Electrical Power System Design of High-Rise Residential

ELECTRICAL POWER SYSTEM DESIGN OF HIGH-RISE RESIDENTIAL/COMMERCIAL CONDOMINIUM BUILDING By: By: Engr. Engr. Emiliano G. Marabulas,PE Marabulas,PEE E

The development of the electrical power system design of high-rise residential and/commercial condominium building is long and tedious. However, in this presentation, the developmen ment is in summary form.

It inclu cludes the the follo llowing: 1. Review of the applicable provisions of codes, laws, and regulations that have jurisdiction over the elect electric rical al Inst Install allat atio ions. ns. A.) A.) Philip lippin pine Elec lectric rical Code Part art 2009 Most of the provisions needed are in chapter 1,2,3,4, ,4, and and art articl icle 6.95.

B.) New Elec lectric rical Engine ineering ing Law Some of the provisions needed are in sections 26,31,32, and 34. C.) National Building Code (PD 1096) D.) Distribution Service Open Access Rules (DSOAR) of the Energy Regulatory Commission (ERC) Some of the provisions needed are those for connec nectio tion point, and serv serviice dro drops.

2. Coordination Works The requirements of of design shall be coordinated with the architect/owner, the engineers involve involve the electric utility, utility, and the government government agencies having jurisdiction over the electrical works. 3. Development Development of the Design Criteria These are agreements of the t he architect/owner and all engineering disciplines regarding data other the mandatory man datory requirements of laws, ordinances, codes, etc.

4. Development of the Design A.) Notes It is assumed that the electrical engineer knows already how to design the electrical system of a single occupancy residential building. B.) Study of the Architectural drawings This is determination whether the area, space, location, other requirements are adequate for the electrical equipment, devices, and mat materia rials to be ins install alled. ed.

C.) Single Line Diagram This is a drawing which shows all the major components of the electrical system. The single line diagram is usually prepared after the detailed computations. However in this presentation, it is shown ahead so that we will be guided where in the particular system the comput mputa atio tion is referr erred to:

D. Computation (Residential) 1. Sub Service Entrance per Floor a.) Compute for the total connected load of each unit b.) Add the total connected load for each floor c.) Compute for the current based on the number of units in each floor and the demand factor sho shown in Table 2.20.4.5 d.) Determine the size of subservice entrance conductors, conduits and protective device based on the computed current.

2. Main Service Entrance a.) Add the connected loads of all the units. b.) Compute for the total current based on the total number of units and the demand factor shown in Table 2.20.4.5 c.) Determine the size of the main service entrance conductors, conductors, conduits or busduct and a protective protective device based on the computed current.

E. Computations (Commercial) Basically the process of computations is simi simillar to the the computation ions for resid sidential F. Comput Computati ations ons (Adminis (Administr trati ation) on) 1. Ligh ighting ing and Convenience nce Outl utlets Basically the process of computations is sim similar to the the computa utation ion for resid sident ential ial

2. Elevators (motor-generator set) (a) Branch Circuit a. Size of conductors and conduits Current=Full load current of the motor (Table 4.30.14.4) multip tiplied by 140% for intermittent duty cycle [Table 4.30.2.2(e)] plus 125% of  othe otherr continu tinuo ous load load curr curren ents ts.. With this value of current, the size of   condu nductors and condui duits can be determ ermine ined.

b. Protective Device The size of the protective device is based on the full load current multiplied by the percentage as shown in Table 4.30.4.2 plus other continuous loads.

(b) Feeder Circuit a. Size of Conductors and Conduits Current=Sum of the full load of all the motors mul multip tiplie lied 140% [Tabl able 4.30 .30.2.2 2.2 (e)] mul multip tiplie lied by demand factor based on the number of   elevator motors (Table 6.20.2.4) plus 125% of  the the other contin tinuou uous loads With this value of current, the size of   condu nductors and condui duits can be determ ermined ned

b. Protective Device The rating of the protective device shall not be greater than the protective device of the highest noted elevator elevator motor plus the sum of the full load current of the remaining motor motor plus other continuous loads as section 6.20.7(c).

(b) (b) Over Overcu curr rren entt Prot Protec ecti tiv ve Devi Device ce With the horsepower rating and code letter, the protective device is determined by the kilo-volt ampere per horsepower as shown in Table 4.30. 4.30.1.7 1.7(b) (b)

3. Fire Pump and Pressure Pump (a) Branc anch Circuit The size of conductors and conduits Current= Full load current multiplied by 125% with the value of current, the size of   conducto ctors and condu nduits can be det determine ined

(b) (b) Over Overcu curr rren entt Prot Protec ecti tiv ve Devi Device ce With the horsepower rating and code letter, the protective device is determined by the kilo-volt ampere per horsepower as shown in Table 4.30. 4.30.1.7 1.7(b) (b)

Current= Current= kilo-vo kilo-volt lt ampere x horsepowe horsepowerr rating rating horsepower horsepower of the fire pump divided by [square root of 3 times line lin e to line voltage (KV)] With the value of current, the rating of the protective protective device can be determined. (c) Overload Protection Protection The power circuit shall be provided with automatic protection against overload

4. Other motors Other motors shall be considered as ordinary motors. 5. Main Service Entrance (a) Size of conductors and conduits The current shall consider all the demand loads of the feeders, subfeeders, subfeeders, and branch, including the application of the 125%.

(b) Overcurrent Protective Device With the value of current and the rating of the protective device of the highest rated motor, the main service entrance protective protective device can be determined

G. Comp Comput utat atio ions ns (Vol (Volttage age Drop) op) With the value of current and the impedance of each part of the circuits, the voltage drop can be computed. H. Compu omputtatio tions (Sho (Short rt Circu ircuit it Curr urrent) ent) With the value of available short circuit capacity at the area, the impedance of the transformer, the impedance of the lines, and the motor contributions, the short circuit current at any point can be computed.

I. Compu Computa tati tion onss (Emer (Emerge gency ncy/S /Sta tand ndby by gene generrat ator or)) The generator shall carry all the loads as per design criteria. The starting of locked rotor current shal shalll also be consi nsidered.

J. Develo elopmen pmentt of Ligh Lighti ting ng Pro Protecti ectio on System 1. Con Conventio entiona nall This is computing the number of air terminals and determining the materials based on height as per Table 2.90.3.5, grounding electrodes, and others to complete the system

2. Enhanced Enhanced lightning protection system ma be used provided it is approved by the authority having jurisdiction or listed by an organization that is also approved

K. Preparation of of all necessary documents With all of the above. The plans, single line diagram, specifications, and other documents as required by PEC 1 2009 can be prepared.