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Planning Microgrids for Resilience and Grid Opera4ons Support
Jim Reilly, Consultant
ISGT Washington, DC
February 19, 2014
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Power System as a Collec1on of Microgrids
“During severe system disturbances, large transmission systems will break up into preplanned islands where load and genera1on are balanced. As DER becomes more integrated into the distribu1on system, it will be possible to break up the distribu1on system into islands that are also self-‐regula1ng, providing extremely high levels of power quality to cri1cal loads.
“These islands may be as small as 10 MW of load or as large as several hundred MW. The islands could be pre-‐planned and ins1tuted as a result of poten1al con1ngencies, or they could be developed in real 1me using a set of algorithms that decide the best system configura1on for any post-‐con1ngency set of available circuits and genera1on.” -‐ The Distribu-on System of the Future, John D. Kueck and Brendan J. Kirbye, The Electricity Journal. 2003.
Advanced Microgrid The value of microgrids to protect the na1on’s electrical grid from power outages is becoming increasingly important in the face of the increased frequency and intensity of events caused by severe weather.
Advanced microgrids will ü Serve to mi1gate power disrup1on economic impacts ü Contain all the essen1al elements of a large-‐scale grid, such as the ability to (a) balance electrical demand
with sources, (b) schedule the dispatch of resources, and (c) preserve grid reliability (both adequacy and security)
ü Be able to interact with, connect to, and disconnect from another grid
An advanced microgrid is aptly named “micro” in the sense that a power ra1ng of 1 MW (plus or minus one order of magnitude) is approximately a million 1mes smaller than the U.S. power grid’s peak load of 1 TW. Some of the complexi1es required for a large grid such as complicated market opera1ons systems, state es1ma1on systems, complex resource commitment, and dispatch algorithms will be simplified. New advanced microgrids will enable the user the flexibility to securely manage the reliability and resiliency of the system and connected loads. By shiUing resources and par11oning the systems in different configura1ons, a system-‐survival resiliency essen1ally is created. System owners can then op1mally use system resources to address threats and poten1al consequences, and even respond to short-‐1me-‐frame priority changes that may occur.
Microgrids and Resilience An advanced microgrid with economically and func1onally op1mized energy storage will § provide voltage and frequency regula1on to maintain desired electric grid balance between loads and generated power in many distribu1on-‐system sectors. § have a built-‐in ability to separate and isolate itself from the u1lity seamlessly with liXle or no disrup1on to the loads within the microgrid. The separa1on can occur as a result of scheduled, dispatched, or autonomous commands. § be dispatched or automa1cally reconnected to an electric grid when condi1ons return to normal… and automa1cally synchronize to primary power sources before reconnec1ng to the restored grid.
Technologies including advanced and secure communica1on and controls, building controls, DG, and inverters already are commercially available, but even more advanced func1onality will be needed for advanced microgrid systems. CHP systems have demonstrated their poten1al by maintaining power and heat at several ins1tu1ons following Superstorm Sandy.
Key Planning Considera1ons
§ Loca1on – Physical and Electrical § Resource Adequacy – Genera1on § Design – Physical and Electrical § Cri1cal and Non-‐cri1cal Loads § Resource for Distribu1on System Operator § Resource for Transmission System Operator
Defini1on of Resilience
Source: Terry Boston, PJM, Grid 20/20. November 2013.
Cri1cal and Non-‐cri1cal Loads
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Microgrids can be designed (configured), installed and operated according to the requirements of critical and non-critical loads.
Power supply issues during disasters are a grid’s problem transferred to load. - Prof. Alexis Kwasinski
REILLY ASSOCIATES
The value streams for microgrids flow from meeting the requirements of customers with respect to their needs for critical and non-critical loads.
System Collapse and Power System Restora1on
Begin restora1on process
Island(s) blackout Load / genera1on
imbalance in island(s)
Forma1on of islands System Separa1on Ini1a1ng event(s)
Common Sequence of Events in Blackout
Source: System Restoration Workshop Part 1, PJM State & Member Training Dept., 2012.
Islands = Microgrids
The islands that are formed by power system operators for purposes of power system restora1on are microgrids. Moreover, exis1ng microgrids that are connected to the grid are stable islands that are resources for power system restora1on.
Microgrid Definition The term “DR island systems”, sometimes referred to as microgrids, is used for electric power systems that:
1. have DR and load 2. have the ability to disconnect from and parallel with the area EPS 3. include the local EPS and may include portions of the area EPS, and 4. are intentionally planned.
DR island systems can be either local EPS islands or area EPS islands.
- IEEE Std 1547.4™-2011, IEEE Guide for Design, Operation, and Integration of Distributed Resource Island Systems with Electric Power Systems
Inten1onal Islanding
Frequency Collapse (T-‐0 min)
Frequency becomes Unstable and Phase Angle difference Exceeds 120⁰
5:10 PM 5:16 PM
120⁰ Diff
Houston Blackout, June 15, 2005
Microgrids and Power System Operations in the Event of Catastrophic Events Impacting the Bulk Power System and Widespread Outages – Blackouts Framework for Grid Resiliency
CONCEPTUAL Microgrids
TOOLS µEMS
PROCEDURAL Inten1onal islanding + interconnec1on
Microgrids and
Power System Opera1ons
Current Situa1on and Opportunity
Synchrophasors / WAMS are extensively installed and PMU data is ready to be made available to system operators. But, WAMS are being used for event analysis, not real-‐1me power system opera1ons or informa1on sharing with other cri1cal infrastructure (ES-‐ISAC). Thus, as currently deployed, these technologies are not used for opera1ons under normal, abnormal, or restora1on condi1ons. However, these technologies can be used today to effec1vely mi1gate disrup1ons to the power delivery system and, in the event of system collapse (blackouts), significantly reduce restora1on 1mes. This can be done by conceptualizing the grid as a collec1on of microgrids. Furthermore, a power system restora1on philosophy built around such a concept is consistent with exis1ng NERC reliability standards and industry prac1ces.*
* EOP-005-1 System Restoration Plans; EOP-005-2 System Restoration from Blackstart Resources; EOP-006-1 Reliability Coordination - System Restoration; EOP-006-2 System Restoration Coordination; and PSR and black start planning and drills.
Technical Solu1on / Tools
§ PMUs in pre-‐defined islands, i.e. real or virtual microgrids
§ Models / Simula1on § GIS / Visualiza1on § Data exchange / communica1on protocols § Informa1on sharing – microgrid operators, DSO, TSO
§ Distributed hierarchical controls from microgrid to DMS to EMS
CONTRIBUTIONS – DOE-‐OE and NERC
DOE-‐OE § Conceptual Model for Microgrids in the Power Delivery System § Research to Develop Opera1onal Tools – DSO + TSO – for islanded configura1ons § Training for system operators on tools (module for drill training) NERC § Tools and procedures to enhance RTO/ISO compliance with Reliability Standards for Black start and System Restora1on.
Future Work
§ Develop solu1ons and tools – R&D on microgrid concepts and visualiza1on of PMU data – for power system restora1on that u1lize exis1ng PMU and WAMS installa1ons and meet power system operator requirements for PSR.
§ Structure scenarios for a PSR drill to apply microgrid concepts and synchrophasor-‐based tools.
§ Develop distributed hierarchical controls from microgrid to DMS to EMS – opera1onal data and controls from local EPS to area EPS to bulk power system.
§ Collect the results of power system operators’ experiences and lessons learned and make recommenda1ons for advances in technology and opera1onal procedures.
MULTI-‐POWER QUALITY MICROGRID
SUPPLEMENTAL SLIDES
Mul1-‐power Quality Microgrid
Defini4on – The Mul1 Power Quality Microgrid (MPQM) enables the supply of power to cri1cal loads
at mul1ple levels of power quality at higher levels than are supplied normally by the distribu1on u1lity.
– The MPQM does this by u1lizing Distributed Energy Resources (DER) and power from the distribu1on u1lity (grid) in a mutually complementary manner.
Func4ons – The MPQM can con1nue to supply power at a high power quality level, when grid
connected, when the DER is grid-‐connected, or when the grid suffers from an outage and the DER is in an islanding opera1on mode.
Simplified Model MPQM – Focuses on the func1onality of “Mul1ple Power Quality Supply” – Describes the supply of classes of power quality
REILLY ASSOCIATES
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REILLY ASSOCIATES
PV Panels 50 kWp
(IPS) Integrated
Power Supply DVRs
200 kVA 600 kVA
MCFC 250 kW Gas Gen-
sets 350 kW X 2
Sendai City
Overview of Sendai Microgrid Geographical location of Sendai City
Sendai Microgrid Mul1ple Power Quality Microgrid
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Simplified MPQM Model Configura1on
REILLY ASSOCIATES
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Generation Facility • Multiple DER • Two operational modes
• Grid Connection Mode • Islanding Mode
Switches • Switch 1 – PCC between
MPQM and commercial grid • Switch 2 – Boundary point of
microgrid islanding mode A ClassLoad
A ClassLoad
A ClassLoad
NormalClassLoad
NormalClassLoad
NormalClassLoad
B ClassLoad
B ClassLoad
B ClassLoad
DVR IPS
Grid DERs
Optimized operation between the grid power and DGs
Power Quality ImprovementNormal
Quality
A Class Quality SystemB Class Quality System
SWITCH1SWITCH2
Configura1on of the microgrid in the diagram above shows three classes of power quality. The Sendai Microgrid offers five classes of power quality (DC Supply, A, B1, B2 & B3) defined according to user needs.
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