epri gmd research update...project - ferc/nerc gmd project arp –gmd vulnerability assessments...

© 2019 Electric Power Research Institute, Inc. All rights reserved.w w w . e p r i . c o m

Bob Arritt, PE

Transmission Resiliency Summit Charlotte, NC3 April 2019

EPRI GMD Research Status

Update:Furthering the Research of GMD Impacts

on the Bulk Power System

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© 2019 Electric Power Research Institute, Inc. All rights reserved.w w w . e p r i . c o m2

Agenda

EPRI GMD Overview

FERC/NERC GMD Project Update

Annual Research Portfolio (ARP) –GMD Vulnerability Assessments

DOE Geomagnetic Current (GIC) Blocker Demonstration



Geomagnetic Disturbance Overview

Credit: NASA GSFC SVS



GMD Research Portfolio

GMD Supplemental Project -

FERC/NERC GMD Project

ARP – GMD Vulnerability Assessments

SUNBURST & Adv. Sensors

• Benchmark GMD Event

• Transformer Assessment

• GMD Harmonics Assessment

• GMD Assessment Guidelines

• Commercial Planning Tools

• Road Map for Future Assessment Methods/Tools

• GIC Monitoring (neutral and line)

• Magnetometers

• Data Analytics



Why the GMD Supplemental Project?

Improved Earth

Conductivity

Models

Improved

Harmonic

Analysis

Capability

Harmonic

Impacts Spatial

Averaging

Transformer

Thermal

Impacts

Latitude Scaling

Factor

Geoelectric

Field Evaluation

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

pu

flu

x

Current, pu

Per Unit Saturation Curve

FERC Order 830 addressed NERC TPL-007-1 (GMD Vulnerability Assessment)

GMD Research Work Plan

October 19th, 2017 FERC Order

Will inform future revisions of TPL-007

Hig

he

st P

rio

rity

Low

est

Priority



Newly Released Material

Improve Harmonics Analysis Capability Tool Product ID# 3002014854

Tool Evaluation and Electric Field Estimate Benchmarking Results Product ID# 3002014853

Use of MagnetotelluricMeasurement Data to Validate/Improve Existing Earth Conductivity Models Product ID# 3002014856

Transformer Vibration Analysis Product ID# 3002014855



How Do GMD Harmonics Threaten Grid Security?

Harmonics can take out critical grid facilities:– False tripping due to distortion– Correct tripping to protect from distortion– Possible damage and failure of grid

equipment

Reactive power sources are particularly vulnerable

Loss of facilities can allow the grid to collapse at a less severe GMD intensity than predicted using intact grid

Harmonic analysis is an essential and integral part of grid GMD impact assessment

Magnetizing

Current 0A GIC

Magnetizing

Current 40A GIC



Transformer level analysis

conventional shell form



System level analysis

Relevant details for buses, elements, and electric field– Buses

– Transformers

– Capacitors

– Reactors



Earth Conductivity Research

Examining the observed differences between new and existing representations of ground response.

Improve existing earth models

FERC Order 830 P78. “… As part of the second research area identified … (i.e., further analyze

earth conductivity models by, for example, using metered GIC and magnetometer

readings to calculate earth conductivity and using 3-D readings), the GMD research work

plan should specifically investigate ...”



Earth Conductivity Research Comparisons – Original 1D

models to new measurement data

Adding new data, some areas are underestimated

some are overestimated.

Examining the observed differences between original models to new measurement data.



Updated 1D models

Regional boundaries are updated based

on recent 3-D measurement data

• Scaling factor recalculation is on-going

• Working with a member utility to compare model results with GIC measurements



Localized Geoelectric Field Enhancements and Latitude Scaling

Have developed comprehensive data set to support GMD analyses.

Using historical data and MagnetohydrodynamicMHD simulations, we can interpolate magnetic field values between observatories

Using historical data and Magnetohydrodynamic(MHD) simulations to show the extent of this southward motion for extreme events.

Data Set providing Ground Truth for Modeling



Studies on the saturation of noise and vibration with GIC currents

0

1

2

3

4

5

6

7

67

70

73

76

79

82

85

88

91

19:26 19:40 19:55 20:09 20:24

GIC

Neut

ral c

urre

nt, A

mps

Soun

d Pr

essu

re le

vel, d

B (A

)

Time

Noise, dB (A)

GIC Current, A

Validation in vibration results from

laboratory and field measurements



Industry Engagement

2019 GMD Workshop

– August 13th

– Exelon Offices

– Chicago, IL



ARP – GMD Vulnerability Assessments:



Background

k-factor

0

0.05

0.1

0.15

0.2

0.25

0.3

1 2 3 4 5 6 7 8 9 10 11

Pe

ak C

urr

en

t in

P.U

. of

RM

S R

ate

Cu

rre

nt

Harmonic Order

200 A/ph dc

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

1 2 3 4 5 6 7 8 9 10 11

Pe

ak C

urr

en

t in

P.U

. of

RM

S R

ate

Cu

rre

nt

Harmonic Order



Q-GIC characteristics of a 5-legged transformer under

changing yoke and return leg cross-section area

0 0.1 0.2 0.30

0.1

0.2

Three Phase Transformer Reactive Power verses GIC

GIC (pu per phase)

Q.e

xc(

pu)

on T

rans

form

er B

ase

0.237

0

Five_LeggedGIC( )

Five_Legged.Min GIC( )

Five_Legged.k GIC( )

0.30 GIC

Provide k-factor ranges for various

core sizes



2019 ARP Projects

GMD Planning Software Benchmarking– Benchmarking the GIC

simulation of non-uniform electric fields To ensure accuracy and

consistency across platforms, and coordinate individually with each vendor in a confidential matter and adjust where needed.

Goal is to allow vendors to expand their capabilities and to ensure accuracy across multiple platforms

“commercially-available modeling tools now advertise

capabilities that could be used to model

localized GMD enhancements, …

these capabilities have not been used extensively by

planners, nor have the different software

tools been benchmarked for

consistency in results.” – NERC statement in

FERC 851



2019 ARP Projects – EPRI Operations Guide

Preparation– System studies

– Modeling uncertainties

– GIC monitoring

Using the results to select the most strategic locations to monitor

2-3 day NOAA Alert ≥ k7– Assess system configuration against planning

configuration

– Safe posture

During event if still ≥ K7 for x time– Actions to take with monitored GIC

Sophisticated monitoring infrastructure

Nominal monitoring infrastructure

Minimal/non-existent monitoring infrastructure

– Monitor var reserves

Reliability issues – PT/CT calibration

State estimator

PMU issues

– Emergency operation (not n-1)

– Load shedding

– GIC redirection

– Account for ambient temperature discount on at-risk transformers.

Time of day consideration (Result of GMD supplemental work)

– Leverage DGA monitoring – primarily to assess transformer condition.

– Recognize sub-storm waveforms, etc.



DOE Support of Executive Order 13744



DOE GIC Blocker Pilot Program

EPRI is working with DOE to help develop the pilot program plan to protect transformers in the field as directed in Executive Order 13744.

EPRI is providing the following:

– Market Survey (Completed)

– System approach to selecting sites (Completed)

Minimal impact to adjacent substations, positive impact

– Hardware specifications (for monitoring and equipment) (Completed)

– Evaluate GIC blocking devices in the field (Phase 2)

Neutral blocking device in the field.

Courtesy of EMPRIMUS, LLC



Phase 2 Project Overview

Task 1 - Choose utility host site

collaborator(s).

Task 2 - Mitigation Technology Selection

Task 3 - Site Requirements and

Specifications

Task 4 - Mitigation and Monitoring

Equipment Specifications

Analyze and evaluate system

performance

Task 5 - Site Acceptance Tests

(SAT)



Together…Shaping the Future of Electricity


epri gmd research update...project - ferc/nerc gmd project arp –gmd vulnerability assessments...

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