Partial Discharge Measurement & Analysis for Power Cables
uploaded by Chris Dodds | Thorne & Derrick Sales Marketing Manager
MPD 800 universal partial discharge (PD) measurement and analysis system, the next generation of the widely-used and innovative MPD PD testing technology from OMICRON.
Advanced hardware and software features ensure highly-sensitive single- or multi-channel PD measurements for reliable, industry-standard PD testing on power transformers, rotating electrical machines (motors and generators), power cables, instrument transformers, switchgear, industrial drives and electrical components.
The configurable, multi-language MPD 800 software allows you to select only the PD measurement and analysis features you need for specific PD tests and individualised reporting. Powerful noise suppression and PD source separation techniques ensure reliable PD analysis in areas with high levels of interference.
The MPD 800 PD testing system accurately detects and localizes insulation defects and helps you to assess the risk of failure in electrical equipment during research and development, factory testing, site acceptance testing (commissioning), as well as in-service troubleshooting for effective maintenance planning.
“The MPD software guides you through the entire PD measurement process on power cables, and it provides you with detailed analysis and individualized reporting.”
➡ Featured with the kind permission of David Brazier (Area Sales Manager & Site Manager at Omicron Electronics)
♦ MPD 800 Universal Partial Discharge Measurement & Analysis System – Brochure
 Meets industry standards. The MPD 800 measures partial discharge in compliance with the IEC 60270 standard to ensure the reliable detection of PD activity in high-voltage power cables. |
 Reliable noise filtering. The MPD 800 provides you with a free choice of measurement frequency and bandwidths to maximize measurement sensitivity in environments with high interference. |
 Advanced analysis tools. MPD 800 uses advanced graphical tools, such as 3PARD (3-Phase Amplitude Relation Diagram), to separate multiple partial discharge sources for reliable fault detection. |
Established since 1985, T&D International based in the UK distribute the most extensive range of LV, MV & HV Cable Jointing, Terminating, Pulling & Installation Equipment – contact us today for a competitive quotation.
Key Products : MV Joints & Terminations, Access Chambers, Cable Cleats, Duct Seals, Cable Transits, Jointing Tools, Feeder Pillars, Cable Duct, Earthing & Lightning Protection, Electrical Safety, Cable Glands, Arc Flash Clothing Protection & Fusegear.
Distributors for : 3M, Pfisterer CONNEX, Nexans Euromold, Elastimold, Catu, Roxtec, Emtelle, Centriforce, Lucy Zodion, Alroc, Cembre, Prysmian, Ellis Patents, ABB & Furse.
T&D Providers Of Jointer Training Courses By Pfisterer CONNEX & Nexans Euromold
Republished from LinkedIn with kind permission of Neil Davies | EA Technology Australia | Helping Owners and Operators of Electrical Assets Improve Reliability and Efficiency
uploaded by Chris Dodds | Thorne & Derrick Sales Marketing Manager
Neil Davies
Partial Discharge (PD) can be classified into 3 main types:
Internal Partial Discharge, occurring inside insulation
Surface Partial Discharge, tracking across insulation
Corona Partial Discharge, from a sharp electrode into gas
Internal PD is the silent defect where there will be no sound, smell or visual indication of a problem prior to failure. If you witness the aftermath of a compound insulated cable box failure, you will see how the build-up of pressure can lead to a very disruptive and dangerous explosion.
Surface PD occurs across the surface of insulation. When alternative materials to porcelain started to be introduced into switchgear and dry cable terminations started being widely introduced, some critical aspects of design and installation were not fully appreciated. This led to a spike in failure rates due to surface PD. When developed, it will produce the crackling and ozone smell.
Corona PD is what we often hear in outdoor switchyards, particularly when humid. Corona at sharp points in switchyards isn’t usually detrimental. However, if corona activity occurs inside enclosed chambers and there is no airflow to remove chemical reactions, then it can lead to the onset of surface PD and problems.
At EA Technology, we’re specialists in asset management solutions for owners and operators of electrical assets. We’re part of a global company, but bring local knowledge and advice in servicing the particular needs of the Australasian and Asia-Pacific market. This includes:
✔ Keeping ageing electricity networks operating reliability and safely.
✔ Adapting to major changes in network transformation, including smart grids, solar, wind and electric vehicles – while keeping costs down for customers.
✔ Predicting and preventing critical plant failures – literally keeping the lights on.
✔ Providing better visibility of the condition of electrical assets to allow for more informed planning and management.
✔ Investigating failure of electrical plants and assets to determine the cause and reduce future risk.
In Australia and the Asia-Pacific, we’ve been active for more than 20 years. Our teams have deep domain knowledge and provide unrivalled support to clients across Australia, New Zealand, China, and South-East Asia.
We are supported by a global team with headquarters in the UK. There, EA Technology was founded in 1966 and has a rich heritage as a ground-breaking research and development organisation serving the electricity industry.
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
Joints, Terminations & Connectors for MV HV Power Networks
10 Things You Should Know About Electrical Safety & Protection | Image ABB
by Chris Dodds T&D - estimated reading time 5 minutes
T&D Largest UK Stockist – CATU Electrical Safety Equipment For LV HV EHV Electricity Cables, Lines & Substations
The world of electrical safety, insulation and protection is rife with potential hazards and dangers. Electrocution risks prevail throughout low and high voltage power systems – whether by underground cable or via overhead line where the ampere flows danger goes with it.
Electrical Safety Foundation International has confirmed every 30 minutes during the work day, a worker suffers an electrically induced injury that requires time off the job for recovery.
Over the last ten years, more than 46,000 workers have been injured from on-the-job electrical hazards.
Engineers, installers, maintenance and other operatives working on or near HV and LV electrical installations are at risk from the dangers an arc flash, power surge or short circuit can cause.
Arc flash clothing is essential to provide “head-to-toe” worker protection against arc incidents – this includes a complete range of arc flash gloves, arc flash helmets and garments for utility workers carrying out installation and maintenance tasks on LV MV HV underground cables, overhead lines and electrical substation equipment.
Cable jointers working on underground cables, linesmen stringing overhead conductors and SAP’s switching high voltage substations all confront daily dangers of electrocution which can only be moderated by a responsible attitude to electrical safety and risk assessment.
In a seperate post we have covered the all too real risk of cable jointers exposed to arc flash risk.
T&D World Magazine authored the following thought provoking article : Utility Line Workers: One of the Top 10 Most Dangerous Professions
Nothing has changed. Serious injury, high degree burns, electrocution and all to commonly death are the dangers that face these workers daily if the proper electrical safety precautions are not taken.
Here, we take a look at 10 of the most important factors that need to be considered regarding LV-HV Electrical Safety.
The list below is by no means exhaustive, however it does cover 10 of the most pertinent points that must be considered prior to carrying out any electrical installation, maintenance or other work:
Image: Jim McDonald (Owner/Live Line Training at Powerline Training Consultants)
The most common hazards typically faced when working on LV HV electrical cables, switchgear and substation installations are electrical arcing (often called a ‘flashover’ or ‘arc flash’).
♦ Arc Flash Statistic: According to NFPA and IEEE from 1992 to 2002, over 2,000 workers a year or more than 5 workers a day were victims of an arc flash.
Arc flash can generate intense levels of heat and flames which can cause deep set burns and serious injury. The dangers of arc flash incidents are well documented and calculating the potential level and power of an electrical arc to provide adequate arc flash protective clothing can save lives should an arc flash incident occur.
We recently asked Hugh Hoagland (Partner at ArcWear & e-Hazard.com) and “leading-light” in arc flash protection to recommend the 3 most effective and reliable software packages for Calculating Arc Flash Risk & Hazard in accordance with NFPA 70E and IEEE 1584.
Read more: Calculating Arc Flash Risk & Hazard To Enable Arc Flash Clothing Protection Selection
T&D Stockists Of Arc Flash Clothing | Coveralls | Jackets | Helmets | Sweatshirts | Gloves
In addition to the intense heat, the levels of ultraviolet radiation from an electrical arc can also cause damage to the eyes. It is often the case that those working with or near electricity do not appreciate the risk of serious injury and consequential damage to equipment that can arise from arcing.
Read more: CATU MO-180-ARC All Integrated Helmet With Arc Flash Face Shield
In the case of oil filled switchgear, burning oil and gas can be ejected causing serious injury or death to those nearby and major damage to buildings located in the vicinity of the arc flash blast. Switchgear that may be using SF6 gas as the insulating medium presents other risks that must be controlled and managed as the presence of F-gas is pervasive throughout industries.
These risks are managed effectively through the installation of an SF gas detector. The Crowcon F-Gas is a fixed point gas detector enclosed in an IP54 case and delivers reliable detection of freon gases (F-gases).
The F-Gas monitors levels of a range of refrigerant gases and also sulphur hexafluoride (SF6) and can be connected to any control system that can accept an analogue signal and is ideal for use in substations, switchgear, plant rooms, MV switches, ring main units, contactors and circuit breakers covering the electrical safety and gas detection requirements of the electrical distribution industry.
Read more: SF6 Gas Detection For HV GIS Switchgear – Crowcon F-Gas Detector
By providing SF gas detection, electrical safety is improved generally and the potential risks are managed.
Not only is damage to human life a real hazard, electrical fire and the subsequent damage to property and electrical infrastructure can cause considerable financial loss.
GIS Gas Insulated Switchgear 220kV. Image ABB
Adequate training and the lack of it is a continuing theme as a contributory cause of arc flash incidents and accidents….
Occupational Injuries From Electrical Shock and Arc Flash Events – extract from Final Report (2015) by The Fire Protection Research Foundation.
The Full Report is available as Slideshare download :
CATU, a world leader and respected voice in the world of electrical safety recommend the following 5 points to determine the selection of suitable arc flash clothing for protecting against arc flash :
This information enables an estimate of the arc flash risk level and determines the selection of arc flash clothing and PPE to use : 12 to 100 cal/cm³ or class 1 or 2. Arc flash site surveys and electrical risk assessments can be carried out by specialist service providers. For instance in the UK, ESUK is a specialist company concerned with the safe management of risk associated with LV-HV electrical work activities.
The vast majority of electrical incidents occur because:
By not taking the required safety precautions and selecting the correct equipment for protection from the threats mentioned seriously increases the chances of an electrical incident occurring.
Here, we return again to the role of training and professionally educating electrical workers.
Investment both in terms of time and cash is required by responsible contractors to ensure the safety of their greatest asset, their workers.
Train and train some more. Training builds skills and confidence, it reinforces best working practises and should be encouraged throughout the lifetime of the career.
There is no shortage of training resources available, such as the High Voltage Training Courses for HV electrical engineers conducted by EA Technology’s Power Skills Centre.
Whether HV or LV, EA Technology are leading power engineering consultants and their courses and solutions are adopted by utilities across the globe.
CableSniffer – Cable Fault Location For Low Voltage Cables
Lock-Out Tag-Out
Quite simply, lock-out tag-out (LOTO) is the safety procedure of securely locking machines and equipment with numerous electrical safety padlocks to ensure that it cannot be energised without the necessary workers being present.
LOTO controls the flow of electrical energy and in practice is the isolation of power from the system by physically locking it in safe mode. In most cases, the safety switch has a series of holes through which a number of securing devices are fastened to ensure the switch cannot be turned.
Only the authorised individual is permitted to lock out and is the only one who can unlock the devices. LOTO is vital to to maintain worker safety while these systems are being operated when non-routine activities such as maintenance, repair, or set-up; or the removal of jams, clogs or misaligned feeds are performed.
Send an e-mail to [email protected] to request your FREE copy. Please include within the e-mail your name, ship to address, company and your job title.
There are many steps and precautions that should be taken in order to minimise the risk of electrical accidents occurring. Firstly, a risk assessment should always be carried out prior to any work starting and this should focus specifically on the electrical hazards present.
Secondly, the equipment used should be suitable for the application in which it is to be used. It must be properly designed, constructed, installed and maintained so that it does not present a risk of electric shock, burns or explosion.
Certified “explosion-proof” equipment must be used in areas that are classified as hazardous areas where flammable gases and vapours constitute potentially explosive atmospheres. Also where possible live work should be avoided during commissioning and fault finding. There must also always be adequate light, space and access to work safely.
T&D – Worldwide Suppliers Of Hazardous Area Electrical Equipment
The arc flash point is worth re-iterating and here is why.
According to OSHA, 80% of electrically related accidents and fatalities involving “Qualified Workers” are caused by arc flash / arc blast. Between 2007 and 2011, more than 2,880 fines were assessed for not meeting OSHA regulation 1910.132(d) which averages out to 1.5 fines a day.
As mentioned earlier, the electrical hazard dangers posed by an arc flash or electrical explosion can seriously injure or kill workers and also cause significant financial damage to infrastructure and cause significant downtime. If an electrical arc does occur, it is imperative that workers are already protected by wearing the correct clothing, whether that is insulating gloves, insulating matting, helmets and insulating boots or a full arc flash protection suit.
T&D Largest UK Stockist – CATU Electrical Safety Equipment
Apologies for further product placement, but leading manufacturers have innovated a series of electrical equipment geared towards eliminating, reducing or quenching arc flash.
Here are just 4 of them :
A circuit breaker equipped with an Arc flash Reduction Maintenance System by Eaton can improve safety by providing a simple and reliable method to reduce fault clearing time. Work locations downstream of a circuit breaker with an Arc flash Reduction Maintenance System unit can have a significantly lower incident energy level. Read more.
Ultra-fast clearing of arc flash faults in medium voltage (MV) switchgear panels is essential in controlling arc flash hazards. Reducing the arcing time through faster detection is the most practical way of reducing incident energy levels and improving workplace safety. ABB’s innovative REA fast arc flash detection system uses fibre-optic sensors to cut the typical relay operating time to less than 2.5 ms – far faster than conventional relay technology. Read more.
Littelfuse AF0500 and PGR-8800 Arc-Flash Relays help improve safety and reduce equipment downtime in the event of an arc flash. Both relays use reliable light to send a trip signal to the breaker in 1ms to interrupt power before damage occurs. Their simple plug-and-play installation make them the perfect, cost-effective solution to lowering equipment incident energy (HRC). Read more.
Safe-T-Rack® is an innovative, patented tool for circuit breaker remote racking and control. The product was specifically developed to provide users of low and medium voltage circuit breakers, including GE vertical lift (MagneBlast) designs and a variety of horizontally racked breakers, a comprehensive alternative to arc flash protection garments. Read more.
The video below demonstrates the need for effective arc flash protection as when it does occur, the results can be deadly.
British Standards
According to UK Wiring Regulations, the main standard governing electrical installations is BS7671 ‘Requirements For Electrical Installations’.
This BS standard describes how electrical systems and equipment can be designed, conducted and installed in order for them to be used safely – to provide electrical safety in the workplace and in our homes.
Non compliant “BS7671” installations often feature a potentially lethal cocktail of manufacturers devices that may not have been tested as a completed unit – whilst this “pick and mix” attitude might be acceptable practice in Europe, it definitely does not comply with British Standards.
Read more: BS7671 Non-Compliance – Safe Selection of Devices For Installation in Assemblies
Earlier this year, we joined forces with Michael Halverson, owner of M-Spec Services Electrical Contractors, a respected UK based electrical contractor. We discussed the recent changes to the BS7671 Wiring Regulations and their affect on the selection and installation of Domestic Household Consumer Units.
Read more: Consumer Units For Use In Domestic (Household) Premises – The Impact Of Amendment No.3 To BS7671
“Shoddy cowboy builder charged £49,000 to turn our home into a deathtrap. One light switch turning on a bulb elsewhere in the home.” Via Daily Mail.
In addition, further guidance can be taken from three British Standards – BS6423, BS6626 and BS6867.
HSG230 Keeping Electrical Switchgear Safe includes guidance on the selection, use, care and maintenance of high voltage and low voltage switchgear.
When using electrical equipment in explosive atmospheres, certified products must be used and the Dangerous Substances and Explosive 
Atmospheres Regulations 2002 covers the regulations that should be followed for onshore installations.
For offshore applications, the Offshore Correct Selection & Use Of Equipment Electricity at Work : Safe Working Practices Page 8 of 33 Health & Safety Executive Installations (Prevention of Fire and Explosion, and Emergency Response) Regulations 1995 should be followed.
Partial Discharge Damage To Electrical Cable Insulation. Image HVPD
A Partial Discharge (PD) is an electrical discharge or spark that bridges a small portion of the insulation between two conducting electrodes.
Partial discharge is an electrical discharge or spark that bridges a small portion of the insulation between two conducting electrodes.
PD can occur at any point in the insulation system, where the electric field strength exceeds the breakdown strength of that portion of the insulating material.
Electrical failures of three phase HV switchgear are most likely to occur during, or shortly after, switchgear operation. The way switchgear is operated, its condition and the conditions in the electrical system at the time it operates will largely determine whether it will function safely.
The use of handheld partial discharge equipment can be considered for use as an additional safety measure during a routine inspection or when entering a substation. The use of partial discharge detection equipment can reduce the risks to people who perform inspections by providing a warning that something may be wrong.
HV electrical switchgear should not be used where its strength and capability may be exceeded unless there is no potential danger of anybody being exposed to the results. In order to prevent any future danger, switchgear and machines must be adequately maintained and details for guidance on the maintenance of HV electrical switchgear can be found in BS6626.
BS6626 is a British Standard which gives recommendations and guidance for the maintenance of electrical switchgear and controlgear having a rated a.c. or d.c. voltage above 1kV and up to and including 36kV.
Older switchgear may contain parts that were manufactured from asbestos or asbestos-containing materials (ACMs).
Read more: Video Tutorial Masterclass – PD Partial Discharge & Electrical Cable Breakdown
Getting it right first time. When electrical installations are commissioned and installed, the correct equipment must be used to not only prevent electrical explosions and arc flash but to also minimise the financial costs associated.
If any old equipment is still in use including old type switchboards and fuse-boards used by electricity distributors, then this is not designed to prevent people touching live conductors and suffering injuries from shock or burns.
Electrical equipment to be used in hazardous areas must be certified for use and have adequate certification.
Consideration must also be given to the environment in which the equipment is being used and whether there is any potential for an explosion or leak to occur.
Potentially explosive atmospheres are regulated under the ATEX Directive in Europe and geo-specific hazardous area classifications cover the rest of the world. Adverse external factors should be considered for the electrical equipment such as excess damp or humidity conditions.
The assessment of the working area must be carried out before work commences – given average travel distance from an oil rig to the nearest hospital (by helicopter) offshore locations consequently have extremely rigorous electrical safety working practises. We covered BP’s recently….
Read more: ATEX Solenoid Valves – ASCO Valves for International Hazardous Area Installations
Assessing safe working electrical practices can be divided into four stages :
This basic flow chart for assessing safe working practices helps to assess exactly what should be taken into consideration:
Selection chart for assessing safe working practices
The age of switchgear and other electronic equipment should be taken into account as the risk of catastrophic failure increases with age and a process of assessment should be carried out to decide on the appropriate action for dealing with aged switch-gear.
Working either live or dead is dependent upon the work being carried out and the equipment being worked upon. Working dead simply means working on or with electrical equipment of which the power source has been switched off. Working live means the opposite – the power is still on and the equipment is live.
Typically, normal policy is to work dead and deciding whether to work dead or live is extremely important. It is normal for utilities to recommend work on or near electrical apparatus to be on de-energised equipment, not live, i.e. isolated.
There are a series of questions and points to consider when deciding between working and working dead live:
Thorne & Derrick are global distributors for the full range of CATU electrical safety products.
The range that ensures your worker safety and prevents and injury or serious harm occurring.
LV ♦ MV ♦ HV
T&D distribute the most extensive range of LV, 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 LV, 11kV, 33kV and EHV transmission and distribution voltages.
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T&D, CATU Electrical Safety & Arc Flash Protection Specialists for SAP’s, Linesmen, Jointers & Electrical Engineers – Largest UK Stockist
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