Testing and Commissioning of Diesel Generator Set - qaqcconstruction.com (2023)

Testing and commissioning of the diesel generator set in compliance with the specified tolerance and limitations outlined with industrial standards, guidelines with reference to the project specification, manufacturer’s instructions, and authority requirements.

The entire Testing and Commissioning of Diesel Generator Set shall be performed by the supplier’s specialist/third party-experienced engineer.


The purpose of this method statement is to outline the method of testing and commissioning of the following:

  • Diesel Engine and Auxiliaries
  • Generator/Alternator
  • Instrumentation/Control
  • Fuel Storage and Transfer
  • Air intake and Exhaust System

Specialist supplier/third-party team, an experienced commissioning engineer will thoroughly inspect all the working drawings and specification, and become totally familiar with all systems and the design intent.

Application Location

Diesel Generator Room

General Requirements

Specialist Equipment & Liaison

An engineer available to liaise with the manufacturers commissioning engineers and assist with checking pressure rates setpoints etc. as necessary.

Items of equipment to be commissioned by specialists include, but are not limited to the following:
The diesel generator set and support system.


Before commencing commissioning works, the following information/items will be made available.

Full set of up-to-date installation drawings and system schematics detailing all systems to be commissioned.

Capacity and schedule.

Commissioning, operating and maintenance instruction’s equipment.

Any special operating keys, tools, etc.

Access to all areas; plant etc. through doors, risers, false ceilings, etc.

Safety Precautions

Safety awareness should be followed during the execution of testing & commissioning works.

Secure Work Permit in conjunction with the approved safety plan and Risk Assessment before Starting the work.

Usage of proper tools, instrument to be handled by the authorized person only.

Usage of proper safety shoes, safety belts, safety helmets, gloves, goggles, mask, earplugs & any other safety accessories as required during commissioning works.

Guards of approved design shall be provided for all V-belts drives, coupling shafts and exposed rotating machinery.

Electrical power supply shall be isolated and panel switch gear shall be locked whenever carrying out work on any rotating equipment or electrical panels.

No commissioning works shall be carried out without adequate lighting available.

Approved Project Safety Plan & procedures shall be followed during execution of commissioning works.

Provide Warning Boards/ Tapes as required during Testing & Commissioning of Diesel Generator Set.

Preliminary Checks

State of the Building and System

  • Equipment installations as per approved layout and site requirements
  • Fuel supply connected and commissioned by infrastructural.
  • All panel termination fixed and ready for Commissioning.
  • Access available to all areas to be tested.


Diesel Generator Set-

  • Diesel Engine and Auxiliaries
  • Generator/ Alternator
  • Instrumentation/ Control
  • Fuel Storage and Transfer
  • Air intake and Exhaust System

Pre-Commissioning – Checks

Building & Services

• Building & Installation of main equipment as per approved drawing/ submittal. The site is clean from all/ any construction materials and debris.
• All necessary Building services are installed, commissioned, and in operation.
• Lighting/ Emergency lighting
• Electrical auxiliary supplies
• Water/Drainage

Generator Room – General

• Generator set is clean with all guards in place as approved drawing.
• Ensure there are no loose materials left around the diesel generator set.
Air ducts are clean and the path is clear with no obstruction.
• Control & maintenance positions are clear with no obstruction.
• Room is secured for “NO UNAUTHORIZED” access.

Generator Set

• Ensure the diesel generator set installed at the proper level as required/approved.
• All pipe works are installed and secured in place.
• Radiator is clean from dust and free from obstruction.
• Radiator air outlet connected to outlet duct properly.
• Check for any hot air re-circulation.
• Ensure the radiator top is accessible for coolant top-up.
• Pipework is complete and no damage.

Fuel Storage – Day Tank

• Tank installation done as per approved drawing/ specification.
• Ensure fuel inlet/return line is connected.
• Check for no valve in spill return
• Flexible connections to engine is well connected and no damage.
• Connections for fill, overflow and vent is completed.
• Tank content indicator gauge installed and clear.

Exhaust System

• Installation done as per approved drawing/ specification.
• Ensure no re-circulation of exhaust fumes
• Flexible connection to the engine connected and secured
• Ensure for enough support to prevent load on turbo-charger manifold
• Pipe work/ muffler supported well in right interval
• All pipe joints are welded/flange connect with proper gaskets. Exhaust exit directed away from the building/ personnel.
• Pipe network is lagged/ clad as required.
• All flammable materials are protected properly.

Ventilation & Attenuations

• Installation done as per approved drawing/ specification.
• Ensure air intake is at least I 50% area of inlet.
• Ensure the airflow direction is from alternator to radiator.
• Ensure the radiator outlet is ducted to louver.
• Installation must prevent hot air recirculation & rain ingress.

Electrical System General

• Installation done as per approved drawing/ specification.
• Auxiliary electrical supply customer wiring/ termination are completed.
• Grounding/ earthing system complete and tested.
• Utility power supply available as required.
• All small power & lighting circuits tested and complete.

Instrumentation/ Control

• Installation done as per approved drawing/ specification.
• All customer wiring terminations are completed.
• Field device & wiring is complete with termination.
• Interconnection to remote start is complete.
• Emergency stop controls wired and complete.

Switch Gear/ Change Over/ Transfer

• All switch gear installation done as per approved drawing/ specification. Ensure all cables installed, terminated and complete.
• All power connections complete with torque check.
• Voltage and phase rotation checked and ensure proper.
• Ensure all indications are correct and healthy.

Testing and Commissioning- Diesel Engine Start Up

Safety checks prior to start-up.
Ensure starting is inhibited.
Diesel generator set is clean and fully assembled.
Battery status is healthy and proper voltage is available.
Ensure the battery charger is in operational and charging.
No loose materials around generator set.
Controls and maintenance are unobstructed.
Warn personnel of impending equipment start up.
Initial start up.
Manual start up, idle run check.
Run in full speed check.
After completing speed checks set for rated speed.
Setting of desired voltage & frequency.
Check oil level, pressure, and temperature.
Ensure the radiator operation and any leakage of coolant.
Fuel supply is proper and no leakage.
Ensure exhaust system operation and smoke status.
Control calibrations checked.
Phase rotation checked.
Local stop/emergency & stop control checked.
Remote start/stop & emergency stop checked.
Load test performed.
Now generator can be checked with load available at site.
Variable load as per requirements.
Record the relevant readings during the load test.

Automatic Operation

Open the reference power supply to the startup panel and ensure the diesel generator set getting ON in stipulated time.
After successful automatic turn ON, now restore the reference power supply back to normal position.
Now ensure the diesel generator set goes OFF in the stipulated time delay set.
Ensure the proper transfer of power supply in switch gear as per electro-mechanical logic interlocks provided.
Record all relevant reading and indications in the commissioning format.
Ensure compliance to all manufacturer’s start-up and commissioning instructions, as applicable.

Witness Demonstrations/Completion

The commissioning engineer will ensure that the following works are carried out.

The final test and results are demonstrated to the accepting authority on a random spot check basis, and that repeatability.

All equipment final settings are permanently marked, speed gauge indicators, radiator/engine head hot water temperature using an agreed method.

Submittal of all records of data obtained during testing, in accordance with, and on the approved forms.

Preparation of test report and hand over certificated and duly signed by the main contractor and consultant.

Noise level acceptance test shall be carried out to meet requirements as specified.

Test Instrumentation

The following test instruments will be used for the commissioning and testing activities. These will be selected as having the maximum field measuring accuracy and being the best suited to the function being measured and will be applied as recommended by the manufacturer.

List of Instruments

The list of instruments that are used in the Testing and Commissioning of the Diesel Generator system.

Electrical Measurement

1Tong Tester (Analog)To measure current, voltage and Resistance
2Tong Tester (Digital)To measure current, voltage and Resistance
3MeggerTo measure the insulation resistance of cables, winding
4Phase DetectorTo check the sequence of phases
5Electrical Tool Kit

Mechanical Measurement

1IR ThermometerTo measure space temperature

Calibration Frequency

All the instruments are calibrated externally once in 12 months or as per the recommendation of the manufacturer whichever comes earlier and the records are maintained.

All are used under their allowable ranges and limits.

All equipment is stored in the service station under suitable environmental conditions when they are not in use and verified their accuracy at regular intervals.

Prior to the commencement of Testing & Commissioning activities, Test Certificates of all instruments will be submitted for Consultant approval.

Certificates will be available for presentation prior to the commencement of the works.

Commissioning and Standards Implemented

NFPA standards, guidelines with reference to project specification and manufacturer’s instructions.


Inspection request shall be raised promptly to Consultant m accordance with the approved documents.

Inspection shall be carried out as per approved documents.

Inspection shall be recorded in the approved checklist.

Reference Documentation

Manufacturer’s catalog

Approved submittal

Shop drawings

Safety Manual

Risk Assessment


Prepare as-built drawings where necessary to allow the client to amend his own drawings.

All the test results shall be recorded and the inspection request, ITP, and the forms used shall be signed by both the contractor and Consultant.

All permits shall be signed off and returned.

The Certificates for the completion of work shall be submitted to engineers for records.

Signed-off Pre-commissioning Checklists.

Commissioning Reports.

Calibration certificates of testing instruments.

Hand Over Certificate


Testing and Commissioning (T & C) Report

Inspection and Test Plan (ITP)

Risk Assessment


What is generator commissioning? ›

In the simplest of terms, Diesel generator Commissioning is the process of installing your Diesel generator. Kind of like getting someone to put in your new washing machine at home.

What are the 3 major components of a diesel generator? ›

The main components of a diesel generator are: Diesel Engine. AC Alternator. Base frame, usually with a tank.

How often should a diesel generator be tested? ›

We recommend load bank testing at least once a year to ensure reliable performance during power outages. When running a load bank test, the electrical load is increased to full capacity, which allows the generator to really stretch its legs.

What is the maintenance of diesel generator? ›

Preventive maintenance should include a regular general inspection that includes checking the coolant level, oil level, fuel system, and starting system. The charge-air cooler piping and hoses should be inspected regularly for leaks, holes, cracks,dirt and debris that may be blocking the fins or loose connections.

What is a commissioning checklist? ›

A commissioning checklist is used to ensure the safety and functionality of new or modified systems in a facility. Efficiently validate the performance of HVAC, pumping, piping, and lighting systems using this comprehensive checklist.

What is a generator load test? ›

A generator load test checks how a generator handles specific load situations by using a load bank. A load bank is a tool that can simulate electrical loads. The load test helps ensure that the generator can perform throughout its entire operating range without issues.

What is DG working principle? ›

Diesel generators convert some of the chemical energy, contained by the diesel fuel, to mechanical energy through combustion. This mechanical energy then rotates a crank to produce electricity. Electric charges are induced in the wire by moving it through a magnetic field.

How long should a generator test run? ›

How Long Does a Generator Test Last? While 30 minutes is the industry standard, the appropriate duration of a power generation test can depend on several factors. For instance, load tests typically last longer than when exercising under no-load conditions.

What is a 4 hour load bank test? ›

A 3-year 4-hour test is required where the load is a connected load from the facility and must reach a minimum of 30%. A supplemental load may be used if the connected load cannot reach 30%, but that is not the case for you.

How many hours should a diesel generator run? ›

On average, a standby generator can run for up to 3,000 hours powering a medium-sized home, though it is recommended you do not run a generator for longer than 500 hours continuously.

What is ABC check in DG? ›

1) A-check is done on daily basis here we check: a) oil level b) coolant level c) gauge valve level d) check for any leakage. e) cleanliness of DG set. 2) B-check(done after 300hrs of cycle or 6 months whichever is earlier. )

How do you maintain a generator set? ›

Check for leaks at all connections, welds, gaskets and joints, and make sure that the exhaust pipes are not heating surrounding areas excessively. Repair any leaks immediately. Fuel system: With the generator set operating, inspect the fuel supply lines, return lines, filters and fittings for cracks or abrasions.

What is safety of DG set? ›

Transport the fuel in safe and closed containers to prevent accidents. Do not place flammable materials near the generator. Finally, ensure not to smoke cigarettes or light matchsticks near the generator. Diesel or LPG vapours might just be hanging around to cause a disaster.

What is testing and commissioning procedure? ›

Testing and Commissioning is a quality-oriented process for achieving, verifying, and documenting that the performance of facilities, systems, and assemblies meets defined objectives and criteria. It is an all-inclusive process consisting: Planning.

What is the commissioning process? ›

Commissioning is the process of planning, documenting, scheduling, testing, adjusting, verifying, and training, to provide a facility that operates as a fully functional system per the Owner's Project Requirements.

What are the types of generator testing? ›

Offline Mode
  • Visual Inspection Of Stator And Rotor.
  • Endoscopic Inspection.
  • EL-CID Test On Stator Core.
  • Wedge Tapping Test Or Wedge Deflection Test.
  • Capacitance And Tan Delta Test.
  • Dielectric Discharge Test.
  • Partial Discharge Test.
  • I.R./P.I. Measurement.

How do you test generator output? ›

Electrical Output Testing Procedure - YouTube

How is generator output measured? ›

The accepted formula is Watts = Volts X Amps. Therefore, when you purchase a 5kW generator delivering 120 Volts, it can give you an output of 41.67 amps. Similarly, you have dual voltage generators that can provide an output of 120 Volts as well as 240 Volts.

What is the minimum load ratio for diesel generator? ›

For diesel generator sets, Caterpillar recom. mends loading the generator set to a minimum of 30 percent load for approximately 30 minutes for every four hours of light load operation.

Is diesel generator AC or DC? ›

The diesel generator is coupled to the AC–bar of the system (AC–generator). As the maximum load demand (14 kW) is smaller than the nominal power of the diesel generator (25 kW) it always runs at part load.

Why DG set rating in KVA? ›

If we connect inductive or capacitive load (When power factor is not at least unity), The output would differ as there are losses due to low power factor. For this reason, KVA is an apparent power which does not take into account the PF (Power factor) instead of KW (Real Power).

What is the power factor of DG? ›

Most of DG manufacturers mention0. 8 as the rated power factor of DG. But it doesn't mean that DG must be operated at 0.8 power factor at all the time, rather it is the minimum limit on the power factor of the load which can be served by it without affecting its performance in the long run.

What is DG efficiency? ›

What is DG Efficiency. Fuel is the major portion of diesel Genset, owning and operating cost for power applications. Modern diesel plant, at its near-optimal loading ( 65- 70%) generate 3.3 to 3.5 kWh per litre. That is a 30% fuel efficiency ratio.

How many parts are in a diesel generator? ›

However, there are three parts of a generator that are common to all diesel units – the engine, AC alternator and radiator. Diesel fuel powers the engine of the generator, enabling it to turn a spindle at high velocity.

What is the function of alternator in diesel generator? ›

The alternator within your diesel generator is responsible for converting the mechanical energy of the engine into electrical energy that is used to power your business. Therefore, it's an incredibly important element of your generator.

How many parts are in a diesel generator? ›

However, there are three parts of a generator that are common to all diesel units – the engine, AC alternator and radiator. Diesel fuel powers the engine of the generator, enabling it to turn a spindle at high velocity.

What are the 8 main parts of diesel engine? ›

A medium or high speed diesel engine has such components and parts as engine body, crankshaft, connecting rod, piston, cylinder liner, heat exchanger, cylinder cover, high-pressure fuel pipe and alarm, connecting rod bolt, supercharger, fuel injection pump assembly.

What are the parts of generator and their function? ›

The stator is a stationary part containing a set of coils that conduct electricity. The rotor moves to create a constantly rotating electromagnetic field around the stator. The alternator generates electrical voltage. The generator must regulate the voltage to produce a constant current suitable for practical use.

What are the essential parts of the generator operation? ›

Main components of the generator
  • The main components of a generator can be broadly classified as follows. - engine. ...
  • Engine. The engine is the source of the mechanical energy that is fed to the generator. ...
  • Alternator. ...
  • Fuel system. ...
  • Voltage regulator. ...
  • Cooling and exhaust systems. ...
  • Exhaust fumes. ...
  • Lubrication system.

What is the function of actuator in diesel generator? ›

The actuator is controlled either by a mechanical governor or an ECU / ECM. When you apply load to a diesel engine, the actuator reacts by allowing more fuel into the engine, to try to maintain its speed. When you remove load, the actuator restricts the fuel, again to maintain the speed.

How many types of DG are there? ›

There are three main types of generators: portable, inverter and standby.

What are the 5 components of a diesel fuel system? ›

A basic diesel fuel system is made up of five essential components. These are the tank, the fuel transfer pump, filters, the injection pump, and the injection nozzles. The fuel tanks in diesel systems are typically crafted from aluminum alloys or sheet metal.

What are 4 major components of a diesel engine? ›

The components of a diesel engine include pumps, mechanical pumps, high pressure pumps and common rail technology.

What is the most important part of a diesel engine? ›

Fuel Injectors

They need a fuel and air mixture to start, as well as a tremendous amount of heat. For this reason, fuel injectors are one of the most important parts of a diesel engine. These components release diesel gas into the combustion chamber where it mixes with air, and the ignition starts the car.

What are the 2 types of generator? ›

There are two fundamental types of generators known as AC (alternating current) and DC (direct current) generators. While the technique of producing electricity is the same in both types, AC and DC power become different in terms of their applications – the way in which loads receive electric power.

How does a generator work step by step? ›

How Do Generators Create Electricity? Generators don't actually create electricity. Instead, they convert mechanical or chemical energy into electrical energy. They do this by capturing the power of motion and turning it into electrical energy by forcing electrons from the external source through an electrical circuit.

What are the systems of a generator? ›

A generator has various components, including an engine, an alternator, a fuel system, a voltage regulator, cooling and exhaust systems, a lubrication system, a battery charger, a control panel, and a frame or main structure.

What is the rotating part of a generator called? ›

Mechanically a generator consists of a rotating part and a stationary part: Rotor: The rotating part of an electrical machine. Stator: The stationary part of an electrical machine, which surrounds the rotor.

Why is iron used in a generator? ›

Below: Iron is able to concentrate magnetic fields, and can greatly increase the power of an electromagnet. Strong magnets are necessary for generators, motors, transformers and other electrical uses.

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