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 Earth’s

Magnetic

Field

nT/min

Planetary Science

Space

Image: 2012 NERC GMDTF Interim Report

Maxwell

Equations

and Earth

Conductivity

(σ) Model

V/km

Physics (E&M) Power Engineering

Near Earth’s 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 (PSS®E)

– 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

Angle

(deg)

Electric Field Magnitude (V/km) where Powerflow fails to solve

(Idaho GIC DC Volts and MVAR Loss Excluded)

0 7.4

30 6.61

60 5.2

90 4.0

120 4.8

150 4.8

180 7.4

• Indicates Problem Areas are Outside of Idaho Area

Idaho Bus Voltage

Wide Area Scenario

SRWG Discussion Topics

• As network modelers – we should start thinking about how we are

going to collect and maintain GIC Modeling Data

• GIC Modeling and Data Reporting Requirements

– Include in DPM?

– Include as part of WECC basecase data?

– Include in separate GIC database?

• data submittal process similar to PRC-006-WECC-CRT-1

– Include GIC data tables in the BCCS?

– Regional Standard / Regional Business Practice / Regional Criteria

• Until a draft Version of TPL-007-1 is available, it might be too

soon to completely define GIC Data Reporting Requirements

• WECC Regional Criteria for TPL-007-1

– WECC Regional Criteria contain data reporting requirements

Questions

Eric Bakie, P.E.

SYSTEM PLANNING ENGINEER

Idaho Power | System Planning

(208) 388-5677

ebakie@idahopower.com