SOW RMLCAMPUS ELECTRICAL MAINTENANCE - ATTACHMENT B - NETA TABLES JUNE 2021.pdf

ATTACHMENT B

TABLES

STANDARD FOR

MAINTENANCE TESTING SPECIFICATIONS

FOR

ELECTRICAL POWER

EQUIPMENT AND SYSTEMS

ANSI/NETA MTS-2019

TABLE 100.1

Insulation Resistance Test Values

Electrical Apparatus and Systems Other Than Rotating Machinery Nominal

Rating of Equipment (Volts)

Minimum Test Voltage

(DC)

Recommended Minimum Insulation Resistance

(Megohms)

250 500 25

600 1,000 100

1,000 1,000 100

2,500 1,000 500

5,000 2,500 1,500

8,000 2,500 2,500

15,000 2,500 5,000

25,000 5,000 10,000

34,000 5,000 100,000

46,000 and above 5,000 100,000

Notes:

1. In the absence of consensus standards dealing with insulation-resistance tests, the NETA Standards Review Council suggests the above representative values.

2. See Table 100.14 for temperature correction factors.

3. Test results are dependent on the temperature of the insulating material and the humidity of the surrounding environment at the time of the test.

4. Insulation-resistance test data may be used to establish a trending pattern. Deviations from the baseline information permit evaluation of the insulation.

5. For rotating machinery insulation-resistance test values, refer to Table 100.11.

6. For medium-voltage cables, the values shown are typical. Conductor and insulation geometry, temperature, and overall cable length, need to be taken into account per manufacturers published data for definitive minimum insulation resistance criteria.

TABLE 100.2

Switchgear Withstand Test Voltages

Type of Switchgear

Rated Maximum Voltage

(kV) (rms)

Maximum Test Voltage (kV)

AC

DC

Low-Voltage Power

Circuit Breaker Switchgear

.254/.508/.635

1.6

2.3

.730/1.058

2.2

3.1

Metal-Clad

4.76

8.25

37.5

15.0

37.5

27.0 a

38.0

Station-Type Cubicle

15.5

72.5

Metal-Enclosed Interrupter Switchgear

With stress cone type terminations

With IEEE 386 type terminations

With stress cone type terminations

With IEEE 386 type terminations

15.0

14.4

26.3

26.6

1. Derived from IEEE C37.20.1-2015 Standard for Metal-Enclosed Low-Voltage Power Circuit-Breaker Switchgear, Paragraph 5; IEEE C37.20.2-2015, Standard for Metal-Clad Switchgear, Paragraph 6.5; and IEEE C37.20.3-2013 Standard for Metal-Enclosed Interrupter Switchgear, Paragraph 6.19. This table includes 0.75 multiplier with fraction rounded down.

2. The column headed “DC” is given as a reference only for those using dc tests to verify the integrity of connected cable installations without disconnecting the cables from the switchgear. It represents values believed to be appropriate and approximately equivalent to the corresponding power frequency withstand test values specified for voltage rating of switchgear. The presence of this column in no way implies any requirement for a dc withstand test on ac equipment or that a dc withstand test represents an acceptable alternative to the power-frequency withstand tests specified in these specifications, either for design tests, production tests, conformance tests, or field tests. When making dc tests, the voltage should be raised to the test value in discrete steps and held for a period of one minute.

a. Because of the variable voltage distribution encountered when making dc withstand tests, the manufacturer should be contacted for recommendations before applying dc withstand tests to the switchgear. Voltage transformers above 34.5 kV should be disconnected when testing with dc. Refer to IEEE C57.13-2016 (IEEE Standard Requirements for Instrument Transformers) paragraph 8.5.

TABLE 100.2

Switchgear Withstand Test Voltages (continued)

TABLE 100.3

Maintenance Test Values

Recommended Dissipation Factor/Power at 20º C Liquid-Filled Transformers, Regulators, and Reactors

Oil

Maximum Silicone

Maximum Tetrachloroethylene

Maximum

High Fire Point Hydrocarbon

Maximum

Ester Fluids

Power Transformers

1.0%

0.5%

3.0%

2.0%

Distribution Transformers and

Apparatus

2.0%

0.5%

In the absence of consensus standards dealing with transformer dissipation/power factor values, the NETA Standards Review Council suggests the above representative values. Maximum values for oil are based on data from Doble Engineering Company.

TABLE 100.4.1

Suggested Limits for Class I Insulating Oil

Mineral Oil 1

Test

ASTM Method

Acceptable Values

69 kV and Below Above 69 kV – Below 230 kV

230 kV and Above

Dielectric breakdown, kV minimum 2

D877 26 kV minimum @ 1 mm

(0.04 inch) gap

D1816 kV minimum @ 2 mm

(0.08 inch) gap

D1816

Interfacial tension mN/m minimum

D971

Neutralization number, mg KOH/g maximum

D974

0.20

0.15

0.10

Water content, ppm maximum @ 60º C 3

D1533

Power factor at 25º C, D924

0.5

Power factor at 100º C, D924

5.0

5.0

Color 4

D1500

3.5

Visual Condition

D1524 Bright, clear and free of particles Bright, clear and free of particles Bright, clear and free of particles

Specific Gravity (Relative Density) @

15º C Maximum 5

D1298

0.91

1. IEEE C57.106-2002 Guide for Acceptance and Maintenance of Insulating Oil in Equipment, Table 7.

2. IEEE 637-1985 Guide for Reclamation of Insulating Oil and Criteria for Its Use, Table 1.

3. IEEE C57.106-2002 Guide for Acceptance and Maintenance of Insulating Oil in Equipment, Table 5.

4. In the absence of consensus standards, NETA’s Standard Review Council suggests these values.

5. IEEE C57.106 Guide for Acceptance and Maintenance of Insulating Oil in Equipment, Table 1.

TABLE 100.4.2

Suggested Limits for Less-Flammable Hydrocarbon Insulating Liquid

Test ASTM Method Acceptable Values

Dielectric breakdown voltage, kV minimum D877 24

Dielectric breakdown voltage for 1 mm (0.04 inch) gap, kV minimum D1816 34

Dielectric breakdown voltage for 2 mm (0.08) gap, kV minimum D1816 24

Water content, ppm maximum D1533 B 35

Dissipation/power factor, 60 Hertz, % max.

@ 25º C D924 1.0

Fire point, º C, minimum D92 300

Interfacial tension, mN/m, 25º C D971 24

Neutralization number, mg KOH/g D664 0.20

1. IEEE C57.121-1998 Guide for Acceptance and Maintenance of Less-Flammable Hydrocarbon Fluid in Transformers, Table 4.

2. The values in this table are considered typical for acceptable service-aged LFH fluids as a general class. If actual test analysis approaches the values shown, consult the fluid manufacturer for specific recommendations.

3. If the purpose of the HMWH installation is to comply with the NFPA 70 National Electrical Code, this value is the minimum for compliance with NEC Article 450.23.

TABLE 100.4.3

Suggested Limits for Service-Aged Silicone Insulating Liquid

Test ASTM Method Acceptable Values

Dielectric breakdown, kV minimum D877 25

Visual D2129 Colorless, clear, free of particles

Water content, ppm maximum D1533 100

Dissipation/power factor, 60 Hertz, maximum @ 25º C D924 0.2

Viscosity, cSt @ 25º C D445 47.5 – 52.5

Fire Point, º C, minimum D92 340

Neutralization number, Mg KOH/g max D974 0.2

1. IEEE C57.111-1989 (R1995) Guide for Acceptance of Silicone Insulating Fluid and Its Maintenance in Transformers, Table 3.

TABLE 100.4.4

Suggested Limits for Service-Aged Tetrachloroethylene Insulating Fluid

Test ASTM Method Acceptable Values

Dielectric breakdown, kV minimum D877 26

Visual D2129 Clear with purple iridescence

Water content, ppm maximum D1533 35

Dissipation/power factor, % maximum @ 25º C D924 12.0

Viscosity, cSt @ 25º C D445 0

Fire point, º C, minimum D92 -

Neutralization number, mg KOH/g maximum D974 0.25

Neutralization number, mg KOH/g maximum D664 -

Interfacial tension, mN/m minimum @ 25º C D971 -

1. Reference: Instruction Book PC-2000 for WecosolTM Fluid-Filled Primary and Secondary Unit Substation Transformers, ABB Power T&D.

TABLE 100.4.5

Suggested Limits for Continued Use of In-Service Natural Ester Liquids

Grouped by Voltage Class (See also IEEE C57.147) 1

Test and ASTM Method IEEE Value For Voltage Class

≤ 69 kV > 69 kV < 230 kV ≥ 230 kV 2

Dielectric strength 3, ASTM D1816, kV, 1 mm gap 2 mm gap

Dissipation factor (power factor), ASTM D924, %, maximum 25º C

3%

Water content: ASTM D1533, mg/kg, maximum 450 350 200

Optional 3 Fire Point, ASTM D92, º C, minimum 300 300 300

Kinematic viscosity increase from initial value ≥ 10% ≥ 10% ≥ 10%

1. The test limits shown in this table apply to natural ester insulating liquids as a class. Due to differences in their chemistry, certain values are significantly different than the limits for mineral oil. Refer to IEEE C57.147 for details. Specific typical values for each brand of insulating liquid should be obtained from each insulating liquid manufacturer. If test results, while in compliance with this table, are significantly different from published typical values, it is recommended that the insulating liquid manufacturer be contacted.

2. Provisional for ≥ 230 kV.

3. Most outdoor transformer installations do not require NEC “Less-Flammable” designation. After retrofilling with unused natural esters a reduction in the fire point of the ester liquid due to residual mineral oil. For transformers requiring a less-flammable rating, or otherwise known to require its insulating liquid to meet a minimum 300 °C fire point, any sample testing with a fire point below 300 °C indicates excessive residual mineral oil and should be investigated. For more information, please refer to Fig. B.4 and Annex C.1.

This table was derived from Reference IEEE C57.147, Section 8.3, Table 4 and Annex B, Table B.2.

TABLE 100.4.5 (continued) B.2 Service-Aged Natural Ester Liquids

Provisional Guidelines for Key Property Values of Service-Aged Natural Ester Liquids for Triggering Prompt Additional Investigation 1, 2

Test and ASTM Method IEEE Value For Voltage Class

≤ 69 kV > 69 kV < 230 kV ≥ 230kV

Dissipation factor (power factor), ASTM D924, at 25º C, % ≥ 3 ≥ 3 ≥ 3

Viscosity increase from value at time of initial energization, ASTM D445, at 40º C, %

≥ 10

Acid number, ASTM D974, mg KOH/gm 3 ≥ 0.5 ≥ 0.3 ≥ 0.3

Flash point, ASTM D92, ºC ≤ 275 ≤ 275 ≤ 275

Color, ASTM D1500 ≥ 1.5 ≥ 1.5 ≥ 1.5

Interfacial Tension ≤ 10 ≤ 12 ≤ 14

Inhibitor content (see footnote 4) (see footnote 4) (see footnote 4)

1. Applies only for transformers originally designed for and filled with unused natural ester liquid.

2. These values are based on limited accelerated aging and field samples taken over a period of up to twenty years.

As statistically significant data is developed for each property, the property listing should be moved to Table

100.4.5 on previous page.

3. For samples with significant discoloration, ASTM D664 may be the preferred test method.

4. Contact the manufacturer of the specific liquid for recommended inhibitor test method and trigger point values.

TABLE 100.5

Transformer Insulation Resistance

Maintenance Testing

Transformer Coil Rating Type

(Volts)

Minimum DC Test Voltage

Recommended Minimum Insulation Resistance (Megohms)

Liquid Filled

Dry

0 – 600

1,000

601 – 5,000

2,500

5,000

Greater than 5,000

25,000

1. In the absence of consensus standards, the NETA Standards Review Council suggests the above representative values.

2. See Table 100.14 for temperature correction factors.

3. Since insulation resistance depends on insulation rating (kV) and winding capacity (kVA), values obtained should be compared to manufacturer’s published data.

TABLE 100.6.1

Medium-Voltage Cables

Maintenance Test Values DC Test Voltages

Rated Voltage Phase-to-Phase

(kV)

Conductor Size AWG or kcmil

(mm)

Nominal

Insulation Thickness mils (mm)

Maximum DC Field Test Voltages (kV) First 5 Years After

Installation

100% Insulation Level

133% Insulation Level

100% Insulation Level

133% Insulation Level

8-1,000

(8.4-507) (2.29) (2.92)

Above 1,000 140 140

(507) (3.56) (3.56)

6-1,000

(13.3-507) (2.92) (3.56)

Above 1,000 175 175

(507) (4.45) (4.45)

2-1,000

(33.6-507) (4.45) (5.59)

Above 1,000 220 220

(507) (5.59) (5.59)

25 1-2,000

(42.4-1,013)

(6.60)

(8.13)

1-2,000 (42.4-1,013)

(7.11)

(8.76)

1/0-2,000 (53.5-1,013)

(8.76)

(10.7)

4/0-2,000 (107.2-1,013)

(11.3)

(14.7)

1. Reproduction of tables from ICEA S-94-649-2004 Standard for Concentric Neutral Cables Rated 5,000 – 46,000 Volts and ICEA S-97-682-2007 Utility Shielded Power Cables Rated 5,000 – 46,000 Volts.

TABLE 100.6.2

Field Test Voltages for Laminated Dielectric, Shielded Power

Cable Systems Rated 5 kV to 500 kV System Voltage System Voltage, kV rms, Phase-to-Phase

System BIL, kV Crest

Maintenance Test, kV dc, Phase-to-Ground 5 75 23 8 95 29

15 110 46 25 150 61 28 170 68 35 200 75 46 250 95 69 350 130

115 450 170 115 550 205 138 650 245 161 750 280 230 1,050 395 345 1,175 440 345 1,300 488 500 1,425 535 500 1,550 580 500 1,675 629

1. Voltages higher than those listed, up to 80% of system BIL, may be considered, but the age and operating environment of the system should be taken into account. The user is urged to consult the suppliers of the cable and any/all accessories before applying the high voltage.

2. When older cables or other types/classes of cables or other equipment such as transformers, switchgear, motors, etc. are connected to the cable to be tested, voltages lower than those shown in the table may be necessary to comply with the limitations imposed by such interconnected cables and equipment. See IEEE 95 [B5] and Table 1 of IEEE C37.20.2-1999 [B7].

3. If the test voltage exceeds 50% of system BIL, surge protection against excessive overvoltages induced by flashovers at the termination should be provided.

4. It is strongly recommended that the user consult with the manufacturer(s) of all components that will be subjected to such testing before performing any tests on cables and cable accessories rated 115kV and higher.

5. If should be noted that this table and the test procedures suggested in this guide do not necessarily agree with the recommendations of other organizations, such as those of the Association of Edison Illuminating Companies [B1], [B2], [B3], [B4]. Where there is concern, a user should consult the supplier of the cable and accessories to ascertain that the components will withstand the test.

Reproduction of table 1 from IEEE 400.1-2007 IEEE Guide for Field Testing of Laminated Dielectric, Shielded Power Cable Systems Rated 5 kV and Above with High Direct Current Voltage.

TABLE 100.6.3

Very Low Frequency Testing Levels of Medium-Voltage Cables

0.1 Hz Test Voltage (rms)

Very Low Frequency Testing Levels

0.1 Hz Test Voltage (rms)

System Voltage Phase-to-Phase

(kV)

Maintenance Phase-to-Ground

(kV) rms rms peak

5 7 10

8 10 14

15 16 22

25 23 33

35 33 47

1. Adaptation of table from IEEE 400.2-2004 Guide for field testing of shielded power cable systems using very low frequency (VLF).

TABLE 100.6.4

DAC Test Voltage Levels (20 Hz to 500 Hz) as Used for Maintenance Testing (50 DAC excitations) of Repaired/Refurbished Power Cables

Power cable rated voltage U [kV] phase-to-phase U e [kV] DAC test voltage level V t [kVpeak] phase-to-ground

3 2 5

5 3 6

6 4 10

8 5 11

10 6 14

15 9 21

20 12 28

25 15 35

30 18 41

35 21 48

45-47 26 60

60-69 35 80

110-115 64 145

132-138 77 150

150-161 87 170

220-230 127 204

275-2871 159 237

330-3451 191 282

380-4001 220 293

1. Test voltage levels given above 230 kV are provisional and given for study purposes only.

Extracted from IEEE 400.4-2015, Guild for Field Testing of Shielded Power Cable Systems Rated 5 kV and above with Damped Alternating Current (DAC) Voltage, table A.2.

TABLE 100.7

Molded-Case Circuit Breakers

Inverse Time Trip Test (At 300% of Rated Continuous Current of Circuit Breaker)

Range of Rated Continuous Current (Amperes)

Maximum Trip Time in Seconds for Each Maximum Frame Rating 1

≤ 250 V

250 – 600 V

0 – 30

31 – 50

51 – 100

101 – 150

151 – 225

226 – 400

401 – 600

601 – 800

801 – 1,000

1,001 – 1,200

1,201 – 1,600

1,601 – 2,000

2,001 – 2,500

2,501 – 5,000

6,000

Derived from Table 3, NEMA AB 4-2009, Guidelines for Inspection and Preventative Maintenance of Molded-Case Circuit Breaker Used in Commercial and Industrial Applications.

1. Trip times may be substantially longer for integrally-fused circuit breakers if tested with the fuses replaced by solid links (shorting bars).

TABLE 100.8

Instantaneous Trip Tolerances for Field Testing of Circuit Breakers

Breaker Type

Tolerance of Settings

Tolerances of Manufacturer’s Published Trip Range

High Side

Low Side

Electronic Trip Units (1)

+30% -30%

Adjustable (1) +40%

-30%

Nonadjustable (2)

+25%

-25%

NEMA AB4-2009 Guidelines for Inspection and Preventative Maintenance of Molded-Case Circuit Breaker Used in Commercial and Industrial Applications, Table 4.

1. Tolerances are based on variations from the nominal settings.

2. Tolerances are based on variations from the manufacturer’s published trip band (i.e., -25% below the low side of the band; +25% above the high side of the band.)

TABLE 100.9

Instrument Transformer Dielectric Tests

Field Maintenance

Nominal System (kV)

BIL

(kV)

Periodic Dielectric Withstand Test Field Test Voltage (kV)

AC

DC 2

0.6 10 2.6 4

1.1 30 6.5 10

2.4 45 9.7 15

4.8 60 12.3 19

8.32 75 16.9 26

13.8 95 22.1 34

13.8 110 26.0 34

25 125 32.5 40

25 150 32.5 50

34.5 150 45.5 50

34.5 200 61.7 70

46 250 91.0 Note 1

69 350 120.0 Note 1

115 450 149.0 Note 1

115 550 149.0 Note 1

138 550 178.0 Note 1

138 650 178.0 Note 1

161 650 211.0 Note 1

161 750 256.0 Note 1

230 900 256.0 Note 1

230 1,050 299.0 Note 1

Table is derived from Paragraph 8.5.2 and Table 2 of IEEE C57.13-2016, Standard Requirements for Instrument Transformers.

1. Periodic dc potential tests are not recommended for transformers rated higher than 34.5 kV.

2. Under some conditions transformers may be subjected to periodic insulation test using direct voltage. In such cases the test direct voltage should not exceed the original factory test rms alternating voltage. Periodic direct-voltage tests should not be applied to (instrument) transformers of higher than 34.5 kV voltage rating.

TABLE 100.12.1

Bolt-Torque Values for Electrical Connections

US Standard Fasteners 1 Heat-Treated Steel – Cadmium or Zinc Plated 2

Grade SAE 1&2 SAE 5 SAE 7 SAE 8

Head Marking

Minimum Tensile

(Strength) (lbf/in2)

64K

105K

133K

150K

Bolt Diameter (Inches) Torque (Pound-Feet)

1/4 4 6 8 8

5/16 7 11 15 18

3/8 12 20 27 30

7/16 19 32 44 48

1/2 30 48 68 74

9/16 42 70 96 105

5/8 59 96 135 145

3/4 96 160 225 235

7/8 150 240 350 380

1.0 225 370 530 570

1. Consult manufacturer for equipment supplied with metric fasteners.

2. Table is based on national coarse thread pitch.

TABLE 100.12.2

US Standard Fasteners 1

Silicon Bronze Fasteners 2, 3 Torque (Pound-Feet)

Bolt Diameter (Inches) Nonlubricated Lubricated

5/16 15 10

3/8 20 15

1/2 40 25

5/8 55 40

3/4 70 60

2. Table is based on national coarse thread pitch.

3. This table is based on bronze alloy bolts having a minimum tensile strength of 70,000 pounds per square inch.

TABLE 100.12.3

Aluminum Alloy Fasteners 2, 3 Torque (Pound-Feet)

Bolt Diameter (Inches) Lubricated

5/16 10

3/8 14

1/2 25

5/8 40

3/4 60

2. Table is based on national coarse thread pitch.

3. This table is based on aluminum alloy bolts having a minimum tensile strength of 55,000 pounds per square inch.

TABLE 100.12.4

Stainless Steel Fasteners 2, 3 Torque (Pound-Feet)

Bolt Diameter (Inches) Uncoated

5/16 15

3/8 20

1/2 40

5/8 55

3/4 70

2. Table is based on national coarse thread pitch.

3. This table is to be used for the following hardware types:

Bolts, cap screws, nuts, flat washers, locknuts (18-8 alloy) Belleville washers (302 alloy).

Tables in 100.12 are compiled from Penn-Union Catalogue and Square D Company, Anderson Products Division, General Catalog: Class 3910 Distribution Technical Data, Class 3930 Reference Data Substation Connector Products.

TABLE 100.13

SF6 Gas Tests

Test < 30 PSIG Max Limits ≥ 30 PSIG Max Limits

Water Content -23° C or 90 ppmw -36° C or 25 ppmw

SO2 Decomposition Products 12 ul/l (12 ppm) 12 ul/l (12ppm)

Total Decomposition Products 50 ul/l (50 ppm) 50 ul/l (50 ppm)

Mineral Oil 1 10 ppm 10 ppm

Air and/or Carbon Tetrafluoride 3.0% volume 3.0% volume

This table is derived from IEC 60480 Guidelines for the checking and treatment of sulfur hexafluoride taken from electrical equipment and specification for re-use, Table 2

1. If all gas handling equipment is oil-free (compressor, pump), then oil content measurement is not necessary.

TABLE 100.14.1

Insulation Resistance Conversion Factors (20° C)

Temperature Multiplier

° C

° F Apparatus Containing Oil Immersed Insulation

Apparatus Containing Solid

Insulation -10 14 0.125 0.25 -5 23 0.180 0.32 0 32 0.25 0.40 5 41 0.36 0.50 10 50 0.50 0.63 15 59 0.75 0.81 20 68 1.00 1.00 25 77 1.40 1.25 30 86 1.98 1.58 35 95 2.80 2.00 40 104 3.95 2.50 45 113 5.60 3.15 50 122 7.85 3.98 55 131 11.20 5.00 60 140 15.85 6.30 65 149 22.40 7.90 70 158 31.75 10.00 75 167 44.70 12.60 80 176 63.50 15.80 85 185 89.789 20.00 90 194 127.00 25.20 95 203 180.00 31.60

100 212 254.00 40.00 105 221 359.15 50.40 110 230 509.00 63.20

Derived from Megger, Stitch in Time…The Complete Guide to Electrical Insulation Testing.

Formula:

Rc = Ra x K Where: Rc is resistance corrected to 20° C

Ra is measured resistance at test temperature

K is applicable multiplier

Example: Resistance test on oil-immersion insulation at 104° F Ra = 2 megohms @ 104° F K = 3.95 Rc = Ra x K Rc = 2.0 x 3.95 Rc = 7.90 megohms @ 20° C

TABLE 100.14.2

Insulation Resistance Conversion Factors (40° C)

Temperature Multiplier

° C

° F Apparatus Containing oil Immersed Insulation

Apparatus Containing Solid

Insulation -10 14 0.03 0.10 -5 23 0.04 0.13 0 32 0.06 0.16 5 41 0.09 0.20 10 50 0.13 0.25 15 59 0.18 0.31 20 68 0.25 0.40 25 77 0.35 0.50 30 86 0.50 0.63 35 95 0.71 0.79 40 104 1.00 1.00 45 113 1.41 1.26 50 122 2.00 1.59 55 131 2.83 2.00 60 140 4.00 2.52 65 149 5.66 3.17 70 158 8.00 4.00 75 167 11.31 5.04 80 176 16.00 6.35 85 185 22.63 8.00 90 194 32.00 10.08 95 203 45.25 12.70

100 212 64.00 16.00 105 221 90.51 20.16 110 230 128.00 25.40

Derived from Megger, Stitch in Time…The Complete Guide to Electrical Insulation Testing and IEEE 43-2000 IEEE Recommended Practice for Testing Insulation Resistance of Rotating Machinery.

Notes: The insulation resistance coefficient is based on the halving of the insulation resistance to the change in temperature.

Apparatus Containing Immersed Oil Insulation Table uses 10° C change with temperature halving.

Apparatus Containing Solid Insulation Table uses 15° C change with temperature halving.

Formula:

Rc = Ra x K Where: Rc is resistance corrected to 40° C

Ra is measured resistance at test temperature K is applicable multiplier

Example: Resistance test on oil-immersion insulation at 68° F/20° C Ra = 2 megohms @ 68° F/20° C K = 0.40 Rc = Ra x K Rc = 2.0 x 0.40 = 0.8 megohms @ 40° C

TABLE 100.16

High-Potential Test Voltage for Periodic Test of Line Sectionalizers

Nominal Voltage Class (kV)

Maximum Voltage (kV)

Rated Impulse Withstand Voltage

(kV)

Maximum AC Field Test Voltage (kV)

15 Minute DC Withstand (kV)

14.4 (1 ø, 3 ø) 15.5 95 26.2 39

24.9 (1 ø) 27.0 125 40.0 78

34.5 (3 ø) 38.0 150 50.0 103

Notes:

1. Derived from IEEE C37.63-2013 Standard Requirements for Overhead, Pad-Mounted, Dry-Vault, and Submersible Automatic Line Sectionalizers for Alternating Current Systems Up To 38 kV, Table 2.

2. The table includes a 0.75 multiplier with fractions rounded down.

3. In the absence of consensus standards, the NETA Standards Review Council suggests the above representative values.

4. Values of ac voltage given are dry test, one-minute, factory test values.

TABLE 100.17

Metal-Enclosed Bus Dielectric Withstand Test Voltages

Type of Bus

Rated kV

Maximum Test Voltage (kV)

AC DC

Isolated Phase for Generator Leads

24.5 37.0 52.0

29.5 45.0 --

34.5 60.0 --

Isolated Phase for Other than Generator Leads

15.5 37.0 --

27.0 45.0 --

38.0 60.0 --

Nonsegregated Phase

1.058 2.25 --

4.76 14.2 --

8.25 27.0 --

15.0 27.0 --

15.5 37.5 --

Segregated Phase

15.5 37.0 --

DC Bus Duct 1

0.3/.325 1.6 2.3

0.8 2.7 3.9

1.2 3.6 5.4

1.6 4.0 5.7

3.2 6.6 9.3

Notes:

Derived from IEEE C37.23-2015 Standard for Metal-Enclosed Bus and Calculating Losses in Isolated-Phase Bus, Tables 3A, 3B, 3C, 3D and paragraph 6.4.3. The table includes a 0.75 multiplier with fractions rounded down.

1. The presence of the column headed “DC” does not imply any requirement for a dc withstand test on ac equipment. This column is given as a reference only for those using dc tests and represents values believed to be appropriate and approximately equivalent to the corresponding power frequency withstand test values specified for each class of bus.

Direct current withstand tests are recommended for flexible bus to avoid the loss of insulation life that may result from the dielectric heating that occurs with rated frequency withstand testing.

Because of the variable voltage distribution encountered when making dc withstand tests and variances in leakage currents associated with various insulation systems, the manufacturer should be consulted for recommendations before applying dc withstand tests to this equipment.

TABLE 100.18

Thermographic Survey

Suggested Actions Based on Temperature Rise Temperature Difference (∆T)

Based on Comparisons Between Similar Components Under Similar

Loading

Temperature Difference (∆T) Based Upon Comparisons Between

Component and Ambient Air Temperatures

Recommended Action

1° C - 3° C 1° C - 10° C Possible deficiency; warrants investigation

4° C - 15° C 11° - 20° C Indicates probable deficiency; repair as time permits

- - - - - 21° - 40° C Monitor until corrective measures can be accomplished

> 15° C > 40° C Major discrepancy; repair immediately

Notes:

1. Temperature specifications vary depending on the exact type of equipment. Even in the same class of equipment (i.e., cables) there are various temperature ratings. Heating is generally related to the square of the current; therefore, the load current will have a major impact on ∆T. In the absence of consensus standards for ∆T, the values in this table will provide reasonable guidelines.

2. An alternative method of evaluation is the standards-based temperature rating system as discussed in Section 8.9.2, Conducting an IR Thermographic Inspection, Electrical Power Systems Maintenance and Testing by Paul Gill, PE, 2008.

3. It is a necessary and valid requirement that the person performing the electrical inspection be thoroughly trained and experienced concerning the apparatus and systems being evaluated as well as knowledgeable of thermographic methodology.

TABLE 100.19

Dielectric Withstand Test Voltages for Electrical Apparatus

Other than Inductive Equipment Nominal System

(Line) Voltage 1 (kV)

Insulation Class (kV)

AC Factory Test (kV)

Maximum Field Applied AC Test (kV)

Maximum Field Applied DC Test (kV)

1.2 1.2 10 6.0 8.5

2.4 2.5 15 9.0 12.7

4.8 5.0 19 11.4 16.1

8.3 8.7 26 15.6 22.1

14.4 15.0 34 20.4 28.8

10.8 18.0 40 24.0 33.9

25.0 25.0 50 30.0 42.4

34.5 35.0 70 42.0 59.4

46.0 46.0 95 57.0 80.6

69.0 69.0 140 84.0 118.8

In the absence of consensus standards, the NETA Standards Review Council suggests the above representative values.

1. Intermediate voltage ratings are placed in the next higher insulation class.

TABLE 100.20.1

Rated Control Voltages and Their Ranges for Circuit Breakers

Operating mechanisms are designed for rated control voltages listed with operational capability throughout the indicated voltage ranges to accommodate variations in source regulation, couple with low charge levels, as well as high charge levels maintained with floating charges. The maximum voltage is measured at the point of user connection to the circuit breaker [see notes (12) and (13)] with no operating current flowing, and the minimum voltage is measured with maximum operating current flowing.

(11) Rated Control

Voltage

Direct Current Voltage Ranges

(1)(2)(3)(4)(5) (8)(9)

Opening Functions All Types

Rated Control Voltage (60 Hz)

Alternating Current

Voltage Ranges (1)(2)(3)(4)(8)

Closing and Auxiliary Functions

Single Phase

Closing, Tripping, and

Auxiliary Functions

Indoor

Circuit Breakers

Outdoor Circuit

Breakers

Single Phase

24 (6) 48 (6)

38 – 56

100 – 140 200 – 280

36 – 56 90 – 140

180 – 280

14 - 28 28 – 56

70 – 140 140 – 280

104 – 127 (7) 208 – 254 (7)

Polyphase Polyphase

208Y/120

180Y/104 – 220Y/127 208 – 254

Derived from Table 8, IEEE C37.06-2000, AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis – Preferred Ratings and Related Required Capabilities.

(1) Electrically operated motors, contactors, solenoids, valves, and the like, need not carry a nameplate voltage rating that corresponds to the control voltage rating shown in the table as long as these components perform the intended duty cycle (usually intermittent) in the voltage range specified.

(2) Relays, motors, or other auxiliary equipment that function as a part of the control for a device shall be subject to the voltage limits imposed by this standard, whether mounted at the device or at a remote location.

(3) Circuit breaker devices, in some applications, may be exposed to control voltages exceeding those specified here due to abnormal conditions such as abrupt changes in line loading. Such applications require specific study, and the manufacturer should be consulted. Also, application of switchgear devices containing solid-state control, exposed continuously to control voltages approaching the upper limits of ranges specified herein, require specific attention and the manufacturer should be consulted before application is made.

(4) Includes supply for pump or compressor motors. Note that rated voltages for motors and their operating ranges are covered by NEMA MG-1-1978.

(5) It is recommended that the coils of closing, auxiliary, and tripping devices that are connected continually to one dc potential should be connected to the negative control bus so as to minimize electrolytic deterioration.

(6) 24-volt or 48-volt tripping, closing, and auxiliary functions are recommended only when the device is located near the battery or where special effort is made to ensure the adequacy of conductors between battery and control terminals. 24-volt closing is not recommended.

(7) Includes heater circuits

(8) Voltage ranges apply to all closing and auxiliary devices when cold. Breakers utilizing standard auxiliary relays for control functions may not comply at lower extremes of voltage ranges when relay coils are hot, as after repeated or continuous operation.

(8) Voltage ranges apply to all closing and auxiliary devices when cold. Breakers utilizing standard auxiliary relays for control functions may not comply at lower extremes of voltage ranges when relay coils are hot, as after repeated or continuous operation.

(9) Direct current control voltage sources, such as those derived from rectified alternating current, may contain sufficient inherent ripple to modify the operation of control devices to the extent that they may not function over the entire specified voltage ranges.

(10) This table also applies to circuit breakers in gas-insulated substation installations.

(11) In cases where other operational ratings are a function of the specific control voltage applied, tests in IEEE

C37.09 may refer to the “Rated Control Voltage.” In these cases, tests shall be performed at the levels in this column.

(12) For an outdoor circuit breaker, the point of user connection to the circuit breaker is the secondary terminal block point at which the wires from the circuit breaker operating mechanism components are connected to the user’s control circuit wiring.

(13) For an indoor circuit breaker, the point of user connection to the circuit breaker is either the secondary disconnecting contact (where the control power is connected from the stationary housing to the removable circuit breaker) or the terminal block point in the housing nearest to the secondary disconnecting contact.

TABLE 100.20.1 (continued)

TABLE 100.20.2

Solenoid-Operated Devices

Rated Voltage (DC) Closing Voltage Ranges for Power Supply

125 90 – 115 or 105 – 130

250 180 – 230 or 210 – 260

230 190 – 230 or 210 – 260

Notes:

1. Some solenoid operating mechanisms are not capable of satisfactory performance over the range of voltage specified in the standard; moreover, two ranges of voltage may be required for such mechanisms to achieve an acceptable standard of performance.

2. The preferred method of obtaining the double range of closing voltage is by use of tapped coils. Otherwise it will be necessary to designate one of the two closing voltage ranges listed above as representing the condition existing at the device location due to battery or lead voltage drop or control power transformer regulation. Also, caution should be exercised to ensure that the maximum voltage of the range used is not exceeded.

TABLE 100.23

Online Partial Discharge Survey for Switchgear

Notes:

1. Any signal level present without a phase-angle related component is not indicative of partial-discharge activity.

2. Perform partial-discharge surveys every 12 months, or in accordance with Appendix B, Frequency of Maintenance Tests.

3. Compare measured levels to established background readings.

4. Background readings higher than values listed in these tables should be investigated and mitigated.

TABLE 100.23.1

Suggested Actions Based on Nature and Strength of Signal

(TEV)

dB Phase-Angle Related

Component Recommended Action

Any1 No Survey in 12 months for trending 2

< 20 Yes Survey in 6 months for trending

20 – 30 Yes Locate and repair as soon as practical

> 30 Yes Locate and repair as soon as possible

TABLE 100.23.2

Suggested Actions Based on Nature and Strength of Signal

(HFCT)

pC dB Phase Related Component Recommended Action

Any Any No Survey in 12 months for trending

< 250 < 10 Yes Survey in 6 months for trending

200 – 500 10 – 20 Yes Locate and repair as soon as practical

> 500 > 20 Yes Locate and repair as soon as possible

1. The use of HFCTs for cable testing is outside the scope of this standard.

TABLE 100.23.3

Suggested Actions Based on Nature and Strength of Signal

(UHF)

dBmV Phase Related Component Recommended Action

Any No Survey in 12 months for trending

< 10 Yes Survey in 6 months for trending

10 – 20 Yes Locate and repair as soon as practical

> 20 Yes Locate and repair as soon as possible

TABLE 100.23.4

Suggested Actions Based on Nature and Strength of Signal

(VIS)

dB Phase Related Component Recommended Action

Any No Survey in 12 months for trending

20 – 29 Yes Survey in 6 months for trending

30 – 39 Yes Locate and repair as soon as practical

> 40 Yes Locate and repair as soon as possible

TABLE 100.23.5

Suggested Actions Based on Nature and Strength of Signal (Contact/Airborne Acoustic) dB Phase Related Component Recommended Action

Any No Survey in 12 months for trending

< 3 Yes Survey in 6 months for trending

3 – 6 Yes Locate and repair as soon as practical

> 6 Yes Locate and repair as soon as possible

APPENDIX A

Definitions

NOTE: The definitions in Appendix A provided by NETA are specific to electrical testing and to this document.

NETA defines equipment voltage ratings in accordance with IEEE C37.84.1 American National Standard for Electrical Power Systems and Equipment – Voltage Ratings (60 Hertz).

As-found Condition of the equipment when taken out of service, prior to maintenance.

As-left Condition of equipment at the completion of maintenance. As-left values refer to test values obtained after all maintenance has been performed on the device under test.

Comment Suggested revision, addition, or deletion in an existing section of the NETA specifications.

Commissioning The systematic process of documenting and placing into service newly installed or retrofitted electrical power equipment and systems.

Electrical tests Electrical tests involve application of electrical signals and observation of the response. It may be, for instance, applying a potential across an insulation system and measuring the resultant leakage current magnitude or power factor/dissipation factor. It may also involve application of voltage and/or current to metering and relaying equipment to check for correct response.

Equipment condition Suitability of the equipment for continued operation in the intended environment as determined by evaluation of the results of inspections and tests.

Errata A correction issued to a NETA Standard, published in NETA World, available on the NETA website and included in any further distribution of the Standard.

Exercise To operate equipment in such a manner that it performs all its intended functions to allow observation, testing, measurement, and diagnosis of its operational condition.

Extra-high voltage A class of nominal system voltages greater than 230,000 volts.

High voltage A class of nominal system voltages equal to or greater than 100,000 volts and equal to or less than 230,000 volts.

Inspection Examination or measurement to verify whether an item or activity conforms to specified requirements.

Low voltage

APPENDIX A (continued) Definitions

A class of nominal system voltages 1000 volts or less.

Maintenance, Condition of The state of the electrical equipment considering the manufacturer’s instructions, manufacturer’s recommendations, and applicable industry codes, standards, and recommended practices.

Manufacturer’s published data Data provided by the manufacturer concerning a specific piece of equipment.

Mechanical inspection Observation of the mechanical operation of equipment not requiring electrical stimulation, such as manual operation of circuit breaker trip and close functions. It may also include tightening of hardware, cleaning, and lubricating.

Medium voltage A class of nominal system voltages greater than 1000 volts and less than 100,000 volts.

Ready-to-test condition Preparing equipment which is to be tested in an isolated state, source and load disconnected, necessary protective grounds applied, and control and operating voltage sources identified.

Shall Indicates mandatory requirements to be strictly followed in order to conform to the standard and from which no deviation is permitted (shall equals is required to).

Should Indicates that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others; or that a certain course of action is preferred but not necessarily required (should equals is recommended that).

System voltage The root-mean-square (rms) phase-to-phase voltage of a portion of an alternating-current electric system. Each system voltage pertains to a portion of the system that is bounded by transformers or utilization equipment.

Verify To investigate by observation or by test to determine that a particular condition exists.

Visual inspection Qualitative observation of physical characteristics, for example: cleanliness, physical integrity, evidence of overheating, lubrication, etc.