evaluation of interactive electric thermal storage...

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Evaluation of Grid‐Interactive Electric Thermal Storage (GETS) Heaters for Islanded Renewable Energy‐Diesel Microgrids

in Cold Regions2014 International Conference on Cold Climate Technology

May 27, 2014

Richard WiesAssociate Professor

University of Alaska Fairbanks (UAF) Institute of Northern Engineering (INE)

Presented by: Marc Mueller‐Stoffels, Assistant Research Professor,

Alaska Center for Energy and Power

Co‐Investigators:Nick Janssen, Graduate Student, UAF INE

Rorik Peterson, Associate Professor, UAF INE

This work was supported by: 1) Alaska Energy Authority‐Emerging Energy Technology Fund Round 1

2) U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Awards #DE‐PS02‐09ER09‐12 and #DE‐SC0004903.

3) Data Management by the Alaska Center for Energy and Power (ACEP)

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► Goals: Use of Wind Energy► Space Heating & Storage► Grid Frequency Control

► GETS Controller Testing► Steffes 2102 Ratings► Laboratory Test Setup► Results: Response to Frequency

► Wind‐Diesel‐ETS Model► Voltage & Frequency

Dynamics

► Conclusions (Take‐Aways)

Photo Credit: Dennis Meiners, Intelligent Energy Systems

Photo Credit: SteffesCorporation

Evaluation of Grid‐Interactive Electric Thermal Storage (GETS) Heaters for Islanded Renewable Energy‐Diesel Microgrids

in Cold Regions

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► Electrothermal Space Heating/Storage: ► Excess Wind to Displace Oil Heating► Masonry Heaters (Steffes Units)

► On/off control strategies► Voltage/frequency control

► Secondary (Dump) Load

Use of Excess Wind Energy for Electric‐Thermal Heating/Storage

30%

50%

20%

Fuel Use in Rural Alaska Villages

Electricity

Space Heating

Transportation


Photo Credit: SteffesCorporation

Credit: Nick Janssen, UAF

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GETS Controller (Unit Tested)

Reference: Steffes Corporation

(active frequency range: 60‐60.5 Hz; 0.1 sec hold time)

Photo Credit: Steffes Corporation, Grid- Electric Thermal Storage (GETS) Circuit Board Replacement Procedure for 2100 Series, Document # 1200721, Rev. 1, 11/12/2013.

Programmed Frequency Response

Cycles ON & OFF: at four discrete load levels

between 60 Hz and 60.5 Hz with 0.1 sec hold

time to check frequency

(measures frequency of current using CT)

Configuration in ETS

2102 Steffes Unit: single‐phase 120 VAC feed

at 1.33 kW with four heating elements active

GETS: programmable response to frequency

f > 60 Hz with four discrete load steps

(elements) actuated by a solid state relay

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UAF Power Lab Test Setup

Photo Credit: Nicholas Janssen, UAF INE Graduate Research Assistant

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Laboratory Test Setup Circuit

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GETS System Response: Frequency Rise and Dip

Frequency Rise

Frequency Dip

Time to first response (s)

0.50 0.49

Time to appropriate response (s)

1.51 1.35

Ramp rate (Hz/s) 8.00 2.6710 10.5 11 11.5 12 12.5

58

60

62

64

66

68

X: 10.03Y: 60.5

Time (s)

Freq

uenc

y (H

z)

Frequency of Voltages

X: 9.984Y: 60.25

X: 9.809Y: 59.95

FanFbnFcn

10 10.5 11 11.5 12 12.5

2

4

6

8

10

12

14

X: 11.54Y: 6.018

Time (s)

RM

S C

urre

nt

RMS Line Currents

X: 10.53Y: 1.745

IaRMSIbRMSIcRMS

Frequency Rise (60 to 65 Hz)

1 1.5 2 2.5 3 3.5 4 4.5

56

58

60

62

X: 2.16Y: 60

Time (s)Fr

eque

ncy

(Hz)


FanFbnFcn

1 1.5 2 2.5 3 3.5 4 4.50

5

10

15

X: 3.506Y: 8.832

Time (s)

RM

S C

urre

ntRMS Line Currents

IaRMSIbRMSIcRMS

Frequency Dip (60.5 to 57 Hz)

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GETS System Response: Cycling to Frequency Change

4 6 8 10 12 14 1656

58

60

62

Time (s)

Freq

uenc

y (H

z)


FanFbnFcn

4 6 8 10 12 14 160

5

10

15

X: 4.338Y: 9.53

Time (s)

RM

S C

urre

nt

RMS Line Currents

X: 3.338Y: 2.044

X: 13.34Y: 9.707

X: 12.34Y: 1.869

X: 7.332Y: 10.29

X: 6.332Y: 1.501

X: 10.34Y: 9.214

X: 9.34Y: 1.642

IaRMSIbRMSIcRMS

Zero to Full ETS

Load

¾ to Full ETS Load

Delay Time (s) 1.00 2.00

2 4 6 8 10 1255

60

65

70

Time (s)Fr

eque

ncy

(Hz)


FanFbnFcn

2 4 6 8 10 12

2

4

6

8

10

12

X: 10.51Y: 8.538

Time (s)

RM

S C

urre

ntRMS Line Currents

X: 9.483Y: 9.314

X: 7.483Y: 8.062

X: 6.505Y: 10.02

X: 4.505Y: 8.349

X: 3.483Y: 10.37

X: 1.483Y: 8.393

IaRMSIbRMSIcRMS

Zero to Full ETS Load

¾ to Full ETS Load

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GETS System Response: Switching to Engage ETS Load

2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.459

60

61

62

Time (s)

Freq

uenc

y (H

z)


FanFbnFcn

2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.48

9

10

11

X: 2.69Y: 9.76

Time (s)

RM

S C

urre

nt

RMS Line Currents

X: 2.79Y: 9.163

X: 2.97Y: 10.08

X: 3.07Y: 9.496

X: 3.251Y: 10.54

X: 3.351Y: 9.883

IaRMSIbRMSIcRMS

Off: ~0.1 sec

On: ~0.2 sec

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GETS System Response: Switching to Disengage ETS Load

3.2 3.4 3.6 3.8 4 4.258.5

59

59.5

60

60.5

61

Time (s)

Freq

uenc

y (H

z)


FanFbnFcn

3.2 3.4 3.6 3.8 4 4.21

2

3

4

5

Time (s)

RM

S C

urre

nt X: 3.926Y: 4.373

X: 3.608Y: 1.574

X: 3.507Y: 4.389

X: 3.407Y: 1.491

X: 3.29Y: 4.421

X: 3.19Y: 1.368

X: 3.708Y: 4.421

X: 3.826Y: 1.698

RMS Line Currents

IaRMSIbRMSIcRMS

On: ~0.1 sec

Off: ~0.1 sec

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ETS‐Wind‐Diesel Model (ACEP PSIL)active frequency range: 60‐60.5 Hz (1‐1.0083 pu); 0.1 sec hold time

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0 2 4 6 8 10 12 14-5

0

5

10

15x 104

Time (s)

Pow

er (W

}

WTG Real Power

No ETS Units5 Units/Phase10 Units/Phase15 Units/Phase20 Units/Phase

0 2 4 6 8 10 12 140.96

0.98

1

1.02

1.04

Time (s)

Freq

uenc

y (p

u)

Bus Frequency


0 2 4 6 8 10 12 14400

450

500

550

600

Time (s)

Vol

tage

(V)

Bus Voltage


0 2 4 6 8 10 12 140

10

20

30

40

Time (s)

Rot

or A

ngle

(°)

SM Rotor Angle


Zoom-in on next slide (voltage stability)

75 kW

61.2 Hz with 15 units

550 V with 15 units

125 kW with 15 units

Multiple GETS‐PSIL Model Results f & V Response to 15, 45 & 75 kW Steps in Wind Power Output

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8.5 9 9.5 10 10.5 11 11.5 12 12.5-5

0

5

10

15x 104

Time (s)

Pow

er (W

}

WTG Real Power


8.5 9 9.5 10 10.5 11 11.5 12 12.5400

450

500

550

600

Volta

ge (V

)

Bus Voltage

Time (s)


8.5 9 9.5 10 10.5 11 11.5 12 12.510

20

30

40

Rot

or A

ngle

(°)

SM Rotor Angle

Time (s)


9.4 9.6 9.8 10 10.2 10.4 10.6 10.8 11 11.2 11.40.99

1

1.01

1.02

1.03

Freq

uenc

y (p

u)

Bus Frequency

Time (s)


61.2 Hz with 15 units

550 V with 15 units

125 kW with 15 units

65.6 kW

Multiple GETS‐PSIL Model Results Zoomed in f & V Response to +75 kW Step in Wind Power Output

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0 2 4 6 8 10 12 14 16 18 20

0

5

10

x 104

Time (s)

Pow

er (W

}

WTG Real Power

0 2 4 6 8 10 12 14 16 18 20

0.99

1

1.01

Time (s)

Freq

uenc

y (p

u)

Bus Frequency

0 2 4 6 8 10 12 14 16 18 20470

475

480

485

Time (s)

Vol

tage

(V)

Bus Voltage

0 2 4 6 8 10 12 14 16 18 20

0

10

20

30

Time (s)

Rot

or A

ngle

(°)

SM Rotor Angle

no GETS30 GETS

Multiple GETS‐PSIL Model ResultsResponse to Rayleigh Wind Regime (50 kW Mean Wind Power)

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► Excess Wind to Electric Heat► Displace oil heat & storage potential

► Wind‐Diesel System Stability► GETS could assist with frequency regulation► Effect on voltage stability with multiple ETS loads

► Further Investigation► Effect of multiple GETS units coming “ON” at same time► Distributed control and sequential timing of GETS units

Conclusions (Take Aways)

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Questions?Contact Info:Richard Wies, Ph.D., P.E.Electrical and Computer EngineeringEmail: [email protected]: (907) 474‐7071‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐Rorik Peterson, Ph.D.Mechanical EngineeringUniversity of Alaska FairbanksEmail: [email protected]: (907) 474‐5593

The Heat is ON in the Arctic!!


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Steffes 2102 Ratings (As Tested)

Electric Ratings Heat Elements: 120 V; 1.33 kWBlower: 120 V; 30‐100W

Weight Bricks (16): 176 lbsHeater: 105 lbs

Storage Capacity 46,062 BTU or 13.5 kWh

Heat Capacity (Bricks) 0.22 BTU/°F*lb

Temperature Rise 1100 °F (900 K)

Loss of Heat through Insulation 2.4 BTU/°F*h

Heat Delivered on Demand 20,000 BTU/hPhoto Credit: SteffesCorporation

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