1

infrared temperature measurement

1)≤110kV: 6 months

2) When necessary

No abnormal temperature rise in any part, detected and analyzed Method reference DL/T664.

Measure the cable using an infrared thermal imager Terminal connectors and non buried indirect connections Head on.

2

Main insulation resistance

1) After A and B level maintenance (new) After being used as a terminal or connector

2) ≤ 6 years

3) When necessary

Generally, it should not be less than 1000M Ω.

Rated voltage 0.6/1kVFor cables 1000V megohmmeter; 6/10kVAnd to The cable can also be connected at 2500V or 5000V megohmmeter.

3

DC withstand voltage test

1) After maintenance (new work)After the terminal or connector)

2) ≤ 6 years

3) When necessary

1) The test voltage value shall be pressurized according to the (standard number) regulations time interval 5 m i n , no hit wear ：

voltage level Test voltage

4.5Uo

4.5Uo

35kV 4 5Uo

2) Voltage resistance 5minThe leakage current value should not be large Withstand voltage 1minLeakage current value at time;

3) The imbalance coefficient of leakage current between three phases is not should big Yu 2 .

Leakage current of cables below 6/10kV less than 10 μ A, 6/10KV and above The leakage current of the cable is less than 20 μ AThere is no regulation on the imbalance coefficient.

4

Phase check

1) After B-level maintenance (new work)After the terminal or connector)

2) When necessary

Consistent with the phase of the power grid.

1

infrared temperature measurement

1)≥330kV: 1 month

2)220kV: 3 months

3)≤110kV: 6 months

4) When necessary

No abnormal temperature rise in any part, detected and analyzed Method reference DL/T 664.

Measure the cable using an infrared thermal imager Terminal connectors and non buried indirect connections Head on.

2

Main insulation DC resistance press

1) After maintenance (new work) After the terminal or connector)

2) When necessary

Voltage should be applied between each conductor and shield,The pressurization time is 15 minutes, and the test voltage values are shown in the table below

According to the regulations, the insulation should not break down during the test process operating voltageUalU DC test voltage 36/66 4 5Uo

64/110 4.5 Uo

127/220 4 0Uo

190/330 3.5 Uo

290/5003 Uo

3

Pressure box:

1) Fuel supply characteristics

2) Cable oil breakdown voltage

3) The dielectric of cable oil Quality loss factor

if necessary

1) The fuel supply of the pressure box should not be less than the fuel supply capacity 90% of the nominal supply represented by the sex curve;

2) The breakdown voltage shall not be less than 50kV;

3) The dielectric loss factor should meet the following requirements:

a) 110 (66) kV and 220kV cables are not Greater than 0.0050;

b)330kVThe cable size is not greater than 0.0040;

c) 500kV cables shall not exceed 0.0035.

1) Oil supply characteristic test according to GB According to section 6.1 of 9326.1;

2) Cable oil breakdown test according to GB/T 507 regulations shall be followed;

3) When measuring the dielectric loss factor, oilTemperature is (100 ± 1) ℃, electric field strength It is 1MV/m.

4

Oil pressure warning system:

1) Signal indication

2) Control cable Core to ground insulation

1) Signal indication: 6 moon ；

2) Control cable core pair Ground insulation resistance: put into operation Within the next year, to Not exceeding 3 years thereafter.

1) Signal indication: able to correctly issue corresponding warnings 信 number ；

2) Control cable core to ground insulation resistance: per thousand The insulation resistance of the meter shall not be less than 1M Ω.

1) Test of closing the warning signal device The switch should be able to issue the corresponding signal correctly Sound and light warning signals;

2) Using a 100V or 250V megohmmeter Measurement.

5

Cross Interconnection System

Not exceeding 3 years

Refer to Article 13.5.

6

Inside cables and accessoriesCable oil:

1) Breakdown voltage

2) Dielectric loss due to number

3) Dissolved gas in oil body

1) Breakdown voltage and dielectric Loss factor: 1 after operation Conducted within the year, not in the future More than 3 years;

2) Dissolved gases in oil: Suspected cable insulation overheating Aging or severe localized presence of terminal or plug joints Perform during discharge.

1) The breakdown voltage shall not be lower than 45kV;

2) The dielectric loss factor should meet the following requirements:

a)110(66)kVAnd 220kVThe cable is not Greater than 0.03;

b) 330kV and 500kV cables shall not exceed 0.01;

3) Injection of dissolved gas component content in cable oil The values are shown in the table below:

Total combustible gas: ≤ 1500 μ L/L

H₂:≤500μL/L

C₂H₂ : mark quantity

CO: ≤100μL/L CO₂:≤1000μL/L

CH4:≤200μL/L

C₂H₆:≤200μL/L

C₂H4:≤200μL/L

1) Cable oil breakdown test according to GB/T 507 regulations shall be followed;

2) When measuring the dielectric loss factor, oil Temperature is (100 ± 1) ℃, electric field strength It is 1MV/m;

3) Dissolved gases in oil according to DL/T

722 proceed, as listed in the 'Requirements' column The attention value is not to judge the oil filled cableThe indicators, when gas When the body weight reaches the attention value, it should be Track and analyze to identify the cause.

7

Metal protective layer and bonding

Ground circulation measurement

1≥330kV: 1 month 2) 220kV: 3 months 3)≤110KV: 6 months 4) When necessary

1) The current value meets the design requirements;

2) There should be no significant changes in the three-phase imbalance.

1) Measure with a clamp ammeter;

2) When selecting cable lines with high loads Measurement.

8

Phase check

1)New terminal or connectorafter

2)if necessary

Consistent with the phase of the power grid.

1

infrared temperature measurement

1) 6 months

2) When necessary

No abnormal temperature rise in any part, detected and analyzed Method reference DL/T 664.

Measure the cable termination using an infrared thermal imager End connectors and non buried intermediate connectors that 's ok.

2

Main insulation insulation resistance

1) After A and B level maintenance(New terminal or connector) after )

2) ≤ 6 years

3) When necessary

Generally not less than 1000 M Ω.

1000V cable with rated voltage of 0.6/1kV Megohmmeter;; 6/10KV and above cables are also included A 2500V or 5000V megohmmeter can be used.

3

Cable outer sheath insulation resistance

1) After A and B level maintenance (New terminal or connector) after )

2) ≤ 6 years

3) When necessary

Insulation resistance value per kilometer ≥ 0.5MQ.

Use a 500V megohmmeter.

4

Copper shielding layer

Resistance and conductor electricity Resistance ratio（Rp/Rx)

1) After maintenance (new work)After the terminal or connector)

2) When necessary

1) The resistance ratio measured before commissioning is the initial value, The resistance ratio measured after remaking the terminal or connector should As a new initial value for the line;

2) When the initial value increases, it indicates that the copper shielding layer is straight An increase in current resistance may lead to corrosion; Compared to the initial value When reduced, indicate the conductor connection points in the attachment Resistance may increase;

3) The data is self determined.

1) Measure with a double arm bridge at the same temperature The direct current resistance of copper shielding layer and conductor;

2) This test is only applicable to three core cables.

5

Main insulation communication pressure resistance

1) After maintenance (new work)After the terminal or connector)

2) When necessary

Apply the AC voltage specified in the table and require testing The insulation does not break down during the inspection process. Frequency Hz Test voltage and requirements 20~300 1.7 UoContinuously 60min

Insulation resistance should be tested before and after the withstand voltage test The test results should show no significant changes.

6

Partial discharge testverify

1) After maintenance (new work)After the terminal or connector)

2) When necessary

No abnormal discharge signal.

It can be carried out under live or power-off conditions, Can be used: high-frequency current, oscillating wave, ultra high frequency

Detection methods such as sound waves and ultra-high frequencies.

7

Phase check

1) New terminal or connectorafter

2) When necessary

Consistent with the phase of the power grid.

1

infrared temperature measurement

1)≥330kV: 1 month

2)220kV: 3 months

3)≤110kV: 6 months

4) When necessary

No abnormalities in any partTemperature rise phenomenon, detection and analysissquare Reference DL/T664.

Measure with an infrared thermal imager, forCable terminal joints and non direct burial The intermediate joint is used.

2

Main insulation insulation resistance

1) After A and B level maintenance

2)≥330kV:≤3 年

3)≤220kV:≤6 年

4) When necessary

There is no significant change compared to last time.

Use 2500V or 5000V megawatt European watch.

3

Main insulation communication pressure resistance

1) After maintenance

2) When necessary

AC withstand voltage test with a frequency of 20Hz~300Hz,

The test time is 60 minutes, and the insulation does not break down. Experimental electricity

As specified in the table below:

Voltage level kV Test voltage

110(66) 1.6 Uo

4

Cross connection Unified experiment

1) When the cross interconnection system fails

2) When necessary

Refer to Article 13.5.

5

Metal protective layer and

Grounding wire circulation measurement

1≥330kV: 1 month 2)220kV: 3 months

3)≤110kV: 6 months 4) When necessary

1) The current value meets the design requirements;

2) There should be no significant changes in the three-phase imbalance.

1) Measure with a clamp ammeter;

2) Choose cable lines with high loads Time measurement.

6

Partial discharge testverify

1) After maintenance (new work final) After the end or connector

2) When necessary

No abnormal discharge signal.

Entering under live or power-off conditions Okay, high-frequency current and ultra-high voltage can be used

Detection methods such as sound waves and ultra-high frequencies The law.

7

Phase check

1) After the new terminal or connector

2) When necessary

Consistent with the phase of the power grid.

1

infrared temperature measurement

1) 6 months

2) When necessary

No abnormal temperature rise in any part, detection and analysis methods Reference DLT 664.

Measure with an infrared thermal imager.

2

Outer sheath, insulation Edge joint outer protectionSleeve and insulation clip

Insulation of the board block

1) After A and B level maintenance (new work) After the terminal or connector)

2) ≤ 6 years

3) When necessary

The insulation resistance value per kilometer is ≥ 0.5M Ω.

Use a 500V megohmmeter.

3

Outer sheath groundingcurrent

1) ≤ 6 months

2) When necessary

Single circuit cable laying, generally not greater than cable negative

10% of the current carrying value, multiple circuit cables laid in the same trench

Attention should be paid to the trend of changes in the grounding current of the outer sheath.

Measure with a clamp type ammeter, or alternativelyUsing cable sheath circulation online

Monitoring system monitors data.

4

Outer sheath, insulation Edge joint outer protectionSleeve and insulation clip DC withstand voltage of the board

if necessary

Between the metal shield or metal sheath of each cable and the ground Apply 5kV and apply pressure for 1 minute without breakdown.

The protective layer must be electrified during the experiment The pressure protector is disconnected in the interconnection box

All the electricity on the other side should be connectedAll cable metal sleeves are grounded.

5

Overvoltage of protective layer Limiter

if necessary

1) The DC reference voltage of the protective layer voltage limiter should comply with Regulations on product technical documents;

2) Protective layer voltage limiter and its lead wire insulation to ground The resistance should not be lower than 10M Ω.

Measure with a 1000V megohmmeter.

6

Interconnected Box Knife (or connecting piece) contact resistance

if necessary

The contact resistance of the switch blade (or connecting piece) during normal operation Measure the position, and the contact resistance should not exceed20μ Omega.

Contact resistance using double arm bridge Take measurements.