Overview

• A unique architecture is developed that enables

interconnecting and sharing renewable energy sources

between homes in an inner city neighborhood using DC

microgrid and smart interconnected home concept in order

to drive down participant utility costs

• DC microgrid for home energy interconnection is

potentially less complex and less expensive to deploy,

operate and maintain however, faster protection is a key

element to ensuring resilience, viability and adoptability

Milwaukee Neighborhood DC Microgrid Project

Journal Sentinel,

April 16, 2016

“Historic Garden Homes

District Struggles to Find

its Future”

Load Analysis: Conventional AC Home vs. DC Enabled Home

Solar PV and Battery Sizing

Assumes minimum

wage as household

income

DC enabled home

reduces power usage

• in the summer

from 19% of

income to 9%

• in the winter from

15% to 6%

Determination of Number of Panels per House to achieve

net zero energy consumption in the summer

Battery sizing optimization algorithm

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0 2 1 2 2 2 3 2 4

S U M M E R L O A D P R O F I L E S

4485 4459 4457 2602 2610

2614 4420 4418 4416

0.00

10.00

20.00

30.00

40.00

1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0 2 1 2 2 2 3 2 4

S U M M E R S O L A R P R O F I L E S

4485 4459 4457 2602 2610

2614 4420 4418 4416

The net energy consumption versus the capacity of battery and

the number of solar panels for different seasons

Neighborhood Microgrid Block Diagram

SiC JFET based SSCB solution in radially distributed DC

microgrid structure

1 2

3 4

Fault Characterization without Solid State Circuit Breakers

Fault Location 1

Ia,Ib,Ic

Hub DC Microgrid Feed

Between Hub and Garage 1

Between Hub and Garage 2

Fault Characterization with Solid State Circuit Breakers

House 1

House 2

Hub Feed

Microgrid Feed to House 1

Microgrid Feed to House 2

Fault Location 3

Ia,Ib,Ic

Hub DC Microgrid

Feed

Between Hub and

Garage 1

Between Hub and

Garage 2

House 1

House 2

Hub Feed

Microgrid Feed to

House 1

Microgrid Feed to

House 2

Fault Location 2

Ia,Ib,Ic

Hub DC Microgrid Feed

Between Hub and Garage 1

Between Hub and Garage 2

House 1

House 2

Hub Feed

Microgrid Feed to House 1

Microgrid Feed to House 2

Fault Location 4

Ia,Ib,Ic

Hub DC Microgrid Feed

Between Hub and Garage 1

Between Hub and Garage 2

House 1

House 2

Hub Feed

Microgrid Feed to House 1

Microgrid Feed to House 2

Fault Location 3

Ia,Ib,Ic

Hub DC Microgrid Feed

Between Hub and Garage 1

Between Hub and Garage 2

House 1

House 2

Hub Feed

Microgrid Feed to House 1

Microgrid Feed to House 2

Fault Location 4

Ia,Ib,Ic

Hub DC Microgrid Feed

Between Hub and Garage 1

Between Hub and Garage 2

House 1

House 2

Hub Feed

Microgrid Feed to House 1

Microgrid Feed to House 2

Test Set-Up

1)122111(2121

11)21(2

2

sRCRCRCsRRCC

sCRR

v

v

DS

C

SSCB Coordination Scheme

TL

494

VCC

RT

CT

C1

E1

R1

R2

C2

C1

D1

C4

R8

R5R6

R7

Q4

Q3

Q4

L1

L2

L3

D2

D3 R3

C3 D4 R4

Q1

D5

G

D

S

MOV+

-

vDS+

-

vGS_JFET

+

-

vC3

+-vGS_MOSFET

+

-

vC2

Voltage SensorPWM Signal

Generator

Isolated

DC-DC Converter

)1()(21

1)( 212

)21(

2CCR

CCt

DSC etvCC

Ctv

R1

R2

C2

C1

D1

+

-

vC2

+

-

vDS

Fault Scenarios and Simulation Results in DC Community MicrogridCB1 CB2 CB3 CB4 CB5

Line

Impedence 1

Line

Impedence 2

Line

Impedence 3

Line

Impedence 4Line

Impedence 5

DC

SPDT

Hub FeedResidence

Feed

Garage

Feed House Feed

Home

Inverter

Feed

Fault

Feed

Fault CurrentFault Current

CB1 CB2 CB3 CB4 CB5Line

Impedence 1

Line

Impedence 2

Line

Impedence 3

Line

Impedence 4Line

Impedence 5

DC

SPDT

Hub FeedResidence

Feed

Garage

Feed House Feed

Home

Inverter

Feed

Fault

Feed

Fault Current

Fault Current

Planned Future Work

• Obtain funding to build Community DC microgrids in Arkansas and Wisconsin

• Baseline original SSCB design using the above test set-up

• Order revised hardware SSCBs and validate fault discrimination using test set-up

• Implement fault isolator interface circuit and relay control logic

• Integrate protection into Microgrid and Home Energy Management Systems

• Test prototypes in lab-scale DC microgrid system

• Develop hardware packaging concept and find manufacturing partner

GR-16-05:Fault Protection and Coordination in a DC Community MicrogridKarthik Palaniappan, Mengyuan Qi, Rob Cuzner, Swachala Veerapaneni, Yue Zhao*

Department of Electrical Engineering

University of Wisconsin-Milwaukee, *University of Arkansas