What is the Checklist for HV & EHV Protection Control and Relay Panel for Pre Dispatch Inspection ?

Electrical HV & EHV (100 kV and 220 kV) protection control panel pre dispatch inspection checklist. Quality checks including a test checklist in text or PDF file. Download now!

Q1: What is the purpose of a pre dispatch inspection for HV and EHV control and relay panels?

A:
The purpose of a pre dispatch inspection is to verify that control and relay panels meet all technical, safety, and quality requirements before they leave the factory. This ensures that panels are free from defects, comply with project specifications, and are ready for trouble-free installation and commissioning at site. It also minimizes costly site corrections and enhances operational reliability.

Q2: Which documents required before starting the inspection?

A:
Before inspection, gather and review these essential documents:

• Approved Drawings: Includes general arrangement, wiring, and schematic diagrams.
• Factory Acceptance Test (FAT) Reports: Evidence of completed functional and routine tests.
• Bill of Materials (BOM): To cross-verify all components.
• Quality Assurance/Quality Control (QA/QC) Checklists: For compliance tracking.
• Factory Location and Contact Person Details: For communication and documentation.

Q3: What are the key steps in the visual inspection of HV/EHV panels?

A:
Visual inspection covers the following:

• Dimensions: Confirm the panel’s size matches approved drawings.
• Component Layout: Check that all equipment is arranged as per the general arrangement drawing.
• Wiring:
• Wire Size & Type:
  • CT, PT & Earth Circuits: 2.5 sq. mm flexible stranded copper, PVC insulated (1.1 kV).
  • Other Circuits: 1.5 sq. mm flexible stranded copper, PVC insulated (1.1 kV).
• Color Coding: Ensure CT & PT circuit wires are color-coded as per standards.
• Labeling: All wires, terminals, and devices must be clearly labeled.
• Bill of Materials Verification: Cross-check that all components are present and correctly installed.
• Earthing: Ensure proper earthing and bonding of panels and doors.
• Panel Finish: Inspect paint quality, panel cleanliness, and absence of rust or sharp edges.

Q4: What functional (working) tests should be conducted during pre dispatch inspection?

A:
Key functional tests include:

• Relay Contact Operation: Test all auxiliary and numerical relay contacts for correct operation.
• Scheme Verification: Apply DC supply to check the entire control and protection scheme.
• Power Supply Check: Ensure the power supply rating for numerical relays matches substation supply.
• Relay Testing:
• Test numerical relays, trip relays, and DC supervision relays for correct response.
• Verify annunciator operation for all alarm and trip conditions.
• Interlocking & Logic: Confirm interlocks and logic circuits function as per design.
• Simulation: Simulate fault conditions to verify relay and trip circuit operation.
• Metering and Indication: Check meters, indicators, and mimic diagrams for accuracy and illumination.
• Cable Terminations: Inspect tightness and quality of all cable terminations and lugs.
• Panel Door Operation: Ensure smooth opening/closing and proper gasket sealing.

Q5: What are some additional requirements?

A:

• Push Button Test: Ensure carrier send test push button is installed and operational where needed.
• Spare Parts & Accessories: Ensure all specified spares and accessories are included and listed.

Q6: Who should be present during the inspection?

A:

• Factory QA/QC Engineer
• Client/Consultant Representative
• Project Manager or Site Engineer (optional)
• Panel Manufacturer’s Engineer

Their joint sign-off ensures transparency and acceptance.

Q7: What are common issues found during HV/EHV control and relay panel pre dispatch inspection (100 kV & 220 kV)?

A:

• Wiring Problems: Wrong wire size, loose terminations, missing color coding, or poor labeling.
• Component Issues: Missing or misplaced relays/meters, faulty auxiliary relays, incomplete earthing.
• Documentation Errors: Outdated or missing drawings, incomplete FAT reports, BOM mismatches.
• Functional Failures: Relays or annunciators not operating as per scheme, incorrect relay settings, non-functional interlocks.
• Panel Construction Flaws: Poor door sealing (IP rating), sharp edges, rust, inadequate cable clearances.
• Accessories Missing: Required push buttons, test switches, or spares not provided.

Q8: Which standards are relevant for 100 kV & 220 kV control and relay panel inspection?

A:

• IEC 60255: Protection relays and testing.
• IEC 62271-200: High-voltage switchgear and controlgear.
• IEC 61850: Substation communication protocols.
• IEC 60529: IP (Ingress Protection) rating for panels.
• IS 3231: Indian standard for protective relays.
• IS 8623: Indian standard for switchgear assemblies above 1 kV.

Summary Table: Key Points for Pre Dispatch Inspection