Massachusetts DTE DG Interconnection Collaborative DG Cluster Proposal November 12, 2002

1. Massachusetts DTE DG Interconnection Collaborative DG Cluster Proposal November 12, 2002

2. EPS EPS Customer Customer Customer Customer Customer EPS Customer Facility Customer Facility Customer Facility Customer Facility What Is An Interconnect (Nomenclature)? Basically, the interface between Distributed Generation (DG) equipment and the grid, called the Area Electrical Power System (EPS) Radial Point of Common Coupling (PCC) EPS Customer Facility Network Load 1 Load 2 Load 3 DG

3. DG Cluster Proposal Overview • Standardized Process and Requirements • Ensure safety and reliability • Follows national standards • Equipment must be certified or undergoes design review • For small generation <20MW • Differentiating By: • One of three generator size thresholds • Potential “impact” of generator on Electric Power System (EPS) • Type of EPS at Point Of Common Coupling (PCC)

4. Process Overview • Scope of process shrinks considerably when expedited • Defines screens for certified equipment Generator Application >20MW? Yes >2MW? Historic Application Process Yes Meets Screens? Expedited Application Process Yes Super Expedited Application Process Interconnect Agreement

5. Size Threshold Categories • Less than 10kW • Accepts utility proposal • Three page application/agreement • No review/payments necessary • Less than 2 MW eligible for super-expedited process • Certified equipment • De minimis grid impact • No connection to transmission lines • 2-20MW eligible for expedited process • Check for distribution and transmission impact

6. 10 kW To 2 MW • Units certified by UL or other NRTL against UL1741 (representing IEEE Std1547 Draft 10) • 2 screens for determination of no grid impact • Primary screen – conservative, utility origin • 100% of units that pass are OK • Secondary screen - less conservative • 80-99% of units are OK? • Creates presumption of acceptance

7. Certification • Verifies that equipment is designed to ensure electrical protection safety • Website registry • UL or similar NRTL describes equipment package and test results • Posted w/ 6 week comment period • UL responds to any comments • Once certified -- no type testing and no other equipment can be required • Already UL-approved equipment is grandfathered

8. IEEE Std1547 • Overview • References • Definitions and Acronymns • Technical Specs and Requirements • General Requirements • Response to Area EPS Abnormal Conditions • Power Quality • Islanding • Test Specifications and Requirements • Interconnection Test • Production Tests • Interconnection Installation Evaluation • Commissioning Tests • Periodic Interconnection Tests • Annexes (Informative) • Flicker Information • Interconnection Tests • Commissioning Tests • Bibliography

9. Overall Super-ExpeditedProcess Flow SG Submits Complete Application IP Conducts Initial Review To Expedited Process IP Conducts Supplemental Review (If SG Agrees) Passes Secondary Screens? Passes Primary Screens? Meeting To Discuss Initial Review No No No SG Initiates Yes Yes If Needed, IP & SG Agree To Mods? IP Conducts Limited IC Review Technical Dispute Resolution Yes If Needed, IP & SG Agree To Minor Mods? No (IP Initiates) Yes Interconnect Agreement Note: “SG” is Small Generator “IP” is Interconnection Provider

10. 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

11. Screens – Primary • Aggregate DG capacity limited to a low percentage of the peak load of a distribution circuit (different limits for radial vs spot network vs secondary grid network) • DG contribution to circuit fault current is limited • DG not allowed to cause grid protective devices to exceed 90% of their short circuit interrupting capability • In aggregate, DG cannot be > 10MW where transient stability limits posted • Interconnection configuration-specific limits on single-phase generator hookup and capacity to avoid imbalance, overload, and possible neutral/grounding problems

12. Screens – Secondary • Aggregate DG capacity limited to a higher percentage of the peak load of the distribution circuit • Basically the same limits on fault current contribution and short circuit interrupting impact as primary screen

13. 10kW-2MW Costs • Application fee • Additional surcharge for interconnection review • Limited to reasonable amounts based on size • No other costs for interconnection under Super Expedited procedures

14. Dispute Resolution • Elements • Technical Master • Hotline • ADR for non-technical disputes • IP must initiate if SG Applicant clears secondary screen • Gen Applicant has burden if both screens failed

15. Metering • Only metering required for this agreement is that necessary to implement the interconnection

16. Timing • 10 days to review application • 15 days to review screens • 5 days to execute IA (Interconnect Agreement) • If Primary Screen failed • 10 days for additional review (after surcharge is paid) • 5 days to notify applicant of results • 5 days to send IA

17. Interconnection Agreement • Standard form Agreement • Shorter form for generators <2MW • Can be pre-executed

18. Interconnection Application • Standard form • Shorter Form for generators <2MW

19. 2-20MW Interconnection • Includes transmission impact issues • Direct transmission interconnection as well as distribution • Used by all generator sizes for which <2MW procedures do not apply

20. Basic Process • Optional scoping meeting up front • Three main components • Feasibility study • Impact study (if needed) • Facilities study (if needed) • Patterned after Utility proposal

21. Feasibility Study • Checks to see if generator has an impact distribution or transmission system • load flow (unless no export) • short circuit • grounding • IP shall rely to extent practical on existing studies • Gives generator developer idea of interconnection costs

22. Transmission Impact Study • Only undertaken if Feasibility Study raises questions of transmission impacts • Usually costly -- to be avoided if possible • If no impact study needed - generator drops from queue

23. Distribution Impact Study • Purpose • Identify generator design elements that protect distribution system • Assess impact of generator on distribution • No design review needed if • Certified • Generator meets criteria similar to 0-2MW secondary screens (without secondary network items) • Includes • Distribution load flow study • Equipment interrupt rating analysis • Protection coordination study • System operation impact analysis

24. Facilities Study • Identifies attachment facilities needed for interconnection including distribution system upgrades • If no facilities needed (customer sited generation), no study undertaken

25. 2-20MW Costs • To be discussed • Limit interconnection costs to only those directly related to the application

26. Transmission Queue • To be discussed • FERC is scheduling a conference and possible NOPR on the subject

27. Interconnection Agreement/Application • Forms to be developed

28. Massachusetts DTE DG Interconnection Collaborative Background

29. Feeder Feeder NP NP Customer Customer Customer Customer Customer IEEE Std 1547 General Requirements Summary • Voltage regulation inside ANSI C84.1 Range A • Grounding coordinated with Area EPS • Synchronize without voltage fluctuation at PCC >±5% of prevailing voltages • Networks: • Spot networks only for now

30. 1547 General Requirements Summary (Continued) • DG shall not energize EPS when EPS is de-energized • DG > 250kVA (unit or aggregate at PCC) shall have provisions for monitoring DG status, real power, reactive power • When required by EPS, accessible, lockable, visible-break isolation device (switch) located between DG and EPS Isolation Switch Suitable for 70kW DG

31. Voltage Range (% base voltage)Clearing Time (s) V < 50 0.16 50 <= V < 88 2.00 110 < V < 120 1.00 V >= 120 0.16 1547 Abnormal Conditions Response Summary • Voltages outside of table below shall cause DG to cease to energize within clearing time • Detected at PCC or point of DG connection if: • Aggregate DG capacity <= 30kW • Interconnect equipment certified to pass non-islanding test • Aggregate DG capacity < 50% total local EPS demand AND export of power prohibited

32. 1547 Abnormal Conditions Response Summary (Continued) • DG <= 30 kW, frequencies shall fall in range of 59.3 to 60.5 Hz else cease to energize within 0.16 seconds • DG > 30 kW • cease to energize within 0.16 seconds if >60.5 Hz • cease to energize within an adjustable time delay if undervoltage in range of 59.8 to 57 Hz • cease to energize within 0.16 seconds if <57.0 Hz • After a disturbance, DG reconnect only if voltage and frequency within range • Interconnection equipment shall be designed to coordinate with EPS reclosing practices and include ability to delay reconnect up to 5 minutes

33. Power Quality Summary • DG connected to single phase distribution shall not inject DC current >0.5% DG full rating • “The DG shall not create objectionable flicker for other customers on the area EPS” • DG harmonic injection shall not exceed: Maximum Harmonic Current Distortion (% of current) Harmonic Order (h) h<11 11<=h<17 17<=h<23 17<=h<23 35<=h Percent (%) 4.0 2.0 1.5 0.6 0.3 Current Distortion Total Demand Distortion Maximum = 5.0% Harmonic

34. Testing Requirements Summary • Five kinds of test are defined: • Design test – certifies that interconnection equipment meets the standard requirements • Production test – factory test of DG’s conformance to voltage and frequency variation limits • Interconnection installation evaluation – basically a verification that the DG and interconnection design meet the standard • Commissioning test – conducted at the facility to verify adjustable settings are correct and protective functions are operating properly • Periodic interconnection tests – A periodic test of the interconnect protection system

35. Screens – Primary • <5% of annual peak load on radial circuits • <5% of peak load (or 50kW max) on spot networks (inverters only) • Secondary grid distribution networks • induction generator or inverter • not exceeding 50% of facility minimum load • <10% contribution to circuit max fault current • Not cause grid protective devices to exceed 90% of their short circuit interrupting capability • In aggregate, cannot be >10MW where transient stability limits posted • Phase imbalance limits if single-phase and connected to center tap neutral of a 240V service • <20kVA if single-phase and on a shared secondary • Single-phase connection requirements • <10% of line capacity if single phase and section configuration is three-phase, 4-wire or a mix

36. Screens – Secondary • Radial circuits: <15% of line section design capacity • Spot networks: <5% of peak load on spot networks • Secondary grid networks • On any network, use reverse power protection except: • if generator <50% of min facility load or 500kW • Basically same limits on fault current contribution and short circuit interrupting impact as primary screen