Power System Resilience & Reliability. Robert W. Cummings Senior Director of Engineering and Reliability Initiatives i-pcgrid March 28, 2017

Transcription

1 Power System Resilience & Reliability Robert W. Cummings Senior Director of Engineering and Reliability Initiatives i-pcgrid March 28, 2017

2 NERC, Reliability, & Resilience NERC has addressed reliability and resilience through standards, assessment, security, and programmatic efforts DOE Staff Report to the Secretary of Energy (August 2017) recommended that NERC consider adding resilience to its mission statement NERC Board sought stakeholder input (November 2017 policy input letter) Asked NERC s Reliability Issues Steering Committee (RISC) to consider stakeholder input and NERC s role in resilience Resiliency Reliability 2

3 RISC Recommended Framework Develop common understanding and definition of the key elements of bulk power system (BPS) resilience Understand how key elements of BPS resilience fit in the existing Electric Reliability Organization (ERO) framework Evaluate whether additional steps are needed to address key elements of BPS resilience within the ERO framework 3

4 Understanding and Defining Resilience National Infrastructure Advisory Council s (NIAC s) resilience framework includes four outcome focused abilities: Robustness absorb shocks and continue operating Resourcefulness skillfully manage a crisis as it unfolds Rapid Recovery get services back as quickly as possible Adaptability incorporate lessons learned from past events to improve resilience 4

5 ERO Enterprise Activities Supporting NIAC Framework Robustness Risk, event, and performance monitoring Reliability and emerging risk assessments Technical committee work Operator training and certification Reliability Standards and Reliability Guidelines E ISAC information sharing programs Resourcefulness Situational awareness and industry coordination Government coordination Cross sector information sharing Reliability Standards and Functional Model 5

6 ERO Enterprise Activities Supporting NIAC Framework Rapid Recovery Situational awareness and industry coordination Government coordination Cross sector information sharing Adaptability Reliability assessments Event analysis and forensics Reliability Guidelines Technical committee work 6

7 ERO Next Steps Requested NERC Standing Committees input to the Reliability Issues Steering Committee (RISC) Provide recommendations at the May 2018 Member Representatives Committee (MRC) meeting Monitor the Federal Energy Regulatory Commission (FERC) proceedings 7

8 NERC s Areas of Focus Resiliency Smart Grid Changing Resource Mix Decreasing Inertia Inverter connected Resources Intelligent application of new technologies 8

9 Solar Plant Capacity ~30,000 MW 9

10 Solar Plant Locations 10

11 Blue Cut Fire caused Thirteen 500 kv line faults Two 287 kv line faults 11:45:06 PDT Fault 500 kv line to line fault Cleared normally in 2.5 cycles (41.7 milliseconds) PV resources impacted 1,178 MW 26 different solar developments 16 August 2016 Faults All utility scale connected at 500kV or 230kV 10 different inverter manufacturers No PV site system protection relays/breakers operated All action was by on board inverter controls 11

12 Key Finding #1 Largest solar PV loss (~700 MW) due to underfrequency tripping Inverter sensed near instantaneous frequency of < 57 Hz and tripped Hz 12

13 Key Finding #2 Inverters have three modes of operation: Continuous Operation: injecting current into the grid Trip: cease injecting current, disconnect from grid, wait ~5 mins, automatically return to service if voltage and frequency within bounds Momentary Cessation: momentarily cease injecting current during voltages outside continuous operating range 0.9 to 1.0 pu) 13

14 Blue Cut Fire Recommendations 14 Added time delay to inverter under frequency tripping Allows inverter to ride through transient/distorted waveform period without tripping. Clarify that outside the PRC 024 frequency and voltage ridethrough curves are may trip, not must trip Review PRC 024 to determine if any changes are needed Further study needed for risk associated with momentary cessation (IRPTF) Issue industry Alert to inform and collect information from industry on exposure 14

15 Inverter Alert Survey Results Susceptible to erroneous frequency calculation 6,244 MW of 16,771 MW (37%, 7,150 units) 15

16 Inverter Alert Survey Results 16 Momentary cessation for abnormal voltage 14,113 MW of 16,771 MW (84%, 11,821 units) 16

17 9 Oct 2017 Canyon 2 Fire Another two inverter based events on 9 October kv A B Phase Fault at 12:12:16 PST 682 MW loss (SCADA) 500 kv A C Phase Fault at 12:14:30 PST 937 MW loss Back calculated to be about 1,479 MW loss for second fault based on interconnection wide inertia Canyon 2 Fire Disturbance Report Published February

18 Aggregate SCE Solar PV Performance SCADA Data ~15 minutes ,011 Event 1: = 682 MW Event 2: = 937 MW Back calculated to be about a 1,500 MW loss based on the interconnection wide inertia 18

19 Solar PV Outputs 19

20 Key Findings 1. No erroneous frequency tripping 2. Continued use of momentary cessation 3. Ramp rate interactions with return from momentary cessation 4. Interpretation of PRC voltage ride through curve 5. Instantaneous voltage tripping and measurement filtering 6. Phase lock loop synchronization issues 7. DC reverse current tripping 8. Transient interactions and ride through considerations 20

21 Key Findings #2 Continued use of momentary cessation Most inverters use momentary cessation (V < 0.9 pu) Recovery of current following momentary cessation varies, relatively slow for grid dynamics Blue Cut Fire recommendation interim solution NERC IRPTF studies new recommendation 21

22 Ongoing Work with IEEE NERC is continuing the ongoing work to achieve a cohesive inverter based resource performance: Collaboration with Standard IEEE 1547 and covering distribution level DER Collaborating with the IEEE Wind and Solar Power Plant Interconnection and Design Subcommittee and the Wind and Solar Plant Interconnection Working Group, which report to the IEEE PES Energy Development & Power Generation Committee addressing the DER connected above distribution voltage but below transmission voltages 22

23 Relevant Links 23 Blue Cut Fire Disturbance Report: MW Fault Induced Solar Photovoltaic Resource Interruption Disturbance Report.aspx Canyon 2 Fire Disturbance Report: MW Fault Induced Solar Photovoltaic Resource Interruption Disturbance Report.aspx Webinar on Both Disturbances: MW Fault Induced Solar Photovoltaic Resource Interruption Disturbance Report.aspx NERC Events Analysis: NERC Alerts: NERC IRPTF Page: Based Resource Performance Task Force.aspx

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