one powerful future. powerful future. why are ratings important? • over aggressive use of ratings...

One powerful future.


Topics

COMMITTED TO YOUR SUCCESS

Why are Ratings Important?

ISO8528 Ratings

Caterpillar Ratings

Genset Application and Installation


Cat Electric Power

Rating Definitions

COMMITTED TO YOUR SUCCESSCOMMITTED TO YOUR SUCCESS


Why are Ratings Important?

• Over aggressive use of ratings could result in accelerated wear

and unplanned downtime

• Over conservative use of ratings removes value, increases

cost, can cause performance issues and potentially lead to

maintenance issues.

• Major Considerations

– Number of expected run hours per year.

– Average load versus Peak load

– Ultimate Application: Is the generator set the normal source or

emergency source? Is it normally paralleled with other sources?



Ratings Confusion in Specifications

Specification:

Section 5.A

“Generator shall be rated 2 MW Standby / 1825 kW Prime”

• Ratings are designed to help drive understanding between users,

engineers, and manufacturers

• What is more important to the site?

– Starting time and transient response?

– Fuel consumption and time between overhauls?

• Specifications such as this can drive unnecessary cost into projects

Key: What is the application of the generator set



ISO8528 Ratings



What is ISO-8528

• International standard for diesel and gas generator sets

• Intended to help understanding between manufacturer and customer

• ISO 8528 defines four ratings

– Continuous Power (COP)

– Prime Power (PRP)

– Limited-Time Running Power (LTP)

– Emergency Standby Power (ESP)

Should be considered as a minimum standard for manufacturers



Continuous Power (COP)

COP pow er (100%)

stops for maintenanceTime

Power

COP•UNLIMITED Hours per year

•Load 100% Nameplate

•CONSTANT Electrical LoadDefinition: The maximum power

which the generator set is

capable of delivering continuously

whilst supplying a constant

electrical load when operated for

an unlimited number of hours per

year under the agreed operating

conditions with the maintenance

intervals and procedures being

carried out as prescribed by the

manufacturer.



Prime Power (PRP)

Definition: The maximum power

which the generator set is capable

of delivering continuously whilst

supplying a variable electrical

load when operated for an

unlimited number of hours per

year under the agreed operating

conditions with the maintenance

intervals and procedures being

carried out as prescribed by the

manufacturer.

The permissible average power

output over 24hr of operation

shall not exceed 70% of the PRP

unless otherwise agreed by the

engine manufacturer

PRP pow er (100%)

Permissible average pow er

Time

Power

Actual average pow er

P1

P2

P3

P4

P5

P6

30%

t1 t2 t3 t4 t5 t6Stop

PRP•UNLIMITED Hours per Year

•Not to exceed 70% average load in

24 hours

•VARIABLE Electrical Load



Limited-Time Power (LTP)

Definition: The maximum power

available, under the agreed

operating conditions, for which

the generator set is capable of

delivering for up to 500hr of

operation per year with the

maintenance intervals and

procedures being carried out as

prescribed by the manufactures

Limited time running power at

100% is limited to a maximum

of 500hrs per year

LTP pow er (100%)

Time

Power

stop stop stop

LTP•Limited to 500 Hours per Year

•Load 100% of Nameplate

•CONSTANT Electrical Load



Emergency Standby Power (ESP)Definition: The maximum power available during a variable electrical power sequence,

under the stated operating conditions, for which a generating set is capable of delivering

in the event of a utility power outage or under test conditions for up to 200hr of operation

per year with the maintenance intervals and procedures being carried out as prescribed

by the manufacturer

ESP• Limited to 200 Hours per year

• Not to exceed 70% average

load in 24 hours

•VARIABLE Electrical Load

ESP pow er (100%)

Permissible average pow er

Time

Power

Actual average pow er

P1

P2

P3

P4

P5

30%

t1 t2 t3 t4 t5StopStop Stop

The permissible average

power output over 24hr of

operation shall not exceed

70% of the ESP unless

otherwise agreed by the

engine manufacturer



Caterpillar Ratings



Differences between Caterpillar Ratings and ISO8525 Ratings• ISO8528 ratings states average load factors and usage as hard limitations

• Caterpillar ratings average load factors and usage are not hard limitations

• Additional differences on certain specific ratings



Continuous Rating

• Similar to ISO COP rating

• Power Output: 70-100%

• Load: Non-varying

• Typical hours/year: Unlimited

• Typical peak demand:

– 100% of continuous rated ekW

– 100% of operating hours

Ideal for base loading, where another source supports varying load



Prime Power Rating

• Exceeds ISO PRP Rating

• Average Expected Power Output: ≥

70%

• Load: Varying

• Typical hours/year: Unlimited

• Typical peak demand:

– 100% of prime rated ekW (70%

average in 24 hours)

– 10% overload for emergency use• max of 1 hour in 12

• not to exceed 25 hours per year

Ideal for Island mode operation, where the generator set is the normal source



Load Management Rating

• Similar to ISO LTP Rating

• Nameplate rating same as prime

• Average Power Output: Up to 100%

• Expected usage: 500 hours

• Typical peak demand: 100% of

prime rated ekW

Load Management Rated Generator

2.4

2.7

3Load on Generator

-------------- Nameplate

Avg Load Factor

Time

Chart: Example load profile: 2.7 MW Load Management Rating

Ideal for peak shaving where normal source is available



Standby Rating

• No ISO Equivalent, exceeds

ISO ESP rating

• Expected average Power

Output: 70%

• Load: Varying

• Expected Usage: 500hrs/yr,

but can run for the duration of

any outage

Ideal when normal and reliable source of power is available



Mission Critical Standby

• No ISO equivalent (exceeds

ESP rating)

• Nameplate rating same as

Standby

• Expected Average Power

Output: ≤ 85%

• Load: Varying

• Expected time at nameplate: 5%

• Expected Usage: 500hrs/yr, but

can run for the duration of any

outage

Mission Critical Standby Rated Generator

Ideal when normal and reliable source of power is available



Cat Ratings Example

Incorrect ratings specifications can drive cost and reduce needed performance• Important site requirements: fuel consumption/overhaul intervals vs starting time and block loading

response?

• Is the customer willing to pay 10% to 20% more for a EPS with no added value?



Questions?



Specsizer



CATERPILLAR CONFIDENTIAL: GREEN

Electric Power | Marine | Oil & Gas

Introduction to Diesel Genset

Application & Installation



Agenda

• Engine Room Design

• Foundations & Isolation

• Air Intake Systems and Engine Room Ventilation

• Exhaust Systems

• Fuel Systems





Engine Room Design



Engine Room Design Considerations

• Single or Multiple Use Facility

• Single or Multiple Generators

• Prime Power or Standby

• Ventilation Requirements

• Cooling Requirements

• Serviceability

• Clearances

• Access



Single or Multiple Use FacilitySingle Use Facility

The room is primarily dedicated to generators.

Multiple Use Facility

The multi use facility would not only have generator sets, but also auxiliary

equipment such as boiler units, compressors, etc.



Prime Power versus Standby Power

Engine Room Location Considerations



Serviceability



Serviceability - Safety and Convenience

• Emergency Wash Station

• Fire Suppression System

• Compressed Air

• Ventilation Air

• Water

• Cable Routing

• Load Testing



Serviceability - Clearances

• Generator set

– Overhead

– Side

– Front and Rear

– Underneath

• Electrical Equipment

– Breakers

– Connections

– Buss Bar



Serviceability - Clearances



Serviceability - Access

• Door Width

• Access for Routine

Maintenance

• Major Repair

• Service Elevator

Maintenance, Repair, Upgrades, and replacement

need to be designed for prime and standby units



Access



Several Other Considerations

• Emergency/Rental Generator

• Expansion (future genset)

• Installation Considerations - Lift Points

• Total Package Weight

• Flooring Considerations

• Rooftop Installations

• Lines, Tubes & Hoses





Foundations & Isolation


One powerful future.Functional Requirements for

Foundations• Support total weight (mass) & dynamic loading

of equipment, accessory equipment and fluids

(coolant, oil and fuel)

• Maintain alignment between engine, driven

equipment, and accessory equipment

• Isolate equipment vibration from surrounding

structures



Base Material

• Material supporting the

foundation must carry

the total weight

– Firm level soil, gravel, or

rock

– Fine clay, loose sand, or

sand near ground water

level



Concrete Foundations

• Avoid excessively thick bases

• For paralleled units foundation

must withstand twice the weight

• Minimum 12 inch edge clearance

• Design should still be finalized by

duly registered and qualified

structural engineer/consultant

𝐹𝐷 = 𝑊 ÷ (𝐷 × 𝐵 × 𝐿)

FD = Foundation Depth

W = Total Weight of

Equipment

D = Density of Concrete

B = Foundation Width

L = Foundation Length



Functional Requirements for Package

Isolators

• Limit vibrations transmitted from genset to

foundation

• Correct for small variations in foundation surface

flatness



Isolators

• Types of Isolators

– Bulk Isolation (< spring/rubber isolation)

– Rubber (≤ 90% isolation)

– Spring (> 96% isolation)





Air Intake Systems and

Engine Room Ventilation



• Dirt and debris ingested into the engine are a major

source of wear on moving engine parts.

• The air intake is a significant path for dirt and debris to

enter the engine.

• Sources of dirt and debris in the air intake include:

– Materials left from initial fabrication and assembly of

ducts

– Air Filter changes

– Air intake duct leaks

– Environment

Air Cleanliness



Particles in Intake Air

• Particles under 0.001mm (1 micron) diameter have little

effect and will pass out through the exhaust

• Particles from 0.001 – 0.01mm (1-10 microns) diameter

have a measurable effect on the engine

• One teaspoon of 0.125mm (125 microns) diameter dust

per hour will create catastrophic failure of an engine in

24 hours

The average human hair is 0.08mm (80 microns) in diameter



Air Cleaner Configurations

• Engine mounted

• Remote mounted

• Multiple element

• Multi-stage (Precleaners)



• May be a requirement of the site

configuration

• Best practice: leave engine-

mounted air cleaners on the

engine and route ducts from them

– Less potential for contamination

– Less cost in intake design

• For remote-mounted air cleaners,

ducts must be completely sealed

to ensure all intake air is drawn

through the filter elements

Air Intake Ducts



Ventilation

• Remove Radiant and

Convection Heat

– Genset and Switchgear

performance

– Adequate conditions for

personnel

• Engine Room

Temperature Rise

– 8.5oC to 12.5oC

– Never exceed 49oC

• Air Velocity

– 1.5 m/s in working areas



Ideal Ventilation - Direction

• Airflow Direction

– Generator end to Radiator

– Horizontal flow

– Low entry

• Air should be

– Cool

– Dry

– Clean



Ventilation Considerations - Routing

• Airflow Routing

– Entry as far and low as possible

– Discharge as high as possible

– Do not blow cool air toward hot engine components



Type 1 Ventilation



Type 2 Ventilation



Type 3 Ventilation



Type 4 Ventilation



Incorrect Flow Single Engine



Multiple Engine Arrangement



Incorrect Ventilation





Exhaust Systems



Exhaust System Considerations

• Minimize back pressure

• Reduce noise

• Provide adequate clearance

• Ensure proper mounting



Back Pressure

• Design target – half the

maximum allowable

system back pressure

• Common Culprits that

increase back pressure

– Exhaust pipe diameter

– Sharp bends

– Exhaust pipe length

– Silencer resistance

• Calculate and Measure



Noise Reduction

• Determine Attenuation Level

– Industrial (8-10 dB reduction)

– Residential (15-25 dB reduction)

– Critical (30-35 dB reduction)

• Selecting a Silencer/Muffler

– Balance sound attenuation with back pressure

– Space, Cost, Appearance



Noise Reduction



Clearance and Mounting

• Clearance

– Overhead cranes

– Minimum 9 inches from combustible materials

– Air intake

• Mounting

– Flexible connections

– Weight support





Fuel Systems



Diesel Fuel Supply System

• Fuel Storage System

• Fuel Transfer System

• Fuel Filtration System



Fuel Storage System

• Main Tank

– Sizing: Fuel Consumption

Rate x Hours Between

Refills at 100% load factor

depending on application

• Day Tank

– Required when main fuel

tank is:

• Same level, > 50 ft away

• > 12 ft below engine

• Above engine fuel

injectors

– Local codes apply for sizing,

esp. when above ground



Fuel Transfer System

• Fuel Pump

Capability and

Design

Considerations

– Vertical distance from

tank to pump

– Internal piping system

losses

– Elevation

• Routing

– Avoid hot surfaces

– Avoid formation of

traps

Low to the ground

Note: available lift can vary between

units



Fuel Filtration System

• Engine fuel filters must

never be removed or

bypassed.

– Duplex fuel filters can be

used to allow filter

changes while the unit is

running

• Removal of water and

sediment

– Water separator

– Coalescing filter

– Centrifuge COMMITTED TO YOUR SUCCESS



Thank you.

one powerful future. powerful future. why are ratings important? • over aggressive use of ratings...

Documents