Case Study: Successfully

Designing, Installing, and

Testing a Microgrid

Scott Manson,

Technology Director Schweitzer Engineering Laboratories, Inc.

• Microgrid projects

• Lessons learned

• Technology advancements

• Remaining challenges

Chronological History of Microgrids

• Multifunction protection

• Remote I/O

• Metering

• Power quality monitoring

• Programmable logic

controller

• IEC 61850

• Sequence of Events records

• High-speed

communications

• Continuous

self-diagnostics

• Synchrophasors

• DC battery monitoring

• Human interface displays

• Trip and close controls

• Oscillography recorder

1984–2004 Microgrid Intelligence Multifunction Microprocessor Relays

Evolve Rapidly

2002 – Motor Oil Hellas Korinthos, Greece

Centralized

Microgrid

ControlsFront-End

Processing

Relay Relay Relay Relay Relay

2,500

Relays

Utility

Loads

Front-End

Processing

• Front-end processing facilitates scaled

architecture and subcycle communications

• Crosspoint switch enables subcycle

load shedding

• Subcycle load shedding allows seamless

islanding

2002 – Motor Oil Hellas Speed Is Essential for Seamless Islanding!

2002 – Motor Oil Hellas Lessons Learned

Crosspoint Switch

Trigger

Inputs

Contingency Loads Selected to Shed

1 2 3 4 5 6

G1 Trip X X

G2 Trip X X

G3 Trip X X

G4 Trip X X X

Bus Tie Trip X X X

f

t CB Opens

Load-

Shedding

Outputs

Quantity of IEDs1 10 100 1,000 10,000

0

20

402002 2015

Closed Loop

Load-Shedding

Time (ms)

2006 – Saudi Aramco Shaybah, Saudi Arabia

Plant 3

(69 kV AIS)

Plant 2

(115 kV GIS)

Plant 2

(230 kV GIS)

Plant 1

(230 kV GIS)

2006 – Saudi Aramco Factory Acceptance Tests Improved With

Hardware-in-the-Loop Testing

Controller

Inputs

ControllerStatus

Controls

Dynamic

Simulation

System

Outputs

Generation Runback Making Turbine Respond at Speed of Inverter

MW

t

Contingency Detected (breaker trips)60 MW (actual load)

30 MW (runback target MW load)

Signal Sent by Generation-Shedding System

Maximum Runback MW Setpoint

Speed

Reference

Speed Feedback

Speed ControlValve

Control

Runback Reference

Runback

Selector

Valve

Dynamic Behavior Requires

Modeling Mechanical and

Electrical Systems

0.96

1.0

Power (pu)

Frequency (pu)

1.0

Steady-State

Droop Line

3

21

Transient Governor

Behavior

Governor

Frequency

Set Point

System Synchronization Safely Reconnecting Islanded Grids

Graphical Interfaces Teach Operators to Dispatch Grid Differently

Battery

CFE

(Mexico)

AEP

(U.S.A.)

Local Distribution

Inverter

Google®

2008 – Presidio, Texas 4 MW NaS Battery Microgrid Controls

Short-Term

Capacity Limit

Long-Term

Capacity Limit

Inverter-Based

Generation

Q

P

Q

P

Rotating

Generators

2008 – Presidio, Texas Inverters Are Not as Robust as

Rotating Machinery

Google®

2010 – BHP Worsley Alumina Collie, Australia

Electric Utility

STG-A STG-B STG-C STG-D

15 MW

STG-C Grid Island

55

54

53

52

51

50

49

48

47

Fre

qu

en

cy (

Hz)

Time (ms relative)

120,000 140,000 160,000 180,000 200,000 220,000

47

48

49

50

51

52

53

54

55

120000 140000 160000 180000 200000 220000

Fre

qu

en

cy (

Hz)

Time ( ms relative)

Steam turbine and boiler

control scheme changed

under islanded conditions

2010 – BHP Worsley Alumina Islanded Steam Turbines and Electronic

Loads May Not Mix!

Fre

qu

en

cy (

Hz)

47

48

49

50

51

52

53

54

55

0 50 100 150 200 250 300

Time (seconds)

10:17:35.701

Circuit Breaker

Open

10:18:43

Automatic

Synchronization Start

10:19:10.928

Underfrequency Level 1

Shed 0.93 MW

10:19:25

Oscillation

Start Governor

10:21:38

Isochronous Mode

10:21:46.929

Generator Trip

2010 – BHP Worsley Alumina Intentional Disconnecting at PCC

Increases Reliability

df/dt (Hz/s)

X1 X2

Y1

Y2

–X1–X2

–Y1

–Y2

Δf (Hz)

Trip

Region 1

Trip

Region 2

• Large system designs

were scaled down in

cost and complexity

• Early participation in

designs reduced costs

Protective

Relays

Local

Visualization

Engineering

Applications

Thin Clients

IO modules

Microgrid Controller

Layer 1 – Protection

Layer 2 – Controls

Layer 3 – Visualization

Layer 3.5 – DMZ

Physical Security Perimeter

Firewalls

Firewalls

Layer 3.5 – Business Networks

Firewalls

In-Depth Cybersecurity Is Required!

2012 – Chevron Jack

and St. Malo Offshore Platforms

Complexity Required to Be

Scaled Down for Remote Facility

• User inputs

System inertia

Load composition factors

• Live relay measurements

Loads and source metering (kW)

Frequency and df/dt triggers

Inertia Compensation and

Load Tracking (ICLT) Balances Power Mismatch for

Underfrequency Events!

98

0

97

96

95

94

93

92

91

Po

we

r (M

W)

5 10 15 20Time (seconds)

Electrical Power

Mechanical Power

Speed

Outside

Networks

Security GatewayVisualization, Economic

Optimization, Engineering Tools

Central Controllers

Communications Equipment

Current and

Voltage TransformersCircuit Breakers

Power Generation

Controllers

Protective

RelaysRemote I/O

Metering and

Power Quality

Layer 4

Layer 3

Layer 2

Layer 1

Layer 0

Tier 2 and 3

MGCS

Tier 1

MGCS

Microgrid

2014 – University of California

San Diego, California

Industrial and utility technology,

procedures, modeling, testing, and

commissioning methods were a perfect fit!

21 3 4 5

1.8 MW

12 kV

69 kV

Phase 2

CS CS

Relay Relay

Phase 3

RelayV RelayV

V

Relay

V

Relay

V

Relay

Phase 1

V

Relay

1.8 MW

Automation

Controller

G2

Relay

G1

Relay

Relay

500 kW

Battery

System

Relay

Phase 2

1 MW

Battery

System

Relay

2015 – Borrego Microgrid 2.0 PCC Is Protection Challenge

Protection

Meter and I/O

Protection

Meter and I/O

Tesla

Battery

Synchronous Condenser

and Flywheel

Protection

Meter and I/O

RTAC

Computer

HMI

HMISecurity

Gateway

WAN

Relay

Relay

Computer

Relay

Clamp-On

CTs for

Monitoring

Key Points

of Grid

Microgrid

Controls

Serial

Data

Diode

Portable Control Center

Utility PCC Diesel

GeneratorsWind TurbinesPhotovoltaic

Solar Cells

Monitoring

and

DispatchMonitoring

and

Dispatch

Communication

Three-Phase Power

CT and PT

Relay Relay

Relay

Portable Control Center Protection Panels in Portable Control Center

Synchronous

Condenser and Flywheel

Tesla Battery

2, 250 kW, 4 hour

RTAC

Computer

HMI

HMISecurity

Gateway

WAN

Computer

Microgrid

Controls

Serial

Data

Diode

2016 – Navy Seabees Microgrid Controls, Protection, and

Security Can Be Small and Portable

Modern Microgrids Automatically

Separate, Survive, and Synchronize

Islanded

Operation

Synchronization

Reintegration Reconfiguration

Separation

Grid-Tied

Operation

Questions?

References

[1] E. R. Hamilton, J. Undrill, P. S. Hamer, and S. Manson, “Considerations for Generation in an Islanded Operation,” proceedings of the 56th Annual Petroleum and Chemical Industry Conference, Anaheim, CA, September 2009.

[2] A. Al-Mulla, K. Garg, S. Manson, and A. El-Hamaky, “Case Study: A Dual-Primary Redundant Automatic

Decoupling System for a Critical Petrochemical Process,” proceedings of the 6th Annual Petroleum &

Chemical Industry Committee Europe Conference, Barcelona, Spain, May 2009.

[3] S. Manson, A. Upreti, and M. J. Thompson, “Case Study: Smart Automatic Synchronization in Islanded Power

Systems,” proceedings of the Power and Energy Automation Conference, Spokane, WA, March 2013.

[4] S. Manson, A. Khatib, M. Checksfield, and P. Duffield, “Case Study: Simultaneous Optimization of Electrical

Grid Stability and Steam Production,” proceedings of the 61st Annual Petroleum and Chemical Industry

Technical Conference, San Francisco, CA, September 2014.

[5] S. Manson, G. Zweigle, and V. Yedidi, “Case Study: An Adaptive Underfrequency Load-Shedding System,”

proceedings of the 60th Annual Petroleum and Chemical Industry Technical Conference, Chicago, IL,

September 2013.

[6] S. Manson, B. Kennedy, M. Checksfield, “Solving Turbine Governor Instability at Low Load Conditions,”

proceedings of the 62nd Annual Petroleum and Chemical Industry Technical Conference, Houston, TX,

October 2015.