Railway Electrification Preparation Chapter IX

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Questions and Answers

What should be checked to ensure the proper functioning of MHO relays?

Each relay and contact mechanism individually (correct)

General circuit connections

Only the annunciation system

The wiring diagrams only

Which of the following is NOT included in the checks for annunciations?

Buchholz trip

Transformer efficiency reading (correct)

25 kV feeder circuit breaker trip

Winding temperature trip

What is the importance of checking the detailed wiring diagrams after installation?

To ensure no errors exist in the approved diagrams (correct)

To simplify the operational process

To evaluate compliance with manufacturer guidelines

To verify the visual aesthetic of the panel

What should be done if indicating instruments are found to be malfunctioning?

Ensure movements are free and readings are correct Signup and view all the answers

What is a recommended method for detecting errors in detailed wiring diagrams?

Preparing a simplified schematic or functional diagram Signup and view all the answers

What should be examined on the isolators to ensure their proper function?

Surface cracks and manual operation Signup and view all the answers

Why is it important to check the terminal connections of Current Transformers (CT)?

To ensure contact resistance is recorded Signup and view all the answers

What is the purpose of the earth terminal on a lightning arrester?

To drain excess voltage to the ground Signup and view all the answers

What should be checked for the operation of isolators regarding interlocking?

The functionality between the circuit breaker and isolator Signup and view all the answers

What is essential to confirm about the shielding conductors in a substation?

They must be connected to the earth system Signup and view all the answers

What aspect of Lightning Arrestors should be visually examined?

Hair-line cracks and chipped sheds Signup and view all the answers

What must be checked regarding the oil level in Potential Transformers (PT)?

It needs to be topped up for testing Signup and view all the answers

What is the recommended training timeline for switching station attendants before the commissioning date?

One month prior Signup and view all the answers

Which measurement method is used to measure individual levels of every frequency on the 'send' channel?

Vacuum-Tube Voltmeter Signup and view all the answers

What should the measured levels on the receive side be between?

-17 to -25 dBm Signup and view all the answers

What reading should the send-channel levels not be lower than?

-22 dBm Signup and view all the answers

At which position should the VTVM selector switch be during normal measurements of active circuits?

High Impedance Signup and view all the answers

When should the VTVM selector switch be changed to 150 Ohm or 1120 Ohm?

When the output level is to be measured with the line disconnected Signup and view all the answers

What is the impedance of the send and receive circuits mentioned?

1120 Ohm Signup and view all the answers

What permanent record should be noted after the final adjustment of the levels?

Values of the attenuation pads Signup and view all the answers

What should be used to measure composite levels between tele-command and tele-signal cable pairs?

Vacuum-Tube Voltmeter Signup and view all the answers

What is the impedance of the amplifier output?

150 Ohm Signup and view all the answers

What is the primary requirement for the battery room environment?

Dust-free and well ventilated Signup and view all the answers

What should be checked regarding the condition of the battery plates?

There should be no corrosion or damage Signup and view all the answers

What must be ensured about the alarm bell in the battery system?

It goes off if the supply is interrupted Signup and view all the answers

Which material should the battery stands be made from?

Teakwood Signup and view all the answers

What is an important factor when inspecting the battery charger?

It must have sufficient capacity for different charging types Signup and view all the answers

What type of paint should be used on the battery room walls and floor up to 2 m?

Anti-sulphuric acid paint Signup and view all the answers

What should be checked regarding the inter-cell connectors in the battery system?

They need to be tight and well vaseline Signup and view all the answers

Which design feature must the control room building possess?

It should have a strong door Signup and view all the answers

What type of access should the substation area have?

Good all-weather road and rail access Signup and view all the answers

What is the standard number of discs required for tension strings for a 132 kV supply?

10 discs Signup and view all the answers

How many discs are used for suspension strings at a distance of 1.6 km from the sub-station?

8 discs Signup and view all the answers

For railway crossings, which type of towers should be provided?

Anchor type towers Signup and view all the answers

What is the minimum required insulation resistance for power conductors?

100 Meg Ohm Signup and view all the answers

What device should every tower be fitted with during a detailed inspection?

Anticlimbing device Signup and view all the answers

Which color discs are to be provided on terminal towers to indicate phases?

Red, yellow, and blue Signup and view all the answers

What action should be taken after defects are rectified during inspection?

A general inspection should be carried out Signup and view all the answers

What should be done to warn the public before the lines are energized?

Wide publicity should be given Signup and view all the answers

What is required to confirm the completion of inspections before energization?

A joint certificate from inspecting officers Signup and view all the answers

What should be recorded during the continuity test of each conductor?

Results from the continuity tester Signup and view all the answers

What are the two distinct parts of the pre-commissioning inspections and tests?

Detailed inspection and General inspection Signup and view all the answers

Which of the following standards should be considered during preparations for commissioning?

Comprehensive statutory rules and relevant specifications Signup and view all the answers

Which element is NOT included in the major heads outlined for detailed preparation work in Railway Electrification?

Control systems Signup and view all the answers

What is the primary focus of the chapter's outlined preparations for commissioning?

Technical aspects requiring attention before energization Signup and view all the answers

What is the significance of amendments to rules and standards during pre-commissioning preparations?

They ensure that outdated information does not compromise safety Signup and view all the answers

Which of the following does not form part of the legal framework for ensuring the safety of railway electrification?

Banking and Finance Codes Signup and view all the answers

How should the procedures indicated in the manual be approached during preparations for commissioning?

They are mere suggestions and may require modifications according to latest standards Signup and view all the answers

What condition must be evaluated to ensure the proper sealing of a cabinet in a substation?

Insect-proof status Signup and view all the answers

What must be checked to ensure isolators operate correctly?

The smooth movement and full contact of switch blades Signup and view all the answers

What should be examined on the potential transformers (PT) to ensure proper functioning?

The oil level and dielectric strength Signup and view all the answers

Which component connection is critical for lightning arrestors to function properly?

Connection to a reliable earth terminal Signup and view all the answers

What aspect of the isolators needs verification regarding circuit breakers?

Functionality of interlocking mechanisms Signup and view all the answers

Which examination step is essential for ensuring the safety of shielding and earthing in a substation?

Verifying that the area is well screened against atmospheric surges Signup and view all the answers

What is a necessary condition regarding the terminal connections of Current Transformers (CT)?

They must have low resistance measured preferably with a Ductor Signup and view all the answers

During the inspection of lightning arrestors, which condition should specifically be checked?

The presence of hair-line cracks on the porcelain housing Signup and view all the answers

What must be ensured regarding the insulation resistance of transformers?

That it is consistent between primary and secondary Signup and view all the answers

What is a necessary component to ensure that cabin staff understands the purpose of 'Yellow Warning Collars'?

They should be instructed regarding their purpose. Signup and view all the answers

Which statement accurately describes the responsibility of the OHE supervisors?

They are responsible for updating the sectioning diagrams. Signup and view all the answers

What is essential for Station Masters regarding the system of power blocks?

They need to be well-informed about safety precautions related to train movements. Signup and view all the answers

What kind of training format is suggested for Station Masters and related staff regarding the new electrified traction rules?

A short orientation course at the Zonal Training School. Signup and view all the answers

Which steps are taken to ensure the proper operation of protective relays before commissioning?

Laboratory checks, post-installation checks, and confirmatory tests. Signup and view all the answers

What must be confirmed in writing by the staff with respect to new procedures concerning unwired lines?

Their understanding of the operational guidelines. Signup and view all the answers

What is the minimum distance an earthed structure should be from live OHE for safety?

2 m Signup and view all the answers

What factors must be inspected on a 25 kV feeder line before energization?

Tower footing resistance and insulation resistance. Signup and view all the answers

What procedure is recommended after defects are rectified during inspection?

Re-inspection and documentation of repairs. Signup and view all the answers

Which of the following is NOT a requirement for testing protective relays?

Recalibration of meters only after installation. Signup and view all the answers

What should be included in the detailed and general inspection for 25 kV feeder lines?

Ensuring clearances to road and rail crossings are in accordance with approved plans. Signup and view all the answers

What is a critical requirement for the installation of protective relays?

Familiarization with Manufacturers' instruction manuals. Signup and view all the answers

What must every tower be fitted with during a detailed inspection of the feeder lines?

Proper protective devices. Signup and view all the answers

What does the commissioning engineer need to verify about protective relays after they have been energized?

They have been correctly set and function as intended. Signup and view all the answers

What is the primary consequence of an under-rated trip battery circuit fuse?

It is liable to deteriorate and ultimately fail. Signup and view all the answers

What is required to ensure that a battery fuse is adequately protected?

Alarms are provided to alert the operator of failures. Signup and view all the answers

During insulation resistance testing, what should be done with earthing links?

They should be removed prior to testing. Signup and view all the answers

Which component is essential for conducting a primary injection test?

A primary injection set. Signup and view all the answers

What should be the state of fuses in the control circuit regarding their size?

They should be correctly rated, never undersized. Signup and view all the answers

What is the implication of having connections in the trip circuit that are not tight?

It can result in damaged wiring and potential breaks. Signup and view all the answers

What should be monitored when manually closing relay contacts?

Whether the appropriate device has operated. Signup and view all the answers

What type of ammeter is mentioned for use during testing?

Moving coil center-zero type low range ammeter. Signup and view all the answers

What should happen after modifications are made following testing?

Verification from the Manufacturer should be obtained. Signup and view all the answers

Which aspect of the primary injection test's setup is crucial?

Heavy current should be provided at low voltage. Signup and view all the answers

Study Notes

Chapter IX: Preparation for Commissioning

Prior to commissioning new railway electrification schemes, detailed preparation work is necessary.
Instructions for various equipment are issued separately in technical manuals.
Key aspects for preparation are outlined in this chapter.
Traction sub-stations, transmission lines and 25 kV feeders, protective equipment, switching stations, remote control equipment, and overhead equipment are all major points of focus.
The chapter discusses technical aspects for attention during inspections, tests before energization, and commissioning.

20901 Reference to Rules and Statutory Rules

Safety of public, railway staff, and property is ensured through strict compliance with various rules.
Indian Electricity Act 1910 (latest revision), Indian Electricity Rules (latest edition), Indian Railway Act (amended as needed), General Rules for Indian Railways, associated subsidiary rules, Indian Railways' Schedule of Dimensions, 1935 Rules for Opening of a Railway or Section of a Railway for Public Carriage of Passengers (amended as needed), Bonding and Earthing Code, and relevant IS or IRS specifications and codes of practice for various equipment are all covered.

20902 Pre-Commissioning Inspections

Pre-commissioning inspections and tests cover two parts:
Detailed inspection at the level of ACE and Senior Subordinates.
General inspection at the level of Divisional Officers.
These inspections cover all installations and are independent of inspections performed by administrative officers.
Relevant officers and staff must be involved in the inspections and verification of work quality during construction.
Defects and deficiencies are rectified before transferring sections to the open line.
The three categories of defects and deficiencies are vital safety items, non-vital safety items with related serious shortcomings, and less critical issues.

20904 Planning of Power Supply

Sub-stations in electric traction require substantial care during erection and commissioning.
Careful tests are needed, using reliable and calibrated instruments.
Section-by-section energization and partial traction-change commissioning should be adequately planned where needed.
Operational order for sub-stations should be decided via consultation to maintain reliable supply to energized sections.
The dates when the authorities require power supply must be communicated well in advance to ensure proper scheduling.
Sub-station connections and transmission line crossings must be completed beforehand.
Distribution of load for electric traction systems across the grid must be balanced to avoid strain.

20905 Commissioning of Traction Transformers

Steps for commissioning traction transformers include drying, checking the tap-changer mechanism, verifying transformer bushing condition, ensuring oil tightness, ensuring sufficient oil, and verifying the functionality of Buchholz relay.

20906 Precautions During Commissioning of Traction Transformer

Staff should take care to remove all loose articles from clothes, secure tools, and maintain dry conditions to avoid moisture entering during operations.
Maintenance of electrical contacts and equipment should also be done.

20907 Tests on Transformer Windings

Insulation resistance tests are conducted using a megger at specified temperatures.
Insulation resistance values are determined between EHV winding/earth, 25kV winding/earth, and between EHV and 25kV windings.
Phasing out tests are used for single phase transformers.

20908 Circuit Breakers and Interruptors

Circuit breaker mounting should be vertical and secure.
The operating mechanism and roller/bearing movement must be checked for proper functioning.
All pins, locking plates and split pins should be secure.
Electrical wiring, its insulation and terminal screws must be properly checked for tightness and contact conditions.
Functionality of operation /closing solenoids/motors should be tested.
Checking of dielectric strength of oil and other maintenance aspects.
The porcelain housing condition must be assessed.

20909 Isolators

Inspect insulators for cracks and cleanliness.
Check operation of switch blades, spring pressure, interlocking mechanisms, and earthing (grounding).

20910 Current and Potential Transformers

Check insulation resistance using a megger between primary and secondary winding to earth, and between primary and secondary.

20911 Lightning Arrestors

Inspect outer porcelain housings (looking for cracks or chips).
Ensure that earth connections to lightning arrestors are solid and direct.
Connection to the general earthing grid, and to an independent earth electrode.

20912 Shielding and Earthing

Confirm proper protection and metallic casings connectivity.
Ensure correct neutral terminals connection to the substation earthing grid and comply with "Code for Earthing Power Supply Installations" (Appendix 111).

20913 Busbars and Insulators

Visual inspection for cracks and any paint marks.
Confirm smooth and clean contact surfaces for current carrying joints and pressure, suitable for different metals.

20914 Clearances

Minimum clearances are defined for live equipment in different conditions (e.g., still air, maximum temperature).
Measures, such as fencing and safety procedures, are necessary within a workplace

20915 Auxilaiary Power Supply for Traction Substations & Control Room

Consideration for a 3-phase, 415/240 V, 50Hz supply of 100 kVA to meet power needs at the substation and control room, if possible.

20916 Batteries & Battery Charger

Ensure battery room has good ventilation, protection from dust and moisture.
Battery plates conditions are inspected(including the specific gravity of each cell and voltage across each cell on load. ).
Check for proper functioning of battery charger capacity, indicating lamps and earths.

20917 General

Substation area inspections to ensure proper drainage, roads, rail access, fences, and oil drainage arrangements.
Correct numbering schemes for transformers, isolators, circuit breakers, feeders and correspondence in control panels, and on the mimic diagram board must be verified.

20918 General Inspection of Substations and Commissioning

Confirming defects and deficiencies rectification.
Joint inspections, by the related departments, are performed before energization.
Inspections of equipment, including protective relays, and the care taken during erection.
Compliance with Indian Electricity Act and Rules.

20919 Detailed Inspection of Transmission Lines

A joint-effort inspection is done once contractors declare a section ready regarding the critical installation elements.
Inspection team includes ACE (TrD), construction/contractor staff, and railway representatives.
Any defects are noted, and rectification should be promptly addressed to ensure timely energization.

20920 Compliance with Rules and Approved

Detailed compliance with Indian Electricity Act and Indian Electricity Rules.
Conformity with specific specifications and sag/tension charts for clearances.

20921 Visual Inspection

Visual inspection of masts(checking for defects or damage - paint and other elements)
Testing the integrity and cleanliness of insulators.
Checking tightness of bolts and nuts, and other installation elements including any necessary painting.
Measurements of tower footings to meet minimum requirements and sag of earth wires and conductors.

20922 Clearances and Sag

Clearances for different locations, like open routes, roads, and accessible areas, between live conductors and earth /various structures are mandatory.

20923 Earthing

Correct and individual earthing connections for each tower with a maximum resistance of 10 ohms.

20924 Insulators and Insulation Resistance

Visual inspections for chips, cracks, cleanliness, and arcing/horns on insulators are mandatory at prescribed intervals or distances along line and from stations.
Measurements of insulation resistance using 2500 V to 5000 V megger are required with specific values given.

20925 Continuity Test

Continuity testing across each conductor is done, and the results are documented.

20926 Accessories

Checking and confirming that each tower has the necessary accessories (enamelled number plates, circular discs, and danger boards)

20927 General Inspection and Energization

Inspections by Sr. DEE/DEE(TrD) and relevant construction/contractor staff.
Ensuring proper working conditions for the installation and tele-command signals.
Verification and documentation of earlier inspections.

20928 25 kV Feeders

Inspection of 25kV line elements(such as towers, isolation elements, etc.) and through continuity.
Checking clearances, comparing this with the planned/approved drawings.

20929 Testing of Protective Relays

Equipment testing before commissioning.
Three stages: prior-to-installation checks, post-installation and commissioning checks and confirmatory checks.
Checking of all relays on the equipment for their correct operation.
Ensuring correct operation during various circumstances.
Checking relay functioning in the laboratory followed by commissioning and final checks after energization.

20930 Inspection of Setting of Relays and Calibration of Meters

Checking of relay functionality with specific settings.
Documentation of testing settings and calibration data.
Correct relay operation for current and potential coils is crucial for proper functioning.

20931 Protective Devices at Sub-stations

The types of protective devices to be checked in each electrical transformer station are: Differential protection, Restricted earth fault protection for EHV, 25 kV sides; Buchholz relay, Winding temperature protection and Oil temperature protection
Indicating devices, such as oil level indicator for low oil levels
Indicators for winding/oil temperature are present on the control panels for monitoring.

20936 Primary Injection Test

Primary injection tests are carried out to ensure overall soundness of the circuits; including appropriate connections for testing

20937 Voltage Transformer Ratio and Polarity Check

Procedures are described to confirm voltage transformer ratio and polarity using standard methods.

20938 Electrical Operation of Indicators and Associated Devices

Checks for proper functioning of shunt-connected indicators, annunciators, auxiliary elements and (DC/Master) relays for specified minimum voltage levels.

20939 Secondary Injection Test

Testing of relay settings including operating times and minimum closing values for induction/instantaneous armature, directional relays etc., and their characteristics.

20940 Alarm and Trip Check

Ensure appropriate (fuse) circuits operate according to plan.
Relay operations (manual and automatic) must be validated with alarm/trip indications.

20941 Load Test

Final validation of voltmeter and ammeter operation when normal load currents are passed.
Evaluating performance of differential (Protection) circuits under external/internal fault conditions.
Check polarity of CT and PT for correct operation

20942 Confirmatory Test of OHE Protective Relays

Tests under de-energized conditions to confirm relay operation during fault scenarios.

20943 Power Supply

Power supply for switching stations is sourced from 10kVA transformers.
Voltage records of transformers is mandatory.

20944 Installation of Equipment

Interruptors, isolators, busbars, lightning arresters, wiring, batteries, and their chargers are included in checks.
Minor differences in installations within switching stations.

20945 Clearances

Live conductor clearances above ground level for 25 kV.
Minimum distances between live and earth/earthed parts.
Clearance parameters regarding safety and operation of electrical equipment

20946 Auxiliary Transformers & Booster Transformers

Inspections and tests of (auxiliary/booster) transformers as per prescribed procedures

20947 General

Fencing, gates and safety features for switching stations should be examined.
Verify that the ground around the equipment is properly drained and leveled.
Ensure accessibility for maintenance works at all locations.

20948 Interlocking

Validate correct operation of double-pole isolators, combined with interlocks, and their position indication locks and RC control circuits to prevent accidental operation during critical conditions.

20949 Feeding Posts

Verification of proper relay operation and safety during different scenarios (such as low voltage/faults) and emergency feeds

20950 Number Plates and Boards

Ensure verification of the numbering of equipment (interruptors, isolators, etc.) with control panel schematics and diagrams.
Presence of and conformity with safety, warning, and clearance boards for personnel and public.

20951-20965

Earthing/bonding of structural steel and equipment.
Insulation resistance testing, continuity checks and checks for correctness of connections in different location(s).
Verification and maintenance checks of various relay systems and control equipment along with their corresponding indicators.
Preparation and procedures for operating electrified services and testing with live conditions.
Divisional Officers' inspection and certificate of conformity for proper functioning of installations prior to commencement/start of service.

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Description

Explore the essential preparation steps for commissioning new railway electrification schemes in this informative chapter. Key aspects, including traction sub-stations and safety regulations, are discussed to ensure successful inspections and tests before energization. Delve into the technical guidelines and statutory rules that ensure public and railway staff safety.