Transmission-Distribution Interface
Working Group Meeting
June 21, 2017
Today’s Agenda:
1. Introductions
2. Brief updates on related efforts (15 minutes):
a. White Paper published + upcoming outreach
b. CPUC Grid Modernization – June 5
c. ESDER
d. FERC Storage/DER Rulemaking
e. Other?
3. Presentation on CPUC/CAISO Multi-Use Application Staff Proposal (30 minutes) – Lorenzo Kristov, CAISO
a. Implications on operations at T-D interface
b. Discussion of relevance to WG efforts
4. Working Group Exercise: Two Master Problem: Evaluating Conflicts When Providing Wholesale AND
Distribution Services (90 minutes) – Matthew Tisdale, MTS
5. Lunch Break (30 minutes)
6. Presentation on Implementation of Use Cases A & B + Discussion (60 minutes) -- Mark Esguerra, PG&E
7. Presentation on Stem deployments and perspective from NYISO (30 minutes) – Ted Ko, Stem
8. Discuss future meeting dates, meeting agendas, and next steps (15 minutes)
9. Surprise sendoff
Orientation to 2017 Work Plan
1. Prepare an initial white paper that summarizes the 2016 effort, including description of existing coordination
procedures, anticipated operational challenges with high DER, and communication and coordination
improvements identified to date
2. Educate the WG on grid modernization from IOU perspective (using 1/24 DRP workshop presentations) and
consider implications of operational coordination needs on grid modernization
3. Develop example use-cases reflecting likely DER integration scenarios to ground discussion in practical
implications. Consider how future pilot proposals may stem from identified use cases.
4. Specify potential real-time coordination procedures to manage potential conflicts between DO needs and ISO
dispatches. Begin with scenario approach and then broaden as needed
5. Identify principles for a DO approach to DER curtailment resulting from distribution level constraints
6. Consider any unique perspectives or challenges for municipal utilities w/in ISO footprint
7. Describe the process and timeline for integration of a new DERA into the wholesale market, including utility
process for 30-day review of DERA under ISO DERP tariff as well as ISO integration process
8. Develop methods for short-term DER forecasting and impacts at T-D Interface (IOUs)
9. Develop method for DO feasibility assessment of ISO’s day-ahead DER schedules and real-time dispatches
10. Explore how various DSO models would impact design of the T-D interface coordination framework
The Two Masters Problem:
• Problem Definition: Will DER receive competing dispatch signals from
wholesale and distribution service operators? If so, how will the
conflict be resolved?
• Identified by working group members as a priority question at May
meeting.
• Agreed to further consideration by matrix of services and situations,
allowing for identification of potential conflicts.
• The following draft matrix created by AMS and MTS.
• The following exercise intended to facilitate population of the matrix.
Two Masters?
Distribution - Wholesale Grid Services Conflict Matrix
Distribution Services
Wholesale Services
Energy
Energy Up
Energy Down
Capacity Up
Capacity Down
VAR Up
VAR Down
Regulation Up
Regulation Down
Regulation
Up
Regulation
Down
Spinning
Reserve
Non-Spinning
Reserve
Working Group “Conflict Identification and Resolution” Exercise:
Steps:
1.
2.
3.
4.
5.
6.
Hold hands
Discuss threshold questions on next slide, level-set
Populate matrix by identifying conflicts
Populate matrix by identifying opportunities
Think, Repeat
Behold
Threshold Questions:
• Does the following correctly state the task at hand?
The Working Group is analyzing when providing two or more services — one at wholesale, one at distribution —
could result in a DER receiving conflicting dispatch signals. There are some situations where a conflict would be
created between two dispatch signals for two services, while the same two services may not create a conflict in
other situations. Our task is to identify the situations where conflicts exist and for which services.
• Identified conflicts would be the same under Use Cases C-1, C-2, D-1, and D-2.
Conflicts are not resolved through bifurcated capacity or aggregations. Use Cases E
and F considered at a later date. Correct?
• Matrix enables analysis of conflicts between wholesale and distribution services
identified in most recent version of “T-D Interface Working Group Use Cases.”
Customer services (e.g., demand charge management) and RA not included. Correct?
• Other questions?
PG&E DO Activities Assessing High DER Penetration
Use Cases
• Distribution Operations performed assessment of high DER
penetration feeders
― Identify any impacts to operation of distribution grid
― Discuss key operational considerations for assessing high DER penetration
feeders
• Selected two feeders in PG&E system that are currently experiencing
high penetration of DERs
Feeder A
103441101
Feeder
Capacity
(MW)
12.33
Feeder B
152811105
6.09
Feeder ID
Feeder Name
Peak
Load
(MW)
6.63
3.38
Average Feeder
Node ICA
ICA
(kW)
(kW)
569
2,565
356
798
Penetration
DG
Customers
120%
127
114%
98
High DER Penetration Preliminary Screening Criteria
applied
# Screen Description
Operating N-1 limitations for planned N-1
1 events (surrounding bank, circuit and tie
capability)
Qualititative Review
Feeder A can be offloaded entirely with the
help of Feeder C, this creates a cascaded
switching scheme as Feeder C cannot accept all
the load and therefore must in part be offloaded
onto Feeder D.
Feeder A can be offloaded entirely with the
Operating N-1 limitations for un-planned N-1 help of Feeder C using emergency capabilities.
2 events (surrounding bank, circuit and tie
EX: 5-18-2015 emergency offload of Feeder A,
capability)
May loading conditions all could be offloaded
onto Feeder C
3
4
5
6
7
Power Quality Review (analyze steady state
voltages, harmonics, etc., at substation bus
and on line sections as well as historical
performance and prior
complaints/investigation)
Power factor reviews at substation cirucit
and bank level
Current field and substation COE/failures
which may impact DERP performance or N-1
flexibility
FLISR impact (if applicable)
VVO impact (if applicable)
Risk Factors
If Feeder C ocb fails the Feeder C can pick up
most of the load, but other transfers would
need to be investigated as Feeder C would
not be capable of accepting load from both
Feeder C and Feeder A simultaneously.
Recommended Mitigation (if applicable)Risk Level
Possibly come up with emergency
switching for this scenario to provide
operators an opportunity for transfers
to start while contacting DO
Engineering for assistance
This circuit is OK for power quality. No known
major voltage issues, no harmonic issues, no
major complaints, etc.
If the addition of any new generating
The addition of new generating devices may devices create a power quality
cause new unforeseen power quality issues. problem, they will be dealt with on an
Ad Hoc basis.
NONE
NONE
NONE
NONE
NONE
NONE
N/A
N/A
N/A
N/A
N/A
N/A
Examples of Existing Use Case A in PG&E System
October 2013
October 2016
• Market participation of large
DERs providing regulation
complicates online power flow
calculations and makes load
forecasting very difficult
• DERs providing regulation
service may have multiple
changes in power flow
direction
4MW Battery Output October 2016
• For specific circuit, DER
penetration level relatively low
and is considered to be a
robust feeder. Therefore, no
voltage or power quality issues
recorded
• Managing and Integrating 3rd
party DER aggregations into
utility systems has proven to be
very complex technically.
Standards are immature and
business rules are not yet
established for distribution
services.
Background Slides
Services in Red have been preliminarily deemed “reliability”
Source: CPUC, June 2 Workshop Presentation
Use Cases
Use Case
Configuration
Grid Services Provided
A
Single Resource
Wholesale (only)
B
Wholesale (only)
C-1
Aggregated Resource – consider
single-feeder and multi-feeder
sub-cases
Single Resource
C-2
Single Resource
D-1
Wholesale + Distribution using separate portions of capacity for
each (Multiple Use Application)
D-2
Aggregated Resource – consider
single-feeder and multi-feeder
sub-cases
Aggregated Resource
E
Single Resource
Wholesale + Distribution: enhanced DO/DSO functionality
F
Aggregated Resource
Wholesale + Distribution: enhanced DO/DSO functionality
Wholesale + Distribution using separate portions of capacity for
each (Multiple Use Application)
Wholesale + Distribution using the same capacity
Wholesale + Distribution using the same capacity