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THE INTERMOUNTAIN POWER PROJECT (IPP) HVDC SCHEME

 

 

Between :     The Adelanto Converter Station (ACS) at Adelanto, California and the Intermountain Converter Station (ICS) at Delta, Utah. This system is the Southern Transmission System (STS) of IPP and serves as a link between the Intermountain Generating Station (IGS), a 2 x 800 MW coal-fired power plant in Delta, Utah and the load centers in the Southern California.

 

 

Power Co :    The IPP is owned by the Intermountain Power Agency. Los Angeles Department of Water and Power is the Operating Agent.

 

 

Manufacturer :

              Asea of Sweden was the prime contractor for the converter stations.

 

              Los Angeles Department of Water and Power designed and constructed the transmission lines, A.C. switching stations, microwave systems,and the electrodes.

 

 

Commissioned :

              27 th March, 1986 first stage.

 

 

Main Purpose :

              STS serves as the transmission path for power from the IGS to Southern California areas. It is designed to transmit power in the reverse direction.

             

 

Main Data :

              One bipole of two 12-pulse converter poles.

              The bipole rating is 1920 MW, ± 500 kV D.C.;

              Monopolar  rating is 1200 MW.

              Current rating is 2560 A.

 

              Short-time overload defined on pole basis is 3680 A (1600 MW) for one second then ramp down at a rate 60 MW/min to 1200 MW.

 

 


 

 

 

              Short Circuit Ratio (SCR) :

 

              Operation of STS is tightly coupled with the availability of the IGS units. The operating conditions are :

 

              * 1920 MW with two IGS units in service

              * 1250 MW with one IGS unit  in service

              *  800 MW with  no IGS units in service

 

              These operating conditions were specified based on consideration of SCR, filter performance, reactive power compensation, and unit interactions.

 

              At ICS, based on the above operating conditions, the SCR is 4.18 - 5.09.

 

              At ACS, based on 1920 MW only, the SCR is 5.15 - 10.0.

 

              Converter Transformers :

 

              The converter transformers are single-phase three-winding units with two valve windings for the wye and delta connections. The main data are :

 

             

             

 

 

 

ACS

ICS

 Rated Voltage

 

 

   Line side (kV)

  500/_3

  345/_3

   Valve side (kV)

  202/_3

  207/_3

 Tap-Changer range

+ 16

+ 12

 

}x 1.25%

}x 1.25%

 

- 6

- 6

 Impedance (%)

   12.6

   13.0

 Power, rated (MVA)

  305

  312

   overload continuous

 1.5 p.u.

 1.5 p.u.

 Standard Impulse

 

 

    Voltage Test

 

 

      Line  side (kV)

1300

 900

      Valve side (kV)

1550/1050

1550/1050

 Switching Impulse

 

 

    Voltage Test

 

 

      Line  side (kV)

1080

 845

      Valve side (kV)

1290/870

1290/870

 

 

 

 

 

 

 

 

 

AC filters and Reactive Power Compensation :

 

 

 

              ACS : Primary voltage is 500 kV.

              Fundamental reactive power is

                  3 x 418 MVAr (capacitive)

                  3 x 112 MVAr (shunt reactors)

 

 

              ICS : Primary voltage is 345 kV.

              Fundamental reactive power is

                  3 x 296.6 MVAr (capacitive)

                  3 X  90   MVAr (shunt reactors)

 

 

 

 

              On the 345 kV AC Busbar at Intermountain Converter Station

 

 

Filter

MVAr

C = µF

L = mH

R = ohm

f = Hz

Q

13 TH

 

 

 

 

 

 

Harmonic

 57.9

1.29

 32.27

 6325

  780

  33

 

 

 

 

 

 

 

11 TH

 

 

 

 

 

 

Harmonic

 55.2

1.23

 47.27

 9801

  660

  40

 

 

 

 

 

 

 

3/5/7 TH

 

1.299(C1)

 

 

 

 

 

 58.3

 

 657.8

 1300

  180

 

 

 

10.70(C2)

 

 

 

 

HP

 

 

 

 

 

 

 

 55.6

1.239

 4.506

 180.9

 2130

   3

N° 2

 

 

 

 

 

 

HP

 

 

 

 

 

 

 

 69.6

1.551

 7.986

 358.8

 1430

   5

N° 1

 

 

 

 

 

 

Shunt

 

 

 

 

 

 

 

 90

 

3759

 

 

 

Reactor

 

 

 

 

 

 

 

 

             

 

 

 

 

 

 

 

 

 

 

 

 

 

              On the 500 kV AC Busbar at Adelanto Converter Station

 

 

Filter

MVAr

C = µF

L = mH

R = ohm

f = Hz

Q

13 TH

 

 

 

 

 

 

Harmonic

  76.3

 0.81

 51.43

12600

 780

  40

 

 

 

 

 

 

 

11 TH

 

 

 

 

 

 

Harmonic

  73.0

 0.775

 75.08

15570

 660

  40

 

 

 

 

 

 

 

HP

 164.3

 1.743

 5.97

 175.6

1560

   3

 

 

 

 

 

 

 

Shunt

 104.6

 1.112

 

 

 

 

Capacitor

 

 

 

 

 

 

Shunt

 112

 

5921

 

 

 

Reactor

 

 

 

 

 

 

 

 

             

             

              Transmission Line :

 

              The ± 500  kV  DC transmission line is 785 km in length. There are 1930 free standing lattice steel towers. All insulators have 222 kN M & E rating. Typical leakage distance is 14.7 m for suspension strings, 16.4 m for dead-end strings. For high contaminated areas, 19.7 m of leakage distance is used. The line conductors are three bundled 1235 mm2 Thrasher. Two shield wires afford lightning protection of 13-degree shield angle.

 

 

              Electrode Line and Electrode :

 

              The electrode line conductors are carried on the transmission towers in the shield wire positions for 84.5 km from ACS and 44 km from ICS. The conductors are two 908 mm2 Falcon. The electrode line insulation used ANSI Class 52-5 porcelain insulators. Each ground electrode consits of 60 deep wells. The nominal well depths are 87 m in Utah and 70 m in  California. Each electrode covers an area of approximately 0.65 sq km.

 

 

 

 

 

 

 

References :

              Planning the layout of an HVDC Converter Station - A Case Study - The Intermountain Power Project's Adelanto Converter Station, by T.S. Grewal, P.M. Bhakta, N.L. Look.

              IEEE Power Engineering Society, 10th Conference and Exposition on overhead and underground transmission and distribution ; Sept. 14-19, 1986.

 

              Intermountain Power Project - Design Consideration of a HVDC Transmission System by J.J. Herrera, P.R. Shockley, C.T. Wu.

              IEEE/PES 9th Conference and exposition on overhead an underground transmission and distribution, April 29th, - May 4th, 1984.

 

              .

 

 

System correspondent :

 

              Mr C.T. WU

              Superintendent

              Adelanto Converter Station

              Los Angeles Department of

                 Water and Power

              P.O. Box 699

              ADELANTO

              CALIFORNIA 92301

              USA

 

              Telephone : 619-246-6932

              Telefax :   619-246-1350   



 Code

Redundancy

 Reserv System

 

 Spare parts

 

INTERMOUNTAIN

 

Yes/No

 Yes/No

Min. time needed

Yes/No

Min. time needed

 

 

 

 

 for change 

 

for install spares

 

 

1)

2)

over (hours)

3)

(hours)

 

 

 

 

 

 

 

  AC Filter and Shunt  Bank

 AC-E.F

    Yes

 -

 

    Yes

    4 - 8 hrs

  AC Switchyard Equipment

 AC-E.SW

    Yes

-

 

    Yes

    4 hrs

  AC Control and Protection

 AC-E.CP

    Yes

-

 

    Yes

    2 hrs

  Converter Transformer

 AC-E.TX

    No

-

 

    Yes

    3 - 4 days

  Synchronous Compensator

 AC-E.SC

    -

-

 

    -

      -

  AC and Auxilliary Equipment

 AC-E.AX

    Yes

-

 

    Yes

     4 hrs

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  Valve Electrical

 V.E

    Yes

-

 

    Yes

    4 - 8 hrs

  Valve Cooling (integral with valve)

 V.VC

    Yes *

-

 

    Yes

    4 - 8 hrs

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  Local HVDC Control and Protection

 C-P.L

    Yes **

-

 

    Yes

    2 hrs

  Master HVDC Control and Protection

 C-P.M

    Yes **

-

 

    Yes

    2 hrs

  Telecommunication

 C-P.T

    Yes

-

 

    Yes

    2 hrs

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  DC Filters

 DC-E.F

    No

Yes

2 hrs

    Yes

    4 - 8 hrs

  DC Switching Equipment

 DC-E.SW

    No

-

 

    Yes

    4 hrs

  DC Ground Electrode

 DC-E.GE

    Yes

-

 

    No

      -

  DC Ground Electrode line

 DC-E.EL

    Yes

-

 

    Yes

    4 - 8 hrs

  Other DC Yard and Valve Hall Equipment

 DC-E.O

    No

 - 

 

    Yes

    4 hrs

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  DC Transmission Line

 TL

    No

 

 

    Yes

    4 - 8 hrs

1) 2) 3) Please give more detailed information on table 2

             * Cooling water piping are not redundant         ** Pole Control, Bipole Desk and Mimic controls are not redundant


 

*INTERMOUNTAIN POWER PROJECT*

 

 

1 * REDUNDANCY













 2 * RESERV SYSTEM














 

 3 * SPARE PARTS