Seminar Course 392 N Spring 2011 EE 392

Seminar Course 392 N ● Spring 2011 EE 392 N Lecture Two: The Power Grid and Grid Communications April 4, 2011 Dan O’Neill ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 1

The Energy Grid • Last time… • Intro to the grid – Traditional grid – Change – Intelligent energy system • Communications background – Grid communications today – Future requirements – Alternatives ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 2

Last Time: Intelligent Energy Systems • Nearer term evolution of the grid leading to the Smart Grid • Look at intelligent energy systems from a systems point of view • Focus on information and management ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems Traditional Grid Intelligent Energy Systems Time Smart Grid 3

Backup: Smart Grid The essence of this vision is “a fully– automated power delivery network that can ensure a two-way flow of electricity and information between the power plants and appliances and all points in between”. The three key technological components of the Smart Grid are distributed intelligence, broadband communications, and automated control systems. ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 4

The Energy Grid • Last time… • Intro to the grid – Traditional grid – Change – Intelligent energy system • Communications background – Grid communications today – Future requirements – Alternatives ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 5

Traditional Grid • Worlds Largest Machine! – 3300 utilities – 15, 000 generators, 14, 000 TX substations – 211, 000 mi of HV lines (>230 k. V) – SCADA control – Mostly unidirectional • Capacity constrained graph ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 6

Interconnect ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 7

The Energy Grid Generation Transmission Distribution Conventional Electric Grid Management and Control Data ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems Load Comm IT 8

Three Planes • Electrical power – Supply(t)=Demand(t) – Real and reactive power • Management and Control (MC) – Local protection systems – SCADA: Supervisory Control and Data Acquisition • Data systems – Billing ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 9

Backup: Supervisory Control and Data Acquisition • Collects, processes and displays system data – Coordinates resources – Displays problems • Converging with standard – Communications – IT ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 10

The Traditional Grid is Changing • Incorporating renewables – supply(t) • Replacing old equipment, $1. 5 T $850 B - grid $650 B - users – Electrical efficiency – Reliability – Embedded smarts • Reducing operating costs – Excess capacity: Reserves – Bottlenecks: Transmission • Deregulating ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 11

Nearer Term Initiatives • • Renewables Demand Response Grid optimization All drive a need for IT and communication systems ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 12

Renewables • System characteristics – Time varying – Inherent randomness! • Issues – Centralized/u. Grids? – Grid control and stability – Communications – Supply(t) < Demand(t) ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 13

Renewables: The System Problem National Renewable Energy Laboratory ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 14

Demand Response • A method to reduce peak to average using variable pricing – Static - Look ahead – Dynamic pricing – Real time – Direct Load Control (DLC) – Utility directly reduces load – Interruptible tariffs – Large customers only • Many issues – How communicate? – Consumer response? ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 15

Demand Response Campus and Buildings Home Whirpool Corp. made a public commitment to ship in 2011 a million dryers ready to plug into a smart electric grid , if communication standards • AMI • EMS • Smart devices ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 16

Grid Optimization • Adjusting – Supply(t) – Connectivity • Transmission routing • Distribution Automation – Aggregating DR users • Commercial buildings ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 17

The Energy Grid • Last time… • Intro to the grid – Traditional grid – Change – Intelligent energy system • Communications background – Grid communications today – Future requirements – Alternatives ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 18

MC and Data Flow Generators ISO Transmission 275 -400’s KV Fiber and u. Wave Slow speed wired and wireless/ nothing Substations Distribution 10 -20 KV Manual ? ? ? Industrial ee 392 n - Spring 2011 Stanford University Commercial Business Intelligent Energy Systems Residential 19

Grid Communications • Separate systems • Reliable • Not integrated with existing communications • Secure systems • Integrated • Not visible on the Internet ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 20

Intelligent Energy Network Cisco will talk about this… energy subnet Generation Transmission Distribution Load Conventional Electric Grid Conventional Internet ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 21

Intelligent Energy Systems Communications • Near Future – Transmission Area Network (TAN) – Field Area Network (FAN) – Neighborhood Area Network (NAN) – Home Area Network (HAN) ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 22

Comm. Performance Issues Bandwidth Latency Reliability Comments Field . 5 /20 Mbs 10 us-1 sec 99. 99 Control and SCADA Neighborhood . 1/5 Mbps <50 msec 99. 99 AMI Home 1 -10 Kbps >10 sec ? EMS Comments: HAN • Separate energy net from home datanet? • Can use Internet? Latency • Transmission • Queuing ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 23

Alternative Standards Zigbee Wi. Fi Field 4 G/Wi. Max PLC comments 3 vs 50 X Neighborhood MESH X Europe Home MESH Femto? X Smart Meter X X ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 24

Smart Grid Comm Overview • Many competing ideas and standards • Issues – Performance (interference) – Latency – Security ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 25

Zig. Bee • Zig. Bee smart energy 2. 0 standard (HAN) – ~100 ft – ~250 Kbs IEEE/NIST interface and data standards: Converged USNAP and EPRI home standard • Many suppliers and very inexpensive • Not compatible with PLC • Open upper layers - Flexible • IEEE 802. 15. 4 Physical and Data link layers – Mesh – 900 Mhz/2. 4 Ghz DS-Spread Spectrum ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 26

Power Line Communications • Home. Plug Green Phy – 10 Mbs – IP • Uses the AC lines – Historical use in Transmission – Distribution for AMI 500 Kbs – Use in Europe is diff. than US • HAN applications (Media) – 10 -200 Mbps, OFDM – Multiple standards • Questions – Reliability (Not a mesh) – Interference – Privacy ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 27

Wi. Fi • DAN – Mesh – 802. 11 a backhaul – Upper layer routing optimization and security • HAN - coexistence? – Interference – Reliability – Security • IEEE standard 802. 11 x Tropos – 2. 4(g) /5 Ghz (a), OFDM – Up to 200 Mbs ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 28

3 G/Wi. Max/4 G • FAN (EPRI) • Issues – Priority - latency – Reliability – dropped calls – Cell phone companies • Roughly – 100 Mbs downlink – 50 Mbs uplink • IEEE standards – OFDMA – MIMO ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 29

Communications Challenges • • The last “hop” and in the home Distribution system network (transformers and EV’s) Reliability and security Hierarchical decomposition of functions and applications => grid management – IT structure – Communications systems • Integration with Internet? ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 30

Next Week • Dimitry will talk on Control and Monitoring Basics ee 392 n - Spring 2011 Stanford University Intelligent Energy Systems 31