Managing Risk in Nodal Systems Architecture

1
Managing Risk in Nodal Systems Architecture
Settlements
CRR Auction Model
Network Operations Model Management
20
21
DAM
19
Current Operating Plan
Transmission Security and DRUC HRUC
13
19
8
12
Network Operations Model
18
LFC
11
Constraint Management
14
Network Security Analysis
SCED
State Estimator
Model Update
9
10
Outage Scheduler
15
16
6
5
7
4
3
SCADA
17
1
2
QSEs (to Generating Units)
TDSPs Transmission Data
2
Top 21 Data Flows to Manage Risk

• TDSPs have hard requirements to provide all SCADA
  data to ERCOT at less than 10 sec scan rates.
  Performance of TDSPs must be monitored. All SCADA
  data must be re-verified by ERCOT prior to
  application to nodal.
• QSEs will be sending not only telemetry of
  generation and load resources but also telemetry
  of each Resources status, HSL, LSL, AS Schedule,
  etc.
• Requirement to build logic equations of breaker
  and switch status to detect when devices in the
  outage scheduler is out or comes back in. Also
  requires ERCOT to identify forced outages from
  scheduled.
• The telemetered status of breakers and switches
  must be mapped to the network operations model to
  get the topology of the network to NSA.
• Most importantly, the actual generation and
  actual loads on the grid must be accurately
  determined. Flows on lines and transformers not
  so important. Need to minimize the model size to
  conserve computational resources by modeling only
  whats important.
• Actual generation, Resource status, limits, etc.
  are required to calculate dispatch limits on
  generators.
• LFC will receive actual deployment of Regulation
  by individual resource used in the algorithm to
  minimize ACE. Vendor should be responsible for
  LFC performance and indicate how fast QSEs should
  move their generation to the base points.
• Actual Resource status is compared to that shown
  in COP with warnings if inconsistent
• Data to NSA
• Generation and Load to NSA

• A Network Operations Model for real time that has
  been provided to the market provided to NSA and
  updated with data from Model Update.
• Same model is used for Day Ahead and Hour Ahead
  transmission security studies and RUC analysis.
• COP feeds DRUC and HRUC to get forecasted status
  of resources, AS Schedules etc. enabling
  calculation of individual resource dispatch
  output to verify transmission security in DA and
  HA.
• NSA will provide to ERCOT Operators transmission
  constraints that are potentially binding in SCED.
  ERCOT operators to review
• Constraint Management passes data to SCED to
  recognize transmission constraints in dispatch
  calculations.
• SCED produces Base Points for all generation
  resources based on offer curves and transmission
  constraints and the total generation. SCED must
  product new base points on detection of any
  change in breaker or switch status of
  significance. Can be as many as 4-5 executions in
  any 15 minute period, each producing new base
  points to LFC.
• LFC should send base points and regulation
  control signals to QSEs to assure latest point is
  consistent with the control algorithm
• LFC feeds actual generation to settlements to
  assure consistency
• DAM and RUC sends results of market trades,
  purchases, and sales and RUC outputs to
  Settlements
• CRR auction sends result of market to Settlements
• Validate CRR Offers