IEEE Power & Energy Magazine - September/October 2019 - 38

TSO

Bulk
Generation

TO
DO
Aggregator

DER

figure 10. The New York current coordination framework.
DR: distributed resource.

aggregators for nonwire alternative (NWA) procurement.
DER aggregators and their customers can also access wholesale settlement and billing services through New York Independent System Operator (NYISO). This approach includes
rules for joint participation in utility NWA procurement and
the NYISO markets that form the basis for operational coordination with NYISO.
DSP 2.0 is intended to increase visibility and operational control over DERs to enable integrated markets for
wholesale and distribution services. In DSP 2.0, DSOs, as
an option, would offer wholesale scheduling and dispatch
services. This is proposed to enable customers and aggregators to maximize the value of their resources across NYISO
wholesale and distribution markets. In DSP 2.0, aggregators

can still access wholesale markets directly through NYISO.
NYISO would also need enhanced capabilities to monitor
and control DERs and has proposed an evolution for the
structure of operational coordination. Figure 12 shows the
NYISO's alternative 2, which is similar to the Joint Utilities' conceptual third evolution, called DSP 2.x.
In this conceptual model, aggregators would no longer
interface with NYISO. Instead, the DSO would coordinate
both transactions on the distribution and physical interchange across the T-D interface. The few direct interfaces
between DERs and NYISO would involve distribution-connected BPS resources. This may be a longer-term phase of
operational coordination development that may develop in
response to transactional distribution markets.

Summary
Current TDC coordination structures across the globe exhibit
considerable DO bypassing, with the attendant issues of hidden coupling and bulk system cybervulnerability. All current
models reflect incremental evolution based on the existing
legacy structure and an initial focus on market access for
DER and market efficiency issues. As such, none of the locations has fully addressed the critical architectural structure
issues that will impact operational risk, chiefly reliability and
resilience. A more focused examination of alternative architectural structures in relation to operational risk is needed.
Future coordination alternatives fundamentally involve two
schools of thought regarding coordination structure: 1) a centralized approach in which the TSO performs all coordination
and 2) layered approaches in which a DSO has a significant
role in coordination. The choice of centralized or layered structure is a foundational architectural decision that has significant

Retail Services

Retail Services
NYISO

NYISO

Wholesale Services

Operational Control

Limited Operational Control
Distribution
System
Platform

Aggregators

Wholesale Services

Distribution
System
Platform

Aggregators

DER Customers

Demand Storage
Response
(a)

DER Customers

Demand Storage
Response
(b)

figure 11. Joint utilities of the New York TDC coordination models: (a) DSP 1.0 wholesale and retail services and
(b) DSP 2.0 wholesale and retail services and operational control.
38

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