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With controlled power dissipation

Application

EFEN HV back-up fuse-links type ÜLA meet the requirements of VDE 0670 T4 and were specifically developed to be installed in compact sized enclosed SF6 insulated substations. In these substations HV fuse-links are enclosed in narrow fuse compartments which on the one hand prevent efficient cooling of the fuse-links and on the other hand have a limited thermal power acceptance themselves.

Overheating of fuse compartments in such enclosures is, however, not to be expected, if the fuse-links have been properly selected by their rated current according to the transformer to be protected (see Selection table HV back-up fuse-links acc. to VDE 0670 T4/IEC 60282-1 with controlled power dissipation ÜLA table) and if the melting elements of the fuselins are in faultless condition (see Controlled power dissipation chart).

One or more of the melting elements connected in parallel may, however, be interrupted by transient currents caused by transformer inrush or lightning strikes. Fuse-links having one or more of the paralleled melting elements interrupted, dissipate significantly more heat than faultless fuse-links. There is a certain risk that the limited power acceptance of fuse compartments may be exceeded at or even below rated transformer current. EFEN HV back-up fuse-links type ÜLA prevent such potential overheating when installed in conjunction with a transformer switch having trip-free mechanism.

Function mode

The ÜLA striker system controls the power dissipation of the fuse according to Ohm’s law (ÜLA means controlled power dissipation). The striker pin is released depending on the voltage drop across the fuse and, therefore depending on the power dissipation. The release voltage of the ÜLA striker system has been selected so that the fuse carrying the operating current IB does not exceed the limiting value. The ÜLA striker system controls the power dissipation of the fuse and releases the transformer switch before the permissible power acceptance of the fuse compartment will be exceeded
(see Controlled power dissipation chart).

Controlled power dissipation
Controlled power dissipation chart

 

Selection table HV back-up fuse-links acc. to VDE 0670 T4/IEC 60282-1 with controlled power dissipation ÜLA

Rated voltage range of fuse-link [kV] 6/12 10/24
Service voltage of transformer [kV] 10 20
Rel. short-circuit voltage Transformer output [kVA] Transformer rated current (A) Rated current of fuse-link (A) Transformer rated current (A) Rated current of fuse-link (A)
uK = 4 % 50 2,9 10 1,5 4
100 5,8 16–20 2,9 10
125 7,2 20–25  3,6 10–16
160 9,2 20–31,5  4,6 16–20
200 11,5 25–40 5,8 16–20
250 14,4 31,5–50 7,2 20–25
315 18,2 40–63 9,1 20–31,5
400 23,1 40–80 11,5 25–40
500  28,9 50–100 14,4 31,5–50
630  36,4  63–100 18,2 40–63
uK = 5 % 800 46,2 80–125 23,1 40–63
1000 57,7 100–160 28,9 50–80
1250 72,2 125–200  36,1 63–100
uK = 6,25 % 1600 92,4 125–200 46,2 80–100
Bold typed figures are prefered values
Selection table HV back-up fuse-links acc. to VDE 0670 T4/IEC 60282-1 with controlled power dissipation ÜLA table

 

HV back-up fuse-links acc. to VDE 0670 T4/IEC 60 282-1

Electrical data, dimensions, weights

 Order No.  Rated voltage range Rated current Rated minimum breaking current Rated minimum breaking current Dimensions Resistances and power dissipation Total I2t Weight Pack
  Un In I1 I3 e d Rkalt Pwarm A2s kg  
  kV A kA kA mm mm W      
67220.0019 6/12 1 63 14 292 56 1500 1,6 90 1,6 1
67220.0029 6/12 2 63 16 292 56 510 2 280 1,6 1
67220.0049 6/12 4 63 22 292 56 338 6 500 1,6 1
67220.0069 6/12 6,3 63 30 292 56 190 8 600 1,6 1
67220.0109 6/12 10 63 42 292 56 139 16 1150 1,6 1
67220.0169 6/12 16 63 54 292 56 107 38 1290 1,6 1
67220.0209 6/12 20 63 73 292 56 71 38 3200 1,6 1
67220.0259 6/12 25 63 93 292 56 52 46 5200 1,6 1
67220.0329 6/12 31,5 63 105 292 56 43 65 7200 1,6 1
67220.0409 6/12 40 63 125 292 56 23 54 23300 1,6 1
67220.0509 6/12 50 63 1609 292 56 18 70 34900 1,6 1
67220.0639 6/12 63 63 230 292 56 12 85 58300 1,6 1
67220.0809 6/12 80 63 350 292 65 10,6 114 90000 2,1 1
67220.1009 6/12 100 63 500 292 65 8,5 156 140000 2,1 1
67220.1259 6/12 125 63 480 292 88 4 117 440000 3,7 1
67220.1609 6/12 160 63 560 292 88 4,3 217 500000 3,7 1
67220.2009 6/12 200 63 610 292 88 3,8 333 654000 3,7 1
67240.0019 10/24 1 63 14 442 56 2100 2 90 2,3 1
67240.0029 10/24 2 63 16 442 56 800 3 340 2,3 1
67240.0049 10/24 4 63 23 442 56 550 10 450 2,3 1
67240.0069 10/24 6,3 63 30 442 56 300 13 530 2,3 1
67240.0109 10/24 10 63 43 442 56 220 26 940 2,3 1
67240.0169 10/24 16 63 54 442 56 197 73 1400 2,3 1
67240.0209 10/24 20 63 73 442 56 134 76 3100 2,3 1
67240.0259 10/24 25 63 93 442 56 96 89 4500 2,3 1
67240.0329 10/24 31,5 63 105 442 56 79 127 5900 2,3 1
67240.0409 10/24 40 63 125 442 56 45 114 18800 2,3 1
67240.0509 10/24 50 63 205 442 56 35 147 33500 2,3 1
67240.0639 10/24 63 63 280 442 56 24 170 59600 2,3 1
67240.0809 10/24 80 63 310 442 65 20,5 233 84000 3,1 1
67240.1009 10/24 100 63 430 442 78 18 400 93600 4,1 1
HV back-up fuse-links acc. to VDE 0670 T4/IEC 60 282-1 table

Benefits of thermal protection of the fuse compartment by ÜLA

– ÜLA controls the power dissipation of the fuse-links
– ÜLA is based on Ohm’s law
– ÜLA works independent on the mounting position of the fuse
– ÜLA releases the striker, before an overheating is reached
– ÜLA mechanism is non-ageing