1 Integration of Variable Generation into the Grid: Need for TVLs (Transfer Variability Limits) Gordon Dobson-Mack (Chair) Dynamic Transfer Capability.

1

Integration of Variable Generation into the Grid:

Need for TVLs (Transfer Variability Limits)

Gordon Dobson-Mack (Chair)Dynamic Transfer Capability Task Force

Wind Integration Forum – Steering CommitteeNovember 17 2011

BCCPGBCCPG

2

• Discuss the need for TVLs and what can be done to increase them

Purpose of Presentation

3

1. Variability & its impacts:– Increased variability is a reality for operations;– Dynamic Transfers contribute to variability;– Transfer Variability impacts the grid;– Need Transfers Variability Limits for some systems.

2. DTC Task Force– Mandate & Membership;– Deliverables;

3. What Next?– Questions & Options;

Outline

4

BPA’s Installed Wind

Source: BPA: http://transmission.bpa.gov/business/operations/Wind/WIND_InstalledCapacity_Plot.pdf

6

NWPP Wind Generation Levels

2010 Coincident Peak Load = 60,200 MW

Dec 2010 Installed Wind Gen = 7,800 MW

Dec 2012 Installed+Committed

Wind Gen = 13,200 MW

2010 Spring Min Load (HE04) = 32,745 MW

Source: NWPP & DTC TF: http://www.columbiagrid.org/documents-search.cfm search “DTCTFPhaseFullReport031611.pdf”   

7Source: http://www.westgov.org/EIMcr/meetings/07MAR11/present/panel5/l_beane.pdf see slide #3

• Generation Problem: – Need to maintain Generation Balance;– Want access to least cost & most flexible Ancillary Services

• Transmission Problem…As well:– Transmission system designed historically for routine

predictable changes;– Must be ready to withstand the next worst

contingency;– Voltage control and RAS arming are local measures

that must be factored into the solution.

Generation or Transmission Problem?

9

R L

C

R L R LR L

CCCC

LoadTransmission Line

Transmission Line Physics

10

Maximum TTC,Transmission Tuned

Light Load or line open - High Voltageunless reactive switched off

Low Voltage:Without addedReactive – couldBe a voltage collapse

Reactive “Tuning” And Remedial Action Schemes (RAS)

Power - Voltage Curves andReliability N-1 Limits

N-1 Outage

Acceptable Voltage Range

Vo

ltag

e L

evel

N-1 Outage

Reliability Limits

Operating MW Range no Caps in

MW Power Level

Operating MW Range Caps in

CapacitorSwitched on

NormalN-0

Added Switching

Remedial Action Schemes (RAS) RAS armRAS un-arm

Capacitor In

Capacitor Out

0 10 20 30 40 50 60 Minutes

MW

Flo

w

1850 MW

2050 MW

Path flow with VG

Traditional tie line flow

13

1414

Present Dynamic Schedule Requirements

Montana – NW•50 MW BPA Loads•20 MW Glacier Wind•1318 MW Colstrip Participants•91 MW NWE

Idaho – NW•200 MW PAC•60 MW Boardman

DTC Studies-BPA Report (Feb 2010)

15

DTC Task Force – Part of Wind Integration Study Team (WIST)

DTC Task Force• Convened October 2010• Technical Staff primarily from NW & CA entities• ~55 Meetings to date.

Purpose:1. Develop a technical consensus on how to facilitate

increased Dynamic Transfers without compromising system reliability

2. BAs & TPs to establish DTC Limits on paths3. Determine if & how to expand DTC

16

DTC TF (Phase 3 )Membership

Avista: Rich Hydzik

BPA: Brian Tuck, Ramu Ramanathan

BCH: Steven Pai, Sanjeet Sanghera,

CAISO: Jim Price

Gaelectric: Dan Wheeler

IPCO: Orlando Ciniglio

MSR: Dave Arthur, Ann Fisher

NWE: Rikin Shah, Ray Brush

PAC: Sanman Rokade

PGE: Philip Augustin, Don Johnson

PSE: Alex Berres, Joe Seabrook

TANC: Abbas Abed, Shawn Matchim

SMUD: Richard Buckingham

WAPA (Folsum): Kirk Sornborger

 • 

Powerex: Gordon Dobson-MackDTC TF ChairTel: [email protected]

Columbia Grid: Marv LandauerNorthern Tier: Rich BaylessNWPP: Don Badley 

3

17

DTC TF Work Process

Phase 1 (03/11)

Phase 2 (07/11)

Phase 3 (11/11)

Define Problem &

Identify Assumptions

Develop DTC Limit

Methodology

Calculate DTC Limits, Refine

Methodology & Identify

Enhancements

18

Three Conditions Restricting Transfer Variability Limits

Customer Impacts

Acceptable?

Equipment Impacts

Acceptable?

Operating Points

Reliable?

Condition 1 Condition 2 Condition 3

19

• Does not calculate TVLs for particular Paths;– Recommends a methodology;– Leaves limit calculations to Transmission Providers

• Does not recommend specific projects– Describes generic projects to enhance TVLs

– Leaves specific project recommendations to TPs

Caveats for Phase 3 Report

20

• TVL is a real issue;– Impediment to transfer imbalance energy and

regulation between BAs;– Will limit where & how the region can integrate

wind;– Limits can be raised, but not overnight.

• Need for TVLs will vary by system;

• Should plan for increased transmission flexibility to manage the increasingly variable flows on grid

Bottom Line – so far

21

• How automated is your RAS arming?

• How much automatic voltage control do you have

across your system?

• What are the TVLs for your major flowgates?

• How will your company manage TVLs?

• What capital projects are planned to increase Transmission Flexibility?

Questions for Companies

22

•Modifying some SOL assumptions (e.g. overshedding);

•Automating RAS

•Automating voltage control

•Ensure voltage control equipment is designed for frequent switching

(**Detailed TVL studies needed to identify most effective solutions)

Options for increasing TVLs

Questions?