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New Capacitor Analysis and Maintenance Process at Centerpoint Energy. Presented at SWEDE Conference 2005 by Richard Moffatt. Why do we have Capacitors? (Power Factor = KW / KVA). KVARS. KVA. KW’s. Process Improvement Recommendation. Goal: Reduce Capacitor Maintenance Expense

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New capacitor analysis and maintenance process at centerpoint energy

New Capacitor Analysis and Maintenance Process

at Centerpoint Energy

Presented at SWEDE Conference 2005

by Richard Moffatt


Why do we have capacitors power factor kw kva

Why do we have Capacitors?(Power Factor = KW / KVA)

KVARS

KVA

KW’s


New capacitor analysis and maintenance process at centerpoint energy

Process Improvement Recommendation

  • Goal: Reduce Capacitor Maintenance Expense

  • Send capacitor crews directly to circuits with problem capacitors, and thus eliminate their random search for failed capacitors (Time, temp, fixed banks).

  • Develop program (CAPSURE) to detect capacitor banks that are switching but experiencing a partial failure on 1 or 2 phases. Uses load survey data for circuits (KW & KVAR) on 15 minute intervals.

  • Produce “Bank Shot Report”

  • Produce “Low Power Factor Report”


New capacitor analysis and maintenance process at centerpoint energy

Bank Shot Report

  • Identifies KVAR changes greater than the minimum threshold value based on the smallest cap on circuit.

  • Looks for single phase or two phase failures.

  • Two tests:

    • Magnitude of KVAR change (15 min intervals) compensated by KW load change.

    • KVA phase angle change.

  • In most cases, can infer the probable bank size based on the magnitude of the change in KVARS.

  • Pull in caps on circuit from Capacitor Database.

  • Pull in PF at peak for identified circuits.


New capacitor analysis and maintenance process at centerpoint energy

Bank Shot Report 9-1-04 Left Half of Spreadsheet

Wednesday Sept 1, 2004

8/30/2004

8/31/2004

9/1/2004

CKT

PF

Peak

Peak

Peak

KW Last

KW Last

KW Last

KW This

KW This

KW This

KVAR Last

KVAR Last

KVAR Last

KVAR This

KVAR This

KVAR This

CKT

TIME

PF

PF

PF

A

B

C

A

B

C

A

B

C

A

B

C

This Read

AD 04

1:16

98.8

99.8

99.9

100.0

1389

1501

1529

1318

1413

1441

172

207

-3

309

348

-3

AD 04

9:31

-99.8

99.8

99.9

100.0

1343

1188

1508

1375

1252

1557

292

204

-3

-66

-182

-3

AD 04

12:16

-99.6

99.8

99.9

100.0

1811

1821

1986

1884

1853

2078

137

81

-3

-217

-291

-3

AD 04

21:16

99.9

99.8

99.9

100.0

2239

2359

2500

2187

2370

2450

-90

-87

-3

91

137

-3

AD 04

21:46

99

99.8

99.9

100.0

2071

2155

2370

1965

2197

2299

53

56

-3

397

524

-3

AD 09

12:01

-98.4

99.5

99.9

99.9

1316

1501

1785

1305

1453

1749

-33

18

140

-434

-471

82

AD 09

21:46

97.2

99.5

99.9

99.9

1543

1981

2318

1601

1917

2207

-70

61

583

356

440

583

AF 01

1:01

90.8

99.4

99.9

99.8

1749

1770

1975

1749

1706

1917

799

356

435

831

767

873

AF 01

9:46

96.9

99.4

99.9

99.8

1680

1633

1654

1691

1669

1865

789

673

757

773

251

314

AF 02

8:01

-99.4

-99.7

-100.0

-100.0

1195

1158

1263

1158

1200

1242

282

-128

-139

293

-323

-350

AF 06

12:01

-88.6

-99.6

-98.0

-97.9

1369

1369

1332

1495

1374

1364

-666

-476

-761

-766

-672

-777

AF 06

23:01

-97.7

-99.6

-98.0

-97.9

1727

1548

1532

1590

1580

1559

-492

-381

-487

-360

-170

-497

AF 07

13:01

99.1

98.9

99.3

99.6

1833

1369

1506

1986

1411

1696

525

124

277

330

161

203

AF 07

13:16

97.7

98.9

99.3

99.6

1986

1411

1696

1938

1422

1553

330

161

203

609

145

314

AF 10

10:01

99.9

100.0

-100.0

-99.8

905

1110

1300

915

1153

1342

61

525

314

-371

546

-65

AN 04

22:46

96.5

96.2

96.9

96.7

1754

1800

1814

1754

1730

1765

738

179

292

703

446

281

AN 05

14:46

-99.7

100.0

-100.0

-99.9

1983

2053

1825

2043

2190

1772

25

60

-379

-129

-76

-224

AN 05

22:16

-99.3

100.0

-100.0

-99.9

1768

1905

1519

1828

1825

1501

-224

-192

-312

-31

-59

-509

AN 06

2:31

95.3

96.4

98.8

97.6

2128

2054

2152

2120

2054

2088

809

206

253

786

580

625

AN 06

9:31

98.5

96.4

98.8

97.6

1956

2025

2041

2152

2210

2283

715

564

596

762

208

211

AN 07

19:01

-99.4

98.9

99.3

99.7

2046

1690

1790

2088

1732

1790

132

74

8

-294

-358

21

AN 07

22:46

-98.9

98.9

99.3

99.7

1577

1242

1279

1598

1242

1297

-645

-648

-331

-149

-178

-286

AN 09

0:31

97.8

99.2

99.4

99.3

1466

1642

1459

1318

1533

1389

496

88

-178

436

352

113

AN 09

9:31

-99.9

99.2

99.4

99.3

1575

1628

1621

1617

1645

1673

267

148

-41

302

-150

-319

AN 10

8:01

95

99.2

99.4

99.6

1155

1121

1466

1216

1189

1513

612

541

585

643

66

585

AN 10

22:01

99.9

99.2

99.4

99.6

1202

1076

1825

1247

1044

1772

174

-598

211

177

-144

174

AR 41

4:31

95.9

97.3

98.3

98.5

525

627

657

584

627

657

-422

175

146

233

175

146

AR 41

9:01

-99.9

97.3

98.3

98.5

627

744

759

627

744

846

219

204

131

-422

204

131

AR 42

12:16

97.6

96.5

98.0

97.5

5792

5238

6317

5938

5223

6449

1167

1021

1386

1371

1050

1503

AR 42

12:46

97.5

96.5

98.0

97.5

6026

5369

6390

6230

5457

6697

1474

1123

1532

1459

1138

1619

BA 01

10:01

100

98.1

98.6

98.9

1232

1390

1464

1237

1427

1506

277

393

229

251

-7

-244

BA 01

20:01

97.3

98.1

98.6

98.9

1406

1601

1575

1448

1596

1516

303

24

-239

356

462

266

BA 04

10:31

-100

100.0

-99.8

-99.6

1089

989

978

1137

1000

984

261

277

198

287

-118

-181

BA 04

17:16

99.3

100.0

-99.8

-99.6

1791

1633

1427

1865

1627

1432

219

-228

-424

324

208

55

BAR43

5:16

98.9

94.9

95.3

95.1

3341

3268

3020

3472

3356

3151

802

248

-72

802

306

379

BAR43

10:31

96.8

94.9

95.3

95.1

5690

5690

5165

5792

5675

5150

1882

1328

1503

1940

1298

1036


New capacitor analysis and maintenance process at centerpoint energy

This Reading

Bank Shot Report 9-1-04 Righr Half of Spreadsheet

Load Compensated

Delta

Delta

Delta

Estimated

Estimated

TOTAL

BANKS ON CIRCUIT

Delta kvars

Delta kvars

Delta kvars

Estimated

BANK

Angle

Angle

Angle

Kvars at

Actual

Kvars

CKT

A

B

C

ABC

SIZE?

ABC

A

B

C

90% PF

KVAR

ONLINE

VARS

AD 04

172

185

44

==.

600

6.135

5.984

-0.007

==.

2086

654

1432

5400

450Q,600Q,600TQ,1200F,1200Q,1350Q

AD 04

-374

-418

-24

++.

1200

-15.015

-18.015

0.004

++.

2092

-251

2343

5400

450Q,600Q,600TQ,1200F,1200Q,1350Q

AD 04

-390

-388

-46

++.

1200

-10.897

-11.472

0.004

++.

2907

-511

3418

5400

450Q,600Q,600TQ,1200F,1200Q,1350Q

AD 04

207

218

25

==.

600

4.685

5.42

-0.001

.=.

3503

225

3278

5400

450Q,600Q,600TQ,1200F,1200Q,1350Q

AD 04

397

447

35

==.

1200

9.956

11.926

-0.002

==.

3230

918

2312

5400

450Q,600Q,600TQ,1200F,1200Q,1350Q

AD 09

-395

-465

-40

++.

1350

-16.959

-18.648

-1.8

++.

2253

-823

3076

3300

600F,600F,900Q,1200TQ

AD 09

397

411

55

==.

1200

15.134

11.163

0.68

==.

2862

1379

1483

3300

600F,600F,900Q,1200TQ

AF 01

32

443

467

.==

1350

0.861

12.836

12.063

.==

2686

2471

215

4800

900F,1200Q,1350Q,1350T

AF 01

-21

-440

-548

.++

1800

-0.59

-13.845

-15.036

.++

2612

1338

1274

4800

900F,1200Q,1350Q,1350T

AF 02

29

-216

-200

.++

600

0.921

-8.757

-9.458

.++

1800

-380

2180

4200

600T,600F,900Q,900TQ,1200TQ

AF 06

-163

-198

-32

++.

600

-1.187

-6.89

0.072

.+.

2116

-2215

4331

2900

200Q,450TQ,450F,600F,600T,600TQ

AF 06

200

195

-23

==.

600

3.144

7.686

-0.047

.=.

2364

-1027

3391

2900

200Q,450TQ,450F,600F,600T,600TQ

AF 07

-271

16

-169

+..

900

-6.548

1.334

-3.597

+..

2546

694

1852

2700

600F,900Q,1200T

AF 07

303

-21

182

=..

900

8.011

-0.687

4.605

=..

2456

1068

1388

2700

600F,900Q,1200T

AF 10

-437

0

-400

+.+

1200

-25.927

0.027

-16.352

+.+

1705

110

1595

3600

900F,1350Q,1350TQ

AN 04

-35

302

13

.=.

900

-0.978

8.777

-0.099

.=.

2624

1430

1194

3900

600F,900Q,1200T,1200TQ

AN 05

-184

-204

181

++=

600

-4.335

-3.662

4.527

...

3002

-429

3431

4500

600F,600TQ,900T,1200Q,1200TQ

AN 05

163

173

-188

==+

600

6.249

3.904

-7.125

=.+

2577

-599

3176

4500

600F,600TQ,900T,1200Q,1200TQ

AN 06

-19

374

404

.==

1200

-0.473

10.041

9.959

.==

3131

1991

1140

3600

1200T,1200Q,1200F

AN 06

-51

-448

-506

.++

1350

-0.581

-10.187

-10.998

.++

3322

1181

2141

3600

1200T,1200Q,1200F

AN 07

-447

-453

13

++.

1350

-11.706

-14.186

0.416

++.

2805

-631

3436

3600

600F,900Q,900T,1200TQ

AN 07

485

470

36

==.

1350

16.918

19.397

2.074

==.

2068

-613

2681

3600

600F,900Q,900T,1200TQ

AN 09

14

318

326

.==

900

-0.388

9.864

11.607

.==

2120

901

1219

3600

600T,900F,900Q,1200TQ

AN 09

14

-306

-304

.++

900

0.957

-10.405

-9.346

.++

2467

-167

2634

3600

600T,900F,900Q,1200TQ

AN 10

0

-509

-23

.+.

1800

-0.049

-22.585

-0.615

.+.

1959

1294

665

3150

600T,1200T,1350Q

AN 10

-19

470

-10

.=.

1350

-0.158

21.21

-0.987

.=.

2031

207

1824

3150

600T,1200T,1350Q

AR 41

625

0

0

=..

1800

60.543

0

0

=..

934

554

380

600

600Q

AR 41

-641

0

-43

+..

1800

-53.196

0

-0.99

+..

1108

-87

1195

600

600Q

AR 42

131

36

51

=..

450

1.609

0.337

0.744

...

8805

3924

4881

7050

450TQ,900TQ,900Q,1200F,1800T,1800TQ

AR 42

-117

-29

-66

+..

300

-0.565

-0.034

0.108

...

9192

4216

4976

7050

450TQ,900TQ,900Q,1200F,1800T,1800TQ

BA 01

-28

-418

-494

.++

1350

-1.201

-16.068

-18.093

.++

2085

0

2085

2100

900F,1200Q

BA 01

32

440

534

.==

1800

1.651

15.286

18.58

.==

2280

1084

1196

2100

900F,1200Q

BA 04

2

-400

-382

.++

1200

0.689

-22.376

-21.868

.++

1560

-12

1572

1950

600F,1350T

BA 04

68

439

476

.==

1350

2.884

15.234

18.748

.==

2462

587

1875

1950

600F,1350T

BAR43

-65

14

385

..=

1200

-0.492

0.87

8.224

..=

4989

1487

3502

7300

1200T,1200Q,1300T,1800F,1800TQ

BAR43

7

-22

-459

..+

1350

0.216

-0.254

-4.851

..+

8308

4274

4034

7300

1200T,1200Q,1300T,1800F,1800TQ


New capacitor analysis and maintenance process at centerpoint energy

Bank Shot Report 9-1-04 Critical Information

Load Compensated

Delta

Delta

Delta

9/1/2004

BANKS ON CIRCUIT

Peak

Delta kvars

Delta kvars

Delta kvars

Estimated

Angle

Angle

Angle

CKT

TIME

PF

A

B

C

ABC

SIZE?

ABC

A

B

C

==.

==.

AD 04

1:16

100.0

172

185

44

600

6.135

5.984

-0.007

450Q,600Q,600TQ,1200F,1200Q,1350Q

++.

++.

AD 04

9:31

100.0

-374

-418

-24

1200

-15.015

-18.015

0.004

450Q,600Q,600TQ,1200F,1200Q,1350Q

++.

++.

AD 04

12:16

100.0

-390

-388

-46

1200

-10.897

-11.472

0.004

450Q,600Q,600TQ,1200F,1200Q,1350Q

==.

.=.

AD 04

21:16

100.0

207

218

25

600

4.685

5.42

-0.001

450Q,600Q,600TQ,1200F,1200Q,1350Q

==.

==.

AD 04

21:46

100.0

397

447

35

1200

9.956

11.926

-0.002

450Q,600Q,600TQ,1200F,1200Q,1350Q

AD 09

12:01

99.9

-395

-465

-40

++.

1350

-16.959

-18.648

-1.8

++.

600F,600F,900Q,1200TQ

AD 09

21:46

99.9

397

411

55

==.

1200

15.134

11.163

0.68

==.

600F,600F,900Q,1200TQ

.==

.==

AF 01

1:01

99.8

32

443

467

1350

0.861

12.836

12.063

900F,1200Q,1350Q,1350T

.++

.++

AF 01

9:46

99.8

-21

-440

-548

1800

-0.59

-13.845

-15.036

900F,1200Q,1350Q,1350T

.++

.++

AF 02

8:01

-100.0

29

-216

-200

600

0.921

-8.757

-9.458

600T,600F,900Q,900TQ,1200TQ

AF 06

12:01

-97.9

-163

-198

-32

++.

600

-1.187

-6.89

0.072

.+.

200Q,450TQ,450F,600F,600T,600TQ

AF 06

23:01

-97.9

200

195

-23

==.

600

3.144

7.686

-0.047

.=.

200Q,450TQ,450F,600F,600T,600TQ

AF 07

13:01

99.6

-271

16

-169

+..

900

-6.548

1.334

-3.597

+..

600F,900Q,1200T

AF 07

13:16

99.6

303

-21

182

=..

900

8.011

-0.687

4.605

=..

600F,900Q,1200T

+.+

+.+

AF 10

10:01

-99.8

-437

0

-400

1200

-25.927

0.027

-16.352

900F,1350Q,1350TQ

.=.

.=.

AN 04

22:46

96.7

-35

302

13

900

-0.978

8.777

-0.099

600F,900Q,1200T,1200TQ

++=

...

AN 05

14:46

-99.9

-184

-204

181

600

-4.335

-3.662

4.527

600F,600TQ,900T,1200Q,1200TQ

AN 05

22:16

-99.9

163

173

-188

==+

600

6.249

3.904

-7.125

=.+

600F,600TQ,900T,1200Q,1200TQ

AN 06

2:31

97.6

-19

374

404

.==

1200

-0.473

10.041

9.959

.==

1200T,1200Q,1200F

AN 06

9:31

97.6

-51

-448

-506

.++

1350

-0.581

-10.187

-10.998

.++

1200T,1200Q,1200F

++.

++.

AN 07

19:01

99.7

-447

-453

13

1350

-11.706

-14.186

0.416

600F,900Q,900T,1200TQ

==.

==.

AN 07

22:46

99.7

485

470

36

1350

16.918

19.397

2.074

600F,900Q,900T,1200TQ

.==

.==

AN 09

0:31

99.3

14

318

326

900

-0.388

9.864

11.607

600T,900F,900Q,1200TQ

.++

.++

AN 09

9:31

99.3

14

-306

-304

900

0.957

-10.405

-9.346

600T,900F,900Q,1200TQ

.+.

.+.

AN 10

8:01

99.6

0

-509

-23

1800

-0.049

-22.585

-0.615

600T,1200T,1350Q

.=.

.=.

AN 10

22:01

99.6

-19

470

-10

1350

-0.158

21.21

-0.987

600T,1200T,1350Q

AR 41

4:31

98.5

625

0

0

=..

1800

60.543

0

0

=..

600Q

AR 41

9:01

98.5

-641

0

-43

+..

1800

-53.196

0

-0.99

+..

600Q

AR 42

12:16

97.5

131

36

51

=..

450

1.609

0.337

0.744

...

450TQ,900TQ,900Q,1200F,1800T,1800TQ

AR 42

12:46

97.5

-117

-29

-66

+..

300

-0.565

-0.034

0.108

...

450TQ,900TQ,900Q,1200F,1800T,1800TQ

.++

.++

BA 01

10:01

98.9

-28

-418

-494

1350

-1.201

-16.068

-18.093

900F,1200Q

.==

.==

BA 01

20:01

98.9

32

440

534

1800

1.651

15.286

18.58

900F,1200Q

.++

.++

BA 04

10:31

-99.6

2

-400

-382

1200

0.689

-22.376

-21.868

600F,1350T

.==

.==

BA 04

17:16

-99.6

68

439

476

1350

2.884

15.234

18.748

600F,1350T

BAR43

5:16

95.1

-65

14

385

..=

1200

-0.492

0.87

8.224

..=

1200T,1200Q,1300T,1800F,1800TQ

BAR43

10:31

95.1

7

-22

-459

..+

1350

0.216

-0.254

-4.851

..+

1200T,1200Q,1300T,1800F,1800TQ


New capacitor analysis and maintenance process at centerpoint energy

Report Sent to Field Forces


New capacitor analysis and maintenance process at centerpoint energy

Low Power Factor Report

  • Pulls in power factor at peak, 4:46 PM, for every circuit on the system for 5 consecutive days.

  • Pulls in caps from capacitor database.

  • Calculates the theoretical power factor with all caps on, as well as the number of KVARS off-line.

  • The key is to look for circuits with a low power factor over those 5 days (less that 98%) and with a meaningful magnitude of KVARS off-line.

  • There is no reason to send a crew to a circuit with a poor power factor if all of the caps are working, and there is no reason to send a crew to a circuit with excellent power factor even if some of the caps are off-line.


New capacitor analysis and maintenance process at centerpoint energy

Report Sent to Field Forces


New capacitor analysis and maintenance process at centerpoint energy

Results

  • Piloted this effort during the 2nd half of 2004.

  • Good success rate.

  • In almost all cases, the crews were finding problems on the circuits identified.

  • Crews were entering their work into the Capacitor Database.

  • Needed to develop tracking mechanism and provide monthly reports on the progress of the crews.


New capacitor analysis and maintenance process at centerpoint energy

Issues

  • Needed to integrate this analysis effort into larger capacitor maintenance / capacitor construction program.

  • Issues:

    • Capacitor crews & supervision had other priorities.

    • Work orders & construction of new capacitors was not timely.

    • Material shortages at certain times of the year (Long lead times on materials, plus inventory reduction).

    • New products such as vacuum switches & cutouts.

    • The creator of Capacitor Database left the company.


New capacitor analysis and maintenance process at centerpoint energy

Capacitor Program

  • Capacitor construction strategy

  • Capacitor material strategy

  • Capacitor maintenance strategy


New capacitor analysis and maintenance process at centerpoint energy

Capacitor Construction Strategy

  • Established timeline for new capacitor construction:

    • 1. Identify & issue material requirements to Purchasing based on development plans by 9/1

    • 2. Issue next year’s construction schedule by 9/1

    • 3. Engineering to write work orders by 10/30

    • 4. Material purchases to be driven by bill of materials on work orders via SAP

    • 5. CW Utilities to assemble materials in kits for each work order & deliver to S/C via cross-dock with central stores

    • 6. Complete construction by 3/31

    • 7. Track orders via SAP (10/1 - 3/31)


New capacitor analysis and maintenance process at centerpoint energy

Capacitor Construction Strategy

  • Benefits:

  • Caps completed sooner in the year so crews will be available for maintenance as the weather warms up.

  • (Previous focus was simply to get the banks built by 6/1)

  • Materials for construction will ordered based on material requirements of work orders.

  • Better utilization of materials since construction crews will not be taking the materials needed for maintenance or for other construction jobs.


New capacitor analysis and maintenance process at centerpoint energy

Capacitor Material Strategy

Goal:

Accurately identify material needs for new construction

Accurately identify material needs for maintenance

Acquire materials on a more timely basis

Utilize better materials where necessary


New capacitor analysis and maintenance process at centerpoint energy

Capacitor Material Strategy

  • Revised inventory purchase thresholds based on:

    • 1. Annual & monthly maintenance requirements (avg & peak values to account for weather impacts)

    • 2. Lead time for each material

  • Perform monthly review of materials on hand, on order and at CW Utilities.

  • Order specific materials if necessary.

  • Establish metrics on material acquisition and usage to measure how effective we are on material strategy.


New capacitor analysis and maintenance process at centerpoint energy

Capacitor Material Strategy

  • Metric: Fill rate = % of time material is available when you need it.

    • 2004 overall fill rate was 84%

  • Goal for capacitor materials is 98 - 100%

  • Fill rate will be calculated for each material item


New capacitor analysis and maintenance process at centerpoint energy

Capacitor Maintenance Strategy

  • Established priorities for capacitor crews:

    • 1. Banks identified by Capacitor Analysis

    • 2. Banks identified by RCCS

    • 3. Switching orders for banks taken out of service

    • 4. Banks with hot spot identified by infra-red

    • 5. Field reports of banks out of service

    • 6. Construction for planned capacitor work

    • 7. Other work

  • Held meetings with crews & their management to review priorities.

  • Established flow chart for entire maintenance process.


New capacitor analysis and maintenance process at centerpoint energy

Conclusion

  • Implementation currently underway.

  • Will see how it works in the 2005 - 2006 season.


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