perform calculations and how to interpret the results.

Convener: W. Wiechowski (Poland)

Publication: TB556: POWER SYSTEM TECHNICAL PERFORMANCE ISSUES RELATED TO THE APPLICATION OF LONG HVAC CABLES (Published: 2013-10)