ISSN: 2277-3754 ISO 9001:2008 Certified International Journal of Engineering and Innovative Technology (IJEIT) Volume 4, Issue 2, August 2014 148 Design, Construction and Simulation of a Circuit- Breaker Based Feeder Pillar with over current And Earth-Fault Protection Cum Digitalized Voltmeter Azuatalam 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, Nigeria Abstract -This research embodies the design, construction and simulation of a feeder pillar (415VAC) with over-current, overload and earth-fault protection with the aid of a phase sequence relay, contactor, earth-leakage circuit breaker and three-phase overload relay. The analog voltmeters in the various bus-bars (red, yellow and blue phases) in a conventional feeder pillar is replaced with a digital panel voltmeter indicating the voltage across a phase (240V) or line- to-line (415VAC) flowing through the bus-bars. The major reason for this research study is to prevent the constant changing of fuses. It also provides sufficient protection in electric power distribution, and easy identification of faults when encountered. The feeder pillar not only distributes power through the channels but also protects the transformer against damage through the use of the earth-leakage circuit breakers as well as miniature circuit breakers. The panel of the feeder is well earthed against lightning surges that can bring about damage to the distributing system. I. INTRODUCTION A feeder pillar is essential in a power system distribution network to distribute electric power (three- phase, 415V ac) from a step-down transformer to the low-tension (LT) lines for the consumers. A default feeder pillar consists of a panel which embodies all other sub-units of the feeder pillar, bus-bars in which are connected the incoming and outgoing lines, an ammeter which records the voltage across the bus-bars, the fuse holders holds the fuses, high-rupturing-capacity fuses for making contact and for protection purposes [1,2]. This project consists of all mentioned above but with a digitalized voltmeter and a phase sequence relay, earth- leakage circuit breaker, three phase overload relay and a contactor used for over-current, overload and earth-fault protection. This will solve the problem of constantly changing the fuses when it blows due to excessive current. The circuit breakers will operate on all conditions (on-load and no-load conditions). This set up protects the transformer from direct faults from the feeder pillar and from the feeder pillar to the 415V LT lines, protecting the bus-bars (incoming and outgoing circuit) [2]. II. DESIGN OBJECTIVES The purpose of the design of the feeder pillar is to enhance power system protection by introducing relay and breaker instead of high-rupturing capacity fuses, then change the analogue meter to a digital meter and finally introduce a phase monitor to observe the power in the three-phase in case there is a phase failure in the system.The design of the feeder is done in such a way that restoring of power after fault has occurred will be easy such that after fault is cleared, breakers can be put in normal position to restore power. Also, the system is designed in such a way that there will be easy discrimination. After the source, the bus bar is connected next, then the contactor controlled by a switch.The contactor feeds the phase monitor and three-pole circuit breaker which in turn supplies power to the electric- leakage circuit breaker.Itis then referenced to the single pole circuit breaker which then controls the load and the overload relay [3]. The phase monitor indicates the sequence of the three lines of the source. The feeder pillar is made up of some major parameters that enables it performance. These parameters include the phase sequence relay, the overload indicator, the contactor which energizes the load, the three-pole circuit breaker which 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, the two-pole switch for the ON and OFF of the voltage meter, the bus chamber which contains the bus bars, the glands used to pass the wires and the cables used for interconnections of these components in the feeder pillar [4]. All these components are used to achieve the purpose of the feeder pillar construction that is to ensure the availability of an appropriate protection. III. DESIGN SPECIFICATIONS The design specification include the bus of the bus bars which is 54.5cm by 33.5 cm by 23cm and the steel plate for mounting the earth-leakage circuit breakers, contactors, breakers, phase monitors and overload relay is 55.0cm by 11.5cm, the base holder is 111.0cm by 3.5cm which is in two pairs and the bus bars are 9.0cm by 2cm. The ratings of the electric leakage circuit breaker is 60A, for single-pole circuit breaker is 10A, the three-pole miniature circuit breaker is 15A, a phase sequence or phase monitor is included, a three-phase digital meter is also used to indicate single phase with 220V-240V and line-to-line with a value of 415V. Overload relay is added, the cable ratings and capacity for the three core armor is 6mm 2 . The electric leakage circuit breaker outlet is 1.5mm 2 , from the contactor to the three-pole circuit breaker is 2.5mm 2 , the earthing cables are 6mm and 1.5mm and the earth rod length is 121cm.