Switchgear and Protection - restriking voltage
1 Answer
Switchgear refers to the collection of electrical devices used to control, protect, isolate, and manage electrical circuits and equipment. Protection in the context of switchgear refers to measures taken to prevent damage to equipment and ensure the safety of personnel in case of faults or abnormal conditions in an electrical system.
Restriking voltage, also known as re-ignition voltage or recovery voltage, is a term associated with high-voltage circuit breakers, which are a type of switchgear. When a circuit breaker interrupts a fault or opens a circuit, an arc is generated between the contacts due to the interruption of current flow. This arc is ionized gas that allows current to continue flowing through it. In order to completely extinguish this arc and prevent re-establishment of current flow, the circuit breaker relies on the dielectric strength of the insulating medium (usually air or a specialized gas).
Restriking voltage is the voltage that may reappear across the contacts of a circuit breaker after the main arc has been successfully interrupted. This occurs because the dielectric strength of the medium has not fully recovered immediately after the arc extinction. If the restriking voltage is too high, it could cause re-ignition of the arc, leading to a potentially dangerous situation, increased wear on the contacts, and damage to the equipment.
To prevent re-ignition of the arc, circuit breaker designs take into account factors such as the arc duration, contact material, and the dielectric strength of the medium. Some circuit breakers have mechanisms to ensure that the contacts remain apart until the restriking voltage has dropped to a safe level, thereby preventing re-ignition.
In summary, restriking voltage is a critical factor in the design and operation of circuit breakers within switchgear. Proper consideration and management of restriking voltage are essential for ensuring the reliable interruption of faults and maintaining the safety of electrical systems.
Restriking voltage, also known as re-ignition voltage or recovery voltage, is a term associated with high-voltage circuit breakers, which are a type of switchgear. When a circuit breaker interrupts a fault or opens a circuit, an arc is generated between the contacts due to the interruption of current flow. This arc is ionized gas that allows current to continue flowing through it. In order to completely extinguish this arc and prevent re-establishment of current flow, the circuit breaker relies on the dielectric strength of the insulating medium (usually air or a specialized gas).
Restriking voltage is the voltage that may reappear across the contacts of a circuit breaker after the main arc has been successfully interrupted. This occurs because the dielectric strength of the medium has not fully recovered immediately after the arc extinction. If the restriking voltage is too high, it could cause re-ignition of the arc, leading to a potentially dangerous situation, increased wear on the contacts, and damage to the equipment.
To prevent re-ignition of the arc, circuit breaker designs take into account factors such as the arc duration, contact material, and the dielectric strength of the medium. Some circuit breakers have mechanisms to ensure that the contacts remain apart until the restriking voltage has dropped to a safe level, thereby preventing re-ignition.
In summary, restriking voltage is a critical factor in the design and operation of circuit breakers within switchgear. Proper consideration and management of restriking voltage are essential for ensuring the reliable interruption of faults and maintaining the safety of electrical systems.