* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download 03_Environment
Electrification wikipedia , lookup
Alternating current wikipedia , lookup
Telecommunications engineering wikipedia , lookup
Distribution management system wikipedia , lookup
Distributed generation wikipedia , lookup
Power engineering wikipedia , lookup
Electric power transmission wikipedia , lookup
Amtrak's 25 Hz traction power system wikipedia , lookup
Transmission line loudspeaker wikipedia , lookup
EE379K/EE394V Smart Grids: Renewable Integration Hurdles Brad Bell, Ross Baldick, Director of Customer Solutions Smart Wires, Inc Department of Electrical and Computer Engineering Spring 2017 Copyright © 2017 1 Outline Utility Scale Renewable Project Development Overview Generation Interconnection Overview Generation Interconnection Cost Allocation Overview Existing Barriers in Transmission Steady State Case Studies ERCOT Model vs. Load Flow Cost Allocation Model Future Integration – Environmental Regulations Clean Power Plan State Level Legislation Copyright © 2017 2 Renewable Project Development Overview Copyright © 2017 3 Renewable Project Development Overview Copyright © 2017 4 Renewable Project Development Overview Key inputs for siting new projects/ project selection Transmission Availability Real Estate Availability Local Permitting Requirements Wind/Solar Resource Strength Regulatory Environment Energy/Capacity Market Health Renewable Energy Incentive Programs Copyright © 2017 5 Generation Interconnection Overview Copyright © 2017 6 Interconnection Study Overview Every Transmission Owner in the U.S. requires a set of interconnection studies to be performed for utility scale generation to interconnect to the grid. The primary intent of the interconnection study process is to allow for the reliable interconnection of resources attempting to site within the existing Transmission Owner’s service region. The interconnection studies will verify that the proposed generation asset will be able to meet the reliability and operating criteria for an asset in the region. The interconnection studies will identify the Transmission Interconnection Facilities necessary to physically interconnect the generation resource. The interconnection studies will identify any Network Upgrades necessary to interconnect the generation resource and assign a cost allocation methodology for procuring the Network Upgrades. Upon completion of an Interconnection Study the generation unit looking to interconnect to the grid may do so based upon the terms of a negotiated Interconnection Agreement (IA). Copyright © 2017 7 Interconnection Study Overview Feasibility Study- Informs the generation asset developer of transmission system constraints that could limit the ability of the unit to generate. System Impact Study- In depth evaluation of the impact of inserting the generation asset onto the transmission system. Performed to identify Network Upgrades and Transmission Interconnection Facilities necessary to physically and electrically interconnect the proposed generation asset to the transmission system. Facilities Study- Determine the final cost and time estimates to construct the Network Upgrades and Transmission Interconnection Facilities necessary to physically and electrically interconnect the proposed generation asset to the transmission system. Copyright © 2017 8 Feasibility Study Overview The Feasibility Study informs the generation asset developer of transmission system constraints that could limit the ability of the unit to generate Transmission constraints are determined by either a DC or AC contingency analysis on an expected future case. The Feasibility Study will present to the project developer(s) the following information List of system binding constraints (Overloaded Element & Binding Contingencies) which can limit the output of the generator(s) in the study. Transmission upgrades and costs necessary to mitigate the constraints to obtain full power output. Performed in ~3 months. Generally performed in PSS/E, PSLF, PowerWorld, Tara, DIgSILENT Copyright © 2017 9 System Impact Study Overview System Impact Study- In depth evaluation of the impact of inserting the generation asset onto the transmission system. Performed to identify Network Upgrades and Transmission Interconnection Facilities necessary to physically and electrically interconnect the proposed generation asset to the transmission system. Steady State- Evaluation of the transmission system under both normal and contingency conditions in accordance with NERC TPL Standards. Short Circuit- Identify the increased level of fault duty on the transmission system as a result of the addition of the generator(s) Stability/Reactive Power Requirement – Will determine the impact of the generation asset on transient stability performance of the transmission system due to system disturbances Performed in ~9-18 months Copyright © 2017 10 Steady State Study Overview The Steady State Study will include the evaluation of the transmission system under both normal and contingency conditions in accordance with NERC TPL Standards. The analysis will include both steady state thermal and voltage analysis. The Steady State Study is a more in depth version of the Feasibility Study. The Steady State Study will present to the project developer(s) the following information Maximum output where no constraints exist. List of system binding constraints (Overloaded Element & Binding Contingencies) which can limit the output of the generator(s) in the study. Maximum output under constraint scenarios Transmission upgrades and costs necessary to mitigate the constraints to obtain full power output. Generally performed in PSS/E, PSLF, PowerWorld, Tara, DIgSILENT Copyright © 2017 11 Steady State Study Overview The Steady State Study Analysis will follow the following steps a) Formulation of Basecase scenario(s) to be studied a) b) c) Minimum of a peak loading case along with one sensitivity non-peak case Wind Integration Sensitivity: High Wind / Low Load case Solar Integration Sensitivity: Fall/Spring/Winter Peaking case. b) Evaluation of Basecase scenario(s) to be studied a) b) Run complete N-1 contingency analysis Identify most limiting constraints on the system c) Insert Interconnecting Generator(s) into the basecase to create the final study case a) b) c) Run complete N-1 contingency analysis Identify the Maximum output where no constraint exists Identify acceptable measures to relieve any identified constraints - New Transmission Line Build - Transmission Line Reconductor - Transformer Replacement - Powerflow Control Devices (Series Reactor, Series Capacitor, Phase Shifting Transformer, Distributed Control Devices) - Unit Deration - Unit Relocation - Special Protection Scheme (SPS) / Remedial Action Scheme (RAS) d) Create Study Report a) Report upgrades and necessary costs required to mitigate any system constraints identified during analysis Copyright © 2017 12 Steady State Case Study #1 Base Case N-1 Analysis 244 MVA/292 MVA Sidney Cabo Graham 122 MVA/122 MVA Powel Copyright © 2017 13 Steady State Case Study #1 Interconnection Customer N-1 Analysis Cabo Sidney Graham Powel Copyright © 2017 14 Steady State Case Study #2 Base Case N-1 Analysis 244 MVA/292 MVA Sidney Cabo Graham 122 MVA/122 MVA Powel Copyright © 2017 15 Steady State Case Study #2 Interconnection Customer N-1 Analysis Cabo Sidney Graham Powel Copyright © 2017 16 Steady State Case Study #2 T-Line Reconductor Solution Cabo Sidney Graham Powel * Example Reconductor Cost = $1-1.2M/mile * Project Cost @ 22.6 miles = $22.6M-27.12M Copyright © 2017 17 Steady State Case Study #2 Special Protection System (SPS) / Remedial Action Scheme (RAS) Cabo Sidney Graham Generation Ramp Back Info • The Sidney – Powell 138 kV line overloads to 124% of its 122 MVA /122 MVA rating. • 151 MVA loading on Sidney – Powell 138 kV line post contingency. • Each unit has a post contingency 34% shift factor on the constrained Sidney – Powel line. • A common SPS/RAS strategy is to have a generator back its generation down automatically post contingency to protect existing transmission equipment Powel Copyright © 2017 18 Steady State Case Study #2 Special Protection System (SPS) / Remedial Action Scheme (RAS) 45 MW Cabo Sidney Graham Generation Ramp Back Strategy • For every MW reduced at Gen A 0.34 MW will be reduced from the Sidney – Powel 138 kV facility • Gen A will create an automatic ramp back scheme that will back its generation down to 45 MW after receiving signal from the Transmission Owner that the Graham – Cabo 138 kV line is out of service. • The Transmission Owner will have the right to disconnect Gen A if it fails to achieve ramping in agreed upon timeline Powel Copyright © 2017 19 Steady State Case Study #2 Powerflow Control / Series Reactor Solution Cabo Sidney Graham Powel * 4.05 ohm/phase series reactor may lower line loading to 95% of rated value. * No other lines in area can be overloaded with powerflow control insertion Copyright © 2017 20 Powerflow Control – Series Reactor Main purpose is to increase line reactance. Thus diverting flow away from circuit where the reactor is applied. Often used in highly meshed networks with available capacity on existing circuits. Often seen as a “last resort” as the devices do not create additional capacity on the system. Fixed device that allows for access to existing underutilized circuits. Increasing line reactance lowers system stability, thus in stability constrained regions series reactors are not often utilized Copyright © 2017 21 Smart Wires Guardian – Distributed Series Reactor DSR • Distributed series reactors serve the same core function as traditional devices, increase line reactance • Each device has a fixed reactance injection • As a fleet allows for variable reactance injection • Three methods of operation: 1. Static, no backhaul comms required 2. Manual Control, controlled by grid operator 3. Set Point Control, operated via setpoint with central override • Embedded sensing technology and fleet level communications Copyright © 2017 22 Steady State Case Study #2 Powerflow Control / Smart Wires Solution Cabo Sidney Graham • 4.05 ohm/phase DSR can eliminate the overload condition • At 600A Smart Wires DSR device can deliver 0.0253Ω reactance per device. Powel • 4.05Ω / 0.026Ω per device = • 160 devices per phase • 480 devices total * No other lines in area can be overloaded with powerflow control insertion Copyright © 2017 23 Series Capacitors Series capacitors are primarily installed in systems with extremely long transmission lines as a way to electrically shorten the lines and reduce system instabilities Typically applied on 230kV lines and above Alleviate thermal and voltage constraints Introduce Subsynchronous Resonance risks Copyright © 2017 24 Smart Wires Router– Distributed Static Synchronous Series Compensator (SSSC) • Connected in series to the transmission line. • Controls effective reactance of a transmission line through voltage injection • Operates in both inductive and capacitive mode of operation • Does not introduce Subsynchronous Resonance (SSR) Issues Power Line XM Current Feedback • Three methods of operation: Power Supply SM S2 Cf 1. Static, no backhaul comms required Control 2. Manual Control, controlled by grid operator Comms 3. Set Point Control, operated via setpoint with central override Lf CDC • Copyright © 2017 Embedded sensing technology and fleet level communications 25 Short Circuit Study The goal of the short circuit study is to assess and identify the increased level of fault duty on the transmission system as a result of the addition of the generator(s) in the study. The short circuit study will identify and address the circuit breakers and transmission buses overdutied by the addition of the generator(s) in the study. The short circuit study will be performed with and without the proposed generation assets. This allows the Transmission Owner to assess the impact of the proposed generator(s) on fault duty level for various fault locations. Identified circuit breakers and transmission busses overdutied will be included in the Interconnection Facilities Study Analysis performed on 3-phase and Single Line – to Ground faults Analysis performed on faults within 3-5 busses from point of interconnection Generally performed in PSS/E, Aspen, Cape Copyright © 2017 26 Stability Study Transient Stability – The capability of the system to return to a stable operating point after the occurrence of a disturbance. Tripping of a Generator Or Line Load dropping Occurrence of a fault When a disturbance does occur the system is no longer in a steady state and you will see changes in rotor speeds and node voltages will deviate from the steady state values The system is stable if the fluctuation in system quantities damp out and the system settles to a steady operating point The system is considered unstable when the deviation in system quantities continue to grow and can lead to tripping of facilities and eventually system collapse Copyright © 2017 27 Stability Study Stable Response Copyright © 2017 28 Stability Study Poorly Damped Copyright © 2017 29 Stability Study Unstable Response Copyright © 2017 30 Stability Study Wind and Solar projects tend to be sited in remote areas of power systems where the fuel resource is most prevalent. These areas are generally remote from synchronous generation and load centers and under certain scenarios can be considered “weak grids” System characteristics and challenges that occur in a “weak grid” can be [1] Highly compensated weak grids can see voltage collapse with in the normal operating voltage range. Static Capacitors or Static Var Compensators contribute to this issue and have limited effectiveness to increasing transfer flows. Renewable projects are essentially connected to a common POI in many instances. The close connection creates a condition such that each plant interacts with each other. A grid with low short circuit ratios and high voltage sensitivity of dV/dQ requires special coordination of various control systems. Normal voltage control settings can result in too much voltage support, in a weak system this can lead to undamped oscillations. Detailed control system modeling is required to study this phenomenon. Voltage Ride Through Capability (HVRT & LVRT). Post contingency bus voltages in a weak grid system tend to deviate higher than in a strong grid scenario. Additional HVRT capability is necessary to maintain a stable response. [1] http://www.ercot.com/content/news/presentations/2014/Panhandle%20Renewable%20Energy%20Zone%20Study%20Report.pdf Copyright © 2017 31 Stability Study Steps considered to alleviate “weak grid” conditions caused by addition of asynchronous generation Increase connectivity to rest of grid with additional transmission lines Synchronous Condensor addition Reactor insertion Implementation of Generic Transmission Limits (GTLs) Increased Voltage Ride Through (VRT) requirements for Intermittent Renewable Resources (IRR) Copyright © 2017 32 Facilities Study The Facility Study determine the final cost and time estimates to construct the Network Upgrades and Transmission Interconnection Facilities necessary to physically and electrically interconnect the proposed Generation asset to the transmission system. Results of the System Impact Study are the main inputs to the Facilities Study. The study develops a detailed cost estimate that includes equipment, engineering, procurement and construction costs to the most accurate accuracy possible based on in-service dates provided by the generation asset developer. Results of the Facilities study are included in a deliverable to the generation asset developer. The results are often included in the Generation Interconnection Agreement. Performed in 3-4 months Copyright © 2017 33 Generation Interconnection Cost Allocation Methods Copyright © 2017 34 Definitions Generator Interconnection Facilities (GIF) – Generator owned transmission facilities necessary to interconnect the unit Transmission Interconnection Facilities (TIF) – Transmission Owner owned transmission facilities necessary for the physical interconnection of the unit Point Of Interconnection (POI) – Location where the Generation Interconnection Facilities Interconnect to the Transmission Interconnection Faciliites. “Change of ownership point.” Network Upgrades – Transmission system upgrades necessary to prevent unreliable operating conditions on the grid under prior outage conditions. Copyright © 2017 35 Gen. Interconnection Cost Allocation Copyright © 2017 36 Gen. Interconnection Cost Allocation: ERCOT Method PUCT Substantive Rule §25.195.(c).1 – Terms and Condition of Transmission Service – Construction of New Facilities. When an eligible transmission service customer requests transmission service for a new generating source that is planned to be interconnected with a TSP's transmission network, the transmission service customer shall be responsible for the cost of installing step-up transformers to transform the output of the generator to a transmission voltage level and protective devices at the point of interconnection capable of electrically isolating the generating source owned by the transmission service customer. The TSP shall be responsible, pursuant to paragraph (2) of this subsection, for the cost of installing any other interconnection facilities that are designed to operate at a transmission voltage level and any other upgrades on its transmission system that may be necessary to accommodate the requested transmission service Copyright © 2017 37 Gen. Interconnection Cost Allocation: ERCOT Method Generator Interconnection Facilities (GIF) are physically constructed and financially funded by Generation Owner. GIF include Generator Collector Substation Generator Step-Up (GSU) Transformer Circuit Breaker on high side of GSU Generation Tie Line (Gen can decide ownership) Transmission Interconnection Facilities(TIF) will be physically constructed by the Transmission Owner (TO). Transmission Owner will finance the TIF through their rate base. New substation bay if interconnecting to an existing substation New substation if interconnecting to an existing line Generation Tie Line (Gen can decide ownership) Copyright © 2017 38 Gen. Interconnection Cost Allocation: ERCOT Method Network Upgrades will NOT be constructed. Network Upgrades are NOT required for reliability in ERCOT ERCOT does not have a Generation Deliverability Reliability Standard Transmission Owner is not responsible for guaranteeing any deliverability of an interconnecting Generator to the market. Interconnection Policies were put in service to create greatest amount of competition in ERCOT’s energy only market Copyright © 2017 39 Gen. Interconnection Cost Allocation: Load Flow Cost Allocation Method Generator Interconnection Facilities (GIF) are physically constructed and financially funded by Generation Owner. GIF include Generator Collector Substation Generator Step-Up (GSU) Transformer Circuit Breaker on high side of GSU Generation Tie Line Transmission Interconnection Facilities(TIF) will be physically constructed by the Transmission Owner (TO). Generation Owner will financially fund TIF. TIF include. New substation bay if interconnecting to an existing substation New substation if interconnecting to an existing line Copyright © 2017 40 Gen. Interconnection Cost Allocation: Load Flow Cost Allocation Method Network Upgrades will be physically constructed by the Transmission Owner (TO). Network Upgrades will be financially funded by the Generation Owner. Network Upgrades are deemed necessary for system reliability. Network Upgrades are deemed necessary for Capacity Market operation Copyright © 2017 41 Gen. Interconnection Cost Allocation: Load Flow Cost Allocation Method Transmission Credits/Rights are assigned to Generation Owner in order to offset Network Upgrade Costs Transmission Credits are granted to the Generation Owner to allow the asset owner access their transmission investment. Load Flow Cost Allocation methods are commonly used in regions that utilize a Generation Deliverability Reliability standard. Copyright © 2017 42 Gen. Interconnection Cost Allocation: Load Flow Cost Allocation Method Network Upgrades for a set of projects (one or more identified Network Upgrades) is allocated based on the MW impact from each project on the constrained facilities in the Post Contingency Case. Cost is allocated based on the pro rata share of the MW contribution on all constraints from each project. Copyright © 2017 43 Gen. Interconnection Cost Allocation: Load Flow Cost Allocation Method Total MW Contribution on constrained facilities from generators X, Y, and Z Total MW flowing on all constraints from Steady State Study = X+Y+Z Generator X’s share of the Network Upgrade Costs = X/(X+Y+Z) Generator Y’s share of the Network Upgrade Costs = Y/(X+Y+Z) Generator Z’s share of the Network Upgrade Costs = Z/(X+Y+Z) Copyright © 2017 44 Steady State Case Study #2 Interconnection Customer N-1 Analysis Cabo Sidney Graham Powel Copyright © 2017 45 Steady State Case Study #2 T-Line Reconductor Solution Cabo Sidney Graham Powel * Example Reconductor Cost = $1-1.2M/mile * Project Cost @ 22.6 miles = $22.6M-27.12M Copyright © 2017 46 ERCOT Cost Allocation Ex. Generator A – 150 MW Generator Owner ($) Gen Collector Station- $4M GSU - $2M High Side Breaker - $1M TOTAL = $7M Transmission Owner ($) Gen Tie Line - $5M Substation Bay - $2.5M Total = $7.5M Generator B – 100 MW Generator Owner ($) Gen Collector Station- $4M GSU - $2M High Side Breaker - $1M TOTAL = $7M Transmission Owner ($) Gen Tie Line - $5M Substation Bay - $2.5M Total = $7.5M Copyright © 2017 47 Load Flow Cost Allocation Ex. Cost is allocated based on the pro rata share of the MW contribution on all constraints from each project. Total MW Contribution on constraints from Gens A and B X = x1 + x2 = 51 + 34 = 85 Total MW constraints from System Impact Study = X = 85 MW Copyright © 2017 48 Load Flow Cost Allocation EX. Generator A’s share of the Network Upgrade costs = 51/(51+34) = 60% (x) $27.1M = $16.26M Generator B’s share of the Network Upgrade Costs = 34/(51+34) = 40% (x) $27.1M = $10.84M Copyright © 2017 49 Load Flow Cost Allocation Ex. Generator A – 150 MW Generator Owner ($) Gen Collector Station- $4M GSU - $2M High Side Breaker - $1M Gen Tie Line - $5M Substation Bay - $2.5M Network Upgrades - $16.26M TOTAL = $30.76M Transmission Owner ($) TOTAL = $0M Generator A – 100 MW Generator Owner ($) Gen Collector Station- $4M GSU - $2M High Side Breaker - $1M Gen Tie Line - $5M Substation Bay - $2.5M Network Upgrades - $10.84M TOTAL = $25.34M Transmission Owner ($) TOTAL = $0M Copyright © 2017 50 Future Integration – Environmental Regulations Copyright © 2017 51 Clean Power Plan Overview “Announced August 3, 2015, The Clean Power Plan (CPP) will reduce carbon pollution from power plants while maintaining energy reliability and affordability.” The final Clean Power Plan relies on a federal-state partnership to reduce carbon pollution from the biggest sources – power plants. States develop and implement plans that ensure that the power plants in their state – either individually, together or in combination with other measures – achieve the interim CO2 emissions performance rates over the period of 2022 to 2029 and the final CO2 emission performance rates, ratebased goals or mass-based goals by 2030. Copyright © 2017 52 Clean Power Plan Overview In the final Clean Power Plan, EPA determined that the Best System of Emission Reduction “BSER” consists of three building blocks: Building Block 1 – Reducing the carbon intensity of electricity generation by improving the heat rate of existing coal-fired power plants. Building Block 2 – Substituting increased electricity generation from loweremitting existing natural gas plants for reduced generation from higheremitting coal-fired power plants. Building Block 3 - Substituting increased electricity generation from new zeroemitting renewable energy sources (like wind and solar) for reduced generation from existing coal-fired power plants. State plans must be submitted by September 2016. States could submit an initial plan with an extension to September 2018 Final state submissions must demonstrate that their plan will meet the CO2 emissions requirements by 2030. Copyright © 2017 53 CPP, ERCOT Impacts In 2015 ERCOT performed a study to evaluate the potential reliability implications of CPP compliance; the analysis does not indicate any assessment of the policy merits or legal permissibility of either compliance approach. ERCOT modeled four scenarios over the timeframe 2016 to 2030 to evaluate the implications of the CPP on reliability in the ERCOT region: Baseline – This scenario estimates a baseline of the ERCOT system under current market trends against which anticipated CPP changes are compared. CO2 Limit – This scenario applies the limits in the CPP to the ERCOT system to determine the least-cost way to comply with the limits. This scenario does not place a price on CO2 emissions. CO2 Price – This scenario applies a CO2 emissions price that causes the ERCOT system to achieve compliance with the limits. CO2 Price & Regional Haze – This scenario adds the impacts of compliance with the proposed Regional Haze FIP to the CO2 price scenario. http://www.ercot.com/content/news/presentations/2015/ERCOT_Analysis_of_the_Impacts_of_the_Clean_Power_Plan-Final_.pdf Copyright © 2017 54 CPP, ERCOT Impacts The ERCOT Analysis indicated that the following generation retirements and generation additions would be necessary for the four scenarios. The Baseline case indicates the changes in times due to economics, not compliance with any environmental regulations Unit Retirements by 2030 Capacity Additions by 2030 http://www.ercot.com/content/news/presentations/2015/ERCOT_Analysis_of_the_Impacts_of_the_Clean_Power_Plan-Final_.pdf Copyright © 2017 55 CPP, ERCOT Impacts The following charts provide insight into the magnitude of generation mix change due to varying scenarios Generation by Fuel Year 2022 Generation by Fuel Year 2030 Copyright © 2017 56 CPP, ERCOT Impacts Copyright © 2017 57 CPP, ERCOT Impacts Impact on LMPs and Retail Rates Copyright © 2017 58 State Level Legislation Currently 29 states have enacted Renewable Portfolio Standard (RPS) / Renewable Energy Standard (RES) - Regulatory mandates set to increase production of energy from renewable generation resources. Most often a percentage of renewable energy date May require installed capacity of requirement by date Can have percentage based cost caps which limit increases to ratepayers bills. Copyright © 2017 59 Summary Utility Scale Renewable Project Development Overview Generation Interconnection Overview Generation Interconnection Cost Allocation Overview Existing Barriers in Transmission Steady State Case Studies ERCOT Model vs. Load Flow Cost Allocation Future Integration – Environmental Regulations Clean Power Plan State Level Legislation Copyright © 2017 60 Homework Exercises: Due Thurs Feb, 9th (1) Utilize the PowerWorld Case on the course website titled 13BusSystem_Basecase.PWB to complete the following Steady State Study example. Copyright © 2017 61 Homework Exercises: Due Thurs Feb, 9th 2. The Clean Power Plan allows states to achieve their CO2 emissions performance by Rate-Based or Mass-Based Compliance Pathways. Define Rate-Based and Mass-Based Compliance Pathways What are the units for emissions measured under Rate-Based Compliance? Under Mass-Based Compliance? The following is a link to the PJM Clean Power Plan Compliance Assessment. In a few paragraphs discuss the effects of Mass-Based Compliance and Rate-Based Compliance on the PJM Region. http://www.pjm.com/~/media/library/reports-notices/clean-power-plan/20160901-cpp-compliance-assessment.ashx Copyright © 2017 62