HH Back-Up (BU) — high-voltage current-limiting fuses 3.6–40.5 kV
HH Back-Up (BU) series high-voltage current-limiting fuses for rated voltages from 7.2 to 40.5 kV, additionally 27 and 38.5 kV. Typical breaking capacity is 40–80 kA, and the short-circuit current is interrupted in the first half-cycle. They protect distribution transformers, cables and switching devices in switchgear.
- Rated voltage
- 7.2; 12; 17.5; 24; 36; 40.5 kV (additionally 27 and 38.5 kV) per IEC 60282-1
- Class
- Back-Up (BU), partial range; minimum breaking current 3–5 In
- Breaking capacity
- typically 40–80 kA, some versions over 100 kA
- Breaking time
- in the first half-cycle, milliseconds
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
HH fuses of the Back-Up series are the main line of high-voltage current-limiting fuse-links for medium voltage networks. They protect distribution transformers, cables, switching devices and other equipment against short circuits. They are installed in air- and gas-insulated switchgear, in outdoor installations, and in oil-filled switching devices and transformers, including in harsh climatic conditions.
A silver fuse element with calibrated constrictions is placed in a tube of electrical porcelain or glass-fibre plastic filled with quartz sand. The ends are sealed with elastic seals against moisture, dust and corrosion. The short-circuit current is interrupted already in the first half-cycle: the peak current and the Joule integral I²t are limited, and the mechanical stress on cables and busbars and the arc energy at the fault location are reduced. The Back-Up class interrupts all currents from the rated maximum breaking current down to the minimum breaking current, which is 3–5 times the rated current of the fuse-link.
The rated voltages under IEC 60282-1 are 7.2 kV, 12 kV, 17.5 kV, 24 kV, 36 kV and 40.5 kV, additionally 27 kV and 38.5 kV. Typical breaking capacity is 40–80 kA, and some versions exceed 100 kA. Most fuse-links have a striker with a force of 80 N or 120 N. Fuse-links with an 80 N striker have a built-in temperature limiter that keeps the temperature of the inner wall of the switchgear below 150 °C during prolonged overload. The operating temperature is −25…+40 °C, and above that with derating factors.
Versions are available for oil transformers and outdoor installation (HHx), with a double-wall laminated LM tube (ceramic and heat-resistant glass-fibre plastic) for increased breaking requirements, and Compact Size with a reduced tube diameter, lower consumption of metal, ceramic and sand, and a mass up to 35 % lower with the same connection dimensions and characteristics. In the 17.5 kV range the Compact Size is available with the secondary dimension e = 292 mm and the standard length e = 367 mm.
They are used in transformer substations of utilities, in industrial networks, at wind and solar plants and in railway infrastructure. Compliance with IEC 60282-1 / VDE 0670-4, DIN 43625 (3.6–36 kV) and IEC 60787 / VDE 0670-402 provides selectivity with LV fuses and circuit breakers.
Technical specifications
| Rated voltage | 7.2; 12; 17.5; 24; 36; 40.5 kV (additionally 27 and 38.5 kV) per IEC 60282-1 |
|---|---|
| Class | Back-Up (BU), partial range; minimum breaking current 3–5 In |
| Breaking capacity | typically 40–80 kA, some versions over 100 kA |
| Breaking time | in the first half-cycle, milliseconds |
| Striker | 80 N (with built-in temperature limiter) or 120 N |
| Body | electrical porcelain or glass-fibre plastic; quartz sand; silver fuse element |
| Versions | for air- and SF6-insulated switchgear, outdoor installation, oil transformers (HHx); LM double-wall tube; Compact Size mass up to −35 % |
| Operating temperature | −25…+40 °C |
| Standards | IEC 60282-1 / VDE 0670-4, DIN 43625, IEC 60787 / VDE 0670-402 |
Request a price and lead time
HH Back-Up (BU) — high-voltage current-limiting fuses 3.6–40.5 kV. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What are the rated voltages and breaking capacity of HH Back-Up fuses?
Under IEC 60282-1 the rated voltages are 7.2 kV, 12 kV, 17.5 kV, 24 kV, 36 kV and 40.5 kV, additionally 27 kV and 38.5 kV. Typical breaking capacity is 40–80 kA, and some versions exceed 100 kA.
What striker and temperature limiter do the fuse-links have?
Most fuse-links have a striker with a force of 80 N or 120 N. Fuse-links with an 80 N striker are equipped with a temperature limiter that keeps the temperature of the inner wall of the switchgear below 150 °C during prolonged overload.
What is different about the Compact Size version?
A reduced tube diameter, lower consumption of metal, ceramic and sand, and a mass up to 35 % lower with the same connection dimensions and characteristics. For the 17.5 kV range the secondary dimension e = 292 mm and the standard length e = 367 mm are available.
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