Control and Protection Functions in a Strong and Robust Smart Grid Invited Lecture at SGEPRI, SGCC, Nanjing, China, 12 Aug 2017 Professor Saifur Rahman Director, Virginia Tech Advanced Research Inst., USA President-elect, IEEE Power & Energy Society Virginia Tech Research Center Arlington, Virginia, USA PPT slides will be available at 2 www.saifurrahman.org 2 1
www.saifurrahman.org 3 Lecture Slides on www.saifurrahman.org 4 2
What is the Smart Grid? 5 This is the Electric Power Grid 6 3
Motivation for a Smart Grid Desire to make the grid smarter, safer, reliable and more cost-effective using advanced sensors, communication technologies and distributed computing. 7 Difference Between a Normal Grid and a Smart Grid 8 Normal Phone Smart Phone 4
Smart Grid Starting and End Points From Generator to Refrigerator Power Plant Transmission Distribution Home Business End-use Appliances 9 Merging Power Flow with Information Flow Integrated Communications 10 5
Electric Power & Communication Infrastructures 1.Power Infrastructure Data network Users Central Generating Station Step-Up Transformer 2. Information Infrastructure Control Center Distribution Substation Gas Turbine Receiving Station Distribution Substation Recip Engine Microturbine Distribution Substation Photo voltaics Residential Data Concentrator Recip Engine Cogeneration Fuel cell Commercial Batteries Flywheel Residential Industrial Commercial 11 Source: EPRI Evolution of the Grid 12 Source: Altalink, Alberta, Canada 6
Building Blocks of the Smart Grid 13 Potentials of a Smart Grid * 14 Source: US DoE 7
Attributes of the Smart Grid? 15 Source: EPRI Many Definitions But All Roads Pointing to: Sensors. Two Way Communication. Information Management.Intelligence 16 Source: EPRI 8
Characterization of Smart Grid 1. Increased use of digital information and control technologies 2. Dynamic optimization of grid operations and resources with full cybersecurity 3. Deployment and grid-integration of distributed energy resources 4. Operation of demand response and energy efficiency programs 5. Deployment of smart technologies for metering, communications concerning grid operations and status including distribution automation 6. Integration of consumer-owned smart devices and technologies and 7. Deployment and control of electric vehicles and storage thermal, mechanical and electrical Source: US Energy Independence and Security Act (EISA) of 2007 Section 1301 17 Is Smart Grid the Internet for Electricity? Not Really!! The power network must be absolutely reliable, no delay allowed Endpoints must be much lower cost Device hardware can t be upgraded often Can t just ignore very rural customers Need security all the time, not just sometimes Applications are still being defined Physical - Network - Application 18 9
Secure, Resilient and Adaptable Grid or, A Strong Grid 19 Advanced Control is Needed The smart grid requires advanced control at both component and system levels. Different non-linear controls, such as back-stepping control, feedback linearization, model predictive control, and sliding mode control are applied to control DERs, and their grid integration. 20 10
Relying on Smart Grid Communications As speedy communication facilities, such as fibreoptics, microwave, GSM/GPRS, 3G/4G are becoming the integral parts of the functioning smart grid, the integration of multi-agent systems (MAS) in smart grid applications is becoming simple and feasible. 21 What are Multi-agent Systems (MAS) Agent is a piece of software that is designed to accomplish a certain objective. Multi-agent system (MAS) consists of multiple agents, each of which works independently to achieve a common system goal. MAS features are adaptive, proactive and autonomous and can respond to external environment rapidly without human intervention. 22 11
Value for Multi-agent Systems Multi-agent systems (MAS) provide autonomy, reactivity and proactivity. MAS are complex systems composed of several autonomous agents with only local knowledge and limited abilities, but are able to interact in order to achieve a global objective. MAS use a new programming paradigm to implement agents. 23 Examples of MAS Applications in Smart Grid Distribution domain: Distribution automation/fault isolation and restoration of electric power grid Customer domain: Building energy management Demand response 24 12
MAS for Protection & Circuit Restoration S&C Electric IntelliTeam Allows peer-to-peer communication Can have up to 8 automatically controlled switching/fault-interrupting devices Each Device (e.g., switch, fault interrupting device) Monitors real-time voltage, current and loads Know its key settings, e.g., priority, switch function Exchange information on current, voltage and loads 25 MAS for Circuit Restoration (Cont d) Fault isolation: is handled by protection features built-in in fault interruption and sectionalizing switches. Service restoration: is handled by software agents in IntelliTeam: Seeking all possible sources to restore the service Identifying the source that has sufficient capacity Coordinating switching actions to restore the service Needs the communication layer to allow coordination of software agents and data exchanges for restoration 26 13
8/1/17 Event 1: Loss of Source#1 27 Event 2: Switch Identifies Loss-of-Source and Opens 28 14
Event 3: IntelliTeam Closes the Switch 29 Event 4: Power is Restored in 16 Secs 30 15
Agent Applications Building Energy Management (BEM) BEMOSS is a Building Energy Management Open Source Software (BEMOSS) solution that is engineered to improve sensing and control of equipment in small- and medium-sized commercial buildings. BEMOSS URL: www.bemoss.org Three major loads in buildings HVAC Lighting loads Plug loads Improves energy efficiency and facilitates demand response implementation in buildings. 31 BEMOSS Architecture Sensors/ PowerMeters CT50 (WiFi ) CT80 (ZigBe e SE) CT30 (WiFi) BEMOSS Core Power meter (Modbus) Power meter (BACnet/M odbus) Light sensor (BACnet) ICM (WiFi) Occupanc y sensor (BACnet) Nest (WiFi) HVAC Load Controllers VAV controller (Modbus) RTU (Modbus) Step-dimmed Lighting Philips Hue Light switch ballast load (WiFi) (ZigBee) (WiFi) controller (BACnet) Lighting Load Controllers Plug load controller (BACnet) Smart plug (ZigBee) Smart plug (WiFi) Plug Load Controllers 32 16
Agent Applications in BEMOSS DER monitoring and control (PV, storage) Energy Savings Demand response Fault detection Illuminance-based control 33 Monitoring & Control of Renewables Smart inverter control 34 17
BEMOSS -Plus for Energy Savings Outdoor temperature profiles: Indoor temperature set-points: 25,000 sqft building in Alexandria, VA HVAC load: Raising the set point from 6am-6pm demonstrates 10.5% energy savings in HVAC load per degree increase. 35 OpenADR signal Demand Response BEMOSS accepts an OpenADR signal and performs control of HVAC, lighting and plug loads. BEMOSS Demand limit (kw) & time/duration OpenADR agent Pre-set knowledge of load priority and occupant preference HVAC agents Lighting load agent Plug load agent 36 Increase setpoint Reduce brightness Turn off selected plug loads 18
Fault Detection BEMOSS sends alerts on abnormal indoor temperature behaviors BEMOSS sends alerts when indoor temperature goes above/below certain thresholds Similar applications possible for circuit fault detection 37 The alert was sent at 17:00 when AC was not cooling enough, indicating potential AC failure Illuminance-based Control BEMOSS adjusts light intensity based on ambient light conditions 38 19
Thank You Saifur Rahman, PhD srahman@bemcontrols.com 20