1 intermountain power project stability enhancement (ippse) system presentation to wecc remedial...

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INTERMOUNTAIN POWER PROJECT STABILITY ENHANCEMENT (IPPSE) SYSTEM

Presentation to

WECC Remedial Action Scheme Reliability Subcommittee

April 30, 2010Ontario HiltonOntario, CA

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INTERMOUNTAIN POWER PROJECT STABILITY ENHANCEMENT (IPPSE) SYSTEM

Presented by: Ken Silver-Electrical Service Manager (Manager of

Energy Control and Extra High Voltage Stations ) Travis Smith-Assistant Manager (Manager of

Intermountain Converter Station) Brian Cast–Electrical Engineer (Grid Operation and

Energy Prescheduling Supervisor ) Ken Lindquist – System Protection Engineer

Attendees: Ken Silver, Mukhlesur Bhuiyan, Travis Smith, Tom

Snyder, Brian Cast, Saif Mogri, Ken Lindquist, Carlos Garay and John Hu

Chuck Wu (On Phone)

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Agenda

1. System Overview – Ken Silver2. Performance and Operational History – Travis

Smith3. System Studies – Ken Lindquist4. System Design – Travis Smith5. Arming Function – Brian Cast6. Operation and Monitoring – Brian Cast7. Operating Procedures for Abnormal Conditions -

Ken Silver8. Commissioning, Maintenance, and Testing – Travis

Smith9. Conclusions – Travis Smith

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1. System Overview

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1. System Overview

The Purpose of Intermountain Power Project Stability Enhancement (IPPSE) is to ensure WECC system stability after outages to the Intermountain Power Project DC system (IPPDC). This is achieved by arming predetermined remedial actions prior to the occurrence of a disturbance associated with the IPPDC.

Due to IPPDC system upgrade from 1920MW to 2400MW, the IPPSE is submitted for review.

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1. System Overview

Remedial Actions Required:The Intermountain Power Project (IPP) Contingency Arming System (CAS)has been implemented to mitigate IPPDC disturbances by tripping one or twoIPP generating units. The IPP CAS has been in operation since 1986. Thedesign and operations of this RAS has been reported to WECC on April 1986with a report entitled “Intermountain Power Project Contingency ArmingSystem: One Unit Operation” and on August 1992, with a report entitled“Intermountain Power Project Contingency Arming System: Non-Credibilityof Remedial Action Scheme Failure.”

Formal Operating Procedure:The IPP CAS consists of arming-charts where real-time power output of theIPP generating units and the IPPDC line flows are used to select the no-unit,one-unit or two-unit arming of remedial actions. The IPP CAS and associatedoperating procedures are included with the LADWP’s Energy Control CenterEnergy Management System (ECC-EMS) computers.

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1. System Overview IPP DC Upgrade Project

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1. System Overview Intermountain Power Project System

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1. System Overview System Map

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1. System Overview Intermountain One-line Diagram

One Line Diagram: Adelanto

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2. Performance and Operational History

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The existing IPPSE was installed May 10, 1986

A design criteria of one operational failure in 3 years was used.

How have we done ?

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In 24 years there have been 28 actions. Seventeen of which occurred prior to August 1992.

There have been 6 failures 5 of which occurred prior to August 1992.

The system did not achieve its goal from 1986 to 1992. However from 1992 to the present, the system has achieved its goals.

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What Changed in 1992?

A problem with the Monopolar Out signal was discovered and corrected.

A design change was initiated to allow for 1 restart in Monopolar Operation.

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Success

After the modifications, the system operated correctly.

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3. System Study

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3. Study Process Summary

Co-ordinate with Impacted System Operators (PacifiCorp) in preparing study plan and study conditions.

Determine Impact on the WECC System. Determine Maximum “IPP Net Import”

Capability. Determine Generation Tripping delay times. Determine IPP Contingency Arming Scheme

(CAS) Operational Nomograms.

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3. System Condition Studied IPP DC Upgrade

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3. Utah South Conditions

Stressed TOT2 to Path RatingTOT2C

TOT2B

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3. “Net IPP Import” Sensitivity(Post-Transient Power Flow)

Voltage Deviation at ABAJO 66kV Bus

-0.110

-0.100

-0.090

-0.080

-0.070

-0.060

-0.050

-0.040

-0.030

-0.020

-0.010

0 200 400 600 800 1000 1200

Net IPP Import (MW)

Vo

ltag

e D

evia

tio

n (

Ab

ajo

69k

V u

nd

er C

on

tin

gen

cy)

(pu

)

Threek-Peak-Sigurd Out

IPP Bipole Out Full RAS

WECC N-2 Criteria

Line Loading of Sigurd - Three Peak 345kV Line

1600

1700

1800

1900

2000

0 200 400 600 800 1000 1200

Net IPP Import (MW)

Sig

ura

d-T

hre

ePea

k L

ine

Flo

w (

Am

s)

Huntington-Pinot-SpanishFork DLO

IPP Bipole Out - Full RAS

Line Emergency Rating

* IPP DC Will Operate with Maximum “Net IPP Import” of 600MW – Limited by Line Overload

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3. Determine Delay Generation Tripping

Accommodate possible DC restart sequence after a DC fault;

To lessen the stress by possibly using a less stressful turbine or boiler trip.

DC Fault Restart 1st 2nd 3rd

Deionization Time (ms) 225 325 425

Deionization Time (cycles) 13.5 19.5 25.5

Cumulative (cycles) 13.5 33 58.5

Simulate CAS time (cycles) (trip unit)

18 40 70

Generator Tripping

Methods

Time to 0 Output

Comments

Electrical Trip < 10 CyclesMost Stressful on

boilers and turbines

Boiler Trip~ 42 Second

s

15 second Delay 20 seconds to

100MW, 6 second to

breaker Open

Turbine Trip~ 23 Second

s

15 second delay, 2 seconds to

100MW, 6 seconds to

breaker Open

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3. Stability Plot for Loss of Bipole with Restart (for DC Fault Only)

(Worst Stressed Condition)Trip 1 Unit after First Restart Failed and Second Unit after the Second Restart FailedTrip Both Units after First Restart Failed

* CAS Will Trip Units after 1 Restart Attempt Failed

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3. Stability Plot for Loss of Bipole with Delayed CAS Generation Tripping for Lower IPP DC Schedule

IPP DC Schedule 1500MW IPP DC Schedule 1400MW

* CAS Will Delay Generation Tripping for IPP DC Schedule 1400MW or Less

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3. Delayed CAS Generation Tripping for Loss of 1 Pole

Short Term Overload Capability of IPP DC

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3. Delayed CAS Generation Tripping for Loss of 1 Pole (IPP AC Fault Trip 1 Unit + MWC

Generations)Delayed Tripping

* CAS Will Delay Generation Tripping for Loss of 1 Pole

Fast TrippingNo RAS

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3. IPP CAS Generation Tripping Level Operating Nomogram for Bipole Operation for the Loss of

Bipole

IPP STS Operating Nomogram(For Loss of Bipole in Bipolar Operation)

(Studied Cases Marked)

1908

1907

1830

1796 1795

1758

1758

0

400

800

1200

1600

2000

2400

0 400 800 1200 1600 2000 2400

IPP + MWC Gen (MW)

ST

S D

C S

ched

ule

(MW

)

(Nomogram Limit) Trip all Gen - 1 RS

Trip 1 unit + MWC gen - 1RS

Trip MWC Only - Delayed

NoRAS

0 Import Line

Trip All Gen - Studied

Trip All Gen - Studied

Trip 1 Unit + MWC gen - Studied

No RAS - Studied

Unreliable Operating Region

Limited by Post-transient Sigurd-Three Peaks Flow (A) (Limit 1800A)

IPP STS Operating Nomogram(For Loss of Bipole in Bipolar Operation)

0

400

800

1200

1600

2000

2400

0 400 800 1200 1600 2000 2400IPP + MWC Gen (MW)

ST

S D

C S

ched

ule

(M

W)

(Nomogram Limit) Trip all Gen - 1 RS

Trip all Gen - Delayed

Trip 1 unit + MWC gen - 1RS

Trip 1 unit + MWC gen - Delayed


NoRAS

Linear (0 Import Line)


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3. IPP CAS Generation Tripping Level Operating Nomogram for Bipole Operation for the Loss of

1 Pole

IPP STS Operating Nomogram(For Loss of 1 Pole in Bipolar Operation)


0

400

800

1200

1600

2000

2400

0 400 800 1200 1600 2000 2400

IPP + MWC Gen (MW)

STS

DC

Sch

edul

e (M

W)

Trip 1 unit + MWC gen- Delayed


No Ras

0 Import Line

Trip 1 Unit + MWC - Studied

Trip MWC - Studied

NoRas - Studied


Limited by Post-transient Voltage

Deviation of 5% at Abajo 69kV bus

IPP STS Operating Nomogram(For Loss of 1 Pole in Bipolar Operation)

0

400

800

1200

1600

2000

2400

0 400 800 1200 1600 2000 2400

IPP + MWC Gen (MW)

STS

DC

Sch

edul

e (M

W)

Trip 1 unit + MWC gen- Delayed


No Ras



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3. IPP CAS Generation Tripping Level Operating Nomogram for Mono-pole Operation for the Loss of

1 Pole

IPP STS Operating Nomogram(For Loss of Pole in Mono-polar Operation)

0

400

800

1200

1600

2000

2400

0 400 800 1200 1600 2000 2400IPP + MWC Gen (MW)

ST

S D

C S

ched

ule

(M

W)




NoRAS



IPP STS Operating Nomogram(For Loss of Pole in Mono-polar Operation)


0

400

800

1200

1600

2000

2400

0 400 800 1200 1600 2000 2400

IPP + MWC Gen (MW)

ST

S D

C S

ched

ule

(M

W)




No Ras

0 Import Line

Trip 2 units VDev -Studied

Trip 1 Unit - Thermal Limit Studied

Trip 1 Unit - VDev Limit Studied

No RAS - Studied


Limited by Post-transient Sigurd-Three Peaks Flow (A) (Limit 1800A) and Voltage deviation 5% at Abajo

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3. Study Summary

IPP DC limited to net AC Import capability of 600MW under maximum Utah South export conditions

CAS will Trip Units after 1 Restart Attempt Failed CAS will Delay Generation Tripping for IPP DC

Schedule 1400MW or Less CAS will Delay Generation Tripping for Loss of 1

Pole - Limited by Voltage Deviations

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4. System Design

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4. System Design

Design Philosophy

1. Meet the System Studies Guidelines2. Insure Redundancy3. Reduce the Hardware4. Centralize the Logic

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4. System Design

Following the guidelines established by the system studies were the driving force in the design of the IPPSE.

All parameters of the studies have been met which also allowed for a simpler more efficient design.

Only 1 operational failure in 3 years is allowed.

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4. System Design

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4. System Design

The Bipole Controls are a completely redundant

Mach 2 Control System designed by ABB. All protection actions are routed through this

control system. The IPPSE Logic is fully contained in this system

thus reducing the system hardware requirements. All remedial outputs are generated from this

control system.

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4. System Design The remedials from the IPPSE Logic

have been simplified into two outputs.

Monopolar Out Bipolar Out

Based on these two signals and the Nomograms, all IPPSE actions are appropriately taken.

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4. System Design

Generator Trip Remedials

Electrical Trip (86 Lockout)

Turbine Trip

Boiler Trip

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4. System Design

IPP Digital Microwave System

Original analog system installed 1985

System was replaced with Harris Stratex (now Aviat Networks) digital microwave radios in 2004

LADWP operated and maintained

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4. System Design IPP Microwave Power Redundancy Propane Back up Generators 24 VDC Power Plants

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4. System Design

IPP Microwave One Line

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5. Arming Function

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5. Arming Function

Overview:

Arming is automated by an application running in LADWP’s energy management system.

Nomograms, called “charts”, specify the arming level.

Each chart has a series of curves that provide arming levels as a function of IPP net generation (including Milford generation) and the DC line flow.

The application selects charts based on monitored power system conditions and the specific trigger being armed.

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5. Arming Function

Charts:

One curve per remedial action.

Arming is a function of net gen vs. DC flow.

Top-most curve provides DC flow limit.

Added remedial actions will require an increase in the number of curves per chart.

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5. Arming Function

Chart Sets:

There may be up to five triggers for remedial actions.

Each trigger has its own arming for remedial action.

Therefore, there is one chart per trigger.

The set of charts for the triggers is a “chart set”.

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5. Arming Function

Chart Set Selection:

There are multiple chart sets to accommodate varying system conditions.

Chart sets are functionally organized into rows and columns.

Columns are selected based on monitored line flows.

Rows are selected based on line outages and IPP operating modes.

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5. Arming Function

Chart Set Selection (cont’d):

Original design provided for 24 columns.

Although they no longer affect arming, three power flows are still monitored: Pacific AC Intertie, Arizona–California, and Utah South.

The system study indicates nomogram sensitivity to Utah South power flow, so use of multiple columns may become necessary.

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5. Arming Function

Imports:

Chart shows a 600-MW import limit.

IPP AC lines have 1317-MW import capability.

Chart is worst-case scenario.

Other cases allow more imports.

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5. Arming Function

Import Example:

A 72-MW on Sigurd–Three Peak may allow a 400-MW in imports.

This can be implemented via multiple columns or via dynamic shifting of affected curves.

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5. Arming Function

Summary of Arming Function Changes:

Increase in the number of curves per chart due to increase in number of remedial actions.

Decrease in the number of charts per chart set due to decrease in the number of triggers.

Increase in the number of chart set columns and/or addition of dynamic curve adjustments due to varying AC import limits depending on Utah South flow.

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6. Monitoring and Operation

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Overview:

LADWP’s Energy Control Center (ECC) and IPP both have monitoring capability.

The arming application runs at the ECC, but either site can arm manually.

Except for automatic arming, the RAS operation occurs entirely at IPP, but is monitored by both sites.

The slides that follow show monitoring and operation as seen at the ECC.

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The interface at the ECC includes the following displays:

Curves & DC Limits Columns & Charts Panel Status (i.e. RAS Status) AnnunciatorsThese displays are summarized and shown in the slides that follow.

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Curves & DC Limits:

Shows summary data in upper-right corner.

Provides for viewing and update of curves and charts.

Shows remedial action selected for each active chart.

Shows DC limits from charts and other nomograms.

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Curves & DC Limits Display

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Changes to Curves & DC Limits:

System studies do not show a need for separate nomograms for DC limits from Utah North, Utah South, or Northeast/Southeast flows.

DC limit for power flows flow will be inherent in the contingency arming limit from the selected charts.

Dynamic offsets to curve data, when implemented, will be shown on this display.

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Columns & Charts:

Shows power flows for chart set column selection.

Shows line status.

Shows plant operating mode.

Shows column and chart set selection in the summary data in the upper-right corner.

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Columns & Charts Display

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Changes to Columns & DC Charts:

Column selection is no longer influenced by Pacific AC Intertie and Arizona–California flows.

Additional columns may be needed to model the effects of Utah South flow on AC import capability.

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Panel Status:

The RAS is currently implemented at IPP via redundant hardware systems called “panels”.

Each arming control point is wired to operate both panels from a single control operation.

Each panel independently reports its status.

Arming controls can be issued via the arming application or manually via SCADA control actions.

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Panel Status (cont’d):

Provides a control and pair of state indications for each combination of trigger and remedial action that may be armed.

Provides for manual entry of an arming pattern when in MANUAL mode and shows the application-determined arming pattern when in AUTOMATIC mode.

Shows panel status values. Shows triggers actuated. When a trigger is

actuated, the RAS will execute any remedial actions armed for that trigger.

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Panel Status Display

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Changes to Panel Status:

The application currently implements the arming matrix by using an obscure feature to control multiple arming state points with a single control operation. (This is much quicker than using time-consuming discrete control actions for each arming state point.)

This set of arming state points to specify remedial actions for each trigger will be replaced with a single analog point for each trigger that specifies the remedial actions to execute.

The RAS implementation will be part of the DC control system.

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Annunciator Displays:

The RAS trigger inputs are actually aggregations of multiple triggering inputs from relay and DC control systems.

For this reason, the RAS trigger inputs are in some places called “super triggers”.

The annunciator displays show each trigger input and identify the super triggers that it activates.

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Annunciator Display 1

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Annunciator Display 2

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Annunciator Changes:

According to system studies, many of the triggering inputs will no longer require remedial actions.

Only triggering inputs for monopole and bipole blocks will continue to be relevant.

The number of super triggers needed will reduce from five to two.

The triggering inputs no longer requiring remedial action may be retained on the annunciator displays for reference.

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Summary of Monitoring and Operation Changes:

The RAS function will be located in the DC control system.

Arming will be specified via analog arming levels rather than discrete digital states.

Arming may use real-time power flow to bias affected nomogram curves.

Additional remedial actions are being added. The inputs that affect remedial action arming and

execution are being updated according to study results.

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7. Operating Procedure for

Abnormal System Conditions

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7. Operating Procedures for Abnormal System Conditions

The RAS operates incorrectly (failure to operate or false operation)

As soon as the IPPSE has failed or operated improperly, generation and DC flows will be curtailed to a point where remedial action is not required. The condition will be maintained until repairs can be made or the RAS is proven to be stable.

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One part of a redundant RAS system is unavailable so that complete redundancy is no longer assured

Personnel will be dispatched immediately to work on the unavailable system to restore it to operational status as soon as possible. Curtailment is not required in this condition.

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When unscheduled, or unplanned and not coordinated, unavailability of the subject RAS (complete loss of RAS) impacts operation

Generation and DC flows will be curtailed to a point where RAS is not required or until such time as the RAS becomes available again.

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When a partial or total loss of input data required for arming decisions

All input data required for arming originates from Intermountain Converter Station (ICS) and Intermountain Generating Station (IGS). The ICS operator will manually set the proper arming as directed by the Energy Control Center (ECC). The ICS operator has the ability to determine and set proper arming independent of ECC.

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8. Commissioning, Maintenance and Testing

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8. Commissioning, Maintenance, and Testing

Commissioning Testing of the IPPSE Logic will begin

during the Factory Acceptance Tests in Sweden. This will begin in May 2010.

Commissioning of the new system will begin in October of 2010 when the first Mach 2 control comes on line.

The IPPSE system will be fully operational by Mid December 2010.

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Maintenance All critical components such as

communication links, test switches and computers are monitored by the new Alarm Reporting and Monitoring System (ARMS)

Emergency maintenance can be done on line without degrading the system. Only redundancy will be lost.

Scheduled Maintenance is every 2 years.

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Testing Testing will be “End to End”, from ECC to the

Generator and Milford Intermountain Line 1 Blocking Switches.

Each arming level in the Nomograms will be tested to assure that the proper remedial is sent to the blocking switch.

All intermediate signals, remedial outputs and trip signals will be recorded for analysis.

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9. Conclusions

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9. Conclusions

System Studies Guidelines

System studies were extensive and the results were incorporated into the system design.

All system hardware and software is monitored for correct operation.

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9. Conclusions

Redundancy

All Protections, Control Systems, Communication Systems and Monitoring Systems are completely redundant.

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9. Conclusions

Reduce and Simplify the Hardware

The input triggers have been reduced from 19 to 2.

The Nomograms have been reduced from 38 to 3.

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9. Conclusions

Centralize the Logic

All IPPSE Logic is now contained in the HVDC Mach 2 control system.

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Questions?

1 intermountain power project stability enhancement (ippse) system presentation to wecc remedial...

Documents

system overview slide

system study slide

system condition

wecc system stability

ippdc system upgrade

operational history

system overview ken

ipp dc upgrade slide