Insulation coordination for the electrical system of wind ... - IEA Wind
Insulation coordination for the electrical system of wind ... - IEA Wind
Insulation coordination for the electrical system of wind ... - IEA Wind
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<strong>Insulation</strong> <strong>coordination</strong> <strong>for</strong> <strong>the</strong> <strong>electrical</strong> <strong>system</strong> <strong>of</strong><br />
<strong>wind</strong> farms<br />
<strong>IEA</strong> Meeting London June 18<br />
Presentation by<br />
Dr. Michael Lindgren,<br />
Vattenfall Power Consultant, business unit <strong>wind</strong> power<br />
© Vattenfall AB
Goal <strong>of</strong> <strong>the</strong> presentation<br />
To put focus on insulation <strong>coordination</strong> <strong>coordination</strong> as a critical issue <strong>for</strong> successful design<br />
<strong>Insulation</strong> <strong>coordination</strong> stuides are usually not per<strong>for</strong>med <strong>for</strong> distribution <strong>system</strong>s<br />
© Vattenfall AB<br />
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Lillgrund – one element in <strong>the</strong> conversion to<br />
sustainable energy generation<br />
• 48 <strong>wind</strong> turbines<br />
• 2.3 MW each<br />
• 30/130 kV trans<strong>for</strong>mer plat<strong>for</strong>m<br />
© Vattenfall AB<br />
3
Run <strong>of</strong> cable – submarine (about 7 km)<br />
© Vattenfall AB<br />
4
<strong>Insulation</strong> <strong>coordination</strong> issues<br />
• Damage <strong>of</strong> dry type trans<strong>for</strong>mers has been experienced<br />
• Vaccum circuit breakers result in very fast switching voltage transients. Is <strong>the</strong> existing standard<br />
suitable <strong>for</strong> <strong>the</strong> verification <strong>of</strong> such transients?<br />
• IEC standard available <strong>for</strong> insulation testing <strong>of</strong> main circuit equipment<br />
• In Lillgrund, insulation level as well as arrester arrangement had to be updated following <strong>the</strong><br />
<strong>Insulation</strong> study per<strong>for</strong>med by supplier <strong>of</strong> <strong>the</strong> integrated <strong>system</strong><br />
© Vattenfall AB<br />
5
<strong>Insulation</strong> testing<br />
Generator trans<strong>for</strong>mer<br />
Testing according to IEC 60076, IEC60836<br />
Power frequency 1 minute<br />
Phase to ground<br />
Phase to phase<br />
Across <strong>the</strong> isolating distance<br />
Lightning impulse 1.2/50 micro seconds<br />
Phase to earth and between phases<br />
Across isolating distance<br />
60 kV<br />
60 kV<br />
80 kV<br />
170 kV (8.9 pu phase-ground)<br />
195 kV<br />
Plat<strong>for</strong>m trans<strong>for</strong>mer<br />
Power frequency 1 minute 50 Hz 275 kV/70 kV<br />
50 seconds 120 Hz 272 kV/66 kV<br />
Lightning impulse IEC 60076 1.2/50 micro seconds<br />
HV <strong>wind</strong>ing Phase-Ground<br />
645 kV (8.58 pu)<br />
LV <strong>wind</strong>ing Phase-Ground<br />
196 kV<br />
© Vattenfall AB<br />
6
<strong>Insulation</strong> <strong>coordination</strong> in commercial projects<br />
Present situation concerning insulation <strong>coordination</strong><br />
Suppliers <strong>of</strong> <strong>wind</strong> generators and trans<strong>for</strong>mers are reluctant to take responsibility <strong>for</strong> <strong>the</strong>ir<br />
components concerning over voltages.<br />
As a consequence, specifications must be defined by <strong>the</strong> customers (utilities and<br />
developers) sometimes lacking <strong>the</strong> <strong>system</strong> competence<br />
There are few companies that can take responsibility <strong>for</strong> per<strong>for</strong>ming <strong>the</strong>se studies.<br />
<strong>Insulation</strong> <strong>coordination</strong> studies require detailed models <strong>of</strong> trans<strong>for</strong>mers and cables that may<br />
be difficult to obtain from suppliers.<br />
<strong>Insulation</strong> levels <strong>of</strong> main circuit equipment as well as arrester configuratons should be<br />
standardised<br />
© Vattenfall AB<br />
7