Marine electrical system integrity

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Marine electrical system integrity

  1. 1. Marine Electrical System IntegrityOladokun Sulaiman Olanrewaju
  2. 2. Electrical Safety• Electric shock• Over current• Thermal hazard• Safely procedure
  3. 3. Electrical instrumentElectrical Instrument • Measuring instruments• Analogue • Ammeter• Digital • VoltmeterMeasurement • Ohmmeter-voltage • Multimeter-Current • Insulation tester- Resistance • Wattmeter- Power • Watt-hour meter • Power factor meter • Frequency meter • Voltage indicator • Phase sequence indicator • Earth loop tester • Earth resistance tester • Phase stick tester
  4. 4. Meter specification• Types of meter• Max measuring value• Accuracy• Operating temperature• Resolution• Types of supply (AC or DC)• Connection method• Percentage error• Maximum surge current• location
  5. 5. Continuity test• to check condition of current path• Correct condition• Condition of circuit and equipment• For ie cable, coil, winding-ohmmeter testGood- low ohm readingMalfuntion- high or infinit ohm reading-buzzer test-lamp test
  6. 6. Resistance test• To check condition of equipment winding or coilGood- small resistance- 3 phase expected to have equal resistance value
  7. 7. Insulation resistance test• Check condition of insulation materialTypes-Hand crankingBattery operatedAcceptable values of output250V DC - extra low voltage – 0.5 M- Ohm500V DC - <500V - 0.5 M- Ohm1000V DC – 1000V – 1.0 M-Ohm
  8. 8. Test procedure• For equipment - Remove equipment from circuit• Testing-1 phase- between coil or winding to ground or body-3 phase- between winding to winding or pole to pole-Between each windingFor cable or circuitRemove cable /circuit from supply and loadTesting1 phase- between phase to neutral, phase to earth and neutral to earth3phase- between phase to phase, each phase to neutral, each phase to body or earth, neutral to earth
  9. 9. Current injection test• Primary injectionCT ratio, connection, polarityStability and sensitivity of protection• Secondary injection• To check relay performance- operating current at various TMS and PMS using injection tester
  10. 10. Pressure test• Insulation property of HV• - 2 times voltage is supplied for 1min of AC, and 10min of DC
  11. 11. Earthling testing• Test earthing system items earth loop independence, earth electrode resistance

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