Circuit breaker: loyal guard of power system
In modern power system, circuit breaker is a vital equipment. It is like a loyal guard, silently guarding the safe and stable operation of power network. Whether it is large motor equipment in industrial production or household electricity in daily life, circuit breaker plays an indispensable role in it.
- Basic principle of circuit breaker
The core working principle of circuit breaker is based on the monitoring and control of circuit current. When the circuit is operating normally, the current flows smoothly within the rated range, and the circuit breaker is in a closed state, like an unobstructed road, allowing the current to pass smoothly and provide power support for various electrical equipment. However, once an abnormal situation occurs in the circuit, such as overload or short circuit, the current will increase sharply in an instant. At this time, the induction device inside the circuit breaker will quickly detect this abnormal current change and trigger the tripping mechanism. The tripping mechanism is like a precise switch lock. It acts immediately after receiving the abnormal signal, separating the contacts of the circuit breaker, thereby cutting off the circuit. This process is extremely fast and can isolate the fault circuit from the power supply in a very short time, effectively preventing excessive current from causing further damage to electrical equipment and avoiding serious safety accidents such as fire.
- Main types of circuit breakers
With the continuous development of power technology, the types of circuit breakers are becoming increasingly diverse to meet the needs of different power systems and application scenarios. Among them, the more common ones are vacuum circuit breakers, SF6 circuit breakers,Indoor circuit breakers and Outdoor circuit breakers.
Definition and installation environment:
Indoor circuit breakers are switchgear installed in the electrical system inside a building. It is mainly used to protect indoor electrical lines and equipment to prevent electrical faults such as overload and short circuit from causing damage to the lines and equipment. It is usually installed in places where indoor electrical equipment is concentrated, such as residential, office buildings, factory workshops and other indoor environments.
Protection performance:
The protection level is relatively low because its working environment is relatively stable and there is no risk of severe weather. Generally, the main consideration is to prevent dust, small animals from contacting, etc. For example, some small circuit breakers for residential use will have a casing to prevent dust accumulation from affecting performance.
Size and appearance:
Usually the appearance is more regular and the size is relatively small, which is convenient for installation and arrangement in limited spaces such as indoor distribution boxes. Its design will also consider the coordination with the indoor environment, and the color and shape may be relatively simple.
Operation method:
It is easy to operate, and some can directly manually operate the handle to control the on and off of the circuit. At the same time, some indoor circuit breakers also have remote control functions, which can be remotely operated through smart meters or smart home systems.
Application scenarios:
In the home, it is used to protect various branches such as lighting circuits and socket circuits to prevent fires caused by electrical overload (such as multiple high-power electrical appliances in use at the same time) and line short circuit (such as wire damage causing live and neutral wires to contact). In office buildings, it is used to protect the power supply lines of office equipment, such as circuits of computers, printers and other equipment.
Definition and installation environment:
Outdoor circuit breakers are mainly installed outside buildings or in outdoor power facilities for the protection and control of outdoor power lines. Commonly found in substations, utility poles, outdoor distribution boxes and other locations, exposed to the natural environment, and subject to the test of various weather conditions.
Protection performance:
It has a high level of protection and can withstand harsh natural conditions such as rain, wind and sand, ultraviolet rays, and extreme temperatures. For example, its outer shell is generally made of waterproof, rust-proof, and corrosion-resistant materials with good sealing performance to ensure that the internal electrical components are not affected by the external environment.
Size and appearance:
The size may be larger because it needs to have higher insulation performance and heat dissipation capacity. The appearance is relatively sturdy and heavy to adapt to the physical impact of the outdoor environment and long-term use. The color is usually eye-catching, such as yellow or red, which is easy to identify and maintain in outdoor environments.
Operation method:
The operating mechanism is relatively complex. In addition to manual operation, it may also be equipped with an electric operating mechanism to facilitate remote control or quick operation in an emergency. In addition, due to the particularity of its working environment, the operating mechanism usually has the function of preventing misoperation.
Application scenario:
In substations, it is used to control and protect high-voltage transmission lines. When a line fails, it can quickly cut off the circuit to protect the safety of the entire power system. In outdoor distribution boxes, it is used to distribute and protect the power supply lines of outdoor electrical equipment such as street lights and landscape lighting to ensure that these equipment can operate normally in complex outdoor environments.
Vacuum circuit breakers use a vacuum environment to extinguish the arc. Since there is no medium such as air in a vacuum, the arc is difficult to maintain, so the arc extinguishing performance is better. It has the characteristics of small size, long life, and easy maintenance. It occupies an important position in medium-voltage power systems and is often used in substations, factory power distribution and other places.
SF6 circuit breakers use sulfur hexafluoride (SF6) gas as arc extinguishing and insulating medium. SF6 gas has excellent insulation and arc extinguishing properties, and can quickly and effectively extinguish arcs under high voltage and high current conditions. This type of circuit breaker is suitable for high-voltage and ultra-high-voltage power systems, such as large substations, transmission lines, etc., and plays a key role in ensuring the reliability of long-distance and large-capacity power transmission.
- The important role of circuit breakers in power systems
Protecting electrical equipment:
During the operation of the power system, electrical equipment may be impacted by fault currents such as overload and short circuit due to various reasons. The circuit breaker can detect these abnormal conditions in time and quickly cut off the circuit to isolate the faulty equipment from the power supply, thereby avoiding damage to the equipment due to long-term overcurrent, extending the service life of the electrical equipment, and reducing the cost of equipment maintenance and replacement.
Ensuring the stability of the power system:
The power system is a complex network with various parts that are interrelated and affect each other. When a fault occurs in a certain area, if the fault circuit cannot be isolated in time, the fault current may spread to the entire power system, resulting in a large-scale power outage, which seriously affects social production and people's lives. The rapid action of the circuit breaker can limit the fault to the minimum range, prevent the spread of the fault, maintain the normal operation of other parts of the power system, and ensure the stability and reliability of the power system.
Facilitate the maintenance and overhaul of the power system:
When the power system needs maintenance, overhaul or equipment update, the circuit breaker can easily cut off the power supply of a specific area or equipment, provide a safe operating environment for the staff, and avoid the safety risks of working under power. At the same time, through the operation of the circuit breaker, the operation mode of the power system can be flexibly adjusted to achieve the reasonable distribution and control of the power load.