The breakdown phenomenon of medium voltage cables
As an important equipment for power transmission, medium voltage cables have the function of transmitting electrical energy. However, during power transmission, cables may experience breakdown.
medium voltage power cable breakdown refers to the phenomenon where the electromagnetic field strength of a cable is too high under the action of an electric field, causing damage to its insulation layer. When the electric field strength exceeds a certain value, electrons in the cable insulation material will be ejected and form electron hole pairs. These electron hole pairs will form a chain reaction and cause ionization within the insulation layer, ultimately leading to cable breakdown.
Reasons for breakdown of cable medium voltage
1. Electric field strength
The main reason for the breakdown of medium voltage cables is the high electric field strength. The electric field strength in the insulation layer of a cable is determined by the voltage and the geometric shape of the cable. When the electric field strength in the insulation layer of a cable is greater than its destructive electric field strength, the insulation layer will be broken down.
2. The ultimate withstand electric field strength of dielectrics
Dielectric materials have a certain limit of electric field strength, exceeding which can cause damage to the dielectric material. Therefore, the dielectric material of medium voltage cables should have sufficient electric field strength to withstand and ensure the safe operation of the cables.
3. Bubbles and pollutants in dielectrics
Bubbles and pollutants in dielectrics can affect the distribution of electric field strength. Bubbles and pollutants can increase the heterogeneity of electric field strength, leading to extremely high electric field strength at certain locations in the insulation layer of medium voltage wire, which is prone to breakdown.
The impact of mv cable breakdown
The breakdown of medium voltage power cable can cause power outages, which can have a significant impact on production and daily life. In addition, factors such as wildfires and disasters may cause cable breakdown, leading to accidents.
In short, medium voltage wire breakdown is a serious problem in power transmission, and it is necessary to strengthen cable insulation design and maintenance to avoid cable failures caused by excessive voltage, dielectric damage, and other reasons.
