Frequency Response Initiative Generator Event Survey DL/Frequency_Response_Initiative_… · 12/8/2016 · 1. Always present 2. Default on modern units since ~2011 3. Site specific

Frequency Response Initiative

Generator Event Survey

NERC Resources Subcommittee

North American Generator Forum

December 8, 2016

RELIABILITY | ACCOUNTABILITY2

• Essential for Reliability of the Interconnections Cornerstone for system stability

Line of defense to prevent Under Frequency Load Shedding(UFLS)

Prevent equipment damage

• Essential for System Restoration Droop response is critical in restoration efforts

Hydro units and gas turbines are some of the first units to be restarted

• Compliance with NERC Standards BAL-003-1, BAL-001 Mitigate future regulations related to generator frequency response

performance

• To accurately predict system events (Transmission Models)

Why Primary Frequency Response Is Important


2012 Frequency Response Initiative Report

“Lazy L”


NERC Outreach OEM and Engineering Firms


• Advisory issued February 5, 2015

• Initiated by NERC Resource Subcommittee Interconnections frequency response

has declined

Eastern Interconnection Lazy L profile

2010 and 2013 Generator Survey Data

Generator Governor Frequency Response Advisory

Generator Governor Frequency Response Advisory

http://www.nerc.com/pa/rrm/bpsa/Alerts DL/2015 Alerts/NERC Alert A-2015-02-05-01 Generator Governor Frequency Response.pdf


Turbine OEM Reach Out to Customer Base


Many Deadbands Exceed 36 mHz

• Deadbands Vary Many exceed 36 mHz or 2.16 RPM

• Droops Settings Vary Majority Droops reported 5%

What has been learned –Deadbands Exceed


What has been learned –Outer Loop Control

Coordination with plant DCS is a requirement when operating in MW Set Point Coordinated Control.


• Posted December 15, 2015

Reliability Guideline:Primary Frequency Control

1. Always present

2. Default on modern units

since ~2011

3. Site specific , co-ordination required

Primary response GE perspective 1. Basic governor always present. Used for startup, synch, over speed

protection and other functions in addition to droop

2. Unit level load control with primary frequency regulation bias. Default

on new units starting ~ 2011, also default on many retrofits to larger

units. May need to be disabled or coordinated with plant control.

3. Plant level load control. Plant –plant coordination with A/E. Open loop

vs closed loop, steam unit considerations, coordination with turbine

load controller etc. Simple algorithms, low or no cost in plant design

phase.

• Recommend Plant level primary frequency

response be a contractual requirement on new

plant so not change order mid-commissioning

• Clearly defined requirements ( ex. ERCOT 5.78%)

…also define what constitutes plant rated load (

ISO, prevailing ambient, supplemental sources etc)

• Example , minimum of X % response in Y seconds

for Z mHz change in frequency

• Requirements will trickle down to turbine supplier

• Plant level testing

• Must coordinate frequency injection

between systems

Recommendations

• Clearly defined requirements upfront save time and resources

Outer Closed Loop Controls

• Any closed-loop load controls can “squelch” or “negate” governor droop response (PFR)

• Must add a PFR bias or simulation component

• Subject to tuning:

– Proportional

– Integrating

• Outside controls usually executed at a slower scan rate (1 second)


Illustration

Frequency 60.000 Hz

Graphic from GE info bulletin PSIB20150212


Illustration

450 MW

Frequency 59.940 Hz

153 MW for little more than 1 second

150 MW

+/- Dead Band MW

153 MW for little more than 1 second


Mis

sin

g


Example

450 MW

Frequency 59.940 Hz

153 MW

150 MW

+/- Dead Band MW

153 MW

456 MW

6 MW



Example

400 MW

Frequency 60.000 Hz

150 MW

150 MW

100 MW

400 MW

0 MW



Conventional Steam Plant


Frequency 59.940 Hz

400 MW6 MW

406 MW

+/- Dead Band MW

406 MW


The Capability Goal

Reliability Guideline: Primary Frequency ControlIn order to provide Primary Frequency Control, it is recommended that all resources connected to an Interconnection be equipped with a working governor or equivalent frequency control device.

The primary focus of the Guideline is prime mover governors. Other forms of resources providing frequency response should have similar response characteristics described herein for governor.

3 -175 MW GE7FA Gas Mark VIe Turbine

Frequency Algorithm added to Plant DCS


• Three Interconnections: Eastern, Western and Quebec conduct periodic generator surveys based on selected events over multiple years to measure generators individual performance. The surveys intention is to bring awareness to the industry and assist the

industry in improving primary frequency response. The purpose of this data collection is not related to compliance.

The NERC RS and NERC Staff will select at least two events a year spaced out in such a way to allow generator to address any issues discovered.

Surveys will be sent within a timely manner of selected frequency excursions.

Generator owners should complete and provide survey data for all BES generators online at the time of the event.

Next Step: Generator Survey


• NERC will provide an email address and instructions for survey responses.

• Additional webinars with OEM and Engineering firms to provide resources to the industry.

Additional Details


Generator Survey Form


Generator Survey: Historian Data Entry


Generator Survey: Results


For Generators with headroom(between Pmin and 2% of Pmax),Generators who provide response in the proper direction and sustained it for the lesser of the event duration or for 1 minute.

Generators whose MW output remained unchanged, was in the wrong direction, or withdrew response.

Assessing Performance:Simplistic Grading System


Email: [email protected]

mailto:[email protected]

Documents

Frequency Response Initiative Generator Event Survey DL/Frequency_Response_Initiative_… · 12/8/2016 · 1. Always present 2. Default on modern units since ~2011 3. Site specific