2017 MIT-LL and SEL

Lessons Learned From Hardware-in-the-Loop Testing of Microgrid Control Systems

E. Limpaecher, R. Salcedo, and E. CorbettMassachusetts Institute of Technology Lincoln Laboratory

S. Manson, B. Nayak, and W. AllenSchweitzer Engineering Laboratories, Inc.

DMS

Modbus

Modbus

GovernorGovernor InverterInverter

C-HIL ModelMacrogrid

BansheeMicrogrid

Loads

LoadsLoads LoadsLoads LoadsLoadsPV + BESSPV + BESS

SDG CHP

PCC1 PCC2 PCC3

C-HIL System

MGC System

DER Interface High-Speed Digital Interface

C-HIL Real-Time Simulator

C-HIL ModelMacrogrid

BansheeMicrogrid

Loads

LoadsLoads LoadsLoads LoadsLoadsPV + BESSPV + BESS

SDG CHP

PCC1 PCC2 PCC3

ControllerModbus PCC

Relay

DIO Module

24 V

TTL

24 V

TTL

DIO Module

24 V

TTL

IEC-61850

Standardized Test Sequence for All Microgrid Controller Suppliers

Macrogrid

Microgrid

PCC Relay

Trip/ClosePCC

DERs Controller

Microgrid Control System Grid reconnection

Unintentional islanding

Protection for expensive assets

IEEE 1547 compliance

Metering

Pass-through control

Protective Relay at PCC Provides ~50% of Control Functionality

Trip/CloseTrip/CloseTrip/Close

Load shedding Intentional islanding PCC dispatch PF control Voltage regulation Frequency regulation

Microgrid Controller Load Shedding, Dispatch, and Islanded Regulation

Macrogrid

Microgrid

PCCRelay

Trip/ClosePCC

DERs Controller

Microgrid Control System

Loads

NormalLoading

PCC

V

(0.8 pf)

I

I

(+0.8 pf)Loads

High CurrentLow Voltage

Normal Load Angle

Trip PCC Fast (67)

Directional Current Protection (67)Opens PCC During Short-Circuit Conditions

Import Export

(0.8 pf)I

I

(+0.8 pf)

Fault FAULTI

Trip PCC Fast (67)

Relay Recording of Utility Disconnection Event in 2016

Loads

Loads

PCCRelay

Fault Starts

Relay Trips Load

Current Interrupted

Frequency Recovers!

Microgrid Controller

Sheds Load

CB Opens

Macrogrid Disturbance

Conventional Blackout

t

60

Frequency (Hz)

57

PCC Relay Trips

PCC Opens

DER Trips

PCC TripDER Trip

Fast 81RF Element Detects Open Circuit Conditions

Trip RegionMicrogrid

Blackout

IEEE 1547-2003

df/dt (Hz/s)

Frequency (Hz)

81RF Microgrid Survival

PCC Opens

PCCRelay Trips

Fast 81RF Element Improves Seamless Islanding

Trip RegionMicrogrid

Blackout

IEEE 1547-2003

df/dt (Hz/s)

Frequency (Hz)

Grid Connection

Microgrid Survives

81RF Trips

PCC Opens

Load Shedding

Macrogrid Disturbance

Conventional Blackout

t

60

Frequency (Hz)

57

PCC Relay Trips

PCC Opens

DER Trips

PCC TripDER Trip

81RF Microgrid Survival

PCC Opens

PCCRelay Trips

MacrogridMacrogrid

MicrogridMicrogrid

PCC Relay

Controller

DERDER

V, Slip

Dispatch

Simple Grid Reconnecting MethodWorks With All DERs

(slip)

V

VMACROGRIDVMICROGRID

Two Types of Load-Shedding Systems Employed

Problem to Mitigate Load-Shedding Speed

Frequency collapse Fast

Voltage collapse Fast

DERs out of step Fast

DER overload Slow

Synchronization assist Slow

PCC curtailment Slow

PCC demand charge avoidance Slow

Subcycle(faster than 16 ms)

Slow(~1 second)

Controller Redispatches DER Power Contribution After Sudden Loss of Load

Rea

l Pow

er (M

W)

Diesel BESS PV UtilityCHP

Time (s)0 15010050

5

4

3

2

1

0

1

Controller Redispatches DER Reactive Power Contribution After Sudden Loss of Load

Rea

ctiv

e P

ower

(MV

AR

)

Diesel BESS PV UtilityCHP

Time (s)0 15010050

2.0

1.5

1.0

0.5

0.0

0.5

1.0

Macrogrid

Microgrid

Loads

Loads Loads LoadsPV + BESS

SDG CHP

PCC1 PCC2 PCC3

The Ultimate: Triple Seamless Islanding Event!Only Possible With Integrated Relays and Controllers

59.84

59.88

59.92

59.96

60

60.04

12000 14000 16000 18000 20000

Freq

uenc

y (H

z)

VAB (rms)

Volts vs. Hz

Triple Seamless Islanding Event Only Possible With Fast, Intelligent Load Shedding

FB203FB204FB103 FB306

Time (s)

Freq

uenc

y (H

z)

Time (s)

Freq

uenc

y (H

z) Area 2

Area 3

Area 1

0

0

50 100 150

2010

56

57

58

59

60

6261

56

57

58

59

60

61

62

MGC Drives Bus Voltage Back to Normal After Same Triple Islanding Event

VB203VB204VB103 VB306

Time (s)

Bus

Vol

tage

(pu)

Time (s)

Bus

Vol

tage

(pu)

Area 2

Area 3

Area 1

Load Restoration EventDecoupling Event

20100 30 40 50

1500 50 100

1.10

1.05

1.00

0.95

0.90

1.10

1.05

1.00

0.95

0.90

Grid-Tied Operation

Islanded Operation

Controller

Reconnection Unintentional Islanding

PCC Relay

Relays and Controllers Work Together

Differences Between Industrial and Community Microgrids

Community Microgrid

Industrial Microgrid

Power Reliability Energy Efficiency Payback Period Years Days

Intermittent Energy Sources Inverter-Based Generation

Questions?

Lessons Learned From Hardware-in-the-Loop Testing of Microgrid Control SystemsSlide Number 2Standardized Test Sequence for All Microgrid Controller SuppliersProtective Relay at PCC Provides ~50% of Control FunctionalityMicrogrid Controller Load Shedding, Dispatch, and Islanded RegulationDirectional Current Protection (67)Opens PCC During Short-Circuit ConditionsRelay Recording of Utility Disconnection Event in 2016Fast 81RF Element Detects Open Circuit ConditionsFast 81RF Element Improves Seamless IslandingSimple Grid Reconnecting MethodWorks With All DERsSlide Number 11Two Types of Load-Shedding Systems EmployedController Redispatches DER Power Contribution After Sudden Loss of LoadController Redispatches DER Reactive Power Contribution After Sudden Loss of LoadThe Ultimate: Triple Seamless Islanding Event!Only Possible With Integrated Relays and ControllersTriple Seamless Islanding Event Only Possible With Fast, Intelligent Load SheddingMGC Drives Bus Voltage Back to Normal After Same Triple Islanding Event Relays and Controllers Work TogetherDifferences Between Industrial and Community MicrogridsQuestions?