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IEEE 1584 · Engineering

Leading Relay Coordination Study for Industries in the Philippines

Assess the relay configurations and protection coordination utilizing Care Labs’ established solutions. Capitalize on our proficiency in enhancing your power systems. Carelabs models your facility's one-line diagram in ETAP and verifies every relay and breaker setting against manufacturer data before recommending a change.

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Recovering cleanly after the supply returns

Interruptions are a fact of operation on many Philippine sites. What separates a short stoppage from a long one is whether protection discriminates on restoration and whether the plant can restart in a controlled sequence.

What We Deliver

Grading verified across every path

Time-current curves are checked from final circuit to incomer with margins calculated against real device operating times, so a fault on one circuit is cleared locally instead of taking the incomer.

WHY IT MATTERS

The outage ends and the plant will not restart

Supply returns, everything energises at once, and protection operates on combined inrush. The site then restarts in pieces by trial and error, extending an interruption that the network had already ended.

  • Settings read directly from each relay and trip unit, because the device and the settings schedule frequently disagree after years of adjustment.
  • Transformer and motor inrush assessed together, since simultaneous energisation produces a condition no individual circuit calculation reveals.
  • Grading verified on utility and generator supply separately, as the two present very different fault current behaviour.
  • Undervoltage and under-frequency settings checked, so protection intended to shed load does not instead prevent a legitimate restart.
  • Every recommended change reported with its arc flash consequence, because faster clearing reduces energy and longer grading margins raise it.
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DELIVERABLES

What you receive

Issued against the Philippine Electrical Code and signed by the engineer who carried out the grading.

  1. 1As-found settings register covering every relay and adjustable trip unit
  2. 2Time-current curves per grading path with the achieved margin annotated
  3. 3Discrimination register naming each failing pair and the fault range where it fails
  4. 4An assessed restoration sequence where simultaneous restart is not achievable
  5. 5Recommended settings in the entry format your devices use, with a verification checklist
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How the study runs

01

Audit the installed protection

Settings are read from every device and CT ratios, polarity and burden are verified against the schematics rather than assumed correct.

02

Establish fault levels

Grading depends on fault current at each position, so a verified short circuit basis is established from an existing study or within this scope.

03

Model devices and loads

Manufacturer characteristics are built for every installed device, and transformer and motor inrush behaviour is modelled for the restoration case.

04

Grade and test restoration

Margins are calculated across the fault range, and the simultaneous re-energisation case is simulated to establish whether the plant recovers.

05

Sequence where needed

Where restoration fails, a staggered restart sequence is developed and demonstrated on the model rather than discovered during the next outage.

06

Issue and verify

Settings and the restart sequence are issued with a verification checklist so applied values can be proven against the approved schedule.

Frequently asked questions

Because everything energises simultaneously. Transformer magnetising inrush and motor starting current arrive together, producing a combined current far above normal load that can operate protection which grades perfectly well in service. It is a restoration condition rather than a fault, and it is assessed separately from ordinary grading.
Frequently yes, through staged reclosing or control system sequencing. The study establishes what can energise together and in what order, which is the necessary input either way. Automating a sequence that has not been analysed simply makes an unreliable restart happen faster.
Substantially. A generator's fault contribution decays within seconds, so current available to operate a downstream device late in a fault can fall below its pick-up. Grading correct on utility supply may leave a fault uncleared on generator, which is why the two cases are assessed separately.
Reading settings and verifying CTs is generally done with the plant running, and the analysis is offline. An outage is needed only where settings must be applied to devices that cannot be changed live, or where injection testing is in scope. Any requirement is agreed before mobilising.

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