Railway Electrification Preparation Chapter IX

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.