High-voltage high-breaking capacity VV fuse-links

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Bryan French
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1 High- high- VV fuse-links imum cold resistance power dissipation pre-arcing I t value total I t value [kv] (mm) I n [A] (ka) [mω] [W] [A s] [A s] 1 580,1 57 A ,3 1 A A A A A A A A A A A A A A A /7. 0 A A A A A A A A A A A A A A A A A A A

2 imum cold resistance power dissipation pre-arcing I t value total I t value [kv] (mm) I n [A] (ka) [mω] [W] [A s] [A s] 1 980,1 57 A ,3 1 A A A 80 0, A A A A ,1 57 A ,3 1 A A A 0 0, A A A A A /1 80 A A A A ,1 57 A ,3 1 A A A A A A A A A A A A A A A A

3 imum cold resistance power dissipation pre-arcing I t value total I t value [kv] (mm) I n [A] (ka) [mω] [W] [A s] [A s] ,1 57 A ,3 1 A A A A A A A A A ,1 57 A ,3 1 A A A A A / A A A A A A A ,1 57 A ,3 1 A A A A A A A A A A A

4 imum cold resistance power dissipation pre-arcing I t value total I t value [kv] (mm) I n [A] (ka) [mω] [W] [A s] [A s] ,1 57 A ,3 1 A A A A 31, A A A A ,1 57 A ,3 1 A A A A A / 0 A A A A A A ,1 57 A ,3 1 A A A A A A A A A A A A

imum cold resistance power dissipation pre-arcing I t value total I t value [kv] (mm) I n [A] (ka) [mω] [W] [A s] [A s] 1 900 17,1 57 A 0 1870 5 17,3 1 A 0 7 1390 73 3 30 10 A 08 8 11 1 530 1 A 80 1

5 imum cold resistance power dissipation pre-arcing I t value total I t value [kv] (mm) I n [A] (ka) [mω] [W] [A s] [A s] ,1 57 A ,3 1 A A A ,1 57 A ,3 1 A /3 10 A A A ,5 5 A A A A A** Force / travel striker pin diagram Connection in indoor switchgear, example: striker force 10 N VVT-D striker force 80 N VVC striker force N 105

6 Fuse-link - VV Cut-off diagram for VV-Thermo fuse links Cut-off Prospective Prearcing time (s) Time- characteristics for VV-thermo fuse links A A A 1A 5A 0A A 80A 15A 10A 0A 3A 3A 100A 10A Prearcing time (s) Prospective Prospective 10

7 Selection of fuses for transformer protection For HV fuse-link selection, following transformer technical features has to be known: power P n (kva) Short-circuit U cc (%) I nt usually between 8-1xI nt Short-circuit I cc Overload usually 1. I nt Maximum short-circuit duration. Standard sec for transformers up to 30 kva and 3 sec for higher powers Following HV fuse-link technical features has to be known: U n (kv) I n I/t Characteristics According to the curves Melting (0.1sec) I f (0.1sec) Melting at s ec or 3sec melting time Minimum I 3 Breaking I 1 (ka) General about transformer protection: Fuse-link U n must be higher then network. Maximum fuse-link I 1 must be higher then short circuit- Icc. should not melt the fuse-link. Melting at 100 msec must be higher than 1 times transformer Fuse-link has to operate before the expected short-circuit damage the transformer Icc > I f ( sec) or Icc > I f (3 sec) Fuse-link must be able to withstand possible short duration overloads. I n FUSE > 1. I n TRAFO Selection table for VV - THERMO back-up fuse links Pt (kva) Ip at kv /7, kv 10/1 kv 15/17.5kV Ip at 10 kv Ip at 15 kv * * * * 315* * 100 * Note: nonstandard tube dimmension 107

Selection table for VV - THERMO back-up fuse links Pt (kva) Ip at 0 kv 0/ kv 30/3 kv Ip at 30 kv 1 18 3 1 1 3 75 100 1 17 100 100 3 35 10 15 3 10 15 15 3 10 10 9 10 10 10 5 55 10 1 00 3 37 10 00 00

8 Selection table for VV - THERMO back-up fuse links Pt (kva) Ip at 0 kv 0/ kv 30/3 kv Ip at 30 kv pole fuse-base INDOOR MOUNTING OUTDOOR MOUNTING [kv] A [mm] B [mm] C [mm] D [mm] E [mm] F [mm] 7, and ,5 and , and ,5 and internal fuse base 108

9 external fuse base Definitions and terms Back-up fuse-links According to standard IEC 08-1 Fifth edition (00-01), item 3.3.3, Back-up fuse is -limiting fuse capable of, under specified conditions of use and behaviour, all s from the imum (I 1 ) down to the imum (I 3 ). Back-up fuse links should not operate below theirs Ľimum ę. If the short-circuit of the transformer is lower than the imum, additional protection must be provided. range s ETI VV Thermo fuse-links must be ope at the. At lower operating s without limitation provided, please contact ETI team. Breaking I 1 This value (sometimes named imum of indicates, that this is the imum which can be interrupted by the fuse-link. I 1 should be greather than the imum expected short circuit at the fuse-link site. Minimum I 3 This value (sometimes named imum is specified for Back-up fuse-links. Up from this, fuse-link is capable to fault. Power dissipation of a fuse-link P n The power dissipation of a VV Thermo fuse-link is specified at the of the fuse-link. For calculations of protection with VV Thermo fuse-link, it should be noted, that operating is normally below half of the. Time- characteristics I/t characteristics represents the correlation between and time up to the melting of a silver fuse element. For coordination with other protection devices, melting integral must be referred for melting times below 100ms. Current limitation This is most significant advantage of fuse-links compared to mechanical switches. Contacts of that switches need much longer time as fuse-link to interrupt fault s. VV fuse-link interrupt fault within few miliseconds and sinusoidal does not reach its peak value. Switching s Between -limiting process, short circuit must be limited and reduced as soon as possible. This require a switching that exceed the normal system and force the to zero. Permissible value of switching is. times peak value of the imum. 109

High-voltage high-breaking capacity VV fuse-links

High-voltage high-breaking capacity VV fuse-links High- high- VV fuse-links [A] (ka) [mω] [W] [A 2 s] [A 2 s] 12 580 4 6,1 57 4 A 20 370 9 17,3 164 6 A 25 260 10 36 340 10 A 46 55 7 161 1 530 16 A 60 37 13 250 2 270 20 A 80 30 15 430 3 750 25 A 105 25