Generator Paralleling Concepts

Engine Generator Paralleling Concepts Gen. #1

Presenter:

Gen. #2

Gen. #3

Gen. #4

Gen. #5

Daniel Barbersek Power Solutions Manager Generac Power Systems, Inc.

What Topics Will Be Covered RUNNING HEADLINE Upon completion of this presentation, participants will be able to describe the basic concepts and implementation approaches to parallel generator operation including both “Traditional” and today’s “Integrated” techniques. They will also be able to identify the advantages of integrated parallel systems over single generator applications. Specifically they will be able to:



◦

Describe the concept of creating larger power systems using paralleled generators.

◦

Describe generator to grid and generator to generator configurations.

◦

Describe the differences between the “traditional” and “integrated” approach to generator paralleling.

◦

Describe the electrical requirements needed for proper operation of parallel operation.

◦

List and describe the functional and economic limitations of “Traditional” generator paralleling.

◦

List and describe the key benefits of the “Integrated” approach to generator paralleling.

◦

List and describe the key benefits of an “Integrated” parallel system over a “Single” g generator.

RUNNING HEADLINE What is paralleling?



Generator to Utility (Grid Inter Inter-Connected) Connected)



Generator to Generator

to Utility Grid Connection RUNNINGGenerator HEADLINE 

Electrically connected to the utility grid



Energy management ◦ Emissions (natural gas engines) ◦ Spark Spread (cost feasibility) ◦ Utility barriers (standby charges, ratchets, grid interconnect) ◦ EPA Regulated – Tier 4 Required Engines if utilizing diesel

Momentary Grid Paralleling RUNNING HEADLINE



“Make-before-break” transfers ◦ CTTS (less than 100 msec) ◦ Soft-load Closed transition (few seconds) ◦ Synchronize the generator to the utility momentarily ◦ Exercise with load ◦ No outage on retransfer ◦ Circuit Breaker or Contactor Styles available

Generator

Utility

Load

RUNNINGParalleling HEADLINEGenerators for Capacity

•

What is a paralleling system? Two or more generators are electrically coupled together using special equipment to form a larger capacity power source.

52-G1

500 kW

GENERATOR #1

52-G2

500 kW

GENERATOR #2

500 kW + 500 kW 1000 kW

Paralleling Generators for Redundancy RUNNING HEADLINE

•

N+1 The customers load requirements would be 500kW even though the system can create 1000kW. This leaves the system the ability to maintain the critical load in the event that one of the generators is taken off-line.

52-G1

500 kW

GENERATOR #1

52-G2

500 kW

GENERATOR #2

500 kW + 500 kW 1000 kW

RUNNING HEADLINE Paralleling Generators

Why use a paralleling system? Reliability Accepted market reliability for single engine is 98-99% Redundant systems offer multiple nines reliable for the critical loads N+1 reliability (99.96 to 99.99%) N+2 reliability (99.9992 to 99.9999%) Scalable Ability to expand as your client’s needs grow Don’t over build – preserve capital Serviceable Protect the critical loads while servicing the generator(s)

RUNNING HEADLINE Generator to Generator Paralleling

Whyy not use a pparallelingg system? y Traditional implementations have limitations •Cost (capital, installation, commissioning) •Complexity •Space

RUNNING HEADLINE What is Required

to Parallel Generators

S h i i Synchronizing Switching Device Load Sharing Protection

RUNNING HEADLINE Getting Started - Preliminary



Prior to Synchronizing ◦ Electronic governor -- load sharing ◦ Electronic El i voltage l regulator l w// paralleling ll li capability ◦ Identical internal alternator winding pitch (i.e. (i e 2/3, 4/5, etc). ◦ Same number of phases ◦ Same phase to phase voltage ◦ Same phase rotation

RUNNING HEADLINE Synchronization

K Elements Key El t ffor paralleling ll li generators t Light goes dim – Push it in!

RUNNING HEADLINE Synchronizing Controls



Waveform Alignment ◦ Engine Speed needs to be controlled ◦ Alternator Voltage needs to be adjusted

Generator Control

PLC Logic

Bi-Fuel Controller

Load Share Module (kW)

Voltage Reg lator Regulator

Load Sharing (kVAR)

Integrated Solution HMI

Protective Relaying

Speed p Governor Auto Synchronizer

Digital Communications

RUNNING HEADLINE Synchronization – Wave Form Alignment Electrically locking two “machines” together Voltages matched Frequencies matched + Slip frequency offset Phase angles matched

PHASE VOLTAGES MATCHED

PHASE VOLTAGE MISMATCH VX

VY

PHASE ANGLE MISMATCH

0

PHASE ANGLE MISMATCHED

0 0º

90º

180º

270º

360º

PHASE VOLTAGES MATCHED PHASE ANGLES MATCHED

0 0º

90º

180º

270º

360º

0º

90º

180º

VY VX

VX = V Y

SYNCHRONIZED

270º

360º

RUNNING HEADLINE Synchronizing – Stage 1

Voltage level and alignment has been satisfied

RUNNING HEADLINE Device Switching

Traditional Switching – Utilizing Circuit Breakers

RUNNING HEADLINE Integrated Switching

Integrated g Switchingg – Utilizingg Contactor Mounted on Generator

RUNNING HEADLINE Electrical Interlock – Stage 2

•Generators Generators are now electrically interlocked •There is not enough force provided byy the prime p mover to break the generators g apart p

RUNNING HEADLINE Load Sharing – Power Balance

Gen

Gen

kVA

kVAR

kVA

kVAR



 kW

kW

RUNNING HEADLINE Load Sharing Protection

(+ kVAR)

“Reverse Reverse Power Power”

Normal Operation

+ kVAR

+ kVAR - kW

 

- kVAR

 

+ kW

(+ kW)

- kVAR

“Reverse Power” &

“Under-excited”

“Under-excited”

Load Sharing Load Sharing (Matching) Real Power (kW) Isochronous load sharing or speed droop Reactive Power (kVAR) Reactive cross current or voltage droop kW kVA INDUCTIVE (LAG)

kVAR

ENGINE GENERATOR

kVAR

A kV

NET kVAR (LAG)

Phase Angle kW kVA CAPACITIVE (LEAD)

Isochronous Governors

Isochronous governors What happens if two are connected together??

(0 - 100%) Must be 0

Speed Reference (90 - 110%)

+

Throttle Position

PID

Power (kW)

Speed

Understanding Droop

(0 - 100%) Must be 0

Speed R f Reference (100 - 105%)

+

Throttle Position

Power (kW)

S d Speed

-

PID (0 - 100%)

Droop (.05)

Load Sharing Control Circuit RUNNING HEADLINE Traditional load sharing Isochronous load sharingg Reactive Cross Current Compensation Struggles with calibration, stability, electrical noise SPEED ADJUST

SPEED ADJUST

52-G1

52-G2 PT

CT

AUTOMATIC VOLTAGE REGULATOR

AVR

GOVERNOR

ENGINE

GENERATOR #1

kW LOAD SHARING MODULE CT

LOAD SHARING LINES

FUEL (SPEED) BIAS SIGNAL

kW SENSO OR

kW SENSO OR

PT

AUTOMATIC VOLTAGE REGULATOR

AVR

GOVERNOR

ENGINE

GENERATOR #2

kW LOAD SHARING MODULE

FUEL (SPEED) BIAS SIGNAL

Droop Load Sharing Speed droop graphical representation Will two speed p droopp ggovernors share load? What is the negative consequence?

Hz 63.0

SET S PEED

61.5

SET S PEED

60.0

SET S PEED

58 5 58.5

FIXED UTILITY AND BUS FREQUENCY DIESEL GENERATOR 5% DROOP GOVERNOR - VARIOUS SET SPEEDS

RUNNING CONDITION AT TIME OF PARALLELING

57.0

0%

GENERATOR LOAD

100%

kWe

RUNNINGTraditional HEADLINE Control vs. Integrated

Traditional Approach

Integrated Approach • Simple • Reliable R li bl • Single Source

2 wire start

RS485

Generator Controller Integrated Parallel Controller

Gov. Controller Voltage Reg.

CPU

System Controller

kW Share Module kVAR Share Module Generator Controller Gov. Controller

To Emergency Distribution

Voltage Reg. Analog Control Lines Digital Control Lines Sensing Lines P Power Lines Li

Integrated Parallel Controller

To Emergency Distribution

RUNNING HEADLINEProtection •

Synchronizing process PT

– 25 sync check relay 52-G1

•

Real power system (governor & engine)

51G

25 51G

32 CT

– 27 / 59 voltage protection – 24 over excitation & volts/hz

•

Cabling & alternator – 50 / 51 Overcurrent

81 O-U

27/59

40

46

25

50/51 (27)

24

32 CT

87G

Reactive power system (regulation & excitation)

52-G2

50/51 (27)

– 32 reverse ppower – 81 o/u frequency protection

•

PT

GENERATOR #1

87G

GENERATOR #2

81 O-U

27/59

40

46

24

RUNNINGIntegrated HEADLINE Sequence of Operation Critical Transfer Switch

Status: Normal.

Emergency Distribution Panel

Equipment Transfer Switch

System Controller Generator 1

Generator 2


Status: Utility failure.




Generator 2


Status: Generators start.




Generator 2


Status: First generator at rated output. Energizes g the emergency g y distribution panel. p




Generator 2


Status: Picking up the critical load in 10 seconds.




Generator 2


Status: Equipment load transfers to the generators.




Generator 2


Status: If a generator is out of service, it separates from the system. y Non-critical load is shed.




Generator 2


Status: Generator is restarted.




Generator 2


Status: Generator parallels to the system.




Generator 2


Status: Equipment load is re-energized.




Generator 2


Status: Utility is re-energized.




Generator 2


Status: Load is transferred back to utility.




Generator 2


Status: Generators cool down.




Generator 2


Status: Generators disconnect from system. Generators shut down. down




Generator 2

RUNNING HEADLINE Paralleling Advantages

Paralleling Vs. Si l G Signal Generator t PT

Reliability Scalable Cost Footprint Serviceability

52-G1 51G

PT

25

52-G2

50/51 (27)

51G

32 CT

81 O-U

27/59

40

46

25

50/51 (27)

24

32 CT

87G

GENERATOR #1

87G

GENERATOR #2

81 O-U

27/59

40

46

24

RUNNING HEADLINEReliability Accepted market reliability for single unit 98 to 99% (multiple third party references) Integrated paralleling adds redundancy Typical load factors M Minimal l load l d shedding h dd / management Results in redundancy without increasing generator capacity N+1 reliability (99.96 (99 96 to 99.99%) 99 99%) N+2 reliability (99.9992 to 99.9999%)

Vs.

RUNNING HEADLINE Scalability

Start with a single generator Pl Planned d growthh Unanticipated growth Lower initial investment Budget / capital constraints Protection against uncertainty Single generator implementations offers no cost effective expansion capabilities – This solution typically uses sizing safety factors to protect against uncertainty and load growth.

RUNNING HEADLINE Cost of Installation/Ownership



Integrated g Parallelingg /Single g Generator’s Cost ◦ Capital cost  Optimizing market engine pricing (high volume engines)

◦ Installation cost    

Same amps, same distance Potential for smaller cabling (NEC 800 amp breaker roundup rule) Potential crane reduction (40 ton vs. 80 ton) Pad thickness reduction (6” vs. 10-12”)

◦ Maintenance cost  More manageable fluids  Comparable consumables  “Ask for PM quotations for both options”

RUNNING HEADLINE Capital Cost - Traditional

RUNNING HEADLINE Capital Cost - Integrated Generator Control

PLC Logic

Bi-Fuel Controller

Load Share Module ((kW))

Voltage Regulator

Load Sharing (kVAR)

Integrated Solution HMI

Protective Relaying

Speed Governor Auto Synchronizer

Digital Communications

RUNNING HEADLINE

Footprint

Foot Print Size vs. Location Flexibilityy Foot print examples 1000kW (26.1’ x 8.4’) 2 x 500kW (19.2 (19 2’ x 13.5 13 5’)) 1500 kW (33.3’ x 8.4’) 2 x 750 kW (16 (16.9’ 9’ x 16 16.5’) 5’) Location flexibilityy Various layouts Units can be separated Parking garages Rooftops

RUNNING HEADLINEServiceability

Single generator implementations Limited to no protection while servicing Can your critical loads go without protection? g Oil & coolant changes Belts, hoses, batteries Load bank connection Minor repairs Major repairs At what point do you bring in a rental? Change-over time Paralleled implementations provide protection during servicing

RUNNING HEADLINE Conclusion

•Traditional •Integrated Integrated •Scalability •Serviceability •Reliabilityy

Generator Paralleling Concepts

Recommend Documents