The features of designing mocb are to reduce requirement of oil, and. Bulk oil circuit breaker bulk oil circuit breaker or bocb is such types of circuit breakers where oil is used as arc quenching media as well as insulating media between current carrying contacts and earthed parts of the breaker. Different types of circuit breakers and its applications. Pdf performance examination of the bulk oil circuit breaker that is influenced by its parameters at the substation of bogor baru the state. The usual application for this mechanism is for highspeed reclosing duty, but it is some. The legendary cg make bulk oil circuit breaker bocb was a highly reliable product with world wide installations. Bulk oil circuit breaker free download as word doc. However there are other important, tested, safety enhancements that we believe are needed and that rps.
Used for switching any separate electric circuits and electric equipment in a power system it works in normal and. Disadvantage of the oil circuit breakers is the flammability of the oil, and the maintenance necessary i. In oil circuit breaker fixed contact and moving contact are immerged inside the insulating oil 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. Pdf types of circuit breaker and its application in. In bulk oil circuit breaker, oil performs mainly two functions. 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. Retrofitting solutions for brush bulk oil vsi type circuit breakers circuit breaker retrofit is a costeffective alternative to a complete switchgear replacement. Oil circuit breaker bulk and minimum oil circuit breaker electrical4u. Its basic function is to interrupt current flow after a fault is detected. Bulk oil circuit breakers bocb bulk oil circuit breaker or bocb is a such type of the circuit breakers where oil is used as. Which of the following circuit breakers is preferred for eht application a air blast circuit breakers b minimum oil circuit breakers c bulk oil circuit breakers d sf6 oil. 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. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset either manually or automatically to resume.
Oil circuit breaker electric arc insulator electricity. In oil circuit breaker fixed contact and moving contact are immerged inside the insulating oil 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. For bulk oil circuit breaker, we should check contact burning. Used for switching any separate electric circuits and electric equipment in a. The construction is simple and it consists of fixed and moving contacts enclosed in a strong weather tight earthed tank containing oil up to a certain level and an air cushion above the oil level. Bulk oil circuit breaker tank type circuit breakers are becoming obsolete and have been described here in brief. Abb vacuum retrofitting circuit breakers allow the bulk oil based apparatus to be removed, thereby eliminating the fire hazard. 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. Bulk oil circuit breaker electric arc vacuum scribd. The main components of an oil circuit breaker and how does. Bulk oil circuit breaker consumes a large amount of oil.
Boa breaker oil analysis oil circuit breaker sample data. This breaker makes use of oil for quenching the arc. Vacuum circuit breakersthese breakers use vacuum as the interrupting medium due. Technical paper a systematic approach to highvoltage. The bulk oil circuit breaker comprises an earthed tank which contains the contacts and arccontrol. The features of designing mocb is to reduce requirement of oil, and hence these breaker are called minimum oil circuit breaker. The tank type circuit breakers had 3 separate tanks for 72. Oil circuit breaker oil cbs are extensively employed in our power systems. The main components of an oil circuit breaker and how does it. In addition to its use as the arc extinguishing media, the oil serves as the insulating media between currentcarrying contacts and grounded parts of the breaker. In the bulk oil circuit breakers discussed so far, the oil has to perform two functions. Tank type or bulk oil circuit breaker now obsolete.
However, unlike bulk oil circuit breaker, a minimum oil circuit breaker places the interrupting unit in insulating chamber at live potential. Performance of bulk oil circuit breaker aip publishing. Minimum oil circuit breakers mocbcontruction,working. A circuit breaker must also be able to interrupt a wide variety of other currents at system voltage such as capacitive currents, small inductive. Bulk oil circuit breaker bocb in the bocb, oil is used to arc the quenching media and also for insulating media in between earth parts of circuit breaker and current carrying contacts. Jul 03, 2016 oil circuit breaker oil change and clean. The oil used here is same as transformer insulating oil. Inspection of the switching contacts which are in mint condition.
The major parts of a minimum oil circuit breaker excluding the poles are the base frame,the drive which is constructed as a stored energy opening and closing. However, unlike bulk oil circuit breaker, a minimum oil circuit breaker places. Jun 17, 2011 oil circuit breakeran oil circuit breaker is a highvoltage circuit breaker. Abb service experts conduct site audits on existing installations to asses the condition of the equipment, recommend the most suitable solution and technically support the most. Each of those tanks has about 2500 gallons of mineral oil. An oil circuit breaker operated by the type cas6 operating mechanism is closed by compressed air and opened by springs. The main components of an oil circuit breaker and how does it interrupt the arc this is a 230,000 volt circuit breaker. Also, the preferred technology is dependent on the geographical region in which it is applied. Pdf circuit breaker operational health assessment via.
In oil circuit breaker the fixed contact and moving contact are immerged inside the insulating oil. Actuator lever used to manually trip and reset the circuit breaker. The insulating oil is available only in interrupting chamber. Oil circuit breaker minimum oil circuit breakers wholesaler. Which of the following circuit breakers is preferred for eht application a air blast circuit breakers b minimum oil circuit breakers c bulk oil circuit breakers d sf6 oil circuit breakers.
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. Low minimum oil circuit breaker your electrical guide. Application, advantages and disadvantages of all types of. Mineral oil has better insulating property than air. 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. Retrofitting solutions for brush bulkoil vsi type circuit. So, it is called as an arc extinction chamber or current interruption chamber of minimum oil circuit breaker mocb. Oil circuit breaker diagram types of oil circuit breaker.
The quantity of oil required is reduced considerably. In cross blast interrupters, the arc is drawn in front of several lateral vents. It is pneumatically tripfree on automatic operation and mechanically tripfree on hand closing. Bulk oil circuit breakers dead tank design in these circuit breakers oil content is used for arc extinction and also for insulating live parts from the. Since oil pressure developed is independent of the fault current to be interrupted, the performance at low currents is more consistent than with selfblast oil circuit breakers. Case in point, dead tank sf6 filled circuit breakers and bulk oil circuit breakers are primarily used in north america in hv applications, while the rest of the world. The circuit breaker should be operated electrically from local and remote then mechanically from local. Both are widely applied with the former being traditionally used in the usa and the uk and the latter in continental europe.
But insulating material is available in the interrupting. The gas formed by the arc causes high pressure inside the arc control device. The are control device is fitted to the upper to the upper fixed contact. The retrofit of the oil circuit breaker with the rps vacuum unit obviously results in a significant improvement in operator safety and business risk, by removing old oil filled circuit breakers from the substation. Low oil circuit breaker, mocb circuit breaker, minimum oil circuit breakers, minimum oil cb, pdf. The oil circuit breaker is the one of the oldest type of circuit breakers. In figa the arc control device between the fixed and moving contacts is not shown, so making the sketch even simpler. A breaker which uses a large quantity of oil for arc extinction is called a bulk oil circuit breaker. The basic construction of bulk oil circuit breaker is quite simple. New oil inserted metering and protection current transformers in rear of. International surveys on circuitbreaker reliability data for substation and system studies. Over the years, bocb was slowly discarded from the industry due to their high maintenance cost. Aug 09, 2018 the circuit breaker should be operated electrically from local and remote then mechanically from local. Oil circuit breaker article about oil circuit breaker by.
Oil circuit breakerit uses oil as an interrupting and insulating medium. Failures are rare, but where they involve the ignition of oil the results are usually catastrophic. Moisture in oil astm d1533 microscopy dielectric breakdown astm d1816 other interfacial tension astm d971 acid number astm d974 colorvisual exam astm d1500d1524 title. In bulk oil circuit breaker the contacts of being immersed in the oil so the oil is used for two purposes one is the extinction of arc and other is to provide the insulation between the contacts, therefore there is a huge amount of oil required which increased the cost.
A highvoltage circuit breaker in which the arc is drawn in oil to dissipate the heat and extinguish the arc. Principal electrical engineer tennessee valley authority senior member, ieee. There is no special system for arc control other than the increase in length caused by the separation of contacts. For 36 kv and below, single tank construction, phase barriers were provided between phase. This type of circuit breaker uses a steel tank containing oil and the contacts are immersed in the oil. Oil circuit breakers breaker service substation spare. Also indicates the status of the circuit breaker on or offtripped. These breakers are divided into two types based on the pressure and amount of oil used. Bulk oil and minimum oil circuit breaker bulk oil circuit breaker.
Bulk oil circuit breaker construction of bulk oil circuit breaker. Ignition of the oil often results in a rupture of the switch oil chamber. The minimum oil circuit breaker will place the interrupting unit in an insulating chamber at the live potential. Firstly, it acts as an arc extinguishing medium and secondly, it insulates the live parts of the breaker from earth. Circuit breaker technology varies depending on the application. The are extinction process is carried out in the upper chamber. Oil circuit breakers types, working and construction. The quantity of oil requires for arc extinction is only about onetenth of the total and the rest being used for the insulation. Such type of circuit breaker is also known as dead tanktype circuit breaker because their tank is held at ground potential. On the other hand, low oil circuit breaker only uses less oil compared to the bulk oil. Figure 4a 66 kv oil circuit breaker figure 4b bulk oil.
This chamber houses an arc control device, an upper fixed contact and a ring shaped lower fixed contact. Oil circuit breakeran oil circuit breaker is a highvoltage circuit breaker. Jle pole, single throw, oil circuit breaker enclosed in a common tank. Circuit breaker is a mechanical switching device capable of making, carrying and breaking current under. The thermal portion of the circuit breaker provides a time response feature, that trips the circuit breaker sooner for larger over currents but allows smaller overloads to persist for a longer time. This type of operation makes the breaker more reliable by removing any coating developed between sliding surfaces. Transmission and distribution oil circuit breaker retro. Be sure the circuit breaker and its mechanism are disconnected from all electric power, both high voltage and control voltage, before it is inspected or repaired. These types of circuit breakers utilize oil as the interrupting media. The use of the wellproven vd4 type circuit breaker allows the performances available with the abb switchgear to be extended, even for products made by other manufacturers. After the circuit breaker has been disconnected from the. Abb vacuum retrofitting circuit breakers allow the bulkoil based apparatus to be removed, thereby eliminating the fire hazard. Retrofitting solutions for brush bulkoil vsi type circuit breakers circuit breaker retrofit is a costeffective alternative to a complete switchgear replacement.
Here arc energy is used to crack the oil molecules, hydrogen gas may be generated which can be used to sweep, cool and compress the arc plasma and so deionize it in a selfextinguishing process. Pdf performance of bulk oil circuit breaker bocb influenced by. Different types of circuit breakers and its applications elprocus. Bulk oil circuit breaker or bocb is such types of circuit breakers where oil is used as arc quenching media as well as insulating media between current carrying contacts and earthed parts of the breaker. The circuit breaker which uses more oil or which is bulky is called bulk oil circuit breaker. Circuit breaker operational health assessment via condition monitoring data. Apr 16, 2017 they were used 5070 years ago in high voltage. The quantity of oil requires for arc extinction is only about onetenth of the. It consists of current carrying contacts enclosed in a strong, weathertight earth metal tank and the tank is filled with transformer oil. The bulkoil circuitbreaker comprises an earthed tank which contains the contacts and arccontrol.
Electrical test equipment application solutions from megger. New oil inserted metering and protection current transformers in rear of panel. This allows short current spikes such as are produced when a motor or other nonresistive load is switched on. Exhaust the pressure from air receiver of any compressed air circuit breaker before it is inspected or re paired. Firstly, it acts as an arc extinguishing medium and secondly, it insulates the live parts of the breaker.