Introduction to circuit breaker in the power system operation it is often desirable and necessary to break or interrupt the various devices or transmission lines under normal and abnormal conditions. Oil circuit breaker ocb working principle, construction. The working principle of this breaker is rather different from those in any other types of circuit breakers. The features of designing mocb is to reduce requirement of oil, and hence these breaker are called minimum oil circuit breaker. Application, advantages and disadvantages of all types of. Circuit breakers are used in nearly all electrical systems from residential dwellings to electric utility facilities. Oil circuit breaker bulk and minimum oil circuit breaker electrical4u.
An automatic circuit breaker makes and breaks the electrical circuits satisfactorily under normal. Whenever there is a separation of current carrying contacts in the oil, the arc in circuit breaker is initialized at the moment of separation of contacts, and due to this arc the oil is vaporized and decomposed in mostly hydrogen gas and. The oil is utilized primarily as the interrupting media, unlike in a bulk oil circuit breaker where the oil is. Oil circuit breaker bulk and minimum oil circuit breaker. All circuit breaker systems have common features in their operation, but details vary substantially depending on the voltage class, current rating and type of the circuit breaker. Suppose if the breaker is closed initially to make the circuit, if any fault occurs in the circuit or if the operator wanted to open it then the logic signal energizes the trip relay which separates the two contacts by moving the moving coil distant to the fixed coil. Circuit breaker working principle animation instrumentation. Mineral oil has better insulating property than air. It operates in air where airblast as an arc quenching medium at atmospheric pressure to protect the connected electric circuits. Safe operation and maintenance of circuit breakers and switchgear. The maximum voltage per interrupter is 100 kv for airblast and sf6 breakers, 170 kv for minimum oil breakers. Firstly, it acts as an arc extinguishing medium and secondly, it insulates the live parts of the breaker from earth. The vacuum cb is fast in operation so ideal for fault clearing. If the circuit remains complete, the closing spring would discharge under the wrong conditions, this is called pumping.
A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. In the earlier days switches and fuses are used for this purpose to break or close the contact. Electrical test equipment application solutions from megger. Bulk oil circuit breakers often use oil or resinimpregnatedpaper capacitivegraded bushings that are equipped with tap electrodes and have cts mounted on the lower ground sleeve. Automatic circuit breakers, which are generally used for the protection of electrical circuits, are equipped with a trip coil connected to a relay designed to open the circuit breaker automatically under abnormal conditions such as a short circuit. Oil circuit breaker shipping the types f11 and f22 oil circuit breakers are built on the unit basis, i. It has only one chance to operate each time a fault occurs and if it fails to trip, serious damage may result. Accident experience has proven that the majority of switchgear failures occur during or shortly after an operation. Application, advantages and disadvantages of oil, minimum oil, air blast, sulfur hexafluoride, vacuum circuit breaker. Comparing to the sf6 circuit breaker and vacuum circuit breaker, air blast circuit breaker are seldom used nowadays. By this the fresh oil will enter into the gap between the contact from all directions and the gases moves upwards. Performance examination of the bulk oil circuit breaker that is influenced by its parameters. Oil circuit breakers breaker service substation spare.
Oil circuit breaker ocb working principle, construction and. In bulk oil circuit breaker, oil performs mainly two functions. And their subdivision is also discussed along with advantages and disadvantages. Instruction book oil circuit breaker types f11 and f22.
The oil used here is same as transformer insulating oil. Fast reclosing time with pneumatic mech anism permits reestablishment of circuits before parts of the power system fall out of. A sufficient head of oil above the arcing contacts is necessary to provide enough oil pressure at the arc and to prevent the occurrence of the chimney effect. Opening the circuit breaker breaks the path of current flow and the motor stops. In addition to recommended circuit breaker tests, these bushings should be isolated and tested. Lecture notes on veer surendra sai university of technology. Air circuit breaker types of acbs, operation and applications. They assure that the cb is operating within the correct parameters to clear a fault. The oil circuit breaker ocb is highly efficient and there is a. The insulating oil is available only in interrupting chamber. Whenever there is a separation of current carrying contacts in the oil, the arc in circuit breaker is initialized at the moment of separation of contacts. A circuit breaker is an automaticallyoperated electrical switch designed to protect an electrical circuit from damage caused by overload of electricity or short circuit. A circuit breaker is a protective device which can break the circuit automatically under the fault condition.
Reclosing the breaker after the breaker has opened. Air circuit breaker, sf6 circuit breaker, vacuum circuit breaker, and oil circuit breaker have been discussed in a short detailed just to understand the basic concept about these circuit breakers. The usual application for this mechanism is for highspeed reclosing duty, but it is some. Air blast circuit breaker construction, working and types. Power circuit breakers insulating oil and oil handling. The quantity of oil requires in bulk oil circuit breaker depends on the system voltage. Selection of most suitable design can be made to suit appli cation requirements. This enhances the safety of the operating personnel.
Safe operation and maintenance of circuit breakers and. Whenever there is a separation of current carrying contacts in the oil, the arc is initialized at the moment of separation of contacts, and due to this arc the oil is vaporized and decomposed in. It is pneumatically tripfree on automatic operation and mechanically tripfree on hand closing. Routine trip testing should be performed every 3 to 5 years. There is no special system for arc control other than the increase in length caused by the separation of contacts. Oil circuit breaker article about oil circuit breaker by. This switch is used with almost all westinghousetype aa mechanisms. In the ussr, tanktype oil circuit breakers are manufactured for voltages from 6 to 220 kilovolts kv.
For indoor applications, minimum oil circuit breakers can be used upto 36 kv. Sep 22, 2017 oil circuit breaker in hindicb, circuit breakers in hindi,electrical in hindi, electrical mantra. As the contacts are present in the dielectric oil, the oil surrounding the arc attains a high temperature and thus decomposes the releasing gases. The circuit breaker must first detect a fault condition. Therefore the antipump relay prevents the spring from doing the following. Hv circuit breaker type generator circuit breaker fkga8 generator circuit breaker i sc 210 ka u r 33 kv sf 6 circuit breaker designed for power plants from 700 to 1,500 mw it is equipped with a springoperated mechanism per pole.
Oil circuit breakers types, working and construction. When the circuit breaker is closed, a complete path for current exists between the voltage source and the motor allowing the motor to run. This is based on the operator requirement whether the circuit should be closed or opened at the initial case. Minimum oil circuit breakers operate very fast and are used in transmission networks and substations. The circuit breaker is now ready for normal operation warning. In this type of circuit, breaker oil is used, but mineral oil is preferable. Circuit breaker working principle your electrical guide. Pdf reliabilitybased preventive maintenance of oil circuit. For voltages of 10 kv or less and breaking currents of 15 ka or less, all three poles of the oil circuit breaker are located in the same tank. Aug 09, 2018 the circuit breaker should be operated electrically from local and remote then mechanically from local. For effective recloser operation, oil must be reconditioned or replaced before it deteriorates beyond a safe level. A circuit breakers function is to detect a fault condition and, by interrupting continuity, to immediately. Sep 15, 2017 i hope ki ye video dekhne ke bad apko pata lag jayega ki oil circuit breaker kya hai, inka working principle kya hai, construction kaisa or or maintenance kaise hota hai. When replacing the tank and refilling it with oil, be sure the gaskets are.
Air circuit breaker acb is an electrical protection device used for short circuit and overcurrent protection up to 15kv with amperes rating of 800a to 10ka. Oil circuit breaker in hindicb,circuit breakers in hindi,electrical in hindi, electrical mantra. Avoid operating the breaker any more than necessary without oil in the tank as it is designed to operate in oil and. I hope ki ye video dekhne ke bad apko pata lag jayega ki oil circuit breaker kya hai, inka working principle kya hai, construction kaisa or or maintenance kaise hota hai. The breaker tank is tightly bolted to a foundation to bear out vibrations produced at the time of operation of the circuit breaker. The oil is both acts as an arc extinguishing medium and as an insulator between the live part and earth. Under normal operating conditions, the fixed and moving contacts remain closed and the breaker carries the normal circuit current.
Description operation the type w recloser is a selfcontained device that senses single or threephase fault currents and interrupts simultaneously all three phases of a distribution circuit. Plain break oil circuit breakers a plainbreak oil circuit breaker involves the simple process of separating the contacts under the whole of the oil in the tank. An oil circuit breaker operated by the type cas6 operating mechanism is closed by compressed air and opened by springs. Vacuum circuit breaker construction, working and its. Its basic function is to interrupt current flow after a fault is detected. The circuit breaker should be operated electrically from local and remote then mechanically from local. Sf6 circuit breaker type hc operating mechanism english pdf manual oil circuit breaker sbk 12 k 250, sbk 24 k 500 english pdf manual oil circuit breaker sbk 36 mc, sbk 36 n 1500 english pdf manual oil circuit breaker sbk 7,2 mc 350, sbk 24 n english pdf manual. Highvoltage circuit breaker the main task of a circuit breaker is to interrupt fault currents and to isolate faulted parts of the system. Different types of circuit breakers and its applications. Apr, 2017 plain break oil circuit breakers a plainbreak oil circuit breaker involves the simple process of separating the contacts under the whole of the oil in the tank. The main components of an oil circuit breaker and how does. Elden in 1898 installed at the boston electric light company l street plant later boston edison open tank with upward motion operation. The operation of oil circuit breaker is quite simple lets have a discussion. When the current carrying contacts in the oil are separated an arc is.
These types of circuit breakers utilize oil as the interrupting media. This toggle mechanism is the quickmake, quickbreak type, meaning that the speed with which the contacts snap open or close is independent of how fast the handle is moved. A breaker which uses a large quantity of oil for arc extinction is called a bulk oil circuit breaker. For bulk oil circuit breaker, we should check contact burning. However, unlike bulk oil circuit breaker, a minimum oil circuit breaker places the interrupting unit in insulating chamber at live potential. Such type of circuit breaker is also known as dead tanktype circuit breaker because their tank is held at ground potential. The high voltage circuit breaker has three major components. Different types of circuit breakers and its applications elprocus. The concept operation of the oil circuit breaker is simple compared to the. Circuit breaker operation in the following illustration, an ac motor is connected through a circuit breaker to a voltage source. If the timing of the cb is too slow, it will fail to protect the equipment it is assigned to guard. A circuit breaker must also be able to interrupt a wide variety of other currents at system voltage such as capacitive currents, small inductive currents, and load currents. In small mains and low voltage circuit breakers, this is usually done within the device itself. A plainbreak oil circuit breaker is a bulk oil circuit breaker which involves the simple process of separating the contacts under the whole of the oil in the tank.
Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset either manually or automatically to resume. We rely on them to protect our systems from damaging overcurrents and short circuits. Oct 01, 2017 on the other hand, low oil circuit breaker only uses less oil compared to the bulk oil circuit breaker 4. Each of those tanks has about 2500 gallons of mineral oil. It consists of current carrying contacts enclosed in a strong, weathertight earth metal tank and the tank is filled with transformer oil. Circuit breaker introduction and operating principle ece. This type of circuit breaker has been used earlier for open terminal hv application, for system voltages of 245 kv, and 400 kv up to 765 kv, especially where faster breaker operation was required. Avoid operating the breaker any more than necessary without oil in the tank as it is designed to operate in oil and mechanical damage can result from excessive operation without it. Unlike oil circuit breaker ocb or air blast circuit breaker abcb, the explosion of vcb is avoided. A circuit breaker must be kept in good condition if the expected performance is to be obtained.
Oil circuit breakerclassification of circuit breakers. This type of operation makes the breaker more reliable by removing any coating developed between sliding surfaces. A dielectric failure to tank was reported on a westinghouse 345kv, type gw oil circuit breaker late in december 1968. Maintenance procedures for mediumvoltage oil circuit breakers 4 4. The quantity of oil requires for arc extinction is only about onetenth of the total and the rest being used for the insulation.
To ensure its reliable operation, the bocb should be continnuously. The circuit breaker can make or break the circuit either manually or by remote control. Air blast circuit breaker employs a highpressure air blast as an arc quenching medium. The construction and working of different types of air blast circuit breakers are explained in this article. Figure 1 shows the catastrophic nature of an oil circuit breaker failure with figure 2 showing an sf6vacuum circuit breaker failure for comparison. In this article, the different types of circuit breakers, i.
The main components of an oil circuit breaker and how does it. Pdf types of circuit breaker and its application in. Vacuum circuit breaker construction, working and its applicatons. Actuator lever used to manually trip and reset the circuit breaker. Each as sembly is inspected, operated and tested before packing to be sure it is correct. Operating principle of minimum oil circuit breaker whenever the moving contact is drawn out of the. Air circuit breakers acb the circuit breaker which operates in air at atmospheric pressure. Performance of bulk oil circuit breaker aip publishing. These types of circuit breakers are of the livetank design and require only a small amount of oil.