Fuse and disconnector: Guardian in the power system
Fuse: "Safety Valve" of Current
In the power system, the fuse is an important protective device. It is mainly composed of two parts: the fuse and the fuse tube. The fuse is the core component of the fuse, usually made of metal materials with low melting point, easy to melt and good conductivity, such as lead-tin alloy, zinc, silver, etc. When the circuit is working normally, the fuse can conduct electricity normally to ensure the normal operation of the circuit. However, once an overload or short circuit fault occurs in the circuit, the current will increase sharply. At this time, the heat generated by the fuse will increase rapidly. When the heat reaches a certain level, the fuse will melt, thereby cutting off the circuit. This cutting process is completed automatically without human intervention. It can cut off the faulty circuit in a very short time, effectively protect the equipment in the circuit from damage by overcurrent, and avoid safety accidents such as fire caused by overheating.
Disconnector: "Breaker" of the Circuit
Isolator also plays a key role in the power system. It is a switching device without an arc extinguishing device, mainly used to provide a clear disconnection point in the circuit. The structure of the isolating switch is relatively simple, mainly consisting of an insulating base, a conductive part, a transmission mechanism, etc. In normal operation, the isolating switch can be used to connect or disconnect small currents in the circuit, such as the circuits of voltage transformers, lightning arresters and other equipment. However, when performing equipment overhaul or maintenance, the main role of the isolating switch becomes prominent. By operating the isolating switch, the equipment to be overhauled can be reliably isolated from the live parts to ensure the safety of the maintenance personnel. The operation of the isolating switch usually needs to be carried out under no-load conditions, because it does not have an arc extinguishing device and cannot withstand the impact of large currents. When operating the isolating switch, the operating procedures must be strictly followed to ensure the accuracy and safety of the operation.
Synergy between the two
Fuse and isolating switch cooperate with each other in the power system to jointly ensure the safe operation of the power system. The fuse is mainly responsible for quickly cutting off the circuit when a circuit fault occurs, playing a protective role; while the isolating switch is mainly used to provide isolation during equipment overhaul or maintenance to ensure the safety of personnel. In actual applications, fuses and isolating switches are usually installed at different positions in the circuit. For example, on the low-voltage side of the transformer, the fuse can be installed close to the transformer to protect the transformer from overcurrent damage; while the isolating switch can be installed between the transformer and the low-voltage busbar to provide isolation when repairing the transformer. By reasonably configuring the position and parameters of the fuse and isolating switch, the safety and reliability of the power system can be maximized.
In short, fuses and isolating switches are two indispensable devices in the power system. Although they differ in function and structure, they both provide important guarantees for the safe operation of the power system. Understanding their working principles and characteristics is of great significance for the maintenance and management of the power system.