| Electrical Parameters |
Rated Voltage |
Defined as the voltage value at which the PT elbow - type cable is designed to operate continuously under normal conditions. Standard values include but are not limited to 10kV, 15kV, 35kV, etc., corresponding to different power grid voltage levels. |
| Rated Current |
The maximum current that the cable can carry continuously without overheating or causing unacceptable degradation of its insulation and other properties. Standard values such as 200A, 630A, 1250A are specified based on cable design and application requirements. |
| Power - Frequency Withstand Voltage |
Measured as the peak value of the power - frequency alternating voltage that the cable insulation can withstand for a specified time (e.g., 1 minute) without breakdown. A typical value is 42kV, which is crucial for verifying the insulation integrity under normal - frequency over - voltage conditions. |
| DC Withstand Voltage |
The direct - current voltage that the cable insulation can endure for a defined period (e.g., 15 minutes) without failure. This test is used to detect insulation weaknesses that may not be apparent under alternating - current conditions. |
| Lightning Impulse Withstand Voltage |
Specified as the peak value of the impulse voltage that simulates lightning strikes, which the cable must be able to withstand without insulation breakdown. A common requirement is 95kV, safeguarding the cable against transient over - voltages caused by lightning. |
| Partial Discharge Quantity |
Quantified as the amount of electrical charge released in the form of partial discharges within the cable insulation under a given test voltage (e.g., at 48kV). A limit of less than 1.6pC is typically set, as excessive partial discharge indicates insulation defects that can lead to premature failure. |
| Dielectric Loss Factor |
Defined as the ratio of the power dissipated in the cable insulation to the apparent power under an alternating - current electric field. A lower dielectric loss factor indicates better insulation quality, with reduced energy losses and heat generation during operation. |
| Mechanical Parameters |
Applicable Cable Cross - Section |
Defined as the range of cross - sectional areas of the cables that the PT elbow - type cable can be properly connected to. Standard ranges include 35 - 120mm², 35 - 400mm² for cross - linked polyethylene cables, which are specified based on mechanical and electrical connection compatibility. |
| Bending Radius |
Specified as the minimum radius to which the cable can be bent without causing damage to its internal structure (such as insulation damage or conductor deformation) and without significantly degrading its electrical performance. |
| Material and Structure Parameters |
Insulation Material |
Commonly composed of materials such as silicone rubber, which possess excellent electrical insulation properties, weather resistance, aging resistance, and flexibility. These properties ensure long - term reliable operation of the cable insulation. |
| Conductive Material |
Typically made of copper, chosen for its high electrical conductivity, good mechanical strength, and resistance to corrosion, which are essential for efficient current transmission. |
| Shielding Layer Parameters |
Comprising an inner semi - conductive layer and an outer semi - conductive layer. The inner semi - conductive layer is designed to control electrical stress within the cable insulation, while the outer semi - conductive layer, in conjunction with the cable shield, provides continuous shielding and grounding to mitigate electric field non - uniformity and electromagnetic interference. |
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