ACARP ACARP ACARP ACARP
Underground

Research into the Failure of 11KV Plugs & Adaptors Used in Underground Coal

Underground » Detection and Prevention of Fires and Explosions

Published: January 00Project Number: C5032

Get ReportAuthor: Joe Tusek | Pacific Power International

The experience of Oceanic Coal (Teralba, NSW) with failures of High Voltage (HV) underground plugs and adaptors led them to approach Pacific Power to investigate the performance of HV plugs and adaptors used in underground mining. The results of the initial investigations were considered of value to the mining industry as a whole and a research proposal was submitted to ACARP for a grant to do a thorough investigation. The investigation resulted in four reports, this being the final overall report.

The study was conducted in two parts. Firstly, a survey was undertaken to gain feedback from the mining industry and to tap into the body of experience of the users. The second, involved a series of electrical tests that challenged the findings of the survey in an environment that would shed light on the most important aspects of the plug and adaptors design, assembly and use.

The survey showed that moisture in the form of Relative Humidity or free ground water was strongly correlated with the failure of the plugs and adaptors. It also brought to light issues to do with,

  • Test equipment, techniques and training,
  • Standardisation of acceptable pass/fail criteria,
  • Lack of high voltage awareness within the mining industry,
  • Limited appreciation of Australian and International Standards for HV equipment and tests,
  • An increased risk of failure associated with in-house cable termination.

An accelerated aging test was devised to simulate the conditions that the plugs and adaptors would experience in underground operation and give them an electrical duty approximating 10 years of operating life within 3 months. MM supplied the plugs and adaptors and 3M supplied the cable terminating kits, all at no charge.

The first test was carried out on the adaptor components and the tests showed that these components on their own were not a likely source of failure. The test was repeated for a fully assembled plug and adaptor and the results were not as reassuring. The fully assembled units became subject to a number of detrimental, partial discharge sources (similar to sparking). Particular findings are made to the role of the,

  • Phase barrier,
  • Coupler, its shroud, pin and assembly,
  • Insert moulding and component fit,
  • Plug cable entry area.

A number of design weaknesses were identified that lead to the generation of partial discharges within the assembled plug and adaptor. Suggestions were made on how to overcome some of the weaknesses whilst others would require monitoring to ensure that the full working life of the plug and adaptor is realised. Difficulties in monitoring the condition of plugs and adaptors in a high relative humidity environment were discussed. These problems have such a profound bearing on the results obtained in underground environments that they need to be specifically addressed. It is highly recommended that a set of guidelines be produced by the industry, that set out methods and criteria for testing to ensure that consistent acceptable standards are reached.

During the course of the investigation a substantially new design of plug and adaptor was brought onto the market and that was also subjected to a similar accelerated aging test as the MM style units. The results were encouraging although (as only one plug and adaptor was tested) the results were not statistically significant. Given the innovative nature of the design it is expected that over time, other manufacturers will also act to incorporate some aspects of this new design into their own plugs and adaptors.

A primary benefit of this research has been to elevate issues associated with high voltage awareness and safety within the industry. Miner's are able to rely on a large body of knowledge encompassed within Australian and International Standards to guide them in the specification, receipt, application and testing of high voltage equipment. The adoption of practices outlined in this research and within the standards will result in fewer failures of high voltage plugs and adaptors and lead to higher levels of safety and increased production within the industry.

Underground

Health and safety, productivity and environment initiatives.

Recently Completed Projects

C27039True Triaxial Strength Of Coal Measure Rocks And Its Impact On Roadway Stability And Coal Burst Assessment

Rocks in the ground are subject to a range of stresses. The stresses...

C3063Underground Vehicle Design Standards And Statutory Implications

The Australian underground diesel vehicle fleet has evolved since di...

C3064Conveyor Belting And Lagging Shear Characteristics - Drive Drum Slip

The primary aim of this project was to investigate the relationsh...

Underground

Open Cut

Safety, productivity and the right to operate are priorities for open cut mine research.

Recently Completed Projects

C26029Geological Controls On Fluorine And Phosphorus In Bowen Basin Coals

Increasing global restrictions on fluorine in product coal prompted ...

C28033Raw Ash To Yield Relationships

Correct outcomes in yield predictions for product ash from coal bore...

C27038Establishing Self-Sustaining And Recognisable Ecological Mine Rehabilitation

In recent years an increasing interest has been placed on mining ope...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C27064Dry Beneficiation Using FGX And X-Ray Sorters

Conventional dry processing methods engage a single beneficiation de...

C26010Multi-Sloped Screening Efficiency With Changing Strokes, Frequencies, Feed Solids And Feed Rates-Pilot Plant Study

Optimising multi-sloped screens is often described as an art and the...

C28059Impact Of Water Quality In Coal Handling And Preparations Plants

The objective of this project was to deliver a concise reference do...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C23052Novel Stone Dust Looping Process For Ventilation Air Methane Abatement

This multi‐phase project is concerned with the mitigation of m...

C27054Optimisation Of A Thermal Flow Reversal Reactor For Ventilation Air Methane Mitigation

Ventilation air methane (VAM) generally accounts for 50-85% of the t...

C28076Selective Absorption Of Methane By Ionic Liquids (SAMIL) - Phase 2 Demonstration In A Packed Bed Reactor

An alternative approach to high temperature oxidation of ventilation...

Mine Site Greenhouse Gas Mitigation

Low Emission Coal Use

Step-change technologies aimed at reducing greenhouse gas emissions.

Recently Completed Projects

C17060BGasification Of Australian Coals

Four Australian coals were trialled in the Siemens 5 MWth pilot scale ga...

C17060AOxyfuel Technology For Carbon Capture And Storage Critical Clean Coal Technology - Interim Support

The status of oxy-fuel technology for first-generation plant is indicate...

C18007Review Of Underground Coal Gasification

This report consists of a broad review of underground coal gasification,...

Low Emission Coal Use

Mining And The Community

The relationship between mines and the local community.

Recently Completed Projects

C16027Assessing Housing And Labour Market Impacts Of Mining Developments In Bowen Basin Communities

The focus of this ACARP-funded project has been to identify a number...

C22029Understanding And Managing Cumulative Impacts Of Coal Mining And Other Land Uses In Regions With Diversified Economies

The coal industry operates in the context of competing land-uses that sh...

C23016Approval And Planning Assessment Of Black Coal Mines In NSW And Qld: A Review Of Economic Assessment Techniques

This reports on issues surrounding economic assessment and analysis ...

Mining And The Community

NERDDC

National Energy Research,Development & Demonstration Council (NERDDC) reports - pre 1992.

Recently Completed Projects

1609-C1609Self Heating of Spoil Piles from Open Cut Coal Mines

Self Heating of Spoil Piles from Open Cut Coal Mines

1301-C1301Stress Control Methods for Optimised Development...

Stress Control Methods for Optimised Development and Extraction Operations

0033-C1356Commissioned Report: Australian Thermal Coals...

Commissioned Report: Australian Thermal Coals - An Industry Handbook

NERDDC