Technical Information
Electrical clearance and creepage distance detection of nuclear power valve electric devices
[ 12-10-2024 ]
The detection of electrical clearance and creepage distance of nuclear power valve electric devices is an important part of ensuring their electrical performance and safety. The following are the detection methods for these two distances:
1. Electrical clearance detection method
Electrical clearance refers to the shortest spatial distance measured between two conductive parts or between conductive parts and the protective interface of the equipment, that is, the shortest distance that can be insulated through air while ensuring stable and safe electrical performance. The size of the electrical clearance has nothing to do with aging, but it can withstand very high overvoltage. When the overvoltage value exceeds a certain critical value, this voltage will quickly cause an electrical breakdown. Its detection method mainly includes the following steps:
Determine the working voltage:
Measure the peak value and effective value of the working voltage of the nuclear power valve electric device.
Determine the power supply voltage and power supply facility category of the equipment.
Determine the transient overvoltage:
Determine the size of the transient overvoltage entering the equipment according to the overvoltage category.
Determine the pollution level:
Evaluate and determine the pollution level of the nuclear power valve electric device (general equipment is pollution level 2).
Determine the insulation type:
Determine the insulation type (functional insulation, basic insulation, additional insulation, reinforced insulation) of the electrical clearance bridge.
Determine the electrical clearance by looking up the table:
According to the measured working voltage and insulation level, refer to the table in the relevant standards (such as GB4943 or 60065-2001) to retrieve the required electrical clearance value.
2. Creepage distance detection method
Creeppage distance refers to the shortest path between two conductive parts or between conductive parts and the equipment protection interface measured along the insulation surface. Because the insulating material around the conductor is polarized, the insulating material becomes charged and forms a leakage current path. If these leakage current paths form a conductive path, surface flashover or breakdown will occur. The creepage distance detection method mainly includes the following steps:
Determine the working voltage:
Determine the effective value or DC value of the working voltage of the nuclear power valve electric device.
Determine the material group:
Determine the group of insulating materials (Group I materials, Group II materials, Group Ia materials, Group IIIb materials) based on the comparative tracking index. If the material group is unknown, assume that the material is Group IIIb.
Determine the pollution level:
Evaluate and determine the pollution level of the nuclear power valve electric device.
Determine the insulation type:
Determine the insulation type involved in the creepage distance (functional insulation, basic insulation, additional insulation, reinforced insulation).
Determine the creepage distance by looking up the table:
According to the working voltage, insulation level, and material group, refer to the table in the relevant standards (such as GB4943 or 60065-2001) to determine the creepage distance value. If the working voltage value is between the two voltage ranges in the table, the inner difference method needs to be used to calculate its creepage distance.
III. Precautions
Accuracy: When performing electrical clearance and creepage distance detection, the accuracy of the measurement should be ensured to avoid the influence of errors on the test results.
Safety: During the detection process, the safety operating procedures should be strictly followed to ensure the personal safety of the test personnel and the safe operation of the equipment.
Standard compliance: The test methods and results should comply with the requirements of relevant national or industry standards to ensure the electrical performance and safety of nuclear power valve electric devices.
In summary, the electrical clearance and creepage distance detection of nuclear power valve electric devices is an important means to ensure their electrical performance and safety. The accuracy and reliability of the test results can be ensured by strictly following the test methods and precautions.
1. Electrical clearance detection method
Electrical clearance refers to the shortest spatial distance measured between two conductive parts or between conductive parts and the protective interface of the equipment, that is, the shortest distance that can be insulated through air while ensuring stable and safe electrical performance. The size of the electrical clearance has nothing to do with aging, but it can withstand very high overvoltage. When the overvoltage value exceeds a certain critical value, this voltage will quickly cause an electrical breakdown. Its detection method mainly includes the following steps:
Determine the working voltage:
Measure the peak value and effective value of the working voltage of the nuclear power valve electric device.
Determine the power supply voltage and power supply facility category of the equipment.
Determine the transient overvoltage:
Determine the size of the transient overvoltage entering the equipment according to the overvoltage category.
Determine the pollution level:
Evaluate and determine the pollution level of the nuclear power valve electric device (general equipment is pollution level 2).
Determine the insulation type:
Determine the insulation type (functional insulation, basic insulation, additional insulation, reinforced insulation) of the electrical clearance bridge.
Determine the electrical clearance by looking up the table:
According to the measured working voltage and insulation level, refer to the table in the relevant standards (such as GB4943 or 60065-2001) to retrieve the required electrical clearance value.
2. Creepage distance detection method
Creeppage distance refers to the shortest path between two conductive parts or between conductive parts and the equipment protection interface measured along the insulation surface. Because the insulating material around the conductor is polarized, the insulating material becomes charged and forms a leakage current path. If these leakage current paths form a conductive path, surface flashover or breakdown will occur. The creepage distance detection method mainly includes the following steps:
Determine the working voltage:
Determine the effective value or DC value of the working voltage of the nuclear power valve electric device.
Determine the material group:
Determine the group of insulating materials (Group I materials, Group II materials, Group Ia materials, Group IIIb materials) based on the comparative tracking index. If the material group is unknown, assume that the material is Group IIIb.
Determine the pollution level:
Evaluate and determine the pollution level of the nuclear power valve electric device.
Determine the insulation type:
Determine the insulation type involved in the creepage distance (functional insulation, basic insulation, additional insulation, reinforced insulation).
Determine the creepage distance by looking up the table:
According to the working voltage, insulation level, and material group, refer to the table in the relevant standards (such as GB4943 or 60065-2001) to determine the creepage distance value. If the working voltage value is between the two voltage ranges in the table, the inner difference method needs to be used to calculate its creepage distance.
III. Precautions
Accuracy: When performing electrical clearance and creepage distance detection, the accuracy of the measurement should be ensured to avoid the influence of errors on the test results.
Safety: During the detection process, the safety operating procedures should be strictly followed to ensure the personal safety of the test personnel and the safe operation of the equipment.
Standard compliance: The test methods and results should comply with the requirements of relevant national or industry standards to ensure the electrical performance and safety of nuclear power valve electric devices.
In summary, the electrical clearance and creepage distance detection of nuclear power valve electric devices is an important means to ensure their electrical performance and safety. The accuracy and reliability of the test results can be ensured by strictly following the test methods and precautions.