Design, Construction And Simulation Of A Circuit- Breaker .

ISSN: 2277-3754ISO 9001:2008 CertifiedInternational Journal of Engineering and Innovative Technology (IJEIT)Volume 4, Issue 2, August 2014Design, Construction and Simulation of a CircuitBreaker Based Feeder Pillar with over current AndEarth-Fault Protection Cum Digitalized VoltmeterAzuatalam D.T., Diala U.H., Iwuchukwu U.C., Joe-Uzuegbu C.K., Morah F.C. and Ayalogu E.I.Dept. of Electrical and Electronic Engineering, Federal University of Technology Owerri, Imo State, Nigeriathree-phase in case there is a phase failure in thesystem.The design of the feeder is done in such a waythat restoring of power after fault has occurred will beeasy such that after fault is cleared, breakers can be put innormal position to restore power. Also, the system isdesigned in such a way that there will be easydiscrimination. After the source, the bus bar is connectednext, then the contactor controlled by a switch.Thecontactor feeds the phase monitor and three-pole circuitbreaker which in turn supplies power to the electricleakage circuit breaker.Itis then referenced to the singlepole circuit breaker which then controls the load and theoverload relay [3]. The phase monitor indicates thesequence of the three lines of the source. The feeder pillaris made up of some major parameters that enables itperformance. These parameters include the phasesequence relay, the overload indicator, the contactorwhich energizes the load, the three-pole circuit breakerwhich injects power into the earth-leakage circuit breaker,the earth-leakage circuit breaker used to indicate faults,the digital panel meter for reading voltage ranges, thetwo-pole switch for the ON and OFF of the voltagemeter, the bus chamber which contains the bus bars, theglands used to pass the wires and the cables used forinterconnections of these components in the feeder pillar[4]. All these components are used to achieve the purposeof the feeder pillar construction that is to ensure theavailability of an appropriate protection.Abstract -This research embodies the design, constructionand simulation of a feeder pillar (415VAC) with over-current,overload and earth-fault protection with the aid of a phasesequence relay, contactor, earth-leakage circuit breaker andthree-phase overload relay. The analog voltmeters in thevarious bus-bars (red, yellow and blue phases) in aconventional feeder pillar is replaced with a digital panelvoltmeter indicating the voltage across a phase (240V) or lineto-line (415VAC) flowing through the bus-bars. The majorreason for this research study is to prevent the constantchanging of fuses. It also provides sufficient protection inelectric power distribution, and easy identification of faultswhen encountered. The feeder pillar not only distributes powerthrough the channels but also protects the transformer againstdamage through the use of the earth-leakage circuit breakersas well as miniature circuit breakers. The panel of the feederis well earthed against lightning surges that can bring aboutdamage to the distributing system.I. INTRODUCTIONA feeder pillar is essential in a power systemdistribution network to distribute electric power (threephase, 415V ac) from a step-down transformer to thelow-tension (LT) lines for the consumers. A defaultfeeder pillar consists of a panel which embodies all othersub-units of the feeder pillar, bus-bars in which areconnected the incoming and outgoing lines, an ammeterwhich records the voltage across the bus-bars, the fuseholders holds the fuses, high-rupturing-capacity fuses formaking contact and for protection purposes [1,2]. Thisproject consists of all mentioned above but with adigitalized voltmeter and a phase sequence relay, earthleakage circuit breaker, three phase overload relay and acontactor used for over-current, overload and earth-faultprotection. This will solve the problem of constantlychanging the fuses when it blows due to excessivecurrent. The circuit breakers will operate on all conditions(on-load and no-load conditions). This set up protects thetransformer from direct faults from the feeder pillar andfrom the feeder pillar to the 415V LT lines, protecting thebus-bars (incoming and outgoing circuit) [2].III. DESIGN SPECIFICATIONSThe design specification include the bus of the bus barswhich is 54.5cm by 33.5 cm by 23cm and the steel platefor mounting the earth-leakage circuit breakers,contactors, breakers, phase monitors and overload relayis 55.0cm by 11.5cm, the base holder is 111.0cm by3.5cm which is in two pairs and the bus bars are 9.0cm by2cm. The ratings of the electric leakage circuit breaker is60A, for single-pole circuit breaker is 10A, the three-poleminiature circuit breaker is 15A, a phase sequence orphase monitor is included, a three-phase digital meter isalso used to indicate single phase with 220V-240V andline-to-line with a value of 415V. Overload relay isadded, the cable ratings and capacity for the three corearmor is 6mm2. The electric leakage circuit breaker outletis 1.5mm2, from the contactor to the three-pole circuitbreaker is 2.5mm2, the earthing cables are 6mm and1.5mm and the earth rod length is 121cm.II. DESIGN OBJECTIVESThe purpose of the design of the feeder pillar is toenhance power system protection by introducing relayand breaker instead of high-rupturing capacity fuses, thenchange the analogue meter to a digital meter and finallyintroduce a phase monitor to observe the power in the148

ISSN: 2277-3754ISO 9001:2008 CertifiedInternational Journal of Engineering and Innovative Technology (IJEIT)Volume 4, Issue 2, August 5" 12.6"18.8"Fig 1: Side view of project work and earth rod.BLOCK DIAGRAM OF THE SYSTEMFig 2: General Block Diagram of Project Work.(with required ratings and sizes), followed by the detailedconstruction which included welding of metal parts, cablelogging, cutting and sizing of cables (of different sizes),mounting of components and wiring [5,6,7]. Afterconstruction, different tests were carried out to ensurethat the wiring and all, was okay. The behavior of thesystem was modeled using sim power systems software inIV. METHODOLOGYFaults occurring in the LT lines and feeder pillars of adistribution system necessitate the constant changing ofHRC fuses. MCBs when used in place of these fuses donot require constant changing. This was the driving forcefor delving into this research.The first step made was toidentify and to purchase the materials/components needed149

ISSN: 2277-3754ISO 9001:2008 CertifiedInternational Journal of Engineering and Innovative Technology (IJEIT)Volume 4, Issue 2, August 2014MATLAB for normal and abnormal (fault) conditionsIV. The design of the contactor is done in such a way thatthe contactor contains the main contacts and the auxiliaryand results were properly recorded. The alternatingcontacts which feed the whole set-up like the three-polecurrent source is got from the step-down transformer.circuit breaker and three phase monitor.This three-phase source is then connected to the busV. The three-pole circuit breaker is energized to feed thebars.Next are the switch and then the voltmeter. Thedifferent electric leakage circuit breaker with the sameswitch controls the contactor and the contactor suppliesamperage rating.power to the three-pole miniature, the phase monitor andVI. The phase monitor is designed in such a way as tothe electric leakage circuit.The ELCB is thereafterdesignate the status of the three different phases and isreferenced to the single-pole circuit breakers for eachindicated by showing the red light if the three-phase isphases, then the load and the over load relay areoperational, but it is not active if the three-phase is notcontrolled by the electric leakage circuit breaker andactive.single-pole breaker [8,9].VII. Electric leakage circuit breaker is designed in a wayas to detect earth fault at any interval of fault andV. DESIGN OF EACH BLOCK OR MODULE OFdiscriminate immediately so as to isolate fault. Also overTHE SYSTEMcurrent and short circuit can be detected by this circuitI. The voltage source, comprising of three-phasebreaker.supply, is obtained from the transformer after beingVIII. Single-pole circuit breaker is also referenced to thestepped down and collected from the secondary bushingselectric leakage circuit breaker so as to isolate withof the transformer.capacities of whatever load will be attached to the system.II. The design of the bus bar is such that the bars canIX. The load consists of the consumers in the differentwithstand voltages with pressure from the secondary pathlocations, with different appliances whether inductive,of the transformer, mostly voltages of 220-240V withoutcapacitive or resistive loads consuming power from theburning up.feeder.III. The switch is present to control the whole contact andX. The overload relay indicates overload which trips thethe whole system in large.It is designed to ON and OFFelectric leakage circuit breaker, that is used mostly whereas a phase is connected to the contactor terminal.reservoirs is installed with automatic control as the floatsignals the circuit breaker to trip on its own [10,11].SIMULATION OF THE DESIGNED SYSTEM USING SIMPOWERSYSTEMS (MATLAB)1. Simulation with one breaker, three-phase measurement and no faultContinuouspowergui v-Voltage MeasurementScope 1-1.943bCcCThree -Phase SourceDisplay 1Three -Phase Breaker Distributed Parameters LineAVabcIabcBaThree -PhaseSeries RLC LoadScope 3bCcThree -PhaseV-I Measurement1.558 v-Voltage Measurement 1Display 2Scope v-Voltage Measurement 2Scope 20.3727DisplayFig 3: Simulation with one breaker and no fault.150CaBBABAA

ISSN: 2277-3754ISO 9001:2008 CertifiedInternational Journal of Engineering and Innovative Technology (IJEIT)Volume 4, Issue 2, August 2014Fig 4: Voltage and Current signal for all three phases.2. Simulation with one breaker, three-phase measurement and fault before first breakerContinuouspowergui v-Scope 1Voltage MeasurementThree -Phase SourceaBbCcThree -Phase Breaker Distributed Parameters LineAVabcCCABBADisplay 1AIabcBaThree -PhaseSeries RLC LoadScope 3bCcThree -PhaseV -I MeasurementA v-Voltage Measurement 1BDisplay 2ScopeVoltage Measurement 2CThree -Phase Fault v-Scope 2DisplayFig 5: Simulation with one breaker, three-phase measurement and fault before first breaker.Fig 6: Voltage and current signal with fault before load.151

ISSN: 2277-3754ISO 9001:2008 CertifiedInternational Journal of Engineering and Innovative Technology (IJEIT)Volume 4, Issue 2, August 20143. Simulation with one breaker and fault before the breakerContinuous powerguii-Scope 3Current Measurement -Display 3vScope 1Voltage MeasurementbCcCThree -Phase SourceThree -Phase BreakerDistributed Parameters LineCaBAABBDisplay 1AThree -PhaseSeries RLC LoadABCThree -Phase Fault -vVoltage Measurement -1Display 2ScopevVoltage Measurement2Scope 2DisplayFig 7: Simulation with one breaker and fault before the breaker.Fig 8: Current signal with fault before breaker.Fig 9: Voltage signal with fault before breaker.but alsoefficient and cost-effective when utilized in thepower system.Its protection must be total to includeearth-leakage protection. With the best choice of suitableMiniature Circuit Breakers and ELCBs, the faults arewell cleared and on time before it cause any damageVI. CONCLUSION AND RECOMMENDATIONThe principal objective of this workwas to design acircuit-breaker based feeder pillar that will offer adequateprotection to a transformer sub-station feeder pillarsystem. The constructed work must not only be reliable,152