Blackstart and Ravensw ood Steam Units Presentation to NYSRC - RCMS - - PowerPoint PPT Presentation

ON IT

Confidential

ON IT

Blackstart and Ravensw ood Steam Units

Presentation to NYSRC - RCMS February 2, 2012

ON IT

Confidential

ON IT

Contents

• Con Edison’s Restoration Program
• Zone J Generation Capacity
• System Restoration Principles
• Evaluation of TC Units Leaving Program

2

ON IT

Confidential

ON IT

Con Edison’s Restoration Program

• A shutdown could potentially affect neighboring electrical

systems, part or all of our customers, or could cause damage to generation, transmission, and/ or distribution facilities

• Multiple (9) Con Edison plans so that we may return service

to our customers safely and in the shortest possible time

– Plans 1-7, to restore system from neighboring sources – Plan 8 to restore the system as an island – Plan 9 to restore the system from the NYSO backbone

3

ON IT

Confidential

ON IT

Con Edison’s Restoration Program

• All plans involve re-connecting specific electric generating

units, transmission and distribution feeders, shunt reactors and customer load, in a specific order

• Developed using computer simulations which analyze real

and reactive power flows, along with voltage profiles, inrush and transients, as various system elements are energized

• All major units that have blackstart capability are part of

Con Edison’s Blackstart Plan

4

ON IT

Confidential

ON IT

Con Edison’s Restoration Program ►Blackstart Plan 8

• This plan restores New York City’s electric system

initially as an island (without the aid of neighboring systems), starting with blackstart-enabled generation

• In order to minimize system restoration time, Con

Edison will order all blackstart equipped generators to start up immediately after an event

– When an external tie becomes available, Con Edison

will synchronize to that tie as soon as possible

5

ON IT

Confidential

ON IT

Zone J Generation Capacity

• Con Edison recently added the consideration of

blackstart for all new units as an additional requirement in its Transmission Planning Criteria

• Since the NYISO tariff was adopted, 2300 MW of

new units have been added or are under construction, all without blackstart capability

6

ON IT

Confidential

7

ON IT

Confidential

ON IT

System Restoration Principles

• Quick startup Gas Turbines, which have limited real and reactive

capabilities, help energize portions of the Con Edison cable transmission system to reach steam units

• Cables are highly capacitive and require significant leading reactive

resources to prevent excessive voltages during restoration

• High-inertia Steam units have high MW and wide reactive capabilities,

which are needed to stabilize the transmission system and to restore load

– For example, Ravenswood Steam units provide 1,672 MW (2011 Gold Book)

and 657 leading to 1,319 lagging MVAr (2011 FERC Form 1)

– Combined Cycle units behave similarly to Steam units but at this time only

• ne such facility has blackstart capability
• Con Edison system cannot be restored in a timely manner without

blackstart enabled Steam or Combined Cycle units

8

ON IT

Confidential

ON IT

Evaluation of TC Units Leaving Program

• Even under “ideal conditions” there will be a significant

impact

– Removing from the program 1,672 MW, representing around 40%

• f Steam generating resources, that have substantial leading and

lagging capabilities, will cause a high impact to timely load restoration

– Being part of the program enhances readiness for a reliable startup

after an event, due to monthly / annual testing and operator training

– Without a blackstart capability, TC units cannot commence startup

until transmission restoration with sufficient cranking power has reached them

– Transmission and network switching time must also be considered

9

ON IT

Confidential

ON IT

Evaluation of TC Units Leaving Program ►Simulation Assumptions

• The following time assumptions were used (after consultation with

system operators) in the simulation of breaker operation and system restoration using Plan 8:

• Restoration times were evaluated by simulating the energization of the

system and adding the time for numerous breaker closings and the pickup of load and generation using the above task time assumptions

10

Task Duration Time for first breaker in station 5 minutes Time for subsequent breakers 1 minute each Time to pick up load 5 minutes Time to synchronize generation 5 minutes

ON IT

Confidential

ON IT

Evaluation of TC Units Leaving Program ►Approach

• Absolute times are not presented

– Sensitive information – CEII

• The incremental analysis is presented graphically in

simplified form in the following slide

– Unit start-up times were taken from actual blackstart test data – After unit synchronizes to system, the real and reactive capabilities

• f the unit can be used to restore load

– Therefore, impact is measured as the time difference, with and

without blackstart, that the unit synchronizes to the partially restored system

11

ON IT

Confidential

Evaluation of TC Units Leaving Program

►Incremental Graphical Representation

12

A A, C B C Time Zero B A = Light and Power established B = Unit ready to synchronize to system C = Restoration reaches unit interconnection point Impact = B – B With blackstart (From actual test data) Without blackstart (From simulations)

Ravenswood 1 & 2 ~ 4 hours, 10 minutes

(B – B)

Ravenswood 3 ~ 5 hours