Frequency Response Initiative Generator Event Survey. NERC Resources Subcommittee North American Generator Forum December 8, 2016

Transcription

1 Frequency Response Initiative Generator Event Survey NERC Resources Subcommittee North American Generator Forum December 8, 2016

2 Why Primary Frequency Response Is Important 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) 2

3 2012 Frequency Response Initiative Report Lazy L 3

4 NERC Outreach OEM and Engineering Firms 4

5 Generator Governor Frequency Response Advisory 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 5

6 Turbine OEM Reach Out to Customer Base 6

7 What has been learned Deadbands Exceed Many Deadbands Exceed 36 mhz Deadbands Vary Many exceed 36 mhz or 2.16 RPM Droops Settings Vary Majority Droops reported 5% 7

8 What has been learned Outer Loop Control Coordination with plant DCS is a requirement when operating in MW Set Point Coordinated Control. 8

9 Reliability Guideline: Primary Frequency Control Posted December 15,

10 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. Recommendations 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 3. Site specific, co-ordination required 2. Default on modern units since ~ Always present Clearly defined requirements upfront save time and resources

11 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)

12 Illustration Frequency Hz Graphic from GE info bulletin PSIB

13 Missing Illustration Frequency Hz 450 MW 153 MW for little more than 1 second +/- Dead Band MW 153 MW for little more than 1 second 150 MW Graphic from GE info bulletin PSIB

14 Example Frequency Hz 6 MW 450 MW 153 MW 456 MW +/- Dead Band MW 153 MW 150 MW Graphic from GE info bulletin PSIB

15 Example Frequency Hz 0 MW 400 MW 150 MW 400 MW 150 MW 100 MW Graphic from GE info bulletin PSIB

16 Frequency Hz Conventional Steam Plant 6 MW 400 MW 406 MW +/- Dead Band MW 16 Graphic from GE info bulletin PSIB MW

17 The Capability Goal Reliability Guideline: Primary Frequency Control In 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 MW GE7FA Gas Mark VIe Turbine Frequency Algorithm added to Plant DCS 17

18 Next Step: Generator Survey 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. 18

19 Additional Details NERC will provide an address and instructions for survey responses. Additional webinars with OEM and Engineering firms to provide resources to the industry. 19

20 Generator Survey Form 20

21 Generator Survey: Historian Data Entry 21

22 Generator Survey: Results 22

23 Assessing Performance: Simplistic Grading System 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. 23

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