Distribution Automation Smart Feeders in a Smart Grid World DA Communications
Telecommunications Services This diagram depicts the typical telecommunications services used to interconnect a Utility s customers, workers, and assets Customer IHD Customer Call Centre Web Portal Customer Internet Satellite Hub Firewall WIFI Servers Office (strategic) Control Centre, Data Centre Satellite WIFI Print Server Guest Access Leased WAN Office (Regional) WIFI Microwave Satellite Office (Main) Fibre Rings SONET & MPLS WIFI WiMAX Desktop Users (fixed) Microwave Station Microwave WiMAX WiMA AX Field Device Control (collector) Metering LAN Satellite Substation (Grid) Microwave WIFI WiMAX Field Device Monitoring (Meter) Metering LAN Lease Lines WiMAX Lease Lines Microwave WiMAX Microwave PLC Metering LAN Camera (WIFI) WiMAX PLC PLC Generating Station Large, Strategic, Available Energy PLC Substation (Load) WiMAX Mobile Radio Plant Mobile Radio PLC WIFI Substation (Load) Feeder Fibre WIFI Dist. Device Control PDA (WIFI) Off-Site Office (Remote) BlackBerry Remote Access WIFI Mobile Worker Laptop (WIFI) Roaming (Office) Worker Cellular Field Worker Network Operational Support Systems Prepared by Sol Lancashire, BC Hydro Telecom Architect July 27, 2009
General Requirements for DA Communications Coverage Throughput Latency (delay) Communication direction, either one way or two way Availability and Reliability Security Cost to Operate and Maintain
Coverage The DA system must be able to communicate reliably with feeder devices that can be located virtually anywhere in the utility s service territory Maximum communication distances for wireless communication technologies are limited by physical obstructions tions Communication Obstructions Receiver Transmitter Receiver Drawn by R. Uluski, EnerNex Corp Coverage varies widely for the available communication technologies. Maximum communication distance ranges from tens of feet to tens of miles. Some technologies may be altogether unavailable in rural areas
Data Throughput Data throughput amount of information transported by the communication system in a given amount of time. DA applications typically require a bandwidth of 9,600 bits per second or less
Latency latency is a synonym for delay difference between the time that an event occurs in the field and the time that the control center is informed about the event Event occurs 10:30:00 ` Event reported 10:30:30 (30 second latency) instantaneous response is not required for DA applications 30 second latency is common for DA applications
Communication Direction Bidirectional Communications FLISR Application Processor Open/Close Commands FD Status I,V Measurements Remote Controlled Switch Source: R. Uluski, EnerNex Corporation Unidirectional Communications VAR Dispatch Application Processor Real/Reactive Power Meas Open /Close Commands Substation Master Source: R. Uluski, EnerNex Corporation Switched Capacitor Bank
Availability and Reliability The DA communication facility must be able to perform its intended function at any time, including during power system emergencies Several DA communication technologies must be shared with anyone who wishes to use that technology Utilities should be aware of a possible evolving problem with interference for some communication technologies
1.5 1 0.5-0.5-1 -1.5 0 0 1 0 2 0 3 0 4 0 3 2 1-1 -2-3 0 0 2 0 4 0 6 0 8 0 Performance During Power Outages Some DA applications must continue operating during power outages on the distribution feeders DA communication system must also continue operating during faults PLC Performance During Line Fault Power Line Fault Signal Injection Signal Receipt Signal Sent Signal Received Drawn by R. Uluski, EnerNex Corp
Communication Security The DA communication system must be designed to guard against access by unauthorized persons
Cost to Install, Operate, and Maintain DA equipment locations are small and very numerous Communication cost per location is a key factor
Summary of General Requirements DLA Application Communication System Criteria FLISR Volt-VAR Control Coverage Entire service territory or selected portion with Entire service territory or selected portion with VVC FLISR Latency (delay) Less than 1 minute; must be able to complete FLISR operation within 5 minutes Less than 3 minutes; must be able to verify capacitor bank operation via SCADA measurements Availability and Reliability Requires high reliability solution due to impact on customer outages Throughput Minimum bandwidth 4,800 bits per second Less reliable system is acceptable due to failsafe design Data throughput not an issue due to extremely small data transfer requirement Communication direction Must be bidirectional Unidirectional system acceptable (outbound) Security High security solution Can be less secure due to Cost to Install/Operate, and Maintain needed due to potential impact on service to critical customers non-severe worst case impact and failsafe design Must have lowest possible Must have lowest possible cost cost
Communication Architecture Peer to Peer Normal routing of messages Mesh Network ` By: R. Uluski, EnerNex Corp Routing following node failure ` By: R. Uluski, EnerNex Corp
Point to Multipoint to Communications Message Broadcast to all Remote Radios Remote Radio #1 (RECEIVE MESSAGE TAKE ACTION) Drawn by R. Uluski, EnerNex Corp Remote Radio #2 (LISTEN ONLY NO ACTION) ` Message For Radio #1 Remote Radio #3 (LISTEN ONLY NO ACTION) Master Radio
Point to Point to Communications Satellite Drawn by R. Uluski, EnerNex Corp Data Message Remote Radio ` Satellite Dish
DA Communication Technologies Fixed radio Mobile radio Satellite Power line communications
Fixed Radio Paging small telecommunications device that can transmit simple on/off control commands usually very inexpensive Paging latency varies from 20 seconds to several minutes (acceptable for the DA VAR dispatch function)
Fixed Radio Licensed Uses radio frequencies licensed from the Federal Communication Commission (FCC). Very High Frequency (VHF) excellent coverage lower available data throughput UHF band (800 MHz, 900MHz) greater data handling (can exceed 28.8 Kbps) more sensitive to performance degradation from moisture and physical obstructions The lower the frequency the better the coverage 150 MHz 400 MHz 700 MHz 900 MHz 2.4 GHz Better Propagation Source: Power System Engineering (www.powersystem.org). Well suited for implementing the DA FLISR function
Fixed Radio Unlicensed (Spread Spectrum) transmission signal is spread over a wide range of the radio spectrum operate in the 900 MHz, 2.4 GHz, and 5.8 GHz unlicensed frequency ranges users share the entire band, with each using only a small portion of frequency band in a random fashion High bandwidth capability Coverage can be a problem due to obstructions Unlicensed spread spectrum radio is one of the most attractive and viable solutions for DA communications
Mobile Radio Cellular Service Large infrastructure investments by cellular carriers have made cellular technology an attractive option for DA Evolution of cellular services 1 G Analog Cellular 2 G Digital Cellular 2.5 G GSM and CDMA 3 G Advanced CDMA 4 G Advanced CDMA Generation 1: Generation 2: Generation 2.5: Generation 3 Generation 4: < 9.6 Kbps 9.6 Kbps 19.2 Kbps 25 Kbps 80 Kbps 800 Kbps 1,250 Kbps Several Mbps Rollout a few years Source: Communication Technologies for Automated SCADA, AMR, and Other Programs (CRN Project 02-26) by Power System Engineering an attractive alternative to privately owned infrastructure drawback for utility is the possible lack of certain service options and even basic coverage in some rural markets
Satellite Radio Communication via satellites especially useful for hard to reach reach locations Features: Data throughput of 30 to 100 kbps Latency of 2 to 8 seconds Availability from most locations in the United States Two way capability Not recommended for widespread use in DA applications Can be an effective gap filler for hard to reach locations
Power Line Communications uses the high voltage primary distribution wires as the main communications medium Usually cannot be justified solely for the purpose of implementing DA If available for other reasons (e.g. AMR), can be a very cost effective for some types of DA communications Two main types: conventional power line carrier (PLC) broadband over power line (BPL)
Conventional Power Line Carrier signal injected into the primary lines via an interface at the distribution substation Third-Party Communications Link Electric Meter and AMR Module AMR System Substation PLC AMR Equipment Medium Voltage Low Voltage Source: Power System Engineering Disadvantages line capacitors attenuate the signals signals may be disrupted when a line fault occurs and during power line outages potentially too slow for some DA applications
Broadband over Power Line Signal is injected at locations out on the distribution feeders themselves Signal is sufficient to reach up to a mile without isolating theline capacitor banks several signal injection points are needed
Wireless: WiFi Intended to improve the interoperability of wireless local area network products based on the IEEE 802.11 standards. Allows connectivity it in peer to peer mode. Subscriber module sends data to access point over TCP/IP. 900 MHz, 2.4 24GHz, and 5.1 5.7 5157GHz: 900 MHz: latency = 15 ms (1 Mbps) 5 GHz: latency < 1 ms (10 Mbps) Power consumption is high h compared to some other low bandwidth standards, such as ZigBee and Bluetooth. Line of sight is important. Need serial to Ethernet converter for legacy IEDs. No data transmission fees.
Worldwide Interoperability for Microwave Access: wireless data over long distances, from point topoint links to full mobile cellular type access. Based on the IEEE 802.16 standard (also called WirelessMAN). Intended ddto eliminate bridging of WiFi hotspots. Coverage and performance comparable to cellular. From 2 GHz to 11 GHz line of sight backbone, 70 mile range. Not locked into one vendor The terms "fixed WiMAX", "mobile WiMAX", "802.16d" and "802.16e" are frequently used incorrectly Wireless: WiMAX
Wire: Fiber Optic Cost effective for very high data transmission rates in a point to point configuration. Not as cost effective for DA applications, with: point to multipoint configuration Modest data transmission speed requirements Two types commonly used by utilities: Optical power ground wire (OPGW): replaces transmission line s shield wire All dielectric self supporting (ADSS): is not as strong as OPGW, complete immunity to EMI, can be attached directly to phase conductor
Use of AMI Infrastructure for DA Communications
Hybrid Communication Systems