Micro Grids,

Renewable Generation,

Electric Power Resiliency

Patrick E. Mantey

Ali Adabi

CITRIS

Jack Baskin School of Engineering

University of California Santa Cruz

2014

Micro grids:

On Customer Side of the Meter

Micro Grid

MUD

Campus

Building Complex

Apartment Complex

Commercial Building

Farm

Home

Why Micro Grid?

Island operation (no grid to serve)

Rural areas

Electrical power availability

Grid outage

storms

instability

terrorism

Outages

Large areas

Longer time to restoration

Power System Restoration

M.M. Adibi (editor) ISBN: 978-0-7803-5397-8 690 pages June 2000, Wiley-IEEE Press

Power System Restoration

“At a time when bulk power systems operate close to their design limits, the restructuring of the electric power industry has created vulnerability to potential blackouts. Prompt and effective power system restoration is essential for the minimization of downtime and costs to the utility and its customers, which mount rapidly after a system blackout.”

Resiliency

“ability to recover from or adjust easily to misfortune or change”

Micro Grid Management

Research Project

Needs “smart meter” data – and more

Working on low-cost instrumentation

Microgrid

Grid

Fossil Generation

Wind Turbine

Solar Generation

Load

Storage

Microgrid

Instrumentation Overview

Develop and apply – a cost/effective system including: monitoring of disaggregated energy use Load control (shedding / adding) Fossil fuel minimization Management of storage

Control/Operate “small” micro grid (nano-grid?) Transform / integrate data into “intelligence” “Non-Intrusive Load Monitoring”

Micro grid Challenges

Control Challenge does not scale

Small micro grids not easier than large ones

Maintaining voltage, frequency

Renewable Generation volatility

Loads Constraints

Limited Storage

Minimize use of fossil fuel

Microgrid Control: Load Matches Generation

Generation Load

HVAC

Electric Car

Solar Generation

Wind Generation

Microgrid : Load Exceeds Generation(Grid Connected)

Generation Load

HVAC

Washer & Dryer

Electric Car

Solar Generation

Wind Generation

Grid

Microgrid : Load Exceeds Generation(Grid Connected)

Generation Load

HVAC

Washer & Dryer

Electric Car

Solar Generation

Wind Generation

$$Grid $$

Microgrid: Generation Exceeds Loads (Island)

Generation Load

Microgrid Control: Generation Matches Loads(Island)

Generation Load

HVAC

Electric Car

Storage as load

Solar Generation

Wind Generation

Solar Generation

Microgrid : Load Exceeds Generation (Island)

Generation Load

Microgrid

Grid

Fossil Generation

Wind Turbine

Solar Generation

Load

Storage

Microgrid

Microgrid Monitorin

g And

Control

LM

LM

LM

LM=Load Monitor

Do we need a control room for Microgrid?

Control /Synchronization

Ideal – smooth transitions from grid-connected to operation isolated from grid and back to grid connection.

Today

Going off grid – e.g. conventional backup

Grid connection failure initiates local generation

With adequate backup storage and local renewable, may not be disruptive

Otherwise, delay to bring up local generation

Grid to Microgrid

Going off grid requires matching local load to generation

Generation excess – problem of back feed of generator(s)

Generation deficiency – won’t carry load

Local energy storage critical for smooth transition

Need automated load management to match loads to available power when off-grid

Implies good instrumentation and remote control of loads – power on / off, and possibly varying load

Control /Synchronization

Ideal – smooth transitions from isolated micro grid back to grid connected operation

Reconnection to the grid requires synchronization

Today

Reconnecting to grid –synchronization

Requires local generation disconnected

May need to reduce load before reconnect

Load brought back slowly

Reconnect Renewable Generation

(solar, wind) via inverter”

“Power System Restoration”

Conclusion

Micro grids present challenges

Micro grids have value to both

Consumers

Utilities