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Safe Work Method Of Statement For Testing and Commissioning of Diesel Generators


The purpose of this method statement is to define the testing and commissioning procedure of the Diesel Generators within the project.

This includes pre-commissioning checks, commissioning tests and system interface tests.


The scope of this method statement is to define the system checks, type and duration of testing that will be required to test standby generator sets to bring it into a fully working and approved mode of operation.

System Description

There is one generator which will provide power to the emergency and life safety systems in the event of a mains failure.

Location Gen Set Model plant No. Plant Capacity Engine Make Engine Type Alternator Make Alternator Type


After successful commissioning of Diesel Generator as a standalone piece of equipment, it will be interfaced with the ATS panel located within the LV Main Distribution Board and tested for its Auto operation, by simulating a Mains power failure.

BMS interface to be done though RS 485 Generator panel.

Tools Equipments and Calibration

Load Bank :

1) 1 x 1145kVA; 400V, 50Hz 0.80pf reactive load bank.2) 6L of 20m x 240mm² / 1C LV power cable including earth and neutral cable.3) 1 x HHT100 c/w 10m lead.



Testing and commissioning will to be done according to the following codes & standards:

Definitions and Abbreviations

The following definitions and abbreviations will be used throughout this document;

Client                                 :

Consultant                        :

Contractor                        :


HCT                           :    High Coolant Temperature

HOT                           :    High Oil Temperature

LOP                            :    Low Oil Pressure

AMF                           :    Auto Mains Fail

ATS                            :    Automatic Transfer Switch

AC                              :    Alternating Current

DC                              :    Direct Current

Manufacturing / Installation Handover

Installation work should be complete by MEP contractor and ready for commissioning.  All installation checks must be carried out and approved by the relevant parties.

Furthermore the generator room must also be sufficiently completed to facilitate successful and accurate testing and commissioning to be achieved i.e. completion of construction work etc.

Pre – Commissioning Phase

The following pre – commissioning checks will be made to each generator:

a)   All connections are tight and leak proof, including cabling to auxiliary terminal box. Physically checked and tighten.
b)   All protective coverings used in packing are removed. Physically check.
c)   Check the fuel, lubricating oil and coolant levels are adequate; top up if necessary Coolant and oil will be filled at site. Fuel will be supplied by contractor.
d)  Charge battery and connect to unit Batteries are dry charged; they will be filled with electrolyte at site.
e)   Check alternator connections. Physically check.
f)    Check fuses are in holder (if exists). Physically check.
g)   Isolate circuit breaker from load. Switch off circuit breaker.
h)   Make sure the generator operating switch in the off position. Physically check.

All the above data will be recorded on our check sheets which are contained within section 8.3.

Safety Cones and Warning tape will be placed around Generator room and warning sign board will be kept to indicate unauthorized personals not to enter in the area.

During start up and testing Generator, sound level of about 120db will be observed so ear protection  head  sets  will be worn by each one.

Commissioning Phase

Commissioning Procedure / Commissioning Strategy

Commissioning will be carried out as per below sections I, II, III and applicable electrical specifications. All test formats shall be in commissioning agent’s approved format.

  1. Commissioning Checks:
a)   Check the exhaust flow is not obstructed or damaged in order to avoid harmful fumes. Visual Check
b)   Check that the ventilation system is not obstructed. Visual Check
c)   Connect the Battery Cables to the Generating Set. Connect battery cable to starter Motor and batteries.
d)  Check if the Generator is IN RUNNING Status. Test run
e)   Run Generator for 5 minutes without load and Record the following:
·      Oil Temperature : …………………………… Degree0 C.
·      Engine Temperature : …………………………… Degree0 C.
·      Oil Pressure : …………………………….. Bar/Psi
·      Engine Speed : …………………………….. RPM
·      Output Voltage :……………………………. Vac
·      Output Frequency : ……………………………. Hz.
·      Phase Rotation : …………………………….
·      Function of all Instrument : ……………………………

Before commencing load test demonstrate following operations shutdown devices and Alarms.

1)      Fail to Start (Over Crank) Starter motor solenoid wire will be removed.
2)      Emergency Stop Press emergency while engine running.
3)      Auto Start Short Remote start terminals.
4)      Over Speed Reduce set point below actual speed.
5)      High Engine Temperature  Ground sensing terminal
6)      High Oil Temperature Ground sensing terminal
7)      Low Oil Pressure Ground sensing terminal
8)      Alternator Under/Over Voltage Increase / decrease voltage on AVR.
9)      Battery  volt  low Increase set point above actual voltage.
10)  High winding temperature Open circuit  Temperature sensor wiring
11)  Radiator Low coolant level Drain coolant below switch level

All above will be recorded in our standard format attached herewith.

Performance Test ( Load Test)

Standard performance testing is a test to ensure that a generator set will give the required 100% output at specified voltage and frequency.

Interface load bank to generator

Load bank and cables will be brought to site in a truck offloaded and placed approximately 20 Mtrs away from Generator.

Temporary flexible cables will be supplied and terminated by Site technology co. and   laid above the ground with warning signs around and will be terminated to the bus bar’s  of  load bank terminal  and generator output ACB terminals with bolt & nut as follows;

Cable combination

  1. 1145kVA Reactive load bank = 1c x 240 mm x 2 runs per Ph. +1run neutral + 1 run for earth.
  2. Start the set and adjust voltage and speed to required value.
  3. Check that all the control equipment meets the functional requirement of the built
  4. Apply 50% rated load and record all parameters.
  5. Add 25% of rated load to achieve 75% of load and record all parameters in the format.
  6. Add 25% load to achieve 100% of rated load and record all parameters in the format.
  7. At 100% load run the set for 7 hours and checked every 30 minutes to see that the engine normal operating temperature range, oil pressure drop are not exceeded.
  8. Add 10% over load and run set for one (1) hour. Record all parameters every 15 minutes.
  9. Remove rated load and allow the set to stabilize for 5 minutes.
  10. Check the set for Oil leak, coolant leak and any loose items.
  11. Shutdown the set.
  12. Disconnect temporary load cables role it back, load on truck cables and load bank and Shift it to ST Store.

In addition to above, below requirements shall be complied as mentioned in the electrical specification.

With 100% rated load, operate set for seven (7) hours continuously and without interruption at 50 deg. C ambient, taking readings at thirty (30) minute intervals, and record following:

At end of seven (7) hour run increase the load to 110% of the rated value, and take readings every fifteen (15) minutes during one hour of operation.

Before commencing eight (8) hour run, demonstrate following shut down devices and alarms:

Next, install continuous strip chart recorders to record frequency and voltage variations during load switching procedures, with chart speed of 1.3mm/s.

Each load change delayed until steady state conditions exist. Switching increments to include:

Demonstrate (as specified):

Generator control panel shall be tested as follows for each section.


The Contractor shall record noise levels:

Vibration Mounting

Machinery shall be statically and dynamically balanced and shall be isolated from acoustic enclosure as required.

All tests specified here in before shall be repeated on site upon installation of generator set and associated equipment in the presence of the Employer and the Engineer.

Interface Test Procedures

System Demonstration

On completion of commissioning system, operation will be demonstrated to client engineers & other related authority.

Commissioning Documentation

After completion of commissioning, all test certificates of pre- commissioning, Commissioning, Performance test/ load test, will be submitted in hard copy.


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