20
Jul
Three important indicators of wire and cable quality testing
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Select qualified wire and cable products related to the safety of people's production and life. For ordinary consumers, in addition to mastering how to select qualified wire and cable products, it is also necessary to understand the routine monitoring of wire and cable knowledge.
The following is introduced to you in the wire and cable quality testing of the three important indicators.
Insulation resistance test
Insulation resistance type is an important indicator to reflect the insulation characteristics of wire and cable products, and electrical strength, dielectric loss and insulation materials in the working conditions of the gradual deterioration is closely related.
Through the measurement of insulation resistance, can be found in the process of defects, such as insulation dry impermeable or sheath damage moisture; insulation is polluted, and mixed with conductive impurities; insulation cracking caused by various reasons. Wire and cable in operation, often to test the insulation resistance and leakage current, as the main basis for the continued safe operation.
Measurement of capacitance and loss factor
When an AC voltage is added to a cable, a current flows through it. When the amplitude and frequency of the voltage are certain, the magnitude of the capacitive current is proportional to the capacitance (Cx) of the cable. For UHV cables, this capacitive current may reach values comparable to the rated current, which becomes an important factor in limiting the capacity and transmission distance of the cable. Therefore the capacitance of a cable is also one of the main electrical performance parameters of a cable.
Measurement of capacitance and loss factor can detect various insulation deterioration phenomena such as moisture, insulation and shielding layer detachment, etc. Therefore, capacitance and TAN measurements are carried out no matter in cable manufacturing or cable operation. For high-voltage cables, Cx and TAN measurements are measured at high frequency and high voltage operating conditions, usually using a high-voltage Cillin bridge, and in recent years have also begun to use the current ratio transformer bridge.
Partial Discharge Measurement
①Electrometry: There are many ways to measure partial discharges, and the discharge pulse can be measured according to the instantaneous charge exchange generated by the discharge;
②Acoustic measurement method: it can also be based on the ultrasonic waves generated during the discharge, measuring its voltage;
③Light measurement method: can also be based on the light generated by the discharge, measuring the intensity of light;
For the cable is basically the use of electrical measurement method.
Although the cable brings great convenience to our lives, but at the same time there are also many uncontrollable factors, the quality of power cables directly affects the operation of the line safety, once the line can not be safe and stable operation, its failure to cause life and economic losses can not be foreseen, so we must fundamentally prevent the occurrence of cable failures to minimize the cable accidents, from the smallest scratch, and strive to achieve safe and stable power supply this goal.
The following is introduced to you in the wire and cable quality testing of the three important indicators.
Insulation resistance test
Insulation resistance type is an important indicator to reflect the insulation characteristics of wire and cable products, and electrical strength, dielectric loss and insulation materials in the working conditions of the gradual deterioration is closely related.
Through the measurement of insulation resistance, can be found in the process of defects, such as insulation dry impermeable or sheath damage moisture; insulation is polluted, and mixed with conductive impurities; insulation cracking caused by various reasons. Wire and cable in operation, often to test the insulation resistance and leakage current, as the main basis for the continued safe operation.
Measurement of capacitance and loss factor
When an AC voltage is added to a cable, a current flows through it. When the amplitude and frequency of the voltage are certain, the magnitude of the capacitive current is proportional to the capacitance (Cx) of the cable. For UHV cables, this capacitive current may reach values comparable to the rated current, which becomes an important factor in limiting the capacity and transmission distance of the cable. Therefore the capacitance of a cable is also one of the main electrical performance parameters of a cable.
Measurement of capacitance and loss factor can detect various insulation deterioration phenomena such as moisture, insulation and shielding layer detachment, etc. Therefore, capacitance and TAN measurements are carried out no matter in cable manufacturing or cable operation. For high-voltage cables, Cx and TAN measurements are measured at high frequency and high voltage operating conditions, usually using a high-voltage Cillin bridge, and in recent years have also begun to use the current ratio transformer bridge.
Partial Discharge Measurement
①Electrometry: There are many ways to measure partial discharges, and the discharge pulse can be measured according to the instantaneous charge exchange generated by the discharge;
②Acoustic measurement method: it can also be based on the ultrasonic waves generated during the discharge, measuring its voltage;
③Light measurement method: can also be based on the light generated by the discharge, measuring the intensity of light;
For the cable is basically the use of electrical measurement method.
Although the cable brings great convenience to our lives, but at the same time there are also many uncontrollable factors, the quality of power cables directly affects the operation of the line safety, once the line can not be safe and stable operation, its failure to cause life and economic losses can not be foreseen, so we must fundamentally prevent the occurrence of cable failures to minimize the cable accidents, from the smallest scratch, and strive to achieve safe and stable power supply this goal.
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