DESIGN BASIS REPORT
ELECTRICAL
HOTEL BUILDING FOR Mrs. SAHIBJAN
SERVICES CONSULTANT
#1, Adithya Apartments,
Kowdiar, Trivandrum – 695003
Table 1: Revision History
"Revision "Date " Description "
"R0 "28.12.2016 " INITIAL "
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" " "Table 2: Approval " " "
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"Date "Sumanam Engineering"CLIENT " " "
" "Services Consultant" "Remarks " "
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"Sl. "LIST OF CONTENT "PAGE NO "
"No " " "
"1.0 "GENERAL "04 "
"2.0 "LOAD ESTIMATION "05 "
"3.0 "LOAD CALCULATION "06 "
"4.0 "PRIMARY POWER SUPPLY "07 "
"5.0 "SELECTION OF TRANSFORMER "08 "
"6.0 "SELECTION OF GENERATOR "08 "
"7.0 "DISTRIBUTION OF POWER "09 "
"8.0 "UPS "10 "
9.0 EARTHING & LIGTHNING PROTECTION 11
10.0 CABLES 11
11.0 WIRING 12
12.0 HALLWAY LIGHTING 12
13.0 OCCUPANCY SENSOR 13
1.0 GENERAL
The Building
The proposed hotel project IS at Eenchakal, Trivandrum.
Total built up area is approximately 3299 Sqm. The building consists
of two basements, Ground + 4 Floors and terrace. The master plan for
the project consists of the following.
"Floor Details "No of rooms "Area "
" Basement " Car Parking - 11 Nos "501.00 "
" Mezzanine basement " Car Parking - 11 Nos "501.00 "
" Ground floor " Kitchen, restaurant, Reception & "421.20 "
" "Lobby " "
" First floor " 6 Roo,+ Boad room + Banquet Hall "421.20 "
" Second floor " 10 Room + 1 Suit room "421.20 "
" Third floor " 10 Room + 1 Suit room "421.20 "
" Fourth floor " 10 Room + 1 Suit room "421.20 "
" Terrace " Open restaurant / Services "191.34 "
" Total Area (Sqm) "3,299.34 "
2. ELECTRICAL SYSTEMS
A. CODES AND STANDARDS
The Electrical system design is conformed to the requirements of the
following Standards:
a. Indian Electricity Rules.
b. National Electrical Code of India.
c. National Building Code of India (NBC).
d. Applicable standards issued by the Bureau of Indian Standards
(BIS)
e. Regulations of local fire authorities.
f. Requirements stipulated by Pollution Control Board for noise,
air & water pollution.
B. ELECTRICAL LOAD ESTIMATION
Lighting
Lighting for the proposed project is designed as per the norms of
National Electric Code (NEC), National Building Code (NBC) and Bureau
of Indian Standards (BIS) and standards set out by Starwood Hotels.
Lighting system is designed based on the following criteria:
a. Visual Performance
b. Visual Comfort
c. Energy Efficiency & Conservation
d. Cost Effectiveness
e. Maintenance factor
Additional local lightings are provided in each place to suit the
location and purpose.
The lighting level details for different types of areas are tabulated
below.
"Sl. No "Areas "Lux level "
"1 "Office Rooms "300-350 Lux "
"2 "Meeting Room "300-450 Lux "
"3 "Corridor "150 Lux "
"4 "Board Room/GM Room "400-500 Lux "
"5 "Hotel Guest room "50-100 Lux "
"6 "Common area "150-200 Lux "
"7 "Toilets "100 Lux "
Load Calculation
The split up of the load calculation is as follows:-.
"STARWOOD HOTELS "
"Abstract Load Chart "
" "
"Location " Raw Power " UPS Power " Total Load"
" " " " "
"Seventh Floor including "92 "1 "93 "
"HVAC " " " "
"Sixth Floor including "99 "1 "100 "
"HVAC " " " "
"Fifth Floor including HVAC"94 "1 "95 "
"Fourth Floor including "97 "1 "98 "
"HVAC " " " "
"Third Floor including HVAC"97 "1 "98 "
"Second Floor including "106 "1 "107 "
"HVAC " " " "
"First Floor including HVAC"329 "4 "333 "
"+ Kitchen " " " "
"Mezzanine + HVAC "32 "3 "35 "
"Ground Floor "117 "8 "125 "
"Landscape Lighting "5 " "5 "
" " " "
"AC Load " "600 "
"Plumbing Load " "178 "
"Fire " "124 "
"Lift Load " "63 "
"Future Expansion " "420 "
"Total Load "2474 "
Demand Factor and Power Factor
The electrical load of the Hotel is estimated with the following
technical parameters considering the green building concept:
Transformer:
Demand Factor = 0.6
Power Factor = 0.95
Maximum demand calculated as 1563 kVA
Therefore we recommend for two Transformers of 1000 kVA each.
Back up power with Diesel Generators:
Demand Factor = 0.5
Power Factor = 0.8
Max demand is 1280 kVA
Diesel generator selected is 625 kVA one number, 400kVA one number and
250 kVA one number which gives better flexibility.
C. PRIMARY POWER SUPPLY
11kV power is to be brought from the nearest supply point using
3Cx300sqmm 11 KV XLPE Aluminium UG cable to an RMU unit which will be
located in the premises of the building. Even if in future a secondary
connection is needed the same can be taken from the RMU unit. From the
RMU, supply is fed to the HT panel located in the electrical room (MEP
room). There are two numbers of 11kV/433V 1000-kVA dry type cast resin
transformer with OLTC and RTCC. A spare VCB can be provided in the HT
panel for precaution.
D. GUEST ROOM DESIGN DETAILS
There are 120 guest rooms and 24 floating cottages. Sufficient number
of power sockets for the following are considered. Hairdryers, coffee
maker, mini refrigerator, Iron box, mobile and music system power out
let, TV and DVD points, set off box, data and telephone points etc All
the switches/sockets provided will be as per visual aesthetics and as
per requirement of Star wood specification and requirements. i.e., all
the electrical cords will be concealed from guest view which can be
attained by coordinating with the guestroom furnishing plan. A duplex
electrical outlet is provided for the refreshment center. The
compatibility of all the light fixtures and other necessary electrical
co – related equipments like lampshade, saddle socket and the power
ratings will be thoroughly checked. Automation for guest rooms will
be as per Starwood Design Requirements incorporating occupancy sensors
where required. Light points and power points inside the guest rooms
is given as per Starwood design requirements and additional with need.
Electronic in-room control system is considered for the guest rooms
using low voltage system.
E. SELECTION OF TRANSFORMER
The transformers selected are two numbers of 1000 kVA dry type as per
the regulations and the calculations shown above. The transformers are
with OLTC, which maintains constant/stabilized voltage at all times
using RTTC. This will enable healthy working of electrical and
electronic equipments connected to the system. The system uses an AVR
to sense the LV voltage and adjust the tapping as required in order to
obtain a constant voltage output. The RTCC (remote tap changer
controller) sends signal to trigger the tap changing mechanism. The
transformers are of dry type and hence can be placed in the electrical
room inside the MEP block.
F. SELECTION OF GENERATORS
The backup proposed for the hotel is considered as full backup
including HVAC system.
There will be provision for fuel storage, having a capacity of a
minimum of 48 hours running at full load so as to avoid hassles. An
ideal location for the Generator set installation after considering
features like noise, vibration, exhaust emissions, and heat removal is
adjacent to the MEP room. As per the present load calculation three
numbers of diesel generator sets of 625 kVA, 400 kVA and one number
250 kVA are proposed by considering the flexibility of the load
requirements. For any future requirements a provision for connecting
one more DG in the future is considered.
The arrangement of the Generators set will be such that it will not
cause any hindrance to the safe evacuation of the building under
emergency conditions.
In the event of failure of grid supply, multiple generators will start
as per the loads from time to time. The automatic switching and the
load sharing will be controlled by the PLC system. The diesel
generators are having factory made acoustic enclosures with a reduced
noise level less than 70db at a distance of one meter from the
acoustic enclosure.
G. DISTRIBUTION OF POWER
The power from the transformers is fed to the main panel using
Aluminium bus bar trunking. Both the transformers are coupled in Main
Panel using bus couplers considering redundancy. Even if one
transformer fails, almost 85 % of the maximum demand can be loaded in
the other transformer. Bus Risers are used to provide internal
distribution of power in the block from second floor to seventh floor
avoiding bulk cables to be run inside the hotel building. The main
panel distributes power to the sub panels for sub distribution. These
are located in strategic load centres. Common Service Panel providing
power to fire, lift and plumbing services is located in the MEP block
itself. HVAC panel is fed from the main panel and will be located in
the MEP room itself. MCCB Load banks used for distributing power in
each guest room floors are placed in service corridors as no
electrical room is provided in the floors. Separate Distribution board
is provided for each guest rooms with RCBO protection. The main HVAC
load as calculated is fed with Aluminium bus bar feeders from the main
panel. Schematic drawing is provided for closer review and
understanding. The DG supply is fed to the main panel after
synchronising using PLC panel. Siemens make relays or DIYFE relays are
used for the purpose of synchronization. CPRI approved vendors will be
fabricating all the panels. Mostly we are proposing to source factory
made panels. All panels shall be incorporated with integrated
automated extinguisher system utilising a sensing wire.
To maintain the power factor at 0.95, APFC panels are used. These
panels will have harmonic filters to reduce the third harmonic
percentage to the acceptable limit. As two numbers of transformers are
used we have included two APFC panels. With standard calculation two
numbers 300 kVAr APFC panels are proposed which can handle future
requirements also. Capacitors shall be split in step of 100 kVAr x 1 +
50 kVAr x 3 + 25 kVAr x 2.
For distributing power to health club, cottages and external lighting
dedicated feeder pillars are considered. The power distribution for
floating cottages and floating restaurant are through dedicated feeder
pillars also, which are provided in the shore at a suitable location
so that water flooding will not be affected. From there submersible
copper cables will be used for sub-distribution. As currently we are
not planning to construct these cottages, additional spares are
provided in the main panel to accommodate for their loads in the
future. For this one of the transformers is loaded slightly lightly so
as to handle future loads. This can be seen in the schematic layout.
H. Uninterrupted Power supply
UPS system protects critical equipments against over voltage, under
voltage and electrical noise and allows systems to safely shutdown
during prolonged blackouts. An Uninterrupted Power Supply (UPS) System
delivers clean continuous uninterrupted power to all electrical
appliances. They cater for all staircase lighting; IT rooms, mainly
when calamities like staircase shutdown occur. Here, a few light
points are considered in common areas such as corridors, kitchen and
restaurants. All computers in the office spaces and other areas are
powered by UPS backup. Signages, router and CCTV camera power and all
staircase lights are also considered in UPS load. Emergency light
points powered by UPS are also considered in guest rooms as per
Starwood Design requirement. Parallel redundant UPS system is
considered for the project. A separate dedicated UPS shall be
provided for the server.
I. EARTHING AND LIGHTNING PROTECTION
Earthing is done as per IS 3043, IS 2309, IEC 62305 part3, IEC 60364,
IEC 62561 part 2, IS 3043. Earthing electrodes are designed based on
the fault level of the premises. Earth electrode proposed is Cu pipe
of required size. In general, electrode by using earth rods of
required size for both LT and HT sides are proposed to draw fault
current to the earth. All the electrical earth pits are linked
together for dissipation of current during lightning.
Lightning arrester is of prime importance to safe guard the entire
building at the time of heavy lightning strokes. The external
lightning protection is carried out as per IS 2309. Horizontal
conductors and down conductors are made of GI. Test joints are
provided 2.7m above the ground level. All the lightning earth pits
are linked together for better dissipation of current during thunder.
Air terminals based on coverage shall be provided in the roof of the
building to draw the lightning to earth infecting any tall structures
in the roof of the building.
The transformer neutrals will be solidly earthed.
The DG neutrals will be earthed through Neutral Grounding
Resistor.
The overall earth resistance will be limited to less than one
Ohm.
All earthing systems will be interconnected in the ground.
As per IS 2309, smaller of the values of down conductor calculated
based on base area and perimeter of the building is taken for
lightning protection:
One down conductor for 100 sqm, and one down conductor for each 300
sqm or part thereof of the area in excess of 100 sqm or one for each
20 m of the perimeter of the building whichever is less.
Lightning arrester is of prime importance to safe guard the entire
building at the time of heavy lightning strokes. The external
lightning protection is carried out as per IS 2309. Special lighting
protection will be provided for floating cottages like Early Streamer
method or placing a higher pole near to the cottage.
J. Surge Protection:
Lightning protection can be done using surge diverters. A surge
protection devise (or surge suppressor) is an appliance designed to
protect electrical devices from voltage spikes. A surge protector
attempts to limit the voltage supplied to an electric device by either
blocking or by shorting to ground any unwanted voltages above a safe
threshold. All electrical panels used for the project shall be
incorporated with surge diverters.
K. CABLES
The cables proposed are of XLPE insulated armoured aluminium/copper
cables. For UPS distribution flexible copper cables are considered and
the neutral wire provided is the same as phase wire. Design of
distribution cable system is done so as to achieve voltage drop of not
exceeding 3% to the farthest cable termination. Submersible three
phase four wire copper flexible cables are proposed to connect the
floating cottages, floating restaurant power.
L. WIRING
The wiring shall be as per IS 732. The wires shall be Fire Retardant
Low Smoke (FRLS) PVC insulated copper conductor run in 20/25/32mm
thick MS/PVC conduit. The color coding for wires shall be:
Phase: Red, Yellow, Blue
Neutral: Black
Earth: Green
The cross sectional area of wire/cable will be 2.5 Sq. mm. for
workstation, pantry and lighting circuit mains (Load not exceeding
10A).
M. HALLWAY/COMMON AREA LIGHTING
Energy-efficient LED light bulbs are selected appropriate for hotels.
For lights that need to stay on all day every day, switching to more
energy-efficient lighting options can result in significant savings.
Outdated high bay metal halide, in the pool room and outdoor areas
can be replaced with smaller, more energy-efficient LED fixtures.
Occupancy sensors are also incorporated to save even more energy.
OCCUPANCY SENSORS
Stairwells and corridors, toilet areas which are not occupied
continuously, yet they require continuous illumination. This provides
an energy saving opportunity that can be implemented by leaving some
lamps on continuously, while controlling others with occupancy
sensors. Occupancy sensors are mounted on walls or ceilings and wired
to control one or more fixtures.
Technology
Occupancy sensors rely on different technologies to detect the
presence of occupants.
Passive Infrared Sensors
Passive infrared sensors respond to sudden changes in background heat
energy, particularly at wavelengths emitted by humans. A PIR occupancy
sensor requires direct line of sight to detect the presence of an
occupant, around corners. With increasing distance, larger movements
are required to trigger the sensor.
PIR sensors are less expensive than ultrasonic occupancy sensors. They
are well suited for use in corridors that are simple rectangles in
plain view; in such corridors, a single PIR sensor can be used to
control several fixtures. Multiple PIR sensors may be needed in long
corridors or corridors that have complex shapes.
To avoid false triggers, PIR sensors should not be mounted within 8
feet of supply diffusers or on sources of vibration.
Ultrasonic Occupancy Sensors
Ultrasonic occupancy sensors radiate high frequency sound waves that
are undetectable to the human ear. The sound waves bounce off
surfaces, including people. Motion is detected via shifts in
frequency. In rooms with hard surfaces, ultrasonic occupancy sensors
can detect occupants around corners, out of the line of sight. They
are more sensitive than PIR sensors in locations where people are
moving toward or away from the sensor.
In general, ultrasonic occupancy sensors can cover a larger area than
PIR sensors. They are well suited for use in stairwells, where sound
waves can bounce off the hard surfaces & corners. Like PIR sensors,
high levels of vibration or airflow can trigger ultrasonic occupancy
sensors. In corridors, occupant activity can trigger lights on
unnecessarily (this is known as "nuisance triggering").
Therefore, Ultrasonic occupancy sensors are highly recommended for
this project especially in corridor areas.
Conclusion : -
With the above, following are proposed for the project –
Transformer – 2 Nos. 1000 kVA
Diesel Generators – 1 No. 625 kVA, 1 No. 400 kVA and 1 No. 250 kVA
UPS – Parallel Redundant System
APFC Panels – 2 x 300 kVAr
Power Distribution – Using Bus Risers from Second to Seventh Floor.
