Distributed Generation Con Edison

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Distributed Generation Con Edison
A.Kaffashan / M.Rollins April 23, 2004
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Con Edison Electric Distribution System

• Area 604 sq mi Population 8,800,000
• Electric Customers
• Total 3,200,000
• Network 2,300,000
• Radial 835,000
• Peak Load (2001) 12,207 MW

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Design Basis of Distribution System

• Second Contingency
• High density load areas
• Urban and financial districts
• First Contingency
• Low load density areas
• Suburban area
• Separation of feeders

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Network Characteristics

• High Reliability
• Totally Underground
• Multiple Feeders
• Multi-level Electronic Monitoring and Control
  Capabilities
• Analytical Capabilities
• Real-Time Remote Control

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Electric Distribution System Networks

• Networks
  56
• Feeders
  897
• Network Transformers 24,000
• Manholes Boxes 260,000
• Primary Feeder Cable 27,000 km
• Secondary Cable 80,000 km

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Con Edison Electric Distribution System

• Network Many simultaneous paths for power to
  flow to customers.
• Each network is fed from one area substation.
• Typically u 12 - 24 primary feeder
• u 250 - 750 transformers
• u 7,500 - 75,000 customers
• Of 56 major networks u 33 in Manhattan
• u 10 in Brooklyn
• u 7 in Queens
• u 6 in Bronx
• Except for Manhattan, other Areas have extensive
• amounts of isolated networks and radial
  distribution.

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Networks Elements

• Transformer Transform the voltage from primary
  (13 or 27 kV) to secondary (120
  volts).
• Network Protector Isolate network from primary
  feeder fault.
• Fuses On each network protector to backup for
  primary feeder fault
• secondary fault.
• Limiters Weak links on each cable end to
  isolate secondary faults to a single
• section of cable.

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Simplified Area Network Schematic
Transformer
Distributed Network Grid is 120/208
Isolated Network
Network Protector and Fuse
Customer Load
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Typical Area and Spot Networks
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High Tension or High Rise Building
High Rise
Z
125/216V or277/480V
NWP
2500kVA each
2500, 3700, 5000kVA each
13, 27 or 33kV
4 or 13KV
CB (Typ.)
Large Commercial or Industrial Customer
S/S Bus
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Interconnection Process

• Preliminary Discussions
• Major Considerations of Combined Heat and Power
• Method of Electrical Connection
• Application and associated documentation
• Site-specific review by Con Edison
• Detailed Specifications
• Design and OM Specs Developed by Con Edison
• Signed by both the customer and Con Edison
• Verification Testing
• Procedure developed by customer
• Witnessed by Con Edison forces
• Interconnection Charges
• Costs related to the DG billed to the customer

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Interconnection Process

• Major considerations of CHP installation
• Con Edison How does the proposed generator
  affect the existing electric system?
• Available Short Circuit Current
• Fault Current added by the CHP
• Building Load with respect to the size of the CHP
  System
• Will the CHP system be a Qualified Facility?
• Is the system approved and type tested in
  accordance with the NYS SIR?
• Site Is there a continuous minimum electrical
  and mechanical load to allow the CHP system to
  continuously run efficiently?

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Fault Current added by the CHP

• Area Substation Fault Duty Limitations

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Effect of CHP System Sizing

• A short circuit study determines the available
  fault current
• Customer load must be evaluated to size
  generator(s)

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Interconnection Process

• Method of Electrical Connection (Operating modes)
• Supplemental (parallel) CHP system runs
  continuously, Con Ed provides difference
• Buy-back not allowed on distribution network
  system (SC11)
• Standby CHP system runs continuously, providing
  all loads, Con Edison available if CHP system is
  down (SC14RA)
• Isolated no interconnection with Con Ed system

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Interconnection Process

• Application and associated documentation

• NYS SIR (Radial Feeders)
• I. Project Contact
• II. Application Fee
• III. System Drawings
• IV. Equipment Description
• V. Verification Test Procedure
• (presently limited to 300 kVA)

• Con Edison (Networks)
• I. Service Address
• II. Account Information
• III. Service Description
• IV. Contractor Info
• V. Generator Data
• VI. Description of System Operation
• VII. System Drawings

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Interconnection Process

• Site-specific review by Con Edison

• Con Edison (Networks)
• I. Voltage Protection
• II. Frequency Protection
• III. Reverse Power Relay
• IV. Directional O/C
• V. Sync Check Relaying
• DISCONNECT SWITCH

• NYS SIR (Radial Feeders)
• I. Voltage Protection
• II. Frequency Protection
• III. Site Specific Relaying
• IV. Dedicated Transformer
• V. Net Metering
• DISCONNECT SWITCH

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Interconnection Process

• Network interconnection protection requirements
  in Con Edison Handbook for Dispersed Generation
• Anti-islanding protection (81U/O, 27/59)
• Reverse power protection (32R)
• Network protector interlocks
• Overcurrent protection (50/51)
• Synchronizing sync check functions (25)
• Disconnect switch (89)

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Interconnection Process

• Detailed specifications
• Design specifications developed by Con Edison to
  indicate specific equipment required for
  interconnection of CHP system
• OM specifications developed by Con Edison to
  indicate the methods to be followed when starting
  and working with the CHP system
• Final agreement between the customer and con
  Edison

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Interconnection Process

• Verification testing
• Procedure developed by customer to show Con
  Edison how the control and protection equipment
  performs as designed
• Procedure approved and witnessed by Con Edison

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Interconnection Process

• Interconnection charges
• Engineering review of information submitted
  during application
• Cost to perform work on Con Edison system to
  allow for the interconnection of CHP system