1

infrared temperature measurement

1)≤110kV: 6 months

2) When necessary

No abnormal temperature rise in any part, detected and analyzed method referenceDL/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 making a terminal or connector)

2) ≤ 6 years

3) When necessary

Generally, it should not be less than1000MΩ。

rated voltage0.6/1kVFor cables 1000V megohmmeter; 6/10kVAnd to The cable can also be used2500V 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 In terms of voltage resistance1minLeakage 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 than10 μ A, 6/10KV and above The leakage current of the cable is less than20μAThere 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 referenceDL/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, pressurization time15min, 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 The nominal supply represented by the sex curve90%;

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 than0.0050;

b)330kVThe cable size is not greater than0.0040;

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, oil Warm for(100 ± 1) ℃, electric field strength for1MV/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 afterWithin one year, to Not exceeding3 years.

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 than1MΩ。

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 exceed3 years

seeArticle 13.5.

6

Inside cables and accessories Cable oil:

1) Breakdown voltage

2) Dielectric loss due to number

3) Dissolved gas in oil body

1) Breakdown voltage and dielectric Loss factor: after operation1 Conducted within the year, not in the future exceed3 years;

2) Dissolved gases in oil: Suspected cable insulation overheating Aging or termination, blockage The joint has serious localized issues 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)kVand220kVThe cable is not greater than0.03;

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:≤1500μL/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 Warm for(100 ± 1) ℃, electric field strength for1MV/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 connector after

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 referenceDL/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 than1000 MΩ。

rated voltage0.6/1kV cable uses 1000V Megger;6/10KV and above cables are also included available2500V or 5000V megohmmeter.

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.

adopt500V 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. frequencyHz 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 test verify

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 Legal referenceDL/T664。

Measure with an infrared thermal imager, for Cable 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.

use2500V or 5000V megawatt European watch.

3

Main insulation communication pressure resistance

1) After maintenance

2) When necessary

The frequency isAC withstand voltage test from 20Hz to 300Hz,

Test time60min, Insulation does not break through. Experimental electricity

As specified in the table below:

voltage levelkV Test voltage

110(66) 1.6 Uo

4

Cross connection Unified experiment

1) When the cross interconnection system fails

2) When necessary

seeArticle 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 test verify

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 referenceDLT 664.

Measure with an infrared thermal imager.

2

Outer sheath, insulation Edge joint outer protection Sleeve 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

Insulation resistance value per kilometer≥0.5MΩ。

adopt500V megohmmeter.

3

Outer sheath grounding current

1) ≤ 6 months

2) When necessary

Single circuit cable laying, generally not greater than cable negative

The current value of the load10%, multi circuit cable 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 alternatively Using cable sheath circulation online

Monitoring system monitors data.

4

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

if necessary

Between the metal shield or metal sheath of each cable and the ground Add in between5kV, Pressurization for 1 minute should not cause 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 connected All 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 than10MΩ。

useMeasure with a 1000V megohmmeter.

6

Interconnected Box Knife (or connecting piece) contact resistance

if necessary

knife switchThe contact resistance of (or connecting piece), under normal working conditions Measure the position, and the contact resistance should not exceed 20μ Omega.

Contact resistance using double arm bridge Take measurements.