Cable Entries & Earthings
Hauff Technik are leading manufacturers of sealing systems for cables, pipes and building entries. They have been protecting buildings from penetrating water, gas, fire, dirt and vermin for the past 60 years. Specialising in sealing cable entries for secondary substations, Hauff Technik’s innovations help protect and set standards in the energy supply sector.
Secondary Substations Sealing Cable Entries
Hauff Technik Advantages
Secondary substations are a fundamental part of the power network and the energy distribution system. To ensure fault-free operation and high service security in the long term, secondary substations must be equipped with appropriate technology – some of which is very sensitive – to protect against hazards.
Cable entries play an important role here. Hauff Technik specialise in sealing these substation cable entries with the correct system.
In Germany, secondary substations must fulfil a range of requirements, including:
- DIN VDE 0101 (facilities over 1000V)
For prefabricated substations:
- DIN 62271-202 (high-voltage switchgear and control gear part 202:
high voltage/low voltage prefabricated substation)
|No moisture in the substation
A sealed cable entry prevents water and moisture from entering the substation building. This means that the technical equipment is protected against corrosion and the operational safety is increased at the same time.
|No rodents or reptiles
The seal has an additional protective function: no rodents or reptiles can reach the inside of the substation, unlike with non-sealed openings. As a result, damage caused by rodents, especially short circuits and power failures, can be avoided.
|No oil leakage into the ground water or soil
The German Water Resources Act (WHG) stipulates that, when dealing with water pollutants including transformer oil, facilities should be constructed and operated in such a way that there is no risk of them having a negative impact on the properties of water areas. The absolute leak-tightness of a cable entry contributes a great deal to ensuring compliance with this requirement. In the event of damage, a cable entry holds back escaping transformer oil and prevents it from entering the soil or ground water.
The earthing incorporates all of the measures required for connecting an electrical part with the earth. It is an essential component in secondary substations, switch gears, substations, etc.
There is a difference between protective, functional, operational and lightning-protection earthings which is explained below:
- With the protective earthing, a safe connection with the ground is created in order to protect people (and animals) against dangerously high touch voltages in the event of an error. The requirements for the equipotential bonding are described precisely in the VDE 0100-540 standard; the corresponding guidelines for the foundation earth electrode can be found in DIN 18014
- The functional earthing is used to ensure that electrical equipment in the substation can be operated safely. With the functional earthing, fault currents should be diverted safely
- In switchgears, an operational earthing is primarily used to ensure that the system operates without any faults. The EN 50522 (VDE 0101-2):2011-11 standard provides exact specifications on protecting the system against short circuits above 1 KV (max. temperature and no damage on the connection and on the concrete structure)
- With the lightning-protection earthing, lightning currents should be safely diverted into the ground to protect people, animals and buildings. The requirements are regulated in EN 62305-3 (VDE 0185-305-3):2011-10
Hauff Technik Solutions
With earthing entries and earthing fixed points from Hauff Technik, earthing conductors can be fed through the substation walls in a safe and leak-tight manner or connected to the reinforcement. The connection thread (M12 or M16) can be used to connect round or flat steels/ring earth electrodes with connection bolts, cable shoes or lugs, or with cross-clamps.
The HEA-IS-M12/X insulated earthing entry from Hauff Technik is particularly suited to substation construction and is used for various functions, including as an optional test isolating joint for the earthing system. The function of the ring earth electrode can be tested separately outside the substation using the insulated earthing entry.
When feeding the inner earthing to the external earthing system, country-specific requirements must be observed. Their wide range of products provides tried-and-tested solutions for all kinds of applications.
Hauff Technik Example 1
The majority of distribution grid stations in Germany are compact secondary substations. Due to their compact and optimised construction, these secondary substations can even be placed on small plots of land.
To make the connection between the cables and the switchgears easier, the cables are mostly fed into the building through cable entries built into the sloping walls due to the limited room available. This means that the minimum bending radii of the cables can be observed.
Due to the lack of accessibility, special easy-to-install cable entry systems provided by Hauff Technik are required for compact substations. The HSI 150-K cable entry sets the standard for cable entries.
With its factory-mounted closing cover and additional safety cover, the HSI 150-K offers double security in the condition that it is supplied to the customer. Different seal variants such as the heat shrink method, Segmento or split system covers are available.
Walk In Substations
Hauff Technik Example 2
Walk-in secondary substations have the advantage that the system can be operated and maintained from within the building and is therefore not dependent on the weather.
There are numerous installation possibilities for walk-in substation buildings. As a result, transformers, switch gears, inverters, registers and measuring devices can be integrated. Substations are generally installed above ground, but can also be built into slopes or installed underground depending on the requirements.
The Hauff Technik HSI 150 cable entry sets the standard here with the HSI 150-K single wall insert and the HSI 150-K2 double wall insert. With the HSI 150-K2 double wall insert, which is available for wall thicknesses from 100 mm, cables can be sealed and, in addition, cable ducts can be connected in a pressure-tight manner.
Seal variants such as the heat shrink method, split system covers and Segmento are available for sealing cables. It is possible to connect smooth and corrugated cable ducts as well as the flexible Hauff Technik KES-M 150 cable entry system.
Using a duct connection means that additional civil engineering works directly in front of the building are not required when replacing lines or laying new ones, which also means that possible damage to the cables is avoided.
WALL INSERTS AND PLASTIC FLANGE
Cable Entries HSI 150
The HSI 150 cable entry is already embedded in concrete when manufacturing the substation building in the prefabricated part factory. Packages of any size can be formed using the square adapter base.
The leak-tightness of the concrete is achieved using 3-ribbed seals made of thermoplastic elastomer (TPE). There is a seal of quality under the protective foil, which guarantees the leak-tightness of the closing cover when it is undamaged.
For sealing cables and cable ducts, there are different system covers and system seals available from Hauff Technik, which are connected via the integrated bayonet system. All cable entries are pressure tight and sealed with closing covers when supplied to the customer.
HSI 150-K/X single wall insert – one-sided connection on the building exterior
The single wall inserts are the preferred method of cable sealing in compact substations.
The minimum wall thickness is 70 mm. Along with the pressure-tight closing cover, single wall inserts are equipped with a safety cover, which is only removed immediately before laying the cable.
This double security also prevents water from entering if the closing cover is opened accidentally.
HSI 150-K2/X double wall insert – connections on both sides for cable ducts and cables
Double wall inserts are the preferred method of cable sealing in walk-in substations. The minimum wall thickness is 100 mm.
They are equipped ex-works with pressure-tight closing covers with the bayonet system on both sides.
Double wall inserts provide the opportunity to connect cable ducts and also to seal the cable, for example.
|HSI 150-GSM single wall insert with plug-in socket
The single wall insert with plug-in socket is an exceptionally economically and technically sophisticated solution for connecting smooth cable ducts in a pressure-tight manner (Ø 110, 125 or 160 mm).
The HSI 150-GSM is also still pressure-tight after connecting the cable duct thanks to the closing cover that is preinstalled at the factory.
After the cable has been laid, it is preferably sealed with split system seals on the inside of the building.
|HSI 150-DFK plastic flange for retrofitting on sheet steel, sheet metal casings or concreted walls||
The leak-tight connection to the wall is achieved using a 6-mm-thick surface seal made of EPDM.
The fastening elements are made of high quality stainless steel inclusive sealing washer.
The integrated spirit level simplifies the horizontal adjustment. All system covers and system seals from the HSI 150 range can be installed.
BD 90 or BD 68 site power supply entry for a temporary power supply
With the site power supply entry, cables can be temporarily fed into the substation above ground. This means that the doors of the substation can be closed.
When not being used, the site power supply entry is sealed on both sides with screw caps.
On the inside of the substation, the site power supply cover, which can be ordered as an optional extra, provides additional security against vandalism and rodents.
Alongside the HSI 150 cable entry, there is the smaller system, the HSI 90, with different system covers for sealing cables and connecting pipes.
SYSTEM COVERS AND EARTHINGS
Cable Entries HSI 150
System covers and system seals are installed in the single and double wall inserts, which have already been embedded in concrete, or in the plastic or aluminium flanges.
HSI 150 system cover – cold shrink technology
The system covers with bayonet system are installed in the wall inserts before the cables are laid.
To seal the cables, the HSI 150-D1/80, HSI 150-D3/58 and HSI 150-D7/33 system covers are available depending on the requirements.
Hot or, alternatively, cold shrink sleeves are included in the scope of delivery. Empty sockets are sealed with VS blind plugs.
HSI 150-DG split system cover
The HSI 150-DG system cover is installed after the cables have been laid. This means that the entire surface of the cable entry is available when laying the cables. An adapter ring, which is also split, ensures an optimal seal.
Thanks to the patented super segmented ring technology with precisely marked application ranges, the seal insert can be adjusted on site to correspond to the cables that have been laid.
Four variants are available in the application range from 10 – 112 mm.
SEGMENTO for sealing control and communication cables
With Technogel, the seal material used for Segmento, cables can be sealed in a particularly gentle manner.
Four segments, which can be installed in any combination in the HSI 150-S3 system cover, are available in the application range from 5 – 31 mm.
Retrofitting is very simple. All segments are supplied with blind plugs.
HSI 150-D-GSM for connecting smooth cable ducts with plug-in socket
With the system cover, smooth cable ducts with an outer diameter of 110, 125 or 160 mm can be connected.
Quick and easy installation using plug-in technology.
|HSI 150-M for connecting smooth or corrugated cable ducts
With the system cover, smooth or corrugated cable ducts with an outer diameter of 110, 125 or 160 mm can be connected.
The pipe is connected using a flexible and stable rubber sleeve, which is pressed against the system cover and the cable duct with stainless steel bands.
|KES-M 150 cable entry system
The flexible and robust 14150 spiral hose is connected in a gastight and watertight (2.5 bar) manner using the system cover with the rubber sleeve method.
Different seal variants using the shrink- or rubber sleeve method are available.
|HEA-IS-M12 insulated earthing entry
The insulated earthing entry from Hauff-Technik is particularly suited to substation construction and is used for various functions, including as an optional test isolating joint for the earthing system.
The function of the ring earth electrode can be tested separately outside the substation using the insulated earthing entries.
Round or flat steels and cable shoes can be connected using cross-clamps or connection bolts.
Successful short-circuit test in accordance with EN 50522 (VDE 0101-2):2011-11.
|HEA-A-M12 earthing fixed point for welding to reinforcement rods of the substation building
The earthing fixed point for the substation construction can be used for equipotential bonding and earthing the secondary substation.
The connection point of the substation earthing can be integrated internally or externally with the conductor core, which is made of corrosion-resistant stainless steel V2A (AISI 304L).
The reinforcement rods can be welded without changing any material thanks to the transition weld stainless to carbon steel and the practical connection groove.
Suitable for distances of 50 or 70 mm between the shuttering and reinforcement.
Successful short-circuit test in accordance with DIN EN 50522 (VDE 0101-2):2011-11.