Design, Assembly and Quality Testing of Feeder Panel

To design the feeder panel according to the load and requirement of the consumer preparing the general arrangement diagram and the wiring diagram. According to the general arrangement assembling of Bus bars, Circuit breaker and MCCB. Also drawing of wire for the control of the panel and for the power to the control circuit. Quality testing for checking for the requirement to be achieved for the consumer. Keywords— Designing, Assembling, Quality testing.


I. INTRODUCTION
The feeder panel is used for the distribution of the power for different uses and as per the requirement of consumer. It is also used for the interconnection between the different supply and also synchronism with the diesel generator sets as the backup supply. The feeder panel generally consists of MCCB's for the distributions to the output ranging from 16Amp to 630Amps and the ACB's for the incoming lines and the output ranging from 630Amp to 3200Amp. For controlling of the panel we use the Contactors, push buttons, selector switches as per the requirement. With all the controlling and power components for the manipulation of the supply indication and metering are also installed in the panel like light bulbs for different applications and with the Voltmeters, Ampermeters, MFM, CT's, etc.
The following are the General sections of a feeder panel:-➢ Incomer section (TR) ➢ Bus-coupler section (BC) ➢ Output section (O/P) In above general sections of the feeder panel the Bus-coupler section is been the removed or added more as per the application or the number of incoming sections II. GENRAL OVER VIEW The design of the feeder panel starts from the requriments and Single line diagram sent from the consumer. The work starts from the making list of the components, designing of the shell of the panel (fabrication) and electrical designing, to be used to meet the requirement of the consumer. After the Fabrication is completed as per the design, the assembling of the components is been completed component like MCCB's, Circuit breakers, Meters, Indications for Phases(R, Y, B), Current transformers. The wires are drawn for metering, Control Circuit, Power Circuit. After the completion of the assembling of the panel the Quality testing of the panel is done by the Q.C and the panel is dispatched for the installation at the site.
III. DESIGNING The designing is the first step of the production of the panel for designing there are some components that are necessary for it the following are as below:-➢ The requirement sent by the receiver of the panel ➢ The single line diagram including incoming line outgoing line for the applications ➢ The make list for the components to be used ➢ The rateing of the I/P lines and the applications After receiving the above information we should start the design process as per the requirement sent by the consumer. We the designer decide the placement of the bus bar as per the space available for the panel installation and the quantity of the bus bar as per the cost of the production of the panel. The above tables are of the standard used for the design of the outer shell and the width of the panel.
The above dimensions are without any metering and with basic indications like on off status indication. The dimensions will change and will be increased with addition of the meters, selector switches and extra indication of status.

▪ MCB
The MCB box is to be selected as the number of the MCB's the following is the common size to be used the height of the box is fixed to the 250mm but the width will increase as the quantity. If there are 2 MCB's the width selected is 300mm and the width will increase as the quantity like 3 MCB's the width will be increased to 400mm. Now if the line of the MCB is increased the height for 2 line will be 400mm, 3line will be 550mm and 4 line will be 700mm. The line of the MCB should not be more then 4 line it is the general rule for the switch board using MCB's. So, according to formula as per IEC-62271-1 ▪ K = K 1 *K 2 *K 3 *K 4 *K 5 *K 6 K = 1*1*1*0.8*1*1 =0.8 Rated current I = Total 'K' factor * Main Formula 1250Amp=0.8*Main Formula Main formula derived value will be = 1562.5Amp Rated Current=0.8*1562.5 =1250Amp

II. Selection of the Bus Bars
▪ To carry the current of 1066.72Amp one runner of 80*10 mm of copper is enough.

III. Wiring of the panel
The feeder panel consists of 2 type of wiring as follows:-▪ Control wiring. ▪ Power wiring.
The wiring is been design as per the requirement of the consumer. The control wiring includes the indication and metering of the panel, the bus coupler wiring is also important and the auto manual operation selector wiring is a part of the control wiring. The power wiring includes the wiring of the control feeder for the power the wires are generally taken from the bus bar.  ▪ The auto manual indicates the breaker would be operated by the push buttons in case of manual operations and in case of auto operation the breaker operates by the supply to the breaker directly and if the selector switch is on the auto and the breaker should not operate by the push buttons. ▪ This is the last step for the designing after this step the fabricators start the fabrication work as per the approved drawing of the outbox (Shell).

IV.
Assembly ▪ Installation of the equipment in the shell finished with powder coating and ready to be assembled. The breakers are been installed in 2 parts the cradle case and the contacts box. When the installation of the ACB and MCCB is been completed the bus bar are been sent for the making as per the design. The fabrication of the bus bar is been done in some steps. ▪ The following steps shows the steps of the bus bar fabrication:-I. Selecting the size of bus bar as per the specifications of the design. II.
Measuring the length of the bus bar and marking the bends. III.
Making any one bus bar for checking the accessibility in the bus duct and to the ACB or MCCB.

IV.
Approving the bus bar by the designer as a sample if not change in bend and change in length if any changes needed from the designed bus bar. V.
Approved from the designer making of the same sets for all 3 phases as per the approved sample. VI.
Fitting the bus bar in the panel with the help of supporters and spacers as the specified area. VII.
Tighten the face plate and connect the bus bar sections with each other connecting the bus couplers with the other 2 sides of the bus coupler. Checking the tightness of the all the parts of the bus bar connected with the bolt and nut.
• Wiring:-The wiring is the most important part of the panel because the controlling of the panel and some low power transmission is also done through wire. The control wiring is usual done with 2.5 Sq mm copper wire or the 1.5 Sq mm copper wire. We have to draw the wire as per the designed diagram in the panel and select the wire as specified by the designer. The contactors are used for the interlocking the panel in auto or manual mode. The contacts of the ACB are being also connected as per the wiring diagram. The connection of the CT's is been done to the meter for the metering of the panel. ▪ There are some extra accessories to the ACB and MCCB from its already included parts some of the parts are mentioned below. I. Secondary isolating contact and electrical position indicator and cradle secondary isolating contact block. II.
Volt-meteric releases for U-power ACB III.
Closing coil for U-power ACB IV.
Mechanical type door inter lock V.
Operation counter for U-power ACB ▪ There are also some Supplementary modules used to provide addition protection to basic protection and control circuit are listed below The earthing strip is been installed at the bottom of the panel made of copper generally the green wire is been connected between the door and the frame of the panel as earthing.
• Quality Testing ▪ The last process of the panel fabrication is to check the panel meets the requirement of the consumer. There are some test listed below for checking the quality of the panel after the process of assembly is been completed.

Testing of breaker operation
The supply is given to the breaker and the operation of opening and closing was performed multiple times. The breaker should perform the tripping and connecting operation successfully without any problem. At the time of trip condition the current should be zero and in the connected condition rated current must be noted.

▪ Testing of interlocking condition
The panel is given supply and by selecting the manual mode the ON-OFF condition of the breaker would be checked as the table. The condition should be satisfy in any mode the breaker in a interlock condition should not be operated like if TR-1 is in off condition and the interlock condition is satisfy then the TR-1 should not be turned on in any mode.

▪ Contact resistance test
This test is performed by the contact resistance kit. The kit has an auto transformer and a resistance meter like meggar to get the resistance between the contacts of a bus bar with another contact of the bus bar with the face plate in the connection between 2 contact. The resistance should not be more then 0.2micro-ohm.  The maximum temperature reach after 4 hours is 74.6 o C and is are under 90 o C. The ambient temperature was 30 o C. • CONCLUSION This paper has described the process of building Feeder panel from designing of the panel to the testing of panel. This paper also includes the designing parameters to be considered will designing of any rating of feeder panel. We can build any rateing of feeder panel with help of above given data.