Bulk oil circuit breaker
A bulk oil circuit breaker (BOCB) is a type of high-voltage circuit breaker that uses a bulk oil as the arc-quenching medium to extinguish the arc that forms when the breaker opens. BOCBs are commonly used in power systems with voltages above 72 kV.
Here's how a BOCB works:
- When the breaker is closed, the contacts are in contact with each other, and the circuit is closed.
- When the breaker is opened, the contacts separate, and an arc forms between them.
- The arc is sustained by the flow of current through the circuit.
- The bulk oil in the breaker's tank is designed to quench the arc by rapidly cooling it and preventing it from reigniting.
- The oil is pumped into the arc chamber, where it flows around the arc and extinguishes it.
- The breaker's contacts are then separated, and the circuit is opened.
BOCBs have several advantages, including:
- High interrupting capacity: BOCBs can interrupt high currents and voltages without breaking down.
- Low maintenance: BOCBs require less maintenance than other types of circuit breakers, as they do not have moving parts that can wear out.
- High reliability: BOCBs are highly reliable and can operate for many years without failure.
- Low cost: BOCBs are generally less expensive than other types of circuit breakers.
However, BOCBs also have some disadvantages, including:
- Limited flexibility: BOCBs are designed for specific voltage and current ratings, and cannot be easily adapted for use in other applications.
- Limited fault current handling: BOCBs are designed to handle specific fault currents, and may not be able to handle higher fault currents.
- Limited environmental flexibility: BOCBs are sensitive to environmental conditions, such as temperature and humidity, and may not perform well in extreme conditions.
Some common applications for BOCBs include:
- Power transmission systems: BOCBs are commonly used in power transmission systems to protect against faults and ensure reliable operation.
- Power distribution systems: BOCBs are also used in power distribution systems to protect against faults and ensure reliable operation.
- Industrial power systems: BOCBs are used in industrial power systems to protect against faults and ensure reliable operation.
Some common types of BOCBs include:
- Dead-tank BOCBs: These are the most common type of BOCB, and are designed for use in power transmission and distribution systems.
- Live-tank BOCBs: These are designed for use in power transmission systems, and are typically used in applications where the breaker is located outdoors.
- Hybrid BOCBs: These combine the benefits of dead-tank and live-tank BOCBs, and are designed for use in a wide range of applications.
Overall, BOCBs are an important component of modern power systems, and play a critical role in ensuring reliable and efficient operation.