Lightning Proof Fuse
Function
The Lightning Proof Fuse (LPF) protects your distribution Line from over current damage, by isolation of the fault. It is a convenient and cost effective method of over current protection, with the advantage of eliminating nuisance fuse blows.
Conventional Fuse Cut-outs are simply removed and replaced with the Lightning proof fuse. The Lightning proof fuse is not to be used as a line fuse and should only be placed within the vicinity of the pole mounted transformer. According to research 90% of fuse callouts are caused by nuisance Fuse blowing. Both Direct and Indirect lightning strikes are the cause of nuisance fuse blowing.
By utilizing the LPF, Lightning will not cause nuisance outages, as with the use of the conventional fuse-cutout.
Another advantage of utilizing the LPF, is that point location will be achieved when a transformer is down. By simply replacing existing line fuses with links and utilizing the Lightning proof fuse at the Pole mounted transformer , multiple customers can be provided with faster fault recovery, improving power quality during Lightning storms.
Available from sales
Tel : +2718 468 5080
Mobile: +2784 701 3354
Email : sales@liveline.co.za
Operation
- By removing the conventional fuse carrier and replacing it with a Lighting proof fuse, nuisance fuse blows are eliminated. When lightning strikes a line either indirectly or directly, it induces extremely high frequencies on a distribution line which would even traditionally blow , a standard fuse rated to 100A.
- The Lightning proof fuse, is not to be used as a line fuse , and is only to be installed at the Transformer.
- The Power frequency flows through the inductance coil and the standard fuse link, the inductance coil can take a continuous current of 15A.
- The Coil allows the system frequency current to operate through it, but blocks high frequency transients (ie Lightning), not allowing these high transients to flow through the fuse. The fuse thus remains healthy during electric storms.
- The High frequency transient is by-passed via an arching horn.
- Should a fault current occur, it will blow the fuse and cause the unit to fall open as any standard fuse holder would open. This isolates the faulty transformer. Replacement of the fuse is as normal.
Inductance Coil
The Power frequency flows through the inductance coil and then the standard fuse. The inductance coil can take a continuous current of 15A.
The coil allows the system frequency current to operate through it but blocks high frequency transients, not allowing these high frequencies to flow through the fuse. The High frequency transient is by-passed via an arching horn.
Should a fault current occur, it will blow the fuse and cause the unit to fall open as any standard fuse holder would open thus isolating the faulty transformer. Replacement of the fuse is as usual.
Arching Horn
Lightning cannot blow the fuse as it jumps over the Arching horn, which is in place to provide an easy exit for the Lightning. Operators are to ensure that healthy Arrestors are in place so as to provide the Transformer with protection.
Standard Eskom Fuse 5A 15A
The Lightning proof fuse carrier houses a standard fuse element from 5A to 15A.
- The Fuse carrier drops down only when there is a fault, giving a clear indication that a transformer is faulty. The transformer needs to be tested and the fuse needs to be replaced. This fuse never blows for any other reason eg. Lightning
- Installation and removal of the fuse carrier is achieved by the positive engagement of the unit onto a pick up tongue positioned at the hinge end of the expulsion tube. The unit can be operated from ground with the aid of a link stick.
- The screw cap design at the top end of the fuse carrier provides easy opening and closing of the unit. The spent expulsion link can quickly be replaced with a new unit. The Fuse carrier is lined with an anti-flammable polymer fibre, creating easy venting during high fault current interruptions. The units are often subject to extremely high fault currents and are rated to withstand a current rating of 100A.
- The Fuse Carrier is designed to accommodate standard expulsion Fuse links of the button head pattern. The button head flanges over the top edge of the carrier, holding it in position. Two speeds of operation are available :- Type K (Fast operating) and Type T (Slow operating).Each with ratings from 1A to 15A.
- A spring loaded flipper and locking mechanism at the lower end of the fuse carrier ensures consistent tension on the fuse link and prevents element damage during close in. The flipper also assists rapid withdrawal of the fuse link from the tube under low fault conditions.
- Current transfer is via silver plated contacts and is completely independent of the lower support hinge. The lower contact arrangement ensures positive seating at the hinge point and limits the degree of misalignment during closing. It also assists the initial opening movement of the fuse carrier when operating.
- The galvanised steel hood protects the top contact assembly from the natural elements and guides the fuse carrier into its insulator and ensures correct latching position during close in. A spring is also situated inside the top hood so that when the fuse carrier is pushed into the unit, it is compressed into position.
Accessories for a complete Installation
LLT-DPF
The LLT-FC100 Fuse carrier is a standard 100A maximum rated unit
LLTDPF-HB
Cycloaliphadic insulators are lightweight and easy to install.
LLT-PRF
The expulsion fuse link is available in amperages ranging from 1A-100A.
Two speeds of operation are available:
Type K (Fast operating) & type T (Slow operating)
Specifications
| Operating Voltage | – | Distribution lines 3kv = 22kv |
| Fuse Cutout Material | – | Cycloaliphadic Material |
| Fuse Carrier Rating | – | Maximum 15A |
| Fuse (Operating Amperage) | – | Standard Expulsion Links (Type K) Fast expulsion (Type T) Slow operation |
| Product Category | – | Over-current Line protection |
| Specification | – | Eskom specification |
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