Why does the temperature of 10kV high-voltage distribution switchgear rise

Due to the long power supply distance, multiple equipment components, high electrical load, and mostly continuous operation of 10kV distribution lines, the electrical equipment of substations that supply power to the lines has the characteristics of heavy load and high current during operation. Under such conditions, when the connection screws of the substation equipment become loose or the components of each part have poor contact, the temperature of the equipment will abnormally rise due to the continuous passage of high current, resulting in poor material performance of the electrical equipment. If not detected and repaired in a timely manner, serious accidents may occur due to overheating and melting of the welding points of the equipment. That is to say, during the occurrence of faults in high-voltage equipment, there will be a significant increase in temperature. Therefore, monitoring the temperature parameters of high-voltage equipment during operation is very important.

Reasons for high pressure temperature rise

The fully enclosed electrical equipment of the substation refers to the combination of high-voltage components such as high-voltage circuit breakers, isolation switches, and transformers, which are installed in metal enclosed cabinets, such as combination electrical appliances and high-voltage switchgear. During the operation of fully enclosed electrical equipment, if partial discharge occurs in the internal equipment of the cabinet, it can cause abnormal temperature rise at the conductor connection. Due to the hidden heating position, the operating personnel cannot detect it in a timely manner. This can easily expand the fault, causing electrical components to break down and burn out, and affecting adjacent equipment units, resulting in a malignant power outage accident.

The reason for the temperature rise of high-voltage circuit breakers is that the circuit breaker temperature is too high

During the normal operation of high-voltage circuit breakers, the energy generated by the long-term working current is converted into thermal energy, causing the temperature of electrical materials to rise but not exceed the specified range; When the conductive circuit is abnormal, it will cause the temperature of the electrical material to increase beyond the specified range, accelerate the oxidation of the dynamic and static contacts, increase the contact resistance, and further increase the heating temperature, resulting in a decrease in the mechanical and physical properties of the electrical material. When the temperature exceeds the melting point of the material, it will cause the two contacts to melt, ultimately leading to an electrical accident where the circuit breaker cannot be opened. For example, the metal armored enclosed switchgear in substations (switching stations) all use small car type circuit breakers. When the handcart plug is pushed in, if the force is not enough or not shaken in place, it will cause poor contact between the dynamic and static plugs, causing overheating. During operation, the contact will melt, which can cause phase to phase short circuits and lead to a malignant accident of the overall switch burning.

The reason for the high temperature of the busbar is the temperature rise of the electrical contacts

The connection between various electrical equipment in the substation mainly relies on screws for crimping, as well as various methods such as connecting with the main busbar and branch busbar. Due to the limitation of voltage level, it is necessary to consider the requirements for safe distance to ground and the safe operation of connecting busbars. Therefore, an insulation sheath has been installed and enclosed. This makes the connecting wires between devices have many characteristics that are not conducive to operation, such as high installation distance from the ground and strong sealing. If the screws at the connection are not properly maintained or run for a long time, external factors such as wind force and vibration of electric power during operation can cause the screws to loosen and oxidize, resulting in overheating of the contact points at the busbar connection due to excessive contact resistance, which can lead to a malignant accident of large-scale power outage in the entire substation or section of the busbar.