Power Supply Installations Overview
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Questions and Answers

What is the primary function of sub-stations in the electric traction system?

  • To ensure continuous power supply. (correct)
  • To record passenger information.
  • To monitor train schedules.
  • To manage maintenance personnel.

What should be recorded in the inspection book at a sub-station?

  • Train departure times.
  • Weather conditions every hour.
  • Observations made by supervisory officials. (correct)
  • Daily passenger counts.

What is the maximum permissible temperature rise for the winding of a traction transformer at an ambient temperature of 45 degrees Celsius?

  • 40 degrees Celsius.
  • 55 degrees Celsius.
  • 65 degrees Celsius.
  • 50 degrees Celsius. (correct)

After how long can a traction transformer experience another 50% overload following continuous operation at maximum ambient temperature?

<p>3 hours. (D)</p> Signup and view all the answers

Who is responsible for controlling switching operations at sub-stations?

<p>Traction Power Controller. (D)</p> Signup and view all the answers

What is the overload capacity of traction transformers for a 100% overload?

<p>5 minutes. (D)</p> Signup and view all the answers

Which part of the traction transformer has a maximum permissible temperature rise of 35 degrees Celsius?

<p>Current carrying parts. (B)</p> Signup and view all the answers

What is a significant consequence of thermal and electrical stresses in oil-filled equipment?

<p>Gas formation and lowering of flash point (B)</p> Signup and view all the answers

Which method is considered the most sensitive and efficient for detecting incipient faults in transformers?

<p>Dissolved gas analysis (DGA) (B)</p> Signup and view all the answers

What happens to the condition of cellulosic insulation due to insufficient monitoring?

<p>It suffers from reduced mechanical and dielectric strength (A)</p> Signup and view all the answers

Which action should be undertaken to prepare for the overhaul of a transformer?

<p>Ensure spare gaskets of proper quality are available (D)</p> Signup and view all the answers

What is the recommended frequency for drawing oil samples for analysis in transformer condition monitoring?

<p>Annually (A)</p> Signup and view all the answers

What aspect of oil is significantly affected by temperature rise in transformer operation?

<p>Dielectric properties and flash point (D)</p> Signup and view all the answers

What should be done with bushings during the transformer overhaul process?

<p>Carefully remove and protect them (C)</p> Signup and view all the answers

What can dissolved gases indicate in the context of transformer operation?

<p>Incipient faults and deterioration (C)</p> Signup and view all the answers

In extreme cases, what can lower the flash point of the oil in transformers?

<p>Gas formation due to electrical stress (A)</p> Signup and view all the answers

What is one main purpose of conducting gas chromatography on transformer oil?

<p>To timely detect insulation deterioration (B)</p> Signup and view all the answers

What is the primary purpose of tap changers in Traction Transformers?

<p>To adjust output voltage based on load conditions (C)</p> Signup and view all the answers

What voltage level must daily OHE voltage peaks remain below at the traction sub-station?

<p>27.5 KV (B)</p> Signup and view all the answers

How often should a 24-hour record of voltages at neutral sections be taken?

<p>Once a year (D)</p> Signup and view all the answers

What specifications are adopted for EHV grade oil used in transformers?

<p>IS-335 and IS-1866 (C)</p> Signup and view all the answers

Which test can be conducted in PSI depots or sub-stations every six months?

<p>Breakdown voltage (BDV) test (C)</p> Signup and view all the answers

What is the primary purpose of providing wedges in traction transformers?

<p>To hold the windings tightly together against mechanical forces. (B)</p> Signup and view all the answers

What is the purpose of connecting a recording voltmeter at the traction sub-station?

<p>To monitor voltage variations over time (C)</p> Signup and view all the answers

What condition may indicate a failure due to overheating in transformers?

<p>Evidence of carbon deposits or flash marks on critical components. (C)</p> Signup and view all the answers

Which factor requires the CTFO/PSI to stay in contact with supply authorities?

<p>To address changes in grid system connections (A)</p> Signup and view all the answers

What should be done regarding tools used during transformer maintenance?

<p>All tools used must be listed out and accounted for to avoid hazards. (C)</p> Signup and view all the answers

What is a potential consequence of exceeding 27.5 KV at the traction sub-station?

<p>Decreased lifespan of the transformer (A)</p> Signup and view all the answers

What is a characteristic feature of transformer failure due to lightning discharge?

<p>Presence of flash marks on the end coil and nearby grounded parts. (B)</p> Signup and view all the answers

What is the primary characteristic monitored through the acidity test in transformer oil?

<p>Degradation of insulation material (C)</p> Signup and view all the answers

What is recommended to counteract coil displacement in transformers?

<p>Tighten the pressure screws and ensure wedges are fully home immediately. (D)</p> Signup and view all the answers

What should be noted if a transformer has been opened due to an internal fault?

<p>Abnormalities such as carbon deposits and unusual odour (D)</p> Signup and view all the answers

What is the recommended location for replacing a burnt-out coil in a traction transformer?

<p>In the manufacturer's works (A)</p> Signup and view all the answers

What cleaning measures should be taken inside the transformer tank?

<p>Thoroughly clean and wash with fresh oil (D)</p> Signup and view all the answers

What is the best method to remove sludge from inaccessible places in a transformer?

<p>Direct a thin jet of transformer oil under pressure (D)</p> Signup and view all the answers

Which of the following is NOT a recommended practice to protect the windings from moisture?

<p>Ignore the moisture during service maintenance (C)</p> Signup and view all the answers

What should be done to the oil-tight gasket around the valve seat during maintenance?

<p>Lightly polish the valve seat and renew the gasket (C)</p> Signup and view all the answers

How should debris and sludge be removed from transformer components?

<p>With a wooden or fiber wedge to prevent damage (C)</p> Signup and view all the answers

What should you inspect if the coil assembly has been lifted after several years of service?

<p>The amount of sludge formation present (C)</p> Signup and view all the answers

What is the first step in the maintenance process after opening a transformer?

<p>Make a careful note of the internal conditions (A)</p> Signup and view all the answers

What is an important step after cleaning the transformer tank and before painting?

<p>Ensure no rust or traces of oil remain (A)</p> Signup and view all the answers

What is the first action that should be taken to ensure the soundness of bonding and earthing connections?

<p>Check physically the soundness of the connections. (B)</p> Signup and view all the answers

Which procedure is essential before checking the resistance of each group of earth electrodes?

<p>Disconnect the group from the common earth system. (C)</p> Signup and view all the answers

What action should be taken if a battery is found to have excessive sediment accumulation?

<p>Replace the battery with a new set. (A)</p> Signup and view all the answers

How often should the insulation resistance of motor windings be checked for motor-operated isolators?

<p>Annually or as recommended during checks. (B)</p> Signup and view all the answers

What is the purpose of using a ‘Ductor’ in maintenance procedures for bus bars and connectors?

<p>To measure the contact resistances of heavy current connections. (B)</p> Signup and view all the answers

What is the primary quality to be preserved during the purification of transformer oil?

<p>Di-electric strength (A)</p> Signup and view all the answers

What occurs to the insulation resistance during the initial stages of the drying out process?

<p>It drops to a low value due to heating (C)</p> Signup and view all the answers

At which point in the drying process should oil circulation be discontinued?

<p>Upon completion of the drying out operation (B)</p> Signup and view all the answers

When does the insulation resistance rise above the leveling off point during the cooling process?

<p>As oil cools after the drying out operation (C)</p> Signup and view all the answers

Which equipment specifications are referenced for purifying transformer oil?

<p>RDSO’s Specification No.ETI/PSI/103 (A)</p> Signup and view all the answers

What factors can cause moisture absorption in transformer oil?

<p>Defective breathers and untreated make-up oil (B)</p> Signup and view all the answers

What temperature is associated with a low insulation resistance during the drying out process?

<p>75 degrees C (D)</p> Signup and view all the answers

What significant change occurs to the dielectric strength of cellulosic insulation over time?

<p>It decreases due to mechanical stress. (D)</p> Signup and view all the answers

What method is utilized for condition monitoring of power transformers primarily based on gas analysis?

<p>Dissolved gas analysis (A)</p> Signup and view all the answers

What happens to the flash point of transformer oil under extreme thermal stress?

<p>It drops to between 50 degrees C and 80 degrees C. (D)</p> Signup and view all the answers

Why does the Buchholz relay fail to respond during the early stages of trouble in a transformer?

<p>It requires a certain volume of gas to trigger. (C)</p> Signup and view all the answers

In what condition is it recommended to periodically undertake the overhaul of a transformer?

<p>If it is faulty or at the end of 7-10 years. (A)</p> Signup and view all the answers

What is the primary purpose of gas chromatography in transformer condition monitoring?

<p>To analyze the type and amount of dissolved gases. (B)</p> Signup and view all the answers

Which equipment condition requires immediate attention during transformer overhaul?

<p>Excess sludge accumulation. (B)</p> Signup and view all the answers

What must be done with the oil before commencing maintenance work on a transformer?

<p>It should be drained out. (A)</p> Signup and view all the answers

What is the first step when preparing for the removal of a transformer core during overhaul?

<p>Ensure spare gaskets are available. (D)</p> Signup and view all the answers

What is the procedure for monitoring the condition of battery cells?

<p>Check general conditions of all cells and measure specific gravity and voltage of the pilot cell, then for all cells if issues arise. (C)</p> Signup and view all the answers

Which action is required for bonding and earthing of electrical equipment?

<p>Visually inspect all earth connections, ensuring duplicate earths are present for every equipment. (B)</p> Signup and view all the answers

During the inspection of insulators, what should specifically be looked for?

<p>Cracks, chippings, and flashover marks, with replacement considered for badly chipped ones. (B)</p> Signup and view all the answers

What should be monitored regarding traction transformers?

<p>The maximum oil temperature, silica-gel conditions, and gas collection in Buchholz relay. (C)</p> Signup and view all the answers

What must be done if the silica-gel in traction transformers appears pink?

<p>Replace with dry gel and recondition the old silica-gel. (C)</p> Signup and view all the answers

What is the first step in checking oil levels in transformers and related equipment?

<p>Inspect the oil level in the sight gauge glass and check for leaks. (D)</p> Signup and view all the answers

Regarding the operation of circuit breakers, what is a primary maintenance check?

<p>Open the cover of the control box to inspect the operating mechanism. (C)</p> Signup and view all the answers

What should be done with minor chippings on insulators?

<p>Apply a light coating of epoxy resin to prevent moisture ingress. (B)</p> Signup and view all the answers

In the context of traction transformers, which of the following is necessary for maintaining the silica-gel breather?

<p>It must be monitored for color change and substituted when turning pink. (D)</p> Signup and view all the answers

How should checks be conducted for gas collection in Buchholz relays?

<p>Gas collection must be checked continuously to ensure safety. (D)</p> Signup and view all the answers

What should be done if a battery is not in a fully charged condition?

<p>Perform a boost charge and increase the trickle charging rate after investigation. (C)</p> Signup and view all the answers

What is a crucial aspect of maintaining the contact surfaces during maintenance?

<p>Touch up the high spots on the contact surfaces to achieve a good fit. (B)</p> Signup and view all the answers

Which procedure must be followed for PTs during maintenance?

<p>Check the fuse holders on the LV side to confirm their condition. (C)</p> Signup and view all the answers

During quarterly maintenance of batteries and battery chargers, what should be documented?

<p>The specific gravity and cell voltage of every cell. (D)</p> Signup and view all the answers

What is the first step in maintaining booster transformers?

<p>Replace or recondition the silica-gel breather, if necessary. (C)</p> Signup and view all the answers

When conducting inspections on auxiliary transformers, what value should be recorded alongside temperature?

<p>Insulation resistance of the transformer winding. (D)</p> Signup and view all the answers

What maintenance step is specifically mentioned for the earth connections of booster transformers?

<p>Check connections from the bottom to earth electrodes or rails. (C)</p> Signup and view all the answers

During maintenance checks of control and relay panels, what should be done with abnormal voltage or current readings?

<p>Record them and take corrective action. (D)</p> Signup and view all the answers

What is a key maintenance action regarding silica-gel breathers in booster transformers?

<p>Replace or recondition them as necessary. (C)</p> Signup and view all the answers

What should be checked for proper operation during the inspection of control and relay panels?

<p>The state of all indicating and recording instruments. (C)</p> Signup and view all the answers

Flashcards

Sub-station Inspection Book

A record book used to document observations made by supervisors during periodic inspections of sub-stations.

Sub-station Logbook

A record book for tracking traction transformer oil temperature, ambient temperature, currents, and voltages recorded every morning.

Traction Transformer Overload Rating

The maximum permissible load beyond the normal load for a specific time period.

50% Overload (15 minutes)

Traction transformer overload capacity that can operate up to 50% higher than normal load for 15 minutes after steady temperature is reached.

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100% Overload (5 minutes)

Traction transformer overload capacity that allows operating up to double the normal load for 5 minutes after steady temperature is reached.

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Maximum Permissible Temperature Rise (Ambient 45°C)

The highest acceptable temperature increase above ambient for transformer windings, oil, and current carrying parts during overload.

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Hot-spot Temperature Limit

The highest allowed temperature at the warmest point (hot spot) of the transformer during overload operation and ambient 45°C.

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Overload Interval

The minimum time required between successive overloads (50% for 15 minutes or 100% for 5 minutes) when operating at a maximum ambient temperature of 45°C, which is 3 hours.

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Traction Transformer Tap Setting

Adjusting the transformer taps to maintain optimal overhead line (OHE) voltage, usually between 19 kV and 27.5 kV.

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Off-load Tap Changer

A device on traction transformers that allows adjusting the voltage transformation ratio without interrupting power flow.

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Recording Voltmeter

A device used to continuously monitor voltage levels over time, typically 24 hours.

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OHE Voltage

Voltage on the overhead electric line supplying traction.

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Minimum OHE Voltage

The lowest acceptable voltage on the overhead electric line, typically 19 kV.

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Transformer Oil Tests

Checks conducted on transformer oil to assess its condition and predict service life.

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EHV Grade Oil

High-voltage-rating insulating oil used in high-voltage transformers.

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IS 335

Indian Standard specifying requirements for new insulating oil.

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Grid Interconnections

Connections between different power grid systems.

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Dissolved Gas Analysis (DGA)

A method for monitoring the condition of power transformers and other oil-filled equipment by analyzing dissolved gases in the oil.

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Gas Chromatography (GC)

A sensitive and rapid gas analysis method used to detect incipient (early) and growing faults in power transformers.

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Transformer Overhaul

A periodic maintenance or repair of a transformer, often performed every 7-10 years, or when necessary due to fault.

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Insulation Deterioration

Reduction in the mechanical and dielectric strength of insulation materials in transformers, often caused by heat and gases.

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Buchholz relay

A device used to detect gas buildup in a transformer and may be ineffective for early stages of trouble

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Oil Reconditioning

The process of restoring the functional properties of transformer oil.

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Cellulosic Insulation

A type of electrical insulation in transformers known to not be capable of reconditioning after its deterioration.

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Annual Oil Sampling

Regular testing of transformer oil to monitor insulation condition via Gas Chromatography.

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Transformer Oil Examination

Inspect the transformer oil for color, arc marks, carbon deposits, and charring for fault analysis.

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Burnt Coil Replacement

If a coil is burnt, the entire transformer must be disassembled and the damaged coil replaced with a new one.

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Traction Transformer Coil Replacement

Damaged coil replacement for traction transformers is best done at the manufacturer's facility due to specialized equipment and expertise.

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Transformer Tank Cleaning

Thoroughly clean the transformer tank, remove debris, sludge, and wash with fresh oil for a clean internal environment.

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Drain Plug Maintenance

Oil-tight gaskets must be renewed for the drain and sampling valves (if any) ensuring a completely sealed system.

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Sludge Removal

Remove sludge build-up from transformer tanks, metal parts, windings, and interspaces with wooden/fiber wedges carefully to avoid damage to the windings.

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Surface Contamination Removal

Carefully brush and wash to expose clean winding surfaces, while preventing moisture ingress from the air or sweat.

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Moisture Protection

Protect transformer windings during inclement weather and after maintenance by keeping them warm through heating elements and wiping away any sweat to avoid moisture ingress.

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Coil Alignment

Ensure proper alignment of coils and tightening of end-plates for preventing slackness, to avoid operational issues.

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Transformer Coil Support

Components used to securely hold transformer windings in place, preventing displacement during short circuits.

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Short Circuit Forces

High mechanical forces experienced by transformer components during short circuits.

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Transformer Winding Displacement

The shifting or movement of transformer windings due to mechanical forces like short circuits.

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Insulation Abrasion

Wear and tear on the insulating materials in a transformer due to repeated movement of windings or layers.

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Transformer Overhaul

Maintenance process of inspecting, repairing, and/or replacing parts of a transformer.

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Core Assembly

The core structure of a transformer.

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Transformer Bushing

Components that insulate the transformer's terminals, connecting them to the outside electrical system.

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Foreign Objects in Transformers

Tools or other items accidentally left behind during transformer maintenance, potentially causing hazards.

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Transformer Failure Causes

Factors that could lead to transformer damage or failure, including winding displacement, insulation issues, and overheating.

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Lightning Discharge

Sudden electrical discharge caused by lightning strikes.

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Transformer Coil Damage

Damage to the coils of transformer, e.g. break in turns or end leads, or flash marks.

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Transformer Oil Purification

The process of removing contaminants like water, carbon, dirt, sludge, and dissolved moisture from transformer oil to maintain its dielectric strength.

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Dielectric Strength

The ability of a material to resist electrical breakdown.

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Moisture in Transformer Oil

Moisture harms the dielectric strength of transformer oil by weakening its insulating properties.

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Oil Purification Plant

Equipment used to purify transformer oil by removing contaminants.

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Insulation Resistance During Drying

Measurement of electrical resistance between windings and other parts of a transformer during drying out process.

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Drying Out Stages

Four distinct stages of moisture removal, observed through insulation resistance drop, plateau, rise, plateau, and final rise.

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Initial Resistance Drop (Drying)

Insulation resistance drops due to oil heating.

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Maintaining Low Resistance (Drying)

Insulation resistance remains at low levels while moisture is driven out.

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Gradual Resistance Rise

Insulation resistance rises as moisture is completely removed.

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Final Resistance Rise (Cooling)

Insulation resistance further rises as the oil cools down.

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Dissolved Gas Analysis (DGA)

A method used to monitor the condition of power transformers and other oil-filled equipment by analyzing dissolved gases in the oil.

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Gas Chromatography (GC)

A sensitive and rapid gas analysis method used to detect incipient and growing faults in power transformers.

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Insulation Deterioration

Reduction in mechanical and dielectric strength of insulation, often from heat and gas.

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Oil Reconditioning

Restoring functional properties of transformer oil, only possible for oil, not cellulosic insulation.

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Buchholz Relay

A device used to detect gas buildup in a transformer; may not respond in early stages.

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Transformer Overhaul

Periodic maintenance or repair of a transformer, usually every 7-10 years or when faulty.

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Annual Oil Sampling

Regular testing (using GC) of transformer oil for monitoring the condition of insulation.

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Cellulosic Insulation

A type of electrical insulation in transformers that cannot be reconditioned after deterioration.

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Incipient faults

Early stages of transformer problems, where problems are not revealed in routine tests.

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Connector Maintenance

Cleaning and securing the connector's contact surfaces, applying a light coat of lubricant, and tightening connections.

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Control Panel Inspection

Checking for flag indications, instrument operation, and recording voltage/current variations during a 15-minute period. Abnormal readings necessitate corrective action.

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Battery Inspection

Measuring specific gravity and cell voltage of each battery cell, performing boost charging if needed, and inspecting the charger.

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PT/CT Maintenance

Inspecting PTs and CTs similarly to traction transformers, checking fuse holders on the low-voltage side.

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Booster Transformer Maintenance

Maintaining silica-gel breather, checking earthing connections, caution boards, nameplates, anti-climbing devices, foundation, and bolts.

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Auxiliary Transformer Maintenance

Measuring insulation resistance and transformer winding temperature, testing oil, checking fuse holder, rod gap, and neutral earth resistance.

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Battery Inspection

Checking battery cells, measuring specific gravity and voltage, and ensuring proper water levels to identify weak cells, and check battery charger operations.

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Bonding and Earthing

Visually inspecting and tightening all earth connections to ensure proper grounding, and bonding sub-station and feeding posts to avoid risks.

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Transformer Oil Level

Checking oil levels in transformers, circuit breakers, and CTS to detect and repair any oil leaks, ensuring the right oil levels in each equipment.

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Insulator Inspection

Cleaning insulators and verifying for flashover marks, cracks, or chips, replacing badly damaged ones; minor damages are treated with epoxy resin for better moisture protection.

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Traction Transformer Cleaning

Externally cleaning the tank, conservator, radiator, bushings, oil level indicator, gauges and other components of traction transformers with a dry cloth.

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Transformer Oil Temperature

Checking the maximum transformer oil temperature using a dial indicator, noting it down in the register, and resetting the indicator.

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Explosion Vent Diaphragm

Checking the explosion vent diaphragm for any damage and presence of oil on it.

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Silica-Gel Breather

Checking the silica-gel breather for color changes, replacing it with dry gel if pink, and re-conditioning old silica-gel if needed.

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Buchholz Relay

Checking for any gas collection in the Buchholz relay.

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Oil Leakage Check

Inspecting transformer body, conservator tank, oil drain valves and foundations for oil leakage, and rectifying the leaks.

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Circuit Breaker Mechanism

Inspecting the operating mechanism of circuit breakers and interrupters, opening the cover of the control box to check the functionality.

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Lightning Arrestor Discharge Counter Reading

Record the reading of the discharge counter on lightning arrestors.

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Bonding and Earthing Soundness Check

Physically verify the integrity of bonding and earthing connections for all electrical equipment, structural steel, and lightning arrestors.

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Earth Resistance Measurement

Measure and record the earth resistance to the electrical equipment, fencing, and structural steel.

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Overhead Shield Wire Condition

Inspect the overhead shield wire's terminations for physical integrity and proper electrical bonding to structures.

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Earth Electrode Resistance

Measure and record the resistance of each group of earth electrodes after detaching them from the common earth system.

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Transformer Oil Sample Testing

Send samples to a qualified lab and conduct all tests listed, including dissolved gas analysis.

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Transformer Oil Level Check

Inspect and verify the correct oil level in the transformer's bushings.

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Bushing Gasket Inspection

Visually inspect bushing gaskets for potential leaks, and tighten any loose bolts.

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Tap Setting Switch Operation

Test and operate the tap setting switch to ensure good contact by moving it through its full range.

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Tap Setting Verification

Verify the tap setting is set to the correct position, and that tap indication corresponds to main contact position.

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Isolator Blade Tip Smoothing

Remove burrs from blade tips and fixed contact fingers using fine emery paper.

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Isolator Blade Clearance Measurement

Measure and record the clearance in the open blade position and adjust the crank mechanism if necessary.

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Isolator Stop Set-Screws Inspection

Inspect set screws for proper condition and correct positioning.

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Motor-Operated Isolator Motor Test

Measure and record the insulation resistance of the motor windings and contactor coils using a 500 V megger.

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Bus Bar and Connector Resistance

Measure and record contact resistances of heavy current connections with a Ductor type of low-resistance measuring instrument.

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Relay Panel Maintenance

Perform maintenance on relays as detailed in section 20221.

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Control Panel Switch Cleaning

Clean up burnt, corroded, control switches and push button contacts.

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Battery Condition Assessment

Assess the battery health. If unhealthy, replace.

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Battery Charger Cleaning

Open battery charger covers and remove dust.

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Study Notes

2020 Introduction

  • This chapter is divided into four sections
  • Section 1 covers the organization and duties of Chief Traction Foreman (Power Supply Installations)
  • Section 2 details the operation of sub-stations
  • Section 3 covers guiding notes on maintenance of power supply equipment
  • Section 4 outlines a recommended maintenance schedule for power supply equipment

Organization

  • Divisional set-up of senior subordinates under Sr. DEE/TRD is arranged in two patterns:
    • Territorial basis
    • Functional basis

Operational and Maintenance

  • Sub-stations are vital for continuous power supply
  • Transmission lines and associated gear (transformers, switch gear, control, and relay panels) are duplicated in case of component failure
  • Centralized control by a single authority (Traction Power Controller) for switching operations

Overload Capacity of Traction Transformers

  • Overload ratings typically include:
    • 50% overload for 15 minutes
    • 100% overload for 5 minutes
  • Temperature limitations are specified with ambient temperature (45°C)
    • Winding temperature: 50°C (by resistance method)
    • Oil temperature: 40°C (by thermometer)
    • Current-carrying parts temperature: 35°C (by thermometer)
  • Hotspot temperature limits: ≤100°C

Inspection Book and Log Book at Sub Stations

  • Substations maintain "Inspection Books" for recorded observations by supervisors
  • Log books record traction transformer oil temperatures, ambient temperatures, currents, and voltages at set times
  • Investigate any unusual occurrences and implement corrective actions as required

Duties of Chief Traction Foreman, Power Supply Installation

  • Supervises installation maintenance according to schedules, ensuring serviceability
  • Maintains coordination with Power Controller, Chief Foreman (OHE) to ensure power supply reliability
  • Keeps organization prepared for equipment breakdowns/failures
  • Oversees safety equipment (relays, bonding, earthing) function, properly trains staff, and enforces safety precautions
  • Deploys staff for refresher courses for deficient staff
  • Cares for special instruments and tools used for maintenance and operation
  • Keeps close watch on spare parts, initiating timely actions to replenish stocks
  • Ensures proper accounting of all tools and stores
  • Deploys staff to sub-stations and switching stations when remote equipment fails
  • Conducts monthly inspections with emphasis on safety
  • Provides timely updates to AEE/TRD and Sr. DEE/DEE(TRD) on developments
  • Carries out other duties as directed

Protective Devices

  • Protective devices (alarms, trips, etc.) ensure safe operation with settings for extended use
  • Supervisory officials are notified for anomalies
  • Detailed reports are to be submitted to Sr. DEE/DEE(TrD)

Testing of Transformer Oil

  • Performance and longevity of transformers are improved with use of EHV grade oil
  • Standard specifications (IS-335 and IS-1866) apply for new oil and oil in service, and these tests should be carried out regularly

Oil Purification Plant

  • This plant aims to remove contaminants like water, deposits, dirt, sludge, dissolved moisture, and gases.
  • The main quality to preserve is dielectric strength
  • Removal of these contaminants is essential for safe operation.

Insulation Resistance During Drying-Out

  • Temperature and insulation readings are recorded every two hours during the drying process
  • Plotting these values on a graph shows four distinct stages of the process
  • Stages depend on oil temperature and moisture removal, with resistance gradually increasing as moisture leaves

Transformer Overhaul

  • Covered shops with facilities for core lifting are used to overhaul transformers
  • Equipment is thoroughly cleaned for internal faults, and component-by-component conditions are meticulously documented
  • Care must be taken to protect windings during overhaul

Circuit Breakers and Interruptors

  • There are different types of circuit breakers: Minimum oil, SF6, Vacuum etc.
  • Manufacturers' instructions for maintenance are available for all these types, with additional, updated directives by RDSO.

Battery Maintenance

  • Batteries must be in proper working order.
  • Condition assessment and maintenance for control, protection, and indication circuits is essential
  • Battery chargers should be appropriately sized
  • Periodic checks include specific gravity readings to ascertain the health and efficiency
  • Preventative steps for sulphation or over-charging are essential

Protective Relays

  • Specialists conduct maintenance, repair, and test all protective relays; proper records are maintained
  • Strict authorization is required for any relay setting changes
  • A detailed register is required to show specifics of each relay and associated testing/maintenance info
  • This information is also to be shared with the Senior DEE/TRD

Maintenance Schedules

  • Monthly, half yearly, and annual maintenance schedules are provided to ensure proper condition of equipment
  • These schedules should be adhered to, to prevent equipment failures and ensure safety and operational efficiency

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Indian Railways - ACTM-117-161 PDF

Description

This quiz covers key aspects of traction power supply installations, including the organization of Chief Traction Foreman duties, operational details of sub-stations, and maintenance guidelines. It also discusses essential components such as transformers, switch gear, and centralized control operations for efficient power management.

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