1. Distributed Generation (DG) Modeling Criteria
Michelle Pham, P.E.
03/04/16

2. 11/18/2018
DG Modeling Criteria
Voltage (steady state): ANSI C84.1 Service Voltage Range A (+/_ 5% of nominal voltage)
Voltage Fluctuation: IEEE Flicker Curve
Voltage Imbalance: <3 % voltage dip
Equipment Overload: ≤ 100%
Effectively Grounded must be maintained by DG source:
R0/ X1 < 1 and X0/X1 ≤3
Where X0, X1 are zero- and positive sequence reactance at the fault location and R0 is the zero sequence resistance.
DG Customer’s Primary Transformer configuration:
Grounded Wye primary/Delta secondary is not allowed on 12 kV or 35 kV Distribution System
Transformers with UNGROUNDED PRIMARY connections, such as Delta or Ungrounded Wye, is not allowed on 35 kV Distribution System

3. DG Modeling Criteria (Continued)
11/18/2018
DG Modeling Criteria (Continued)
Fault current threshold
≤ approximately 12.5 kA (maximum fault current designed criteria for most distribution overhead circuits)
Transfer Trip: is required for :
any DG > 2 MW
Or when the rated DG>1/3 feeder minimum loading
Or study dependent
Exception: For Closed Transition switching with less than 100ms, CNP does not required TT.
3V0 protection: is required when DG aggregate capacity > 50% minimum transmission section loading serving the area

4. DG Modeling Criteria (Continued)
Harmonics:
The customer’s DG shall not cause voltage harmonic content or total harmonic distortion (THD) in excess of the limits of IEEE 519 and IEEE 1547 when measured at the Point of Common Coupling (CNP) with CNP system.
Per IEEE 519, the THD voltage shall not exceed 5 % of the fundamental 60 Hz frequency or 3% of fundamental frequency for any individual harmonic when measured at PCC with CNP system.
Power Factor: 98% to 100% lagging

5. Questions

6. Thanks!