Protecting equipment against damage caused by overcurrent is the primary function of liquid-type fuses, which are sometimes referred to as high-voltage expulsion fuses. These fuses are a sort of protective device that is employed in electrical power systems. The ability to limit current and interrupt arcs is provided by these fuses by the utilization of a liquid medium, which is commonly oil or a specific insulating liquid. In high-voltage applications, where dependable protection is necessary, liquid-type fuses are frequently used as the circuit-breaker of choice.
The Working Principles Are As Follows:
The interruption of the fault current and the provision of protection for the electrical system are both accomplished through the exploitation of a liquid medium in the operation of fuses of the liquid-type. When there is an overcurrent circumstance, such as a short circuit or an excessive load, the fuse will work to restrict the amplitude of the current and avoid damage to the connected equipment. This is done to prevent the fuse from blowing.
The following actions can be considered a synopsis of how a liquid-type fuse performs its function:
Normal Operation The state of the liquid-type fuse will remain closed during normal working conditions. This will allow current to flow through the fuse and into the circuit that is being protected. The liquid medium that is contained within the fuse has reached a state of quiescence, and there has been no appreciable rise of pressure.
Fault Condition: When a condition of overcurrent exists, the magnitude of the current flows through the fuse at a rate that is more than its rated value. This causes the fuse to begin its activity, which interrupts the flow of the fault current and protects the system. The flow of the fault current through the fuse generates heat, which in turn causes the liquid medium to vaporize. This process is referred to as “vaporization.” The vaporization process results in the formation of a gas bubble with a high pressure all the way around the faulted area. The high-pressure gas bubble quickly expands, which causes the arc to get longer and longer as it goes through the process of extinction. This elongation, in conjunction with the cooling impact that the evaporated liquid exerts, contributes to the arc’s eventual extinguishment.
Current Interruption: The drawn-out arc will, at some point, lose its heat and go out, which will cause an interruption in the fault current. The liquid-type fuse is an excellent method for limiting the size of the current to an acceptable level, hence protecting the connected apparatus.
A Liquid-Type Fuse Consists of the Following Components:
The following is a list of the essential components that make up a liquid-type fuse and contribute to its operation as well as its protection capabilities:
Element de Fuse: The fuse element is a conducting material, which is commonly made of copper or silver, and it has a particular geometry that is designed to manage the rated current. It is the component’s job to carry the normal current and, in the event of a malfunction, cause the component to melt in order to break the circuit.
Liquid Medium: The liquid medium that is employed in liquid-type fuses plays an essential part in arc quenching and the interruption of current flow. It is chosen because of the dielectric qualities it possesses, as well as its thermal stability and arc extinction capabilities. Mineral oil, silicone oil, or a blend of mineral oil and other additives are examples of liquids that are utilized frequently.
Expulsion System: The expulsion system is built to quickly remove any ionized gases and vaporized liquids that have been produced as a result of the fault state. In most cases, it takes the form of a vent or nozzle through which the high-pressure gases are released, making it possible to successfully extinguish an arc.
Container for the Fuse: The container for the fuse offers mechanical support as well as insulation for the fuse element as well as any other components. In order for it to be resistant to high voltage, it is typically constructed out of porcelain or some other suitable insulating material.
Benefits Associated with Liquid-Type Fuses:
Effective Current Limiting: Liquid-type fuses provide good current-limiting capabilities, ensuring that fault currents are immediately terminated and controlled to a safe level. These fuses are known for their excellent current-limiting characteristics. This assists in preventing damage to equipment and minimizes the chance of electrical fires occurring.
High Voltage Ratings: Liquid-type fuses are often used in high-voltage applications because they may be configured to handle large voltage levels, thereby safeguarding important and sensitive electrical equipment. Liquid-type fuses are the most popular form of fuse used in high-voltage applications.
Arc Suppression That Is Dependable The utilization of a liquid media allows for effective arc suppression and extinction, which guarantees