Cable Joints & Terminations HV

Transformer Oils – 11kV 33kV 66kV Substation Transformer Oil Refilling, Sampling & Analysis

Substation Transformer Oil Refilling, Sampling & Analysis MV HV

Transformer Oils

♦ MV HV 11kV 33kV 66kV ♦

• Guest Post by Neil Denbow (Director - Eden Transformer Oil)

The following Guest Article discusses the “end to end service” provided by Eden Transformer Oil and the benefits of their products to maintain transformer oils including MIDEL 7131 and silicon insulating liquids – Eden test, maintain and purify insulating liquids and electrical transformer oils in MV HV transformers and switchgear at 11kV, 33kV and 66kV voltages.

Background

An important and historical site in central London had been refurbished during which five silicone 11kV transformers were replaced with mineral oil filled units.

Due to the room dimensions, materials used and lack of fire prevention equipment the medium voltage substation no longer complied with BS EN 61936-1:2010.

The customer had a choice of further intrusive construction, prolonged power outages and the associated expense of installing fire prevention or whether to upgrade the transformers to a K Class insulating liquid.

The decision was taken to upgrade the existing transformers to MIDEL 7131 and Eden Transformer Oil were contracted to retrofill each transformer in-situ during one weekend day per transformer. Eden Transformer Oil was the first company in the world to be accredited MIDEL Service Partners and has carried out many MIDEL retro-fills on site.

Solution

The mineral oil was removed US specification drums for removal from site to Eden licensed waste oil storage site and over one week day per transformer the units were professionally upgraded to MIDEL 7131.

A professional upgrade requires dedicated MIDEL 7131 equipment, procedures and staff accredited by the manufacturer of MIDEL. The process includes time to allow the removal of excess transformer oil, heating the liquid to 60-80°C, further cycles of purification via vacuum dehydration plant and new gaskets.

Retrofil with MIDEL Transformer Oil

Retrofilling oil-filled MV HV transformers enables the user to enjoy the benefits of MIDEL without having the capital expense of a new transformer, lift and sift, MV HV cable jointing and prolonged productivity outage.

Replacing mineral oil insulating fluid with MIDEL in an existing medium/high voltage transformer means the MV-HV transformer doesn’t need to be removed and the retrofill procedure can be carried out in-situ and on-site.

MIDEL retrofills can be performed by a MIDEL Service Partner who will advise on the ideal MIDEL fluid depending on transformer design and location.

Transformers up to 66kV can be retrofilled with no design change needed.

Benefits of MIDEL 7131 Transformer Oils

Fire Safety

• 100% fire safety record
• High fire point >300˚C
• Classified as K-class transformer oil
• FM Global® approved MV HV transformer fluids for lower insurance premiums (supports Highly Protected Risk status)
• UL® Classified for lower insurance premiums

Environmental Protection

• Readily Biodegradable
• Non-Water Hazardous
• Non-Toxic
• Recoverable and dispersible at sea using standard methods
• Non-Volatile
• Will not evaporate into the environment

Transformer Life Extension

• Use of MIDEL can prolong cellulose lifetime
• This can in turn prolong transformer service
• Wet transformers can also be returned to service
• Suitable for 11kV 33kV 66kV transformer applications

Lower Operating Expense

• MIDEL’s superior moisture tolerance results in lower future maintenance such as purification and / or liquid changes normally associated to mineral oil thereby avoiding maintenance costs and production outages.
• Many insurance companies give improved premiums for MIDEL filled transformers

Improved Overload Resistance

• Based on the IEC 60076-14 curve an MIDEL transformer can run 15˚C hotter with the same lifetime as a mineral oil transformer
• This allows higher normal running temperature
• Temporary overload temperature can also be higher
• MIDEL fluids have a much higher flash point than mineral oil, allows safe running at higher temperatures

Suitable For Transformers In High Risk Areas

• Industrial buildings
• Residential buildings
• Public buildings (schools, hospitals etc.)
• No risk of pool fires
• Reduced clearances to other equipment or buildings (BS EN 61936-1:2010)

Onshore & Offshore Transformers 11kV 33kV 66kV | Medium & High Voltages

MIDEL retrofil checklist

Eden Transformer Oils

About Us

Eden Transformer Oil Ltd was formed by Alan Denbow and Eddie Gregory in August 1985.

Former employees of Burmah Castrol, they realised that the vast majority of electrical engineers were simply replacing expensive transformer oil without fully appreciating the additional technical benefits of purification to the electrical equipment that Eden could achieve using a more convenient solution at a significantly lower cost.

In more recent years the treatment of transformer oil is the first choice for a cost effective and efficient maintenance program: the increasing cost of new oil, the importance of productivity and equipment downtime, coupled with the environmental benefits of avoiding the transportation of hazardous waste and use of virgin products, are all part of the equation – this applies to medium/high voltage (MV-HV) applications distributing electrical power at 11kV, 33kV and up to 66kV.

As well as providing on-site transformer oil treatment, if needed, Eden can supply and install new or reconditioned insulating liquid and provide all of the on and off-site sampling and analysis to ensure transformers are supervised and maintained according to British Standards (BS EN 60422:2013) and insurance underwriters requirements.

Since August 1985 Eden have been testing and maintaining the insulating liquids in transformers and switchgear in the United Kingdom, Belgium, France and Germany.

Eden provides end-to-end MV HV services and products to maintain transformer oil, MIDEL 7131 and silicon insulating liquid. On their webpage “Why Maintain Oil”, they highlight how Eden can provide a safe, economical and environmentally sound solution to maintaining transformers.

Eden do not just process insulating liquid, but they can also supply new liquids, breathers and consumables used for maintaining transformers.

Whether you are an end user, Electrical Engineering Company, Facilities Manager or Senior Authorised Person, Eden will be able to assist you in the testing and maintenance of your liquid insulated electrical equipment for LV (Low), MV (Medium) and HV (High Voltage) applications up to 66kV.

Transformer Oils | Medium & High Voltage MV HV | 11kV 33kV 66kV

LV, MV & HV Jointing, Earthing, Substation & Electrical Eqpt

Thorne & Derrick International are specialist distributors of LV, MV & HV Cable Installation, Jointing, Duct Sealing, Substation & Electrical Equipment – servicing UK and global businesses involved in cable installations, cable jointing, substation, overhead line and electrical construction at LV, 11kV, 33kV and EHV.

THORNE & DERRICK Product Categories: Duct Seals | Cable Cleats | Cable Glands | Electrical Safety | Arc Flash Protection | Cable Jointing Tools | Cable Pulling | Earthing | Feeder Pillars | Cable Joints LV | Joints & Terminations MV HV 

Do You Think That Concentric Neutral Wires That Are Not Evenly Spaced Are Acceptable Or Not?

A Guest Contribution by 

Steven F. Thomas - High Voltage & Interconnection Engineer at Origis Energy

Concentric Neutral Wires

Concentric Neutral Wires

What Are Concentric Neutral Cables? 

Concentric Neutral Cables (CN Cables) are suitable for use above ground in open air, in conduit in air, directly buried, in underground cable duct, or aerially when suspended on a messenger wire. CN cables are suitable for continuous operation at 90ºC wet or dry, and are sunlight resistant. Typical applications include residential, commercial and industrial main underground feeders where cable voltages of 5kV to 46kV are required.

CN cables can also be used in Wind and Solar power distribution when medium/high voltage cables MV HV are to be used in an underground application.

The following Comments have been provided from an original LinkedIn post by Steven F Thomas in February 2019 and include thoughts and opinions from the professional social network on the subject of concentric neutral wires and the process of cable manufacturing, jointing, splicing and termination.

Image: Texcan

➡ Steven F Thomas. A lot of great responses. This cable was for a wind farm that had approximately 1 million linear feet of three phase cable, 3 million feet of single phase cable. What may not be obvious is that 3 core cables aren’t very useful. The size and weight of the overall cable would create an inordinate amount of cable joints or splices – and splices are failure points. We mandated no splices, unless absolutely necessary and must be approved by owner. The normal installation is direct buried, bundled, single phase cables. The US National Electric Code requires that cables be buried at least 1 meter (3 feet) underground, or a physical barrier be installed above. Our common requirement was 4 feet. In this case, these wires are considered concentric neutral wires, not a shield. Although they also provide an electrical screen, they are mostly a neutral/fault path back to the wye-grounded source. The construction of the cable is that the XLPE has a semi-conductor wrapped around it, and the neutral cables are in contact with that. Since the semi-con screen provides a complete non-metallic cover, is it important for the concentric wires to be evenly spaced?

➡ Kai Zhou (Senior Research Engineer at UL). Cable splice is usually the weakest point due to improper installation, contamination introduction, etc. Most of the cable joint failures in cable systems are from installation NOT from cable splice or cable terminations themselves.  Since you have a really long run, what is your grounding design? The concentric neutral is also designed for shielding for power cable. To provide a uniform zero potential in case of cable semi-con problem. We have seen cable semi-con losing conductivity after aging, material absorption, etc. This kind of situation could be avoided by proper factory inspection and order inspection.

➡ Reply Steven F Thomas. You are correct, my experience is that splice failures are almost always installation error. The most common Root Cause was overheating, of which analysis showed that electricians were skipping the wire brushing to remove the aluminium-oxide layer that is not visible to the eye. It “looked” clean and shiny, so they skipped that step, I have seen papers from both 3M Electrical and Tyco Electronics indicating that renewable sources are much more susceptible to cable failure from this mode due to the high load cycling inherent in renewables. Both independently indicated that shear bolts splices & connections are much less likely to do this. If you can’t ensure the electricians will do an important step – then you need to change the step. We now mandate shear-bolt connections.

➡ Paul Knapp (Principal Engineer at UL). This can cause issues because the shield is not uniformly divided around the cable and arcing may occur in the unshielded space under the right conditions.

➡ Ben Lanz (MV HV Cable Reliability Consultant). Paul, I agree. At steady state an uneven concentric wire system might work but wide enough gaps and during transient conditions increased voltage across the outer semiconducting shield might start burning, arcing and pitting from the outside inwards. In addition the velocity of propagation will change with the variation in the wire spacing making fault and PD location difficult.

➡ Tony Haggis (Director at Tony Haggis Consulting Ltd). It would be illegal in the UK as the Electricity Safety Quality and Continuity Regulations (UK Law) requires that all live conductors be surrounded by an earthed metallic screen. The primary reason is to prevent electrocution in the case of a cable strike. The earth gets pierced first so the current is diverted to earth rather than through the person holding the cable cutting tool.

➡ Martin Stephenson (Business Development Manager Cable Services). Tony there are also “protected hydraulic cutters on the market” which have extra long hoses and non conductive oil to protect the operator should they mistakenly go through an energised cable. Also insulated cable cutters are used typically by Jointers on LV cables.

➡  Rick Moynihan (Cable Jointer – Director  Certus Cable Jointing Pty Ltd). The semiconductive layer and screen wires are at the same potential. The screen wire should be rated according to fault current carrying capacity, therefore the termination of the screen wires as required per onsite earthing specification is the critical factor. The screen wire distribution in this cable does not look nice, however I cannot see how it would affect the electrical performance of the cable if it meets the specifications for its use.

➡ John Szabados, PE (Senior Manager at Sargent & Lundy). Rick, I disagree with this. We are talking two separate functions. The screen is there for voltage gradients and keeping a zero references. The neutral is for line to ground faults which with proper protection employed and sizing is there for a very short time frame. There is no test verifying the neutral and shield are touching. According to IEEE, failures of cable mid span are primarily due to manufacturing defect. Of course contributing factors are the cable splices and inadequate installation by the Jointer but this rarely explains faults in midspan. If the cable is specified properly, having an asymmetrical neutral layout by itself is not an issue. However, it does bring to question the QC in the manufacturing process. Based on this, I would ask more questions and initially reject the cable.

➡ Craig Horn (EHV Cable Jointer). That cable would work better without any screen wires rather than random bunches of wires. If cost is such a issue why not opt for aluminium foil screen? I’d like to see the cable manufacturers specification Vs a type test.

➡ Steven F. Thomas Craig, I think we’re talking about two different systems. A grounded wye system requires a neutral ground path for fault current, an ungrounded delta system does not.  An ungrounded delta does not short circuit when one phase goes to ground, it takes two phases before a short circuit occurs. The “shield” on an ungrounded system cannot provide an adequate path for fault current, whereas the concentric neutrals on a grounded wye can provide fault path as well as electrical “shielding” and mechanical protection. In this case, an aluminum foil is totally inadequate as fault current would vaporize the shield. We don’t use tape or foil shields normally, except for control wiring, but I’m doubtful of the ability of an aluminum foil to provide  mechanical protection.

➡ Craig Horn (EHV Cable Jointer) Steven, I would not buy this cable no matter what system it was to used for. The spacing of the screen/ neutral wires will have a negative affect on the efficiency of the conductor due to poor stress control. Aluminium screens can be manufactured with specific current carrying capabilities to avoid vaporisation.

➡ Dan James (Technical Services Engineer – HV Senior Authorised Person at NG Bailey). It would affect the shields ability to handle the field uniformly I would think.

➡ Steven F. Thomas Dan, this concurs with what a cable expert at Tyco Electronics informed me that essentially the semi-con and concentric wires are creating a Faraday cage. If the wires are severely bunched as these are here, the electrical field is not evenly distributed and when it’s not evenly distributed PD can occur which is how XLPE insulated cables fail.

➡ Dan James (Technical Services Engineer – HV Senior Authorised Person at NG Bailey). Steven, what I would imagine would happen, not a expert though. Areas without evenly spaced ground wires would have a higher field. Deteriorating that part more so than areas with more and any imperfections, degradation would be amplified.

➡ Satish Buddhawar (Electrical High Voltage, Offshore). Dan I think yes, this would result in the field concentration near to the unevenly spaced concentric wires, leading to local heating and degradation. In the cables I have seen, there is usually a layer of aluminium foil over the copper wires to radially block the water and also to provide the complete shielding (Faraday cage).

➡ Kai Zhou (Senior Research Engineer at UL). Regarding the electrical shielding, it can be a problem, or not a problem. There is cable insulation semi-con for electrical shielding function. For good semi-con layer, this probably won’t give you an “electrical problem”, as long as your terminating the semi-con and copper shielding wire properly. But for bad semi-con (losing conductivity over time), it could be. In any case, you are losing mechanical shielding protection, one of the major functions for copper shielding wire. From a design point, this should not be accepted since it is not per the design. If I was the user, I would ask the manufacturer to resolve the issue.

➡ Matthew Hadsell (Manager of Engineering at Blattner Energy). First, this really depends on voltage. At 34.5kV (assumed because it is for wind farm), this cable will likely not have any issues. Some independent cable testing laboratories have evaluated this for wind farm applications and come to this conclusion. Neutral bunching happens with many manufacturers over my years of installing cable and a good rule of thumb is as long as there is at least one strand in each of the 90 degree quadrants of the circle the cable will perform as advertised. This is of course not ideal, but it also isn’t a disaster of a problem at this voltage level. Bunching typically happens at cable ends and you can cut off 20 feet or so to remove the problem, so good QAQC when installing can catch and eliminate the concern. If this is encountered on a project, don’t panic and call a reputable cable testing laboratory for a custom report and analysis.

➡ Dan James (Technical Services Engineer – HV Senior Authorised Person at NG Bailey). Matthew, I have only seen one independent 3rd party analysis, submitted to us by the cable manufacturer to show bunched neutrals was not critical, and we rejected it as a faulty report for several reasons. Some cable experts have said this is critical; others seem to think it wise to evenly space the neutral wires, but not critical.

➡ Joe Dowds. Well spacing should not matter the neutral or ground is there to take the current if the cable faults that’s it’s main purpose.

➡ Steven F. Thomas. Joe, is it reasonable to assume that the current form a fault shares equally on every wire? Perhaps not to start if it is truly a fault from inside the cable, but eventually it would spread to all. This would imply that heating from the individual wires would be a percentage per wire. In the case of the one picture, where about 50% of the wires are all bunched at the bottom, would this not also imply that 1/2 of all the heating from a fault was concentrated in that spot? Rather than spread in all directions, the majority of the heating is concentrated in that one spot – so what happens to the thermal limits of the cable jacketing material? I think spacing does matter, particularly if neutral sizing is reduced to limit induced losses, and is closely sized to not overheat the jackets.

➡ Roger Lauricella (Vice President Technical Services & Support MV & Substation Specialist at WECS Renewables). Seen examples over the years from various wind farm customers just like that, it’s usually overseas cable that does not get the rigorous testing and quality production you see in North America, definitely not something one should have excepted or utilised. There are enough challenges with UG cable on wind farms and this is not an acceptable one to allow to go through.

➡ Steven F. Thomas. Roger, I also have seen this with off-shore manufacturers, but this one was not.  This was an American supplier.

➡ Arie M (Senior Technical Expert at Consolidated Edison New York). I enjoyed the comments and depth of knowledge of engineering community for this very specific cable construction topic. All aspects of this issue including operating voltage, specific design, normal and transient mode, and specific installation issues (cable cut and shielding wires displacing) were addressed.

➡ Uxio Ramos (Technical Sales Director in Behr Bircher Cellpack Iberica). Not acceptable at all. That will lead to failure sooner or later. Furthermore, we have seen CWS (copper wire screen) cables without the additional Cu copper tape and the screen wires would eventually be all displaced to the lower side of the cable once laid on the ground… then failure. Poor quality, in my opinion.

➡ Charles Shannon (Senior Application Engineer at IMCORP). Uxio, have you seen the bunching you mentioned when using Cu JCN or CIC?

➡ Uxio Ramos. Charles sorry, can you explain JCN and CIC?

➡ Charles Shannon. Uxio, JCN Jacketed Concertric Neutral cable and CIC Cable In Conduit in essence it’s JCN without the J and instead it’s in a flexible conduit like HDPE or something but the neutrals are exposed to any water that enters the conduit.

➡ Uxio Ramos. Charles many thanks for the clarification. The case happened in single core CWS 16sqmm 36 kV cable. As I stated, the screen did not have the additional Cu copper tape applied in this cases. The cable sheath was PE, the cable isolation was HEPR and there was a plastic foil separating the screen from the sheath.

➡ Thorsten Rösch (Technical Director bei HvCable Solution). The earth wire which are not spaced cannot bare 360 centigrade short circuit temperature the cable is not acceptable. One correction copper screen temp is 250 centigrade.

➡ Kalinath Katuri (Protection Engineer). Everyone correctly points out that the shield will effect and cable may get heated. But, that happens only in multi core cables due to proximity effect but what is shown here is a single core cable. So, if the cable is laid in perforated tray and the other cores are kept at 50D spacing, how will this non-uniform armour cause the cable to heat?

➡ Steve Park (Electrical Power System Testing, Maintenance, and Engineering Executive Leader). Just saw in an earlier post that this cable also has a separate shield so that makes my earlier comments moot. Perfectly distributed concentric wires are probably not absolutely necessary for full life as they are in contact with a semiconductor material that will aid in creating a uniform ground plane to evenly distribute the electric field. However, here we have a significant non-uniformity that is not acceptable. There are large areas that appear not to have any concentric wires and likely to result in a non-uniform electric field leading to accelerated insulation deterioration.

➡ Ivan Jovanovic (Managing Director Cable Accessories at G&W Electric Co). Hi Steven, this looks like a shielded XLPE cable with extruded semicon screen over insulation. Theoretically there should be no field outside the screen but practically in transient and impulse conditions semi con screen is not acting as a perfect conductor and you really want to have these copper screen wires evenly spaced and in good contact with screen so you don’t build voltage gradient that can lead to pitting. There may be an issue from thermal perspective as well. Wires are sized to carry short circuit current and if they are not evenly spaced it is possible to have a hot spots which can thermally degrade both outer jacket but even more critically cable insulation. So from both perspectives if I was in charge of the project I would not accept it.

➡ Kerry Willert (Executive Construction Manager/Director Operations). No substitute for quality products!

➡ Rakesh Pandey (Negotiator/Electrical Engineer/Global Sourcing). Is it underground cable? seems aluminum core with copper neutral. If the sizing of copper is correctly considered then I guess we can use it. ANSI/ICEA S-94-649.

➡ Sjoerd Keijzer (Infratechniek) Not acceptable. There will be a wrong magnetic field around the cable. There will be a concentration on the places where the wires still are and there will be a higher temperature so therefore the insulation value will decrease. The insulation ages much faster and the lifetime of the cable will decrease enormously.

➡ Dominick M (Electrical Superintendent at Wanzek Construction, Inc). Actually had this exact thing happen to us on a project a few years back. WTEC cable. It made us from that point on photo the ends of each cable prior to any cable terminations. Dan James is right it effects the shielding ability and I think a heating aspect of the cable too? I can’t remember 100%.

➡ Marcin Ruta (Power Systems Engineer). Aren’t those neutral wires twisted around cable? It will be random but is it acceptable? What standard do you follow normally for it?

➡ Brian Kolker (Carpenter). Marcin, No I would think not evenly distributed any extra energy that the wires may pickup from lightning strikes or from the ground it’s buried in.

➡ Noel Chamberlain. I personally like uniform in everything I worked on , I am not a cable jointer, I am a linesman, though it does not look the best on the end view, if the cable meets all pre-commissioning requirements I do not see an issue, though I agree it does look a little shoddy.

➡ Jeff McWhirt, PE, CEM. (Critical Infrastructure Manager). Concentric neutrals have two purposes, as the neutral, as well as distribute the electric field around the cable. Spacing is important from the field perspective only.

➡ Mark H (Technical Manager for Electrical Engineering). One would have issues with the EMC of the cable, also the fault carrying capacity for the cable as the earth fault travels down the screen. It would also seriously distort the zero phase sequence, so if your specification asked for it to the IEC standards then it is best advised to reject the cable based on quality grounds under the FATs and SATs. With that kind of screen you may get additional heating due to the effects of circulating currents. Therefore your current carrying capacity would be compromised, but how much more would depend on the HV cable lay too, and what other cables it may cross. It may kill someone also for obvious reasons as the conductor is not covered completely thus you would be found liable under the EAWA.

➡ Paul Churnock, PE (Project Manager at McClure Engineering-St. Louis MEP) Ignoring the electrical characteristics and performance issues, I would reject this cable on the merits of the manufacturer’s lack of proper quality controls. If this visible issue exists, what other less readily apparent issues exist with such a cable. As noted, the shear quantity of cables necessitates proper material meeting the specified characteristics. The subsequent cost and down time necessary to mitigate and remedy potential failures far outweighs allowing non-conforming product.

➡ Faran Kaplan (Vice President, Sales Engineering). It’s not a neutral, it’s a ground. It’s designed to allow for equal radial distribution of corona discharge so that the insulation integrity is maintained.

➡ Axel Born (Cost and Value Engineering bei Siemens / Kabelexperte). At the cable ends the wires will be displaced by the cutting process. The real arrangement could be found by opening the cable some cm distance away from the cut end of cable.

➡ Abdul Kader  (Business Manager HV/EHV Middle East). Axel, you nailed it.

Cable Terminations | Heat Shrink | Cold Shrink | Push-On | MV HV Medium & High Voltage

Nexans

Thorne & Derrick distribute the complete range of medium/high voltage electrical equipment manufactured by Nexans – this includes Euromold bushings for use with oil fluid or gas insulated switchgear or transformers and associated screened separable connectors according to both IEC (Euromold) and IEEE (Elastimold) for the termination, connect+disconnect of MV-HV cables onto power distribution systems. To protect power systems against high voltage surges resulting from lightning or switching a complete range of surge arresters are available to be used with Euromold connectors in 11kV/12kV, 24kV and 33kV/36kV voltage classes.

Key Product Categories: Duct Seals | Cable Cleats | Cable Glands | Electrical Safety | Arc Flash Protection | Cable Jointing Tools | Cable Pulling | Earthing | Feeder Pillars | Cable Joints LV | Joints & Terminations MV HV 

 ➡ Read: Thorne & Derrick Announce Distribution Agreement & Contract With Nexans 

Heat Shrink Cable Joints & Terminations Manufactured By Nexans – Reference List

Heat Shrink Cable Joints & Terminations

The range of Heat Shrinkable Products manufactured by Nexans have been in service on LV & MV Cables and Networks for over 20 years and are approved by the following international electric power utilities:

• ENEL – Italy, Spain & Romania
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• ELECTRICITY AUTHORITY OF CYPRUS
• ENERGIAS DE PORTUGAL (E.D.P)
• RWE — Germany
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• ENDESA — Spain
• DONG ENERGY — Denmark
• CARUNA – Finland
• PPC / DEDDIE – Greece
• ELECTRICA — Romania
• EDESUR — Argentina
• SONELGAZ / CAMEG — Algeria
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• GENERAL ELECTRICITY COMPANY of LIBYA (G:E.CO.L)
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• NATIONAL ELECTRIC POWER COMPANY (N.E.P.CO.) — Jordan
• KUWAIT CONTROL COMPANY (KCC) — Kuwait
• PERUSAHAAN LISTRIK NEGARA (PLN) — Indonesia
• CEYLON ELECTRICITY BOARD (C.E.B.) — Sri Lanka
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• TENAGA NATIONAL – Malaysia
• METROPOLITAN ELECTRICITY AUTHORITY (M.E.A.) — Thailand
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Thorne & Derrick, Specialist Distributors of MV HV Power Cable Products, welcome the opportunity to tender and submit competitive prices for UK and international projects requiring LV MV HV Joints, Terminations & Connectors manufactured by Nexans – this includes the Euromold brand of screened separable connectors.

Nexans Euromold | Joints | Terminations | Connectors

THORNE & DERRICK SPECIALIST ELECTRICAL DISTRIBUTOR

The MV HV Specialists

Thorne & Derrick distribute the most extensive range of MV HV Cable Jointing, Terminating, Pulling & Installation Equipment – we service UK and international clients working on underground cables, overhead lines, substations and electrical construction at 11kV and up to and EHV transmission and distribution voltages.

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• Distributors for: 3M Cold Shrink, ABB, Alroc, Band-It, Catu, Cembre, Centriforce, CMP, Elastimold, Ellis Patents, Emtelle, Furse, Lucy Zodion, Nexans Euromold, Pfisterer, Polypipe, Prysmian, Roxtec.

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11kV Transformers | Introducing Amorphous Core HV Transformers

Manufactured & Designed In UK | Short Lead Time | Transformers LV 11kV

♦ Guest Post from Richard Kerr & Lindsay Brownless from Powerstar

11kV Transformers

The Next Generation Of Distribution Transformers (LV HV Up To 11kV)

Powerstar SO-LO range of super low loss transformers are the only amorphous core transformers designed and manufactured in the UK and provide a cost-effective way of reducing energy consumption by upgrading high voltage (HV) infrastructure up to 11kV.

Distribution transformers have been at the heart of the energy network, and for many large businesses, their sites, for years. However, as technology has advanced it has been an area that has been left in the dark and somehow avoided the wider revolution known as Industry 4.0, referred to as the fourth industrial revolution. Industry 4.0 champions the connectivity of machines to transfer data and give insights into optimising operations.

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These increased efficiencies are perhaps best displayed by the fact that amorphous core transformers can provide up to 75% lower core losses than CRGO transformers. This results in a reduction to energy wasted through load and no-load losses, providing energy consumption savings of up to 3% when replacing ageing transformers.

Bespoke Transformer Offerings Up To 11kV

As a manufacturer, Powerstar understands that every customer has different requirements when it comes to 11kV high voltage (HV) infrastructure and can therefore provide a number of fittings and accessories to maximise the impact of an amorphous core transformer for each site. This is a necessity, with popular sectors for Powerstar SO-LO ranging from manufacturing and industrial, to retail and healthcare.

The most popular fittings that have been applied to Powerstar SO-LO are radiator valves, bi-directional rollers, dehydrating breathers, AVR relays and control panels, winding temperature indicators, close coupled MV switchgears, close coupled LV cabinets/feeder pillars, pressure relief devices, marshalling boxes, forced air cooling systems, and oil temperature indicators.

Additionally, whilst Powerstar SO-LO is an 11kV to 415V amorphous core smart distribution transformer by standard, as a specialist transformer manufacturer with over 20 years’ experience, Powerstar can provide a variety of bespoke solutions including dual voltages, single phase transformers, and three phase transformers.

The solution can also be integrated with Powerstar’s patented voltage management technology to address issues caused by an unnecessarily high voltage profile on the LV side, if applicable, providing additional savings to energy consumption and costs.

Transformers Designed To Connect Power

From LV To 11kV

Due to its remote monitoring capabilities, included as standard, the Powerstar SO-LO 11kV transformer offers 24/7 visibility and understanding of how the equipment is operating, enabling issues to be identified before an event occurs, reducing the risk of operational downtime caused by equipment breakdown or repair.

This is done via a secure platform, accessible by the user from anywhere with an internet connection, which provides comprehensive data in real time. This data can also be used to identify where efficiencies can be made to make further optimisations and enhance the solution’s return on investment.

It is clear that with solutions such as Powerstar SO-LO, the aim to modernise distribution transformers for an age of increased connectivity has been enabled. Through the ability to gain greater efficiencies, amorphous core smart distribution transformers provide a way of ensuring your site’s HV infrastructure is as efficient as possible whilst reducing the risk of downtime in a single, effective solution that is fit for the demands of modern sites.

➡ Case Study 11kV

➡  11kV Case Study Download: Vassiliko Cement Works Public Company Ltd is the largest heavy industry company in Cyprus – learn how Powerstar MAX Transformers achieved significant LV/11kV power and energy consumption savings by reading the Case Study.

11kV & LV Transformers

Powerstar SO-LO is the The Super Low Loss, Smart Transformer – amorphous core distribution transformers with remote monitoring capabilities.

Dr Alex Mardpittas unveils Powerstar SO-LO

THORNE & DERRICK SPECIALIST ELECTRICAL DISTRIBUTOR

The 11kV Specialists

Thorne & Derrick distribute the most extensive range of 11kV Cable Jointing, Terminating, Pulling & Installation Equipment – we service UK and international clients working on underground cables, overhead lines, substations and electrical construction at 11kV and up to and EHV transmission and distribution voltages.

THORNE & DERRICK today welcomed Lindsay Brownless from @PowerstarVO today – look out for a series of online articles from us about their UK manufactured, online, smart #Transformers with amorphous core and remote monitoring capabilities, 415/11kV.#POWER pic.twitter.com/KfmIZoBuPJ

— Thorne & Derrick (@ThorneanDerrick) January 16, 2019

• Key 11kV Products: MV-HV Cable Joints & Terminations, Cable Cleats, Duct Seals, Cable Transits, Underground Cable Protection, Copper Earth Tapes, Cable Jointing Tools, Feeder Pillars, Cable Ducting, Earthing & Lightning Protection, Electrical Safety, Cable Glands, Arc Flash Protection & Fusegear.

• Distributors for: 3M Cold Shrink, ABB, Alroc, Band-It, Catu, Cembre, Centriforce, CMP, Elastimold, Ellis Patents, Emtelle, Furse, Lucy Zodion, Nexans Euromold, Pfisterer, Polypipe, Prysmian, Roxtec.

LV – Low Voltage Cable Joints, Glands, Cleats, Lugs & Accessories (1000 Volts)

MV HV – Medium & High Voltage Cable Joints, Terminations & Connectors (11kV 33kV EHV)

Cable Laying – Underground Cable Covers, Ducting, Seals & Cable Pulling Equipment

T&D, CATU Electrical Safety & Arc Flash Protection Specialists for SAP’s, Linesmen, Jointers & Electrical Engineers – Largest UK Stockist

Using “Heat Shrink Wraparounds” To Repair High Voltage Transmission Cables In Underground Cable Vault

• uploaded by Chris Dodds - Thorne & Derrick Sales & Marketing Manager
  

  Heat Shrink Wraparounds

During an annual inspection of the High Voltage Cable (Transmission & Distribution) Network at a power grid located in Thailand the following cable damage was witnessed to the high voltage underground cable sheath, note the “cracking” effect to the jacket.

Installed in 1996 and originally manufactured by Phelps Dodge the 66kV/115kV high voltage distribution cable was of single core construction with XLPE insulation, lead sheath (Alloy E) and compact copper conductor with 800sqmm cross section area  – the cable specification and project record book noted a nominal overall diameter of the complete cables at 113mm.

The client was concerned about the potential threat of water ingress seeping into the inner cable construction and causing electrical fault breakdown overtime.

Heat Shrink Wraparounds

Under consideration to reinstate the cable sheath damage was a wraparound heat shrink cable repair system – the cable repair sleeve consists of a raised rail profile with interlocking stainless steel channel and thick wall adhesive lined heat shrink tube to wraparound the section of damaged cable to reinstate the electrical insulation to the CABLE sheath/jacket. The “wraparound solution” could be used if the underlying layers of the cable construction had not been damaged. The “wraparound” would be provide excellent moisture sealing and defence against water contamination into the high voltage cable.

Proposed Solution: Heat Shrink Wraparound Cable Repair System

Cable Type: 115kV HXLP-LS 800sqmm (Spec IEC 840)

Cable Sheath Damage

The cable oversheath manufactured from polyethylene material with a nominal thickness of 4.75mm and minimum thickness of 3.73mm incurred jacket damage in service and required repair to prevent potential outage to the high voltage power cable system.

The following Comments from the cable manufacturer were noted with respect to the site condition of the cable and the proposed repair using “heat shrink wraparounds”:

1. From your pictures, it is difficult to express the root cause of the oversheath crack. It may cause from many factors such as hitting by external force, long time immerse in oil or chemical water, age of cable, etc.
2. From the cable construction, the cable has lead alloy sheath which is the perfect barrier for water, oil and chemical. Therefore, the water cannot ingress into the XLPE insulation unless the lead alloy sheath is damaged. The cable is still safe for operation.
3. One concern is the copper wire screen and copper contact tape under the oversheath. Since the oversheath is cracked, the water can come in under the oversheath and cause the corrosion to the copper wire screen. The function of this copper wire screen is to carry the single line to ground fault current in case of fault occur. If the copper wire screen is completely corroded, only the lead sheath is used for carrying the single line to ground fault current. From my rough calculation, the lead sheath alone can carry the earth fault around 23kA for 1 second. You can check the corrosion of the copper wire screen by measuring its resistance and comparing its value with their previous measurement.
4. Since the oversheath is already cracked and water already come in, you may consider in the worst case that the copper wire screen is completely corroded and consider if the earth fault current carrying capacity of lead sheath of 23kA for 1 second is enough for your system or not. If it is okay, you still can use this cable.
5. Please also check with the cable splice supplier if the water leak under the oversheath can cause any harm to the cable splice or not.
6. Periodic maintenance and test to see the trend is recommended such as insulation resistance test of XLPE insulation, on-line or off-line partial discharge test, resistance of copper wire screen and lead sheath test, etc.

Phelps Dodge

HV Cables

Phelps Dodge International (Thailand) Limited (PDITL) was established in 1968 as a joint-venture between an existing Thai firm and Phelps Dodge Corporation – PDITL are pioneers in the local industry and were the first company to introduce the majority of new processes, products and technology related to wire and cable manufacturing. PDITL is the only supplier in Thailand with complete in-house facilities for testing power cable up to 400kV.

PDITL has got its certification type test from International Independent Laboratories such as KEMA, Cable Technology Lab, etc. for LSHF cable, Fire resistant cable, Medium voltage, High voltage and Extra high voltage XLPE cables up to 245kV cables.

PDITL manufactures world-class quality wire and cable, not only for the local market but also for international markets, complying with strict international standards. It is proud of its customer services and long term relationships. PDITL has a team of over 700 employees, which are most important assets.

• Bare Copper Conductors
• Low Voltage Power Cables (XLPE, PVC, PE, EPR Insulation)
• Control Cable & Instrumentation Cables
• Lead Sheathed Cables
• Fire Resistant & LSHF Cables
• Flame Retardant & LSHF Cables
• Medium Voltage Power Cables
• High Voltage Power Cables (69kV | 115kV XLPE Cable)
• Extra High Voltage Power Cables (230kV XLPE Cable)
• Aluminium Conductor (AAC)
• Aluminium Conductor Steel Reinforced (ACSR)
• Aluminium Alloy Conductor (AAAC)
• Weather Proof Cables (WPC)
• Service Entrance Cables (SEC)
• Service Drop Cables (SDC)
• Spaced Aerial Cables (SAC)

High Voltage Cable Manufacturer – PDIT

Thorne & Derrick

T&D are Specialist Distributors to UK Distribution Network Operators (DNO’s), NERS Registered Service Providers, ICP’s and HV Jointing Contractors of an extensive range of LV, MV & HV Jointing, Earthing, Substation & Electrical Eqpt – this includes 11kV/33kV/66kV joints, terminations and connectors for both DNO and private network applications.

Cable Jointing & Pulling Equipment

Cable Blowers | Cable Lubricant | Duct Rods | Cable Socks | Cable Jacks | Cable Rollers | Cable Protection Covers MV HV | Cable Joints MV HV | Duct Sealing

Contact our UK Power Team for competitive quotations, fast delivery from stock and technical support or training on all LV-HV products.