fac-2012-002 (genset)

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INTERPHIL LABORATORIES, INC.

Your Market Partner in Manufacturing

Engineering & Maintenance

Equipment Troubleshooting Report(Generator Set Equipment Breakdown)

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E&M-FAC-12-002

Problem Statement:

During load testing of Genset equipments last 12 May,

Facilities group encountered erratic fluctuation of output voltage

on Generator sets, it was then coordinated to Monark to secure

further check up of both units. Load testing undergone on 19

May to verify fault encountered.

In the course of check up, recorded parameters display

overshooting voltage output & ampere loading to both units

eventually prompting genset #02 to trip & influence Genset #01

cut its supply to demand load (power loss)

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Problem Statement:

Note:

Prior loading both genset

subject for 30 minute test

run @ no load phase

Phases changed after it

sequenced to automatic

(exciter) paralleling. Both

unit display surging

parameters

Load at LVSG panel wasonly 2400 Amps

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E&M-FAC-12-002

Actions Performed:

Monark initiate check up on the unit, they check AVR and

rotating diode on both units but found normal, they recommend

to do check up on Master control center to trace the fault.

Monark send 3rd

party assessor last 23 & 24 May to check thesynchronizing panel, they do synchronization @ no load / load

sequence and found out the grid has circulating harmonic

currentsthat triggers to bust components on genset #02 ,

these are the following;

Automatic Voltage Regulator

Surge supressor

kWhr displays

Droop Current Transformers

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Actions Performed:

Genset #01 check upwith Monark last 19 May Check up of Rotating Diode

Automatic Voltage Regulator

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E&M-FAC-12-002

Damaged Surge Suppressorand melted heat sink

Check up of Genset last 24 May 2012

Genset #02 Rotor ExciterAssembly

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7/14INTERPHIL LABORATORIES, INC. Your Market Partner in Manufacturing

E&M-FAC-12-002

Defective kWhr Display

Voltage Frequency Ampere

Run hour

kWhrDisplay

GENSET #01 MCCGENSET #02 MCC

Master Control Center

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E&M-FAC-12-002

Root Cause Analysis:

By categorizing equipment failure modes based on

encountered fault to genset units, potential areas are;

1. Frequency instability due to maladjustments or component malfunction

2. Output voltage distortion : AVR sensitivity

3. Frequency and voltage instability due to control loop compatibilityconditions

Concentrating from this potential mode, problem can be

identified substantially

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1. Frequency Instability due to maladjustments or componentmalfunction:

Based on visual observation frequency for both genset was stable during

on-load operation, though the engine is hunting. Frequency is steady at

60Hz

Frequency range should not more than 0.5% during paralleling

No adjustment activity was made on the control center during tests

therefore leaving no part of component on the inside panels can contribute

to malfunction.

Frequency Instability would not be a cause

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2. Output voltage distortion : AVR sensitivity (heating effects)

AVR is used to monitor and output voltage and control the field strength of

the machine to maintain a constant voltage on output of generator set

under varying steady state load conditions

The group encountered overshooting of voltage during on load state voltage dips

from 500V to 515V

Loss of Voltage signal was encountered on Genset #01 last 19 May, but upon

check up AVR is found normal. It was also confirmed by 3rd party assessor that

AVR for #01 is OK.

In the case of Genset #02, AVR might already damaged due to circulating

current found on its grid. Unstable resultant voltage

AVR on both units was not yet replaced during the course of acquisition ofthis equipments. Genset #02 has history of breakdown due to reverse

loading. No reports concluded AVR on #02 was replaced during its

breakdown.

Breakdown of AVR on Genset could be a factor of the cause

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3. Frequency and voltage instability due to control loopcompatibility conditions

Deviation on the panel metering on the control center is reported on last

inspection and trouble shooting. Display on ammeter of genset #02 picked

up above its operating limit (2000 A).

Upon check up rectifying diode and suppressor already damaged, Droop

CT might also affected due to circulating currents. Circulating current is

damageable to components if paralleling generators was serviced not

matched to their intended parameters.

Damage on the components was attributed to circulatingcurrents, it may presume that the generator was shedded notparallel on its limits

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Cause of trouble can now be streamlined to 2 major causes;

1. Malfunctioned AVR resulting to distortion on its insidesystem.

2. Paralleling of both units was not attained while on loadmode due to deviations on the metering system resultingto uncontrolled circulating currents damaging rectifierdiode and its suppressor.

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Recommendations;

Replace listed defective comnponents of Genset #02

- AVR, diode and suppressor

Replace defective panel display to avoid misguided readings.

Continue Planned PMS of units and ensure bi-weekly testruns to conform integrity of operation of generator setsystem

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Thank You

Prepared By: Mark C. Centeno

fac-2012-002 (genset)

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