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GIC Modeling SRWG Meeting

March 2014

Introduction

Terminology

Theory

GMD Impacts to Power System Equipment

Historic Events

Regulatory Activities

Geomagnetic Induced Current Modeling

GIC Study Tools

GIC Modeling Data

Challenges

IPCO GIC Study Experiences

SRWG Discussion Topics

Terminology

CME = Coronal Mass Ejection

GMD = Geomagnetic Disturbance

GIC = Geomagnetically Induced Current

HILF = High Impact Low Frequency Events

Coordinated Cyber, Physical, and Blended Attacks

Pandemics

Geomagnetic Disturbances

Electromagnetic Pulse (EMP)

Intentional Electromagnetic Interference (IEMI)

GMDs and the Power System

DC

Network

Grid

Model

GIC

AC

Network

Grid

Model

Powerflow Solar

Flare CME

Perturbation

of Earths

Magnetic

Field

nT/min

Planetary Science

Space

Image: 2012 NERC GMDTF Interim Report

Maxwell

Equations

and Earth

Conductivity

() Model

V/km

Physics (E&M) Power Engineering

Near Earths Surface

GMD Impact on Power System

Equipment

Transformer Half-Cycle Saturation

Harmonics

Increase Reactive Power Consumption

Increased risk of system voltage collapse

Transformer Heating

Increased risk of transformer damage

Protective Relaying Misoperation

Harmonics / DC Offset due to GIC

Electromechanical Relays

Communication System Issues

October 31 - Sun storm causes problems for Swedish

power system. The solar storm has caused technical

glitches in Sweden's power system in the past few

days and may be to blame for a blackout that affected

50,000 people on Thursday, October 30.

Information Notice No. 90-42: FAILURE OF ELECTRICAL POWER EQUIPMENT

DUE TO SOLAR MAGNETIC DISTURBANCES

Specific events occurred at the Three Mile Island Unit 1, Hope Creek Unit 1, and Salem Unit 1

nuclear power plants. inspection of the generator

step-up transformer severe overheating, melted

low

-voltage service connections in phases A and C,

and insulation discoloration in phase B. On

September 19, at Salem Unit 2 nuclear power

plant, a second solar storm damaged the generator

step-up transformer. Sep 1990

Transformer exit-lead

overheating

Transformer winding failure

Historic Events

GMD Regulatory Activities

FERC Order 779

Issued to NERC in May 16, 2013

Directed NERC to develop reliability

standards to address the potential impact of

GMD Events on the reliable operation of

the Bulk-Power System

Directed Standards Development in Two

Stages

Stage 1 Standards

Focus on GMD Operating Procedures

Must be filed by January 2014

Stage 2 Standards

Focus on initial and on-going study

assessments of benchmark GMD events

Must be filed by January 2015

NERC Project 2013-03

Geomagnetic Disturbance Mitigation

Stage 1: NERC EOP-010-1 Geomagnetic Disturbance Operations

NERC BOT adoption 11/7/2013

Filed with FERC 11/14/2013

Stage 2: NERC TPL-007-1 Transmission System Planned

Performance During Geomagnetic Disturbances

Standards Authorization Request (SAR) Completed

Status = Active Formal Development

NERC EOP-010-1

Applicable Entities

Reliability Coordinator

Transmission Operator with a Transmission Operator Area that includes a

power transformer with a high side wye-grounded winding with terminal

voltage greater than 200 kV

Effective Date Timeline

First day of the first calendar quarter that is six months after applicable

approvals (i.e. FERC, NERC BOT, etc.)

Requires TOPs to develop, maintain, and implement GMD

Operating Procedures to mitigate the effects of GMD events

NERC TPL-007-1

FERC Order 779 Requirements

Initial and on-going assessments of the risk and potential impact of

benchmark GMD events on the Bulk-Power System

Identification of benchmark GMD events

Develop and implement action plans to protect against instability,

uncontrolled separation, or cascading caused by GMD events

Proposed Effective Date Timeline

Implementation Period was not addressed in Order 779

Potential Impact to SRWG

May need to develop GIC Modeling and Data Reporting Requirements

GIC Modeling

Image: 2012 NERC GMDTF Interim Report

Qloss_GIC, IGIC QV

PV DC

Network

Grid

Model

GIC

AC

Network

Grid

Model

Powerflow

Qloss_GIC

Contingency

Analysis Transient

Stability

E&M DC Network Model AC Network Model

Equivalent Circuit

Substation

Transmission Line

Transformer

Transmission Lines

Image: 2012 NERC GMDTF Interim Report

DC Voltage Source

Transmission Line GIC Model

LY

SUB 1

(Lat A, Long A)

SUB 2

(Lat B, Long B)

Ex

EY

Lx

System Voltage

Level

(kV)

DC Resistance

(ohm/km)

230 0.072

345 0.037

500 0.013

735 0.011

Series Capacitors

Transmission Lines with Series Capacitors

Block GIC Current from flowing

Image: Idaho Power

Caution Regarding Series Capacitors

Line Shunts can form GIC circuits

Transformers

Transformer GIC Model

Image: 2012 NERC GMDTF Interim Report

Winding Configuration Winding Resistance

Core Type

Substations

Typical Network Resistance Values

Image: Advanced Grounding Concepts

Grounding Resistance Measurement

Fall of Potential Test Method

System

Voltage Level

(kV)

Grounding

Resistance of

Substation

(ohms)

230 0.563

345 0.667

500 0.125

735 0.258

Substation GIC Model

Rgnd

GIC Study Tools

General Electric Positive Sequence Load Flow (GE PSLF)

GIC add-on module available in GE PSLF V18.1_02

Latitude / Longitude in bus record table

Four New tables for Substation, secddg table, trang table, e-field table

Siemens Power System Simulator for Engineering (PSSE)

GIC add-on module available in Versions 32.2 and 33.3

Input data via auxiliary text file *.GIC file or GIC module GUI

PowerWorld Simulator V17

GIC add-on module available

Input data via auxiliary text file or GIC Add-on Analysis Dialog

Calculation Methods are based on NERC GMD Task Force

Recommendations

Default values for some GIC data if unknown

GIC Modeling Data

GIC Modeling Data on an wide area basis

Powerflow Network

Latitude / Longitude of Substations

Substation Grounding Resistance

Transformer Connections

Transformer DC Winding Resistance

Status of GIC Blocking Devices

Equipment Specific GIC Modeling Data

Transformer Core Construction

Transformer Saturation Coefficient (K-Factor)

Challenges

GMD has more impact on Northern Portion of the Interconnection

Defining GIC Data Reporting Requirements

All of WECC?

Portions of WECC?

All elements of the Bulk-Power System (BPS)?

Portions of the BPS?

Transmission Lines 200kV and above?

Transformers with HV grounded-wye windings 200 kV and above?

Additional details are needed in order to completely define new data

reporting requirements

GIC Data Conversion between Software Packages

PSLF, PSS/E, PowerWorld have different input data requirements

Needs

GIC studies should be performed using Wide Area Models

GIC Data needs to be available and shared between Entities

GIC Blocking in one Area impacts GIC currents in adjacent Areas

Whack-a-Mole

IPCO GMD Study Experiences

DC GIC Analysis

Uniform Electric Field

AC Powerflow Analysis with GIC

Wide Area

Idaho Area

N-1 Contingency Analysis with GIC

Idaho Area

Reactive Margin Analysis with GIC

Idaho Area Buses

Northwest Area Buses

Idaho Area Bus Voltage Impact with GIC

Wide Area

Idaho Area

DC GIC Study Results

Transformer GIC MVAR Loss

0

100

200

300

400

500

600

700

0 30 60 90 120 150 180

MV

AR

Compass Angle (degrees)

Idaho Area MVAR Loss due to GIC

7 V/km 4 V/km

Wide Area AC Powerflow Results

Direction Electric Field Magnitude (V/km)

where Powerflow fails to solve

0 degrees 7.4

15 degrees 7.0

30 degrees 6.6

45 degrees 5.6

60 degrees 5.2

75 degrees 5.1

90 degrees 4.0

105 degrees 4.4

120 degrees 4.8

135 degrees 4.8

150 degrees 4.8

165 degrees 8.4

180 degrees 7.4

Wide Area AC Powerflow Results

(Excluding Idaho Area)

Compass

Ang