Nl voorbespreking CIRED 2013 8 mei 2013 session 1: NETWORK COMPONENTS - 1-

Nationale voorbespreking CIRED 13

Session 1, Paper 1231:

CONTROL OF INDUCTIVE LOAD

SWITCHING TRANSIENTS

Gerard Schoonenberg / René Smeets

Eaton / DNVKema

Nl voorbespreking CIRED 2013 8 mei 2013 session 1: NETWORK COMPONENTS - 2-

1231: CONTROL OF INDUCTIVE LOAD SWITCHING TRANSIENTS

3 onderwerpen:

• Overzicht Switching transients (reprise Cired 1989, p.2.17)

• + wanneer protection measures nodig

• Nieuwe ed. IEC 62271-110: Inductive load switching

• Droge trafo’s toename storingen (?) (Overspanningen, Vacuum)

Nl voorbespreking CIRED 2013 8 mei 2013 session 1: NETWORK COMPONENTS - 3-

1231: CONTROL OF INDUCTIVE LOAD SWITCHING TRANSIENTS

Overzicht Switching transients

• Voorontsteking altijd!

• Current chopping

• Herhaalde herontstekingen vacuum en olie

• Virtuele stroombreking

• resonanties

Nl voorbespreking CIRED 2013 8 mei 2013 session 1: NETWORK COMPONENTS - 4-

1231: CONTROL OF INDUCTIVE LOAD SWITCHING TRANSIENTS

IEC 62271-110 (ed.3.0.m sept 2012): Inductive load switching

• Motor circuit t/m 17.5 kV; 4 test duties

• Veel / weinig C aan voedende zijde

= ca Totaal >5 km kabel / totaal < 100m

• Stroom 100 resp 300 A

• TD2 (weinig C, hoge I) virtual current chop

Nl voorbespreking CIRED 2013 8 mei 2013 session 1: NETWORK COMPONENTS - 5-

1231: CONTROL OF INDUCTIVE LOAD SWITCHING TRANSIENTS

Droge trafo’s toename storingen (?) (Overspanningen, Vacuum)

• 0-5 jaar oud, complied with present standards

• Resonance freq 5-200 kHz / overheating (max inrush each closing)

• Design changes? (foil / wire)

• Materials / additives?

• Applications? (rectifiers, inverters, PWM motor drive:pulse trains 20kHz - >40 kHz)

• Diel. Test op trafo:

• 2*Pwf: 2* Ur

• Impulse 1.2/50 μs

• In practice: t_rise <0.1μs possible(closing CB →T2T 2.5*worse than at impulse,

IGBT switching)

• Oil type higher surge withstand test than Dry type

Nl voorbespreking CIRED 2013 8 mei 2013 session 1: NETWORK COMPONENTS - 6-

1231: CONTROL OF INDUCTIVE LOAD SWITCHING TRANSIENTS

Cired 1999 p1.12, ch.5.2 (KU Leuven + Pauwels):

In most cases of transformer failure due to transient overvoltages, the transformer

manufacturers will find themselves in a difficult position. Even if they are

convinced that their product is in full compliance with all applicable standards,

their explanation is often disbelieved.

Whatever effort they make to help the customer, e.g. a replacement by reinforced

windings, it will always be regarded as a confession of guilt, and finally the

customer will always end up asking the replacement of all identical units.

CONCLUSIES:

• Steile spanningssprongen geen specifiek vacuum probleem

• (Droge-) TRAFO STANDARDS aanpassen aan boze buitenwereld?