Studies &
Charles Hendrix
Generator Interconnection Service
Energy Resource Interconnection Service – allows a
generator to be eligible to use the existing firm or
non-firm capacity of the Transmission System on an
“as available” basis
– Customer must still request Transmission Service
Network Resource Interconnection Service – allows
the Transmission Owner to construct the necessary
upgrades to integrate the generator into the
Transmission System in a manner comparable with
other Network Resources
– Customer must still request Transmission Service
Generator Interconnection Service
Neither Energy Resource Interconnection Service
or Network Resource Interconnection Service gives
the generator any right to deliver energy to any
customer or point of delivery
Generator Interconnection Studies Process
Definitive Interconnection System Impact Study
(DISIS) – Studied in Clusters
Facility Study
Limited Operation Study
Interconnection Agreement
DISIS – Powerflow Analysis
• Models built from the Integrated Transmission
Planning Models
• Includes all upgrades with NTC
• Includes a look over the 10 year planning
horizon so no short term outages accounted for
• SPP Footprint divided into 12 sub-regions
(groups) for interconnection study purposes
DISIS – Powerflow Analysis
• Distinct dispatch for each interconnection
request in the cluster study for each season
• All Energy studied to be sunk in SPP footprint
DISIS – Powerflow Analysis
AC Contingency Analysis
Constraints Identified and transmission
reinforcements required for
– ERIS – overloads with 20% sensitivity factor
– NRIS – overloads with 3% sensitivity factor
Neither ERIS nor NRIS conveys right to deliver
Upgrade Costs shared on a MW impact basis
DISIS – Transmission Upgrades
If long lead time upgrades with NTC are found to
mitigate the constraints identified in the DISIS
Study, this is documented in the study as a
required upgrade for the Generator
This requirement also documented in the
Generator Interconnection Agreement (GIA)
Facility Studies
Performed by the transmission owner
+/- 20% estimate of interconnection facilities and
network upgrades
Short Circuit Analysis – verify circuit breaker duty
Limited Operation Impact Study (LOIS)
Customer may request to interconnect before the
completion of long lead time upgrades identified
in the DISIS
An additional study (LOIS) is evaluated taking the
following into consideration
– Customer’s requested COD
– Higher-queued generation in service
Neglecting generators that haven’t built
– Existing transmission infrastructure
Limited Operation Impact Study (LOIS)
AC Contingency Analysis
Constraints Identified – LOIS may be denied (or
temporary cap identified) for
– Overloads with 20% sensitivity factor
Otherwise Generator can interconnect on ‘as
available’ basis until higher queued generator
comes into service
Conditions documented in GIA
Interconnection Agreement
Draft GIA presented to Customer after completion
of Facility Study
Customer given 60 days to negotiate with
transmission owner for construction milestones
GIA is finalized, executed, and filed at FERC if

CHENDRIX_Generator Interconnection