Protective Relay Maintenance — Traction Distribution Notes

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Each electrified division has specialist staff attached to the Central Repair Shop, specifically trained in relay and instrument maintenance/overhaul/testing/calibration. This isn't generic training — such staff must hold Competency Certificate TR-7, the same certificate this subject's Training & Competency Certificates chapter identified as the ONLY one requiring a full three-part (written, oral, practical) test.

The Real Relay Register

Each Supervisor responsible for relay maintenance/testing must maintain a register recording, per relay: type and serial number, PT and CT ratios, range of settings available, characteristic curves (where applicable), installation location, schematic connection diagram, normal settings, and the calculations behind fixing that normal setting — plus all subsequent test/repair records. Identical particulars must ALSO be maintained in the Sr.DEE(TrD) office, not just at the local level.

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Exam Focus — Two Different Approval Levels

No alteration to a protective relay's settings may be made without Sr.DEE(TrD)'s WRITTEN authorization. But if the change itself is significant, Sr.DEE(TrD) must submit proposals with detailed calculations for CEE's PRIOR APPROVAL — a two-tier chain (Sr.DEE authorizes routine changes; CEE approves the underlying proposal for anything requiring recalculation) that's easy to collapse into a single authority in error.

Real Maintenance Attention Schedule

What Actually Needs Doing, and When

Cover gaskets/fixing screws: ensure good condition and tightness so the instrument stays dust-tight — an ongoing check, not scheduled annually.
Manual operation trip-circuit confirmation: must be carried out by AT LEAST AEE level, ONCE A YEAR, for ALL relays — with simultaneous visual checks on relay connections, trip battery condition, trip/alarm circuits, and a maintained record of the date/time this was done.
Distance protection relay: may be calibration-tested ONCE A YEAR using a primary injection set.
Secondary injection tests: done ANNUALLY, preferably BEFORE the onset of the busy season, using portable testing equipment at competent-authority-approved settings — testing not just the normal setting, but ALSO other settings to confirm the relay retains its required characteristic across the range.

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Important — Seal-Breaking Must Be Logged

Every occasion a relay's seal is broken subsequently, the reasons must be recorded in the log book — this isn't optional documentation, it's how a genuinely unauthorised tampering event gets distinguished from legitimate maintenance access after the fact.