Communication Technologies and Standards for Smart Grids EE 772 : - PowerPoint PPT Presentation

Communication Technologies and Standards for Smart Grids EE 772 : Smart Grids Prof. S. A. Khaparde Indian Institute of Technology Bombay

Smart Grid Communications 1. Bi-directional flow of information (along with electricity) – for effective control of generation and consumption 2. Real-time information: Paves way for active consumer participation 3. Technologies used at each level of operation to be in sync with data rate, permissible latency, security and timing requirement of respective application 4. Communication protocols must account for specific needs of the power system applications

Smart Grid Communication Requirements 1. Security - Ensure secure information storage, transportation, privacy, avoid cyber attacks 2. Reliability, Robustness and Availability - Timely availability of time critical information, robustness to distortions and channel noise 3. Scalability - It should be flexible enough to add on new web services and protocols with increasing penetration of renewables and modernization 4. Quality of Service (QoS) - Reduce packet drops, minimize latency and delays

Smart Grid Communications: Key Considerations 1. Availability during power outage – more so during natural calamities – ensure observability of the network not on outage 2. The technology in use should in itself have low power requirement 3. Secured and resilient to attacks and intrusions 4. Scope for open standards and enable interoperability 5. Choice of technology based on density of nodes, last mile connectivity, cost of deployment 6. Choice of technology: Licensed versus Unlicensed -

Information flows in Smart Grid Two way information flow between - 1. Sensors and electrical appliances to smart meters - HAN - Wireless : ZigBee, 6LowPAN, Z-Wave - Wired: Powerline communication - (Mostly) Unliscensed technologies 2. Smart meters to utility’s data center - WAN, NAN - Internet, Cellular Technologies (2G,3G, 4G) - (Mostly) Liscensed technologies

Smart Grid Communication Infrastructure 1. Customer: Home Area Network (HAN) Devices - Smart meters, thermostats, PCs, building automation, pumps Technology - ZigBee, WiFi, OpenHAN, HomePlug 2. Distribution : Neighborhood Area Network (NAN) Devices - Smart meters, relays, distribution automation Technology - WiMAX, PLC, Cellular 3. Transmission and Operations : Wide Area Network (WAN) Devices - EMS, WAMS, lines, towers, sensors and actuators Technology - IEC 61850, DNP3, SANET, Satellite 4. Markets - Enterprise and external Participants - Retailers, Aggregators, Regulators, Customers Technology - Internet protocols

Dedicated and Shared Communication Channels Dedicated - secured communication, exclusive link between source and destination, lesser latency, expensive Example: Differential protection of transmission lines - communication between differential relays (blocking signals) Shared - Message sent by the source is received by all devices connected to the shared channel. An address field in the message specifies for whom it is intended. - higher latency but economic, higher utilization of available resource Example: Communication network inside a substation, star or ring connection of bay controllers and monitoring equipments (CT, PT)

Dedicated and Shared Channels - Dedicated link for differential Relays - Shared Medium - Nodes and routers

Wired Communication Power Line Carrier Communication (PLCC) - - Sending data simultaneously with electricity over same medium - Minimal added installation - Line matching unit injects signals Into HV Transmission lines or LV and MV Distribution lines - Message captured by line traps - Originally used for low-rate SCADA, now being used in Home Automation

Wired Communication Power Line Carrier Communication (PLCC) ● - High data rate and capacity: 200 Mbps within homes, but low bandwidth for NAN restricts usage - Challenge from discontinuity- transformers, circuit breakers, faults - Shared medium – data transmissions are broadcast in nature- security and privacy issues - Transmission medium is harsh and noisy – adds coloured noise, severe signal distortions. Channel modelling is a challenge.

Wired Communication Power Line Carrier Communication (PLCC) ● - Ultra Narrow band (UNB): below 3KHz, low data rate, high connectivity over long distances - Low Data Rate (LDR) Narrow Band (NB): Between 3-500KHz, single carrier based, upto 10kbps - High Data Rate (HDR) Narrow Band (NB): Upto 1 Mbps, for NAN communication - Broadband PLC: Above 1.8MHz, short range, used in HAN

Wired Communication Twisted Pair - two twisted copper cables each with outer PVC or plastic insulator - upto 1.2 GBps - broadband services Coaxial Cables - Outer coaxial conductor provides effective shielding from external interference - reduced losses from skin effect - upto 10 MBps Optical Fibres - Core, cladding and buffer coating - internal reflection - less signal degradation than copper wires, no interference (EMI) - lesser weight than copper but high cost of installation - used for long distance transmission – no need for repeaters upto 100 Km - high capacities upto 1 Tbps - security high because of obscurity

Wired Solutions DSL (Digital Subscriber Lines): High-speed digital data transmission technology that uses the wires of the voice telephone network, Frequency band 0 - 2.208 MHz, inexpensive, scalable, poor data security, high latency, same applications as PLC Ethernet : Frequencies - 16 MHz, 100 MHz, 250 MHz, 500 MHz, 600 MHz, 1 GHz, 1.6-2.0 GHz.

Wireless Communication Radio Communication - Alternative to expensive fibre optic and copper wire for long range, limited bandwidth 1. Ultra High Frequency (300 MHz - 3 GHz) 2. Microwave (3 GHz - 30 GHz) Cellular Technology - service area divided into cells, each cell has a transceiver to control and communicate with users within a cell, operates on CDMA, communication between mobile objects - even when the object moves across different cells. Technologies - 3G, GPRS, GSM. - In India 900, 1800, 2100 and 2300 MHz, short technology life cycle Satellite Communication - Widely adopted for SCADA, microwave network with satellites acting as repeater, key challenge is delay

Short Range Wireless Solutions - 6LoWPAN - Low power RF in 800 MHz, 900 MHz and 2400 MHz bands - Applications: AMI (NAN), SCADA/EMS (NAN), SCADA/DMS(NAN), Building automation, Microgrids, Distributed generation, Electric Vehicles - Lightweight, versatile - can be used with any physical and data link layer - Scalable - Low power RF unreliable due to uncertain radio connectivity, battery drain, physical tampering

Short Range Wireless Solutions - ZigBee - Short range solution (10-100m), same application areas as 6LoWPAN - Low data rates : 20kbps, 250 kbps - Frequency bands ~ 868 MHz (20 kbps) for EU, 915 MHz (40 kbps) for US and AUS and 2.4 GHz (250 kbps) worldwide - High market penetration in home automation ~ Low cost of modules - Low reliability, poor interoperability with non-ZigBee devices - Low power consumption compared to other sub GHz protocols

Short Range Wireless Solutions - ZigBee - Ideal technology for smart lightning, energy monitoring, home automation, and automatic meter reading - Capable of being connected in a mesh of large number of devices ~ 1000 nodes and more - low processing capabilities, small memory size - Interference from other devices using the license free ISM frequency band (2.4GHz) like WiFi, Bluetooth and Microwave

Short Range Wireless Solutions - WiFi - Frequency 2.4 GHz, limited range, low power RF - Applications: Automatic meter reading (AMR), AMI -NAN, home automation - Higher power consumption than ZigBee (WiFi ~ 700 mW, ZigBee ~ 100 mW) - Based on IEEE 802.11 standard for WLAN, optimized for fast data rates - higher than other RF technologies - Cost effective

Other Low Power Short Range Wireless Technologies 1. Bluetooth - 2.4 GHz, only connects two devices at any time, extremely short range, applied mostly for reading meter data 2. Infrared - 2.4 GHz, extremely short range, line of sight communication, inexpensive, low power consumption, application- meter reading 3. Z Wave - 865 MHz to 956 MHz, compared to ZigBee expensive and not scalable, poor penetration in India Applications: SCADA/EMS, SCADA/DMS, microgrids, substation automation

Long Range Wireless Solutions 1. WiMAX : typically coverage of 20kms or more for 1.8 GHz link, based on IEEE 802.16 standard, Data rates up to 140 Mbps, low latency (10-50 ms) 2. Low Power Wide Area (LPWA): Frequency -TV spectrum, 900 MHz, 2.4 GHz, 5 GHz, Applications: SCADA/EMS, SCADA/DMS, Substation automation 3. Satellite Communication : Frequency - 1 to 40 GHz, affected by weather, WAMS application 4. Long Wave Radio: Typically 100 -200 kHz, extremely high range, reliable, propagation affected by obstacles

Comparison of commonly used technologies

Priority of Data 1. Priority level 1: - Critical for safe operation and control - Eg : Inter-control center communication (IEC 60870), PMU communication (C37.118), Substation automation (IEC 61850), Cyber security (NERC CIP 00X) - Latency : very low (relaying), medium (distribution) - Level of assurance (LOA): High 2. Priority level 2: - Eg : Building automation (BACnet ANSI), Substation and feeder device automation (DNP3), Revenue metering (ANSI C12.19) - Latency : Medium, LOA :Medium