REPAIR/MAINTENANCE OF EXTERNAL ELECTRIFICATION SYSTEM NETWORK FOR IMPROVEMENT INCLUDING ALLIED SYSTEM AT GE (U) MEERUT CANTT

Supply, Procurement & Pre-Installation Specification:- Supply of Neutral CT (NCT), copper-wound, oil-cooled, outdoor type. Ratio: 300/1 A, suitable for an existing 33/11 kV EHT Transformer. Technical Meaning: For every 300A flowing through the transformer neutral to earth, the CT secondary will output 1A to the relay. Class PS Accuracy Verification : Technical Meaning: Unlike Class 5P10 (general protection), Class PS is a non-standardized high-accuracy class used specifically for balanced protection like REF (Restricted Earth Fault). to ensures the CT maintains a linear relationship between primary and secondary current without "spilling" current during an external fault. Short Circuit & Thermal Rating Verification: Technical Meaning: 5kA for 3 Seconds. This defines the thermal and mechanical strength of the CT. It must withstand a 5,000A fault current for 3 seconds without the internal windings melting or the casing exploding. Labor Task (SOW Requirement): The contractor must obtain and verify the Type Test Report from the manufacturer confirming this rating, as this cannot be tested on-site without destroying the equipment. Civil & Foundation Inspection: Labor Task: Verified placement of the NCT on the plinth, ensuring a horizontal level within plus/minus 1{ mm} to prevent oil-level discrepancies.

DATA INTERFACE :- Manufacturing & Civil Release Documentation From: Procurement & Civil Team Mechanical Installation TeamApproved Type Test Reports & Factory Acceptance Test (FAT) Sheets: Validating the 5kA/3s short circuit rating and Class PS curves.Foundation Handover Certificate: Confirming the Plus/minus 1mm level alignment.Material Dispatch Clearance: Confirming the NCT oil levels and bushing integrity post-transport.Phase 2: Physical Installation, Mounting & Bus-WorkThis phase covers the mechanical erection of the NCT, bushing assembly, primary copper bus-work connections, and secondary cable routing.Bushing Installation: * Labor Task: Cleaning and mounting of 33kV and 11kV porcelain/RIP bushings. Inspection for hairline cracks and ensuring the gasket compression is uniform (torque-wrench tightened to manufacturer specs).NCT Mounting & Polarity Alignment:Labor Task: Installation of the Neutral CT on the transformer side of the earthing link. Strict verification of P1/P2 polarity.Technical Warning: If the NCT is reversed relative to the phase CTs, the REF relay will trip immediately upon loading the transformer. Ensure the secondary terminal box is oriented for easy access and sealed against moisture ingress.Neutral Bus-Work Fabrication:Labor Task: Fabrication of the copper/aluminium flat for the neutral-to-earth connection. All joints must be tinned and coated with conductive grease (e.g., Aluma-Shield) to prevent oxidation.Earth Pit Connection:Labor Task: Connection to two independent earth electrodes. Measured earth resistance must be <1 ohm.Control & Protection Wiring:Labor Task (Secondary/Relay Technicians): Routing of Class PS NCT secondary leads to the relay panel using 2.5 sq mm}2 copper armoured control cables.

S/I/T/C OF DATA INTERFACE 2: Mechanical & Wiring Handover Protocol From: Installation Testing & Commissioning Engineers Torque Logsheets: Confirming uniform gasket and bus-bar tensioning .As-Built Earthing Reports: Documenting the dual earth pit resistance values (<1.0 Ohm.Cable Continuity & Wire Map: Confirming the physical routing of the 2.5 sq mm 2 core shielded secondary leads with temporary polarity tags intact.Phase 3: Testing, Commissioning & Relay Coordination This phase covers the electrical validation parameters required to safely energize the system and ensure the protection relays function perfectly.Insulation Resistance & High Voltage Testing:Technical Meaning: Rated for 11kV system (Highest system voltage 12kV). The 12.8kV High Volt spec is the factory/site test voltage the insulation must withstand for 1 minute without breakdown.Labor Task: Perform an Insulation Resistance (IR) Test (Megger) at 5kV DC before connection. The value should ideally be in the Giga-ohm {G}Omega range.Ratio and Saturation Testing:Labor Task: Perform a Ratio Test using a primary injection kit. Inject 150A to verify a 0.5A output, ensuring the CT isn't "saturated" or incorrectly wound.Knee Point Voltage (V_K$) Calculation:Technical Meaning: VK > 40 (RCT + 8 Volts. This formula ensures the CT does not saturate during a heavy fault. The VK must be at least 40 times the total secondary loop resistance (where R_{CT} is the CT's internal resistance and 8 ohm is the allowed lead/relay resistance).Secondary Magnetization Curve Test:Labor Task: Apply voltage to the secondary terminals and confirm that a 10% increase in voltage does not result in more than a 50% increase in

current until at least 40 times the total resistance is reached.Excitation Current Verification:Technical Meaning: 30 mA at VK/2. This measures the "leakage" or magnetizing current. At half of the Knee Point Voltage, the CT should draw no more than 030 mA .Labor Task: High-sensitivity milliammeters must be used during the VK test to record this value. High excitation current indicates a faulty core or internal shorting, causing "nuisance tripping."REF/SBEF Loop Testing:Labor Task: Mandatory Primary Injection Test to verify the REF (Restricted Earth Fault) balance between the phase CTs and the NCT, ensuring zero spill current under normal conditions. Note: Verification of P1/P2 polarity and ensuring the secondary terminal box is oriented for easy access and sealed against moisture ingress. Neutral Bus-Work: Fabrication of the copper/aluminum flat for the neutral-to-earth connection. All joints must be tinned and coated with conductive grease (e.g., Aluma-Shield) to prevent oxidation. Earth Pit Connection: Connection to two independent earth electrodes. Measured earth resistance must be <1.0 Ω. Control & Protection Wiring (Secondary/Relay Technicians) REF/SBEF Circuitry: Routing of Class PS NCT secondary leads using 2.5 sq mm copper armoured control cables. CT Loop Testing: Mandatory Primary Injection Test to verify the REF (Restricted Earth Fault) balance between phase CTs and the NCT.

M & L for De-commissioning including Supply installation testing and commissioning of Installation & Mechanical Setup (Replacement)This phase covers the physical placement and structural handling of the new hardware based on the manufacturer's physical specifications. Battery Inspection & Unpacking: Unpack the 30 new 12V DC nominal voltage batteries. Verify that all terminals are the required F6 / Brass with lead coating type and free of defects. Flexible Orientation Positioning: Position the 30 new batteries into the existing rack or housing. Because these batteries utilize AGM (Absorbent Glass Mat) technology, they can be safely installed in any required orientation (vertical, horizontal, or sideways) without risk of electrolyte leakage. Series String Configuration: Mechanically link the 30 batteries in series to achieve the required cumulative DC voltage compatible with the existing Mystique & Joint Securing: Tighten all terminal connections securely to handle the high Short Circuit Current capability of 922 Amps and minimize contact resistance (matching the internal resistance specification of 8 mΩ fully charged @ 27°C).Part 3: Electrical Integration & Commissioning (SMPS Tuning)This final phase involves configuring the charging infrastructure to match the exact chemical and thermal operational requirements of the new AGM batteries to maximize their 2–3 year service life. Job for SMPS Charger Voltage Configuration: Program the parameters of the existing SMPS to align with the mandatory AGM charging profiles: Float Voltage: Set precisely to 13.5V per module (totaling 13.5{V} X 30 = 405V DCfor the string).Boost/Cycle Voltage: Set to 13.8V per module (totaling 13.8V x 30 = 414V DC for the string).Current Limiting: Adjust the SMPS maximum charging current limit so it does not exceed 25%

of the rated capacity (strictly capped at 10.5 Amps max) to avoid thermal runaway. Thermal Compensation Calibration: Connect and configure the SMPS temperature sensors to apply a compensation factor between -18mV to -20mV / °C to protect the cells during shifts within their 0°C to 45°C operating range.Testing & Logging: Measure the total open-circuit voltage of the series bank, initiate a baseline charging cycle from the SMPS, and log the initial internal resistance values to track the 3% monthly self-discharge rate baseline.

M & L for Retrofitting, Installation, and Commissioning of REF / Earth Fault Protection Relay safely dismantle the existing, unserviceable protection relay and execute the Supply, Installation, Testing, and Commissioning (S/I/T/C) of an advanced, flush-mounted, microprocessor-based Restricted Earth Fault (REF) / Directional Earth Fault Protection Relay. REF IR-protection relay comply with the IEC/DIN regulations required for the specific protection application. Plug-in technology & easy operation, quick fault-analysis and optimal communication capabilities are based on the microprocessor technology with following characteristics:Integration of multiple protective functions into one compact housing,User-friendly setting procedure by means of DIP-switches,Compact construction type by SMD~technology & also Complete suitable for earth fault directional detection with Rated data: Nominal current IN : 1A/5A Nominal frequency fN : 50/60 Hz Power consumption : 97% Returning time : 30 ms Minimum operating time : 30 ms Output relay characteristics: Maximum breaking capacity : 250 V AC / 1500 VA / continuous current 6 A Design standard : VDE 0435, part 303, IEC 255.4, BS 142 Specified ambient service Temperature range: for storage : - 40°C to + 85°C for operating : - 20°C to + 70°C Environmental protection class F as per DIN 40040 and per DIN IEC 68 2-3 : relative humidity 95 % at 40°C for 56 days Insulation test voltage, inputs and outputs between themselves and to the relay frame as per VDE 0435, part 303 IEC 255-5 : 5 kV; 1.2/50 Hz; 1 min. (except supply voltage inputs) Impulse test voltage, inputs and outputs between themselves and to the relay frame as per VDE 0435, part 303 IEC 255-5 : 5 kV; 1.2 / 50 μs; 0.5 J High frequency interference test voltage, inputs and outputs between

themselves and to the relay frame as per DIN IEC 255-6 : 2.5 kV / 1MHz Electrostatic discharge (ESD) test as per DIN VDE 0843, part 2 IEC 801-2 : 8 kV Electrostatic discharge (ESD) test as per DIN VDE 0843, part 4 IEC 801-4 : 4 kV / 2.5 kHz, 15 ms Radio interference suppression test as per EN 55011 : limit value class B Radio interference field test as per DIN DVE 0843, part 3 IEC 801-4 : electrical field strength 10 V/m Mechanical tests: Shock : class 1 acc. to DIN IEC 255-21-2 Vibration : class 1 acc. to DIN IEC 255-21-1 Degree of protection - front of relay : IP 54 by enclosure of the relay case and front panel (relay version D) Weight : approx. 1.5 kg Degree of pollution : 2 by using housing type A 3 by using housing type D Overvoltage class : III Influence variable values: Frequency influence : 40 Hz < f < 70 Hz:The new system must fully comply with relevant IEC, DIN, and VDE standards. Job to be carried out by Protection & Commissioning Engineer: Responsible for relay parameter configuration, programmatic validation, secondary injection testing, insulation/impulse test review, and directional feature verification. Senior Electrical Technician (Control Wiring Specialist): Responsible for safe de-termination of legacy panels, flush-mount mechanical modifications, and routing/termination of high-density secondary control wiring. Safety Officer: Responsible for implementing Lockout-Tagout (LOTO), verifying zero-energy states, issuing hot/cold work permits, and ensuring compliance with site safety protocols. The Safety Officer and Control Technician shall isolate the auxiliary AC/DC control supply and completely disconnect the current transformer (CT) secondary links via shorting terminal blocks to prevent open-circuit high-voltage transients. Dismantling: The Technician shall carefully disconnect all trailing wire harnesses from the old, unserviceable

protection relay. Unbolt the legacy unit and extract it from the switchgear panel door cutout. Inventory & Salvage: Hand over the unserviceable hardware to the Engineer-in-Charge along with a signed de-commissioning checklist. Mechanical Preparation: The Technician shall inspect the existing cutout. If required, the sheet metal door must be modified to accept the new flush-mounted compact housing enclosure Environmental Sealing: Ensure the installation preserves an IP54 Degree of Protection at the front panel by properly seating the factory-supplied enclosure gasket (Relay Version D) to block dust and moisture. Harness Routing: Securely mount the relay using its quick-fit plug-in technology chassis, ensuring minimal mechanical stress on terminal blocks. Integration & Wiring Architectur The Control Technician shall execute auxiliary power and CT secondary wiring in strict compliance with the following design rules: Dual-Core Functionality: Route primary directional earth fault sensing and REF inputs into the single compact housing. Terminal Terminations: Wire the output contacts ensuring they map cleanly to the master trip circuit breakers, meeting the maximum breaking capacity metrics: Maximum Breaking Capacity: 250 V AC 1500 VA Continuous Rated Current: 6 Amp Relay Performance & Technical Compliance Matrix The Protection Engineer must verify that the supplied solid-state microprocessor relay complies with the following physical, electrical, and international environmental metrics:

Job for Testing, Commissioning & Handover Protocols The Protection & Commissioning Engineer shall direct all pre-commissioning procedures and document them in an official test log for the Garrison Engineer's (GE) approval: On-Site Diagnostic Routine 1. Insulation Resistance (IR) Check: Prior to powering up the electronics, apply a calibrated 500V DC Megger between inputs, outputs, and the outer metal ground chassis to establish baseline insulation integrity. 2. Secondary Current Injection Test: Use a secondary injection kit to feed precise test currents 1A to 5 {A} into the secondary sensing circuits. Verify pick-up parameters, drop-off dynamics, and minimum operating times le 30 ms. 3. Directional Sensitivity Alignment: Validate proper polarity and angular alignment of the CT cross-connections to guarantee the directional earth fault module accurately discriminates between internal and external grid faults. 4. Trip Circuit Loop Test: Force an artificial trip command via the relay software to confirm that the output relay contacts 250 V AC 6 A cleanly actuate the trip coil of the circuit breaker. Final Document Deliverables Upon successful field tests, the contractor must supply: • As-built schematic drawings of the updated secondary panel wiring. • A certified test sheet displaying injected values versus actual relay response times. • A written workmanship and component warranty statement shall be addressed to the Garrison Engineer.