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Massachusetts DTE DG Interconnection Collaborative Collaborative Results Restructuring Roundtable March 28, 2003. EPS. EPS. Customer. Customer. Customer. Customer. Customer. EPS. Customer Facility. Customer Facility. Customer Facility. Customer Facility.
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Massachusetts DTE DG Interconnection Collaborative Collaborative Results Restructuring Roundtable March 28, 2003
EPS EPS Customer Customer Customer Customer Customer EPS Customer Facility Customer Facility Customer Facility Customer Facility What Is An Interconnect (Nomenclature)? The interface between Distributed Generation (DG) equipment, (the Facility) and the grid (the area Electrical Power System or EPS) Point of Common Coupling (PCC) EPS Radial Customer Site (interconnecting facility) Network Load 1 Load 2 Load 3 DG (generating facility)
Collaborative Effort Has Resulted in the Creation of Four Processes • Simplest process • Minimal or no costs expected • Shortest time • Still reasonably simple • Strict limits • Modest fees, longer time interval • Standardized process • Screens / Supplemental Review technical approach • Moderate fees , longer time interval • Standardized process • Similar to current process • Essentially based on actual costs • Potentially long time interval • Simplified - Radial • Simplified – Network • Expedited – Radial • Standard – Radial or Network
Network or Radial EPS? >7.5% of circuit peak load? ≤10kW Qualified Inverter? Customer Submits Application Complete Simplified Process Radial Yes Yes No No To Network Process To Supplemental Review To Expedited Screens Simplified Radial Process • One sheet application and approval • Only three technical screens • Radial distribution systems only • Limited to 10kW or less • Inverter-based, UL1741 listed • Minimal or no costs expected • 15 business days max
Switch Network Protector Breaker Transformer Network Protector Fuse Secondary Bus Substation Circuit 1 2 3 NP NP NP Primary Feeders Customer Customer Loads Customer Customer Customer Simplified Network Process • One sheet application and approval • Additional technical limits • Spot network only • Tighter capacity limit • $100 or $300 fee • 40 to 100 days max Area or Grid Network Spot Network
ExpeditedRadial Process Is Facility Certified? Supplemental Review No Yes Pass Starting V Drop? • Standardized application • Five additional technical screens • If passed, only a review of possible EPS modifications remains • If not passed, Supplemental Review determines if application can remain in Expedited or go to Standard process • Fee range from $300 to $3,750, possible EPS upgrades • 40 or 60 days max No Yes Pass Fault Contrib? No Yes Pass Config. Screen? No Yes Pass Trans. Stability? No (If required) Company makes EPS Modifications Yes Suppl. Review Determine Req.? Company Sends Written Authorization EPS Modification Check Optional Witness Test Yes Customer Installs Facility No To Standard Process
Basis For Screens Circuit impact Fault handling, fuse desensitizing & nuisance trip Short circuit handling Proper connection Single phase imbalance Circuit size versus DG size DG contribution to fault Short circuit interrupting capability limit Three-wire and four-wire circuit criteria Nameplate limits
Standard Review Process • Standardized application • Initial review • Initial review • Impact study if required • Facility study if required • Fee range from $300 to actual costs (no limit) • 125 or 150 days max (If required) Company makes EPS Modifications initial review optional scoping meeting Impact Study if required Facilities Study if required Company Sends Written Authorization Optional Witness Test Customer Installs Facility
Process InReport Customer submits complete application and application fee 1. Is the Point of Common Coupling on a Radial Distribution System? No Go to Figure 2 Customer opts for Standard Process Yes 2. Is the aggregate generating Facility capacity on the circuit less than 7.5% of circuit annual peak load? Perform Supplemental Review InitiateStandard Process initial review No Yes 3. Does the facility use a Qualified Inverter with a power rating of 10 kW or less? No Yes • Does the facility pass all the following screens? • 4. Is the Facility certified? • 5. Is the Starting Voltage Drop Screen met? • 6. Is the Fault Current Contribution Screen met? • 7. Is the Service Configuration Screen met? • 8. Is the Transient Stability Screen met? No Does Supplemental Review determine requirements? Yes Yes No System Modification Check Company provides cost estimate and schedule for Interconnection Study(ies) Customer accepts Company performs Impact and Facility (if required) Study Facility Processed forSimplified InterconnectionUnder DG Tariff Facility Processed forExpedited InterconnectionUnder DG Tariff Facility Processed forStandard InterconnectionUnder DG Tariff
Simplified Process For Networks Is the Point of Common Coupling on a spot network? No Initiate Standard process Yes Does the facility use a Qualified Inverter? (UL1741) No Yes Is the Facility 10kW or less? No Yes Is the aggregate generating Facility capacity less than 1/15 of Customer’s minimum load? No Yes System Modification Check Yes Facility Processed for Simplified Interconnection Under DG Tariff
Minimum Technical Requirements Set By • IEEE P1547 – “Draft Standard for Distributed Resources Interconnected with Electric Power Systems”. • Underwriters Laboratories Inc. Standard UL 1741, November 1, 2002 “Inverters, Converters and Charge Controllers for Use in Independent Power Systems • IEEE 929-2000, “IEEE Recommended Practice for Utility Interface of Photovoltaic (PV) Systems.”
IEEE Std P1547 Key Clauses • Voltage regulation • Integration with EPS grounding • Synchronization • Surge Withstand • Response to EPS abnormal conditions • Response to EPS faults • EPS reclosing coordination • Voltage detection and limits • Frequency detection and limits Reconnection to EPS Limitation of Flicker Harmonics Unintentional islanding Design testing Commissioning testing
Additional Technical Requirements • For Facilities qualified for Simplified Process • Must be “qualified” to UL 1741 • Disconnect switch may be required • For Facilities >10kW: • Non-export functionality if not allowed to export • Disconnect switch or comparable device • Possible NPCC criteria • For Facilities with rotating generators • Interrupting Device (ID) • Synchronizing Device (could be part of ID) • Additional protection equipment requirements • For large Facilities • Transfer trip? • High speed protection • Communications channels • Reactive capability (Note: Tariff also covers standby gensets that momentary parallel)
Qualified Inverter ≤ 10 kW Qualified DG Any DG Qualified Inverter ≤ 10 kW Fee Schedules
Qualified Inverter ≤ 10 kW Qualified DG Any DG Qualified Inverter ≤ 10 kW Maximum Time Lines
Application Process • Prior Notice • One Point of Contact • Application submittal • Review • Load flow and Voltage constraints • Short Circuit and Protection review • System Modification Review • Agreement
Application Information • General (Single) or Specific Form? • Simplified process (Inverter) • Applicant contact information • Location of generator • Proof of UL1741 • Others • Application contact information • Location of generator • Machine technical data • Proposed drawings
Massachusetts Company Contacts • Boston Edison, Cambridge Electric, Com Electric (NStar Electric) • Frank Gundal • Tel: (781) 441-8151 • Email: frank_gundal@nstaronline.com • Fitchburg Gas & Electric (Unitil) • John Bonazoli P.E. • Tel: (603) 773-6456 • e-mail: bonazoli@unitil.com • Massachusetts Electric Co. (National Grid) • John J. Bzura, Ph.D., P.E., M.B.A. • Tel: (508) 421-7642 • e-mail: john.bzura@us.ngrid.com • Western Massachusetts Electric( Northeast Utilities) • Doug Clarke • Tel: 413-585-1726 • Email: clarkdp@nu.com
How Does DG Affect Distribution Companies? • Protection • Generator Protection • Coordination • Reliability Effects • Planning Procedures • Peak Load Planning • Firm Capacity
Interconnection Process Advantages • Standard Process • Easier planning for customer • More Efficient with time • Less time Consuming • Consistent Fees • Known Costs to customer • Known Process for customer
Challenges for Distribution Company • General Requirements • Interpretations • Analysis of compliance • Testing Requirements • New devices • Time Lines • Reports • Interconnection agreement
Future Efforts • Quarterly Collaborative Meetings • Interconnection updates • Numbers of projects and applications • Annual Documentation sharing • Detailed process information • Process Adjustments as needed
Upcoming Tariff Document 7 2 13 11 2 3 1 2 1 2 • 1.0 Introduction • 2.0 Responsibility of the Parties • 3.0 Process Overview • 4.0 Interconnection Req. • 5.0 General Operating Req. • 6.0 Metering, Monitoring, and Communication • 7.0 Responsibility For Costs of Interconnecting a Facility • 8.0 Dispute Resolution Process • 9.0 Confidentiality Statement • 10.0 Insurance Req. 7 1 2 5 1 3 3 2 Exhibit A – Interconnection Service Agreement template Exhibit B – Third Party Owner Agreement Exhibit C – Simplified Application Exhibit D – Expedited/Standard Application Exhibit E – Supplemental Review Agreement Exhibit F – Impact Study Agreement Exhibit G – Facility Study Agreement Exhibit H – Qualifying Facilities Discussed already,from Collab. report, or new effort