How to Design efficient Street lighting-(Part-1)


Introduction:

  • The basic idea of roadway and Highway lighting is to provide uniform level of illumination on road at horizontal and vertical level and provide a safe and comfortable environment for the night time driver.
  • Lighting design is basic idea of the selection and the location of lighting equipment to provide improved visibility and increased safety.
  • Street lighting systems should be designed in a way to avoid significant differences in luminance levels at the light source and on road areas. Furthermore, continuous variation of lighting levels can cause eye strain and should be avoided, in particular on long roads.
  • Road lighting provides visual conditions for safe, quick and comfortable movement of Road users.

 Designing Factor for Street Light:

  • The factors that are playing a vital role in the Road Lighting are following.

(A) Type of Road

  • Road Classification

(B) Street Light Pole

  • Street Light Pole Arrangements
  • Placement of Pole

(C) Lighting Fixture

  • Lighting Fixture Mounting Height
  • Lighting Fixture Classification
  • Lighting Fixture Distributor

(D) Lighting Factors

  • Maintenance Factor
  • Coefficient of Utilization

(E) Lighting Uniformity

  • Lighting Uniformity
  • Surrounding Ratio

(F) Lighting Pollution

  • Glare
  • Sky Glow
  • Trespass

(G) Selection of Luminas

  • Type of Light
  • Watt
  • Lumen
  • CRI
  • Efficiency

(A) Road Classification:

Table 4 : Road Classes as per SP 72 (Part 8), IS 1944 (Part 1) and IS 1970

Class A1 Important routes with rapid and dense traffic where safety, traffic speed, and driving comfort are the main considerations
Class A2 Main Roads with considerable volume of mixed traffic, such as main city streets, arterial roads and thoroughfares.
Class B1 Secondary roads with considerable traffic such as main local traffic routes, shopping streets
Class B2 Secondary roads, with light traffic
Class C Lighting for residential and unclassified roads not included in previous groups
Class D Lighting for bridges and flyovers
Class E Lighting for town and city centers
Class F Lighting for roads with special requirement such as roads near air fields, railways and docks

 

TYPE OF ROAD

TYPE OF ROAD DENSITY OF TRAFFIC TYPE EXAMPLE
A Heavy and high speed motorized traffic Road with fixed separators, No crossings for very long distance National highways or state highways or called interstate highways, express ways or motor ways
B Slightly lower density and lower speed traffic termed Road which is made for vehicular traffic with adjoining streets for slow traffic and pedestrians as we find in metros Trunk road or major road in a city
C Heavy and moderate speed traffic Important urban roads or rural roads. they do not interfere with the local traffic within the town Ring roads
D Slow traffic, pedestrians Linking to shopping areas and invariably the pedestrians, approach road Shopping street, trunk road
E Limited speed. Slow or mixed traffic predominantly pedestrians, Local streets, collectors road

(B) Street Light Pole:

(1) Street Light Arrangement:

  • There are four basic types of street lighting layout arrangements used for streets or highways illumination.

(A) One Side Pole Layout:

  • In One Side Pole Layout, all luminaries are located on one side of the road.
  • Road Width: For narrower roads.
  • Pole Height: The installation height of the lamp be equal to or less than the effective width of the road surface.

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  • Advantage: There are good indelibility and low manufacturing cost.
  • Disadvantage: The brightness (illuminance) of the road on the side where the lamp is not placed is lower than the on which side the light pole is placed.

(B) Both Side Staggered Pole Layout:

  • In the staggered arrangement, the luminaires are placed alternately on each side of the road in a “zig-zag” or staggered fashion.
  • Road Width: For Medium Size roads.
  • Pole Height: The installation height of the lamp is equal or 1.5 time the effective width of the road.

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  • Advantage: This type of arrangement is better than single side arrangement.
  • Disadvantage: Their longitudinal luminance uniformity is generally low and creates an alternating pattern of bright and dark patches. However, during wet weather they cover the whole road better than single-side arrangements.

(C) Both Side opposite Pole Layout:

  • In Both Side Opposite Pole Layout, the luminaries located on both sides of the road opposite to one another.
  • Road Width: For Medium Size roads.
  • Pole Height: The installation height of the lamp will be 2 to 2.5 time the effective width of the road.

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  • Advantage: opposite arrangements may provide slightly better lighting under wet conditions.
  • Disadvantage:
  • If the arrangement is used for a dual carriageway with a central reserve of at least one-third the carriageway with, or if the central reserve includes other significant visual obstructions (such as trees or screens), it effectively becomes two single-sided arrangements and must be treated as such.

 (D) Twin-central Pole Layout:

  • In Twin central arrangement, the luminaries are mounted on a T-shaped in the middle of the center island of the road. The central reserve is not too wide, both luminaires can contribute to the luminance of the road surface on either lane.
  • Road Width: For Large Size roads.
  • Pole Height: The installation height of the lamp be equal to the effective width of the road.

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  • Advantage: This arrangement generally more efficient than opposite arrangements. However, opposite arrangements may provide slightly better lighting under wet conditions.
  • Disadvantage:

Calculate Size of Pole Foundation & Wind Pressure on Pole


Example:

  • Calculate Pole foundation size and Wind pressure on Pole for following Details.
  • Tubular Street Light Pole (430V) height is 11 Meter which is in made with three different size of Tubular Pipe.
  • First Part is 2.7 meter height with 140mm diameter,
  • Second part of Pole is 2.7 meter height with 146 mm diameter and
  • Third part of Pole is 5.6 meter height with 194 mm diameter.
  • Weight of Pole is 241 kg and there is no any other Flood Light Fixtures Load on Pole.
  • Total Safety Factor is 2.
  • Wind zone category is 3.
  • The Pole is installed in open terrain with well scattered obstructions having height generally between 1.5 m to 10 m.
  • Foundation of pole is 700mm length, 700mm width and 1.95 meter depth. The Average weight of foundation concrete is 2500 Kg/M3.

1

Calculation:

 Wind Pressure according to Location:

  • Wind Zone is 3 so Wind Speed as per following Table.
Basic Wind Speed-Vb (As per IS 802-Part1)
Wind Zone  Basic Wind Speed, vb m/s
1 33
2 39
3 44
4 47
5 50
6 55
  • Wind Speed (vb) = 44Mile/Second.
  • Co-efficient Factor (K0)=1.37
  • K0 is a factor to convert 3 seconds peak gust speed into average speed of wind during 10 minutes period at a level of 10 meters above ground. K0 may be taken as 1.375.
  • The Pole is used for 430Vand wind zone is 3 so Risk Co-efficient (K1) as per following Table
Table 2 Risk Coefficient K1 for Different Reliability Levels and Wind Zones (As per IS 802-Part1)
Reliability  Level Wind Zone-1 Wind Zone-2 Wind Zone-3 Wind Zone-4 Wind Zone-5 Wind Zone-6
1 (Up to 400KV) 1 1 1 1 1 1
2 (Above 400KV) 1.08 1.1 1.11 1.12 1.13 1.14
3 (River Crossing) 1.17 1.22 1.25 1.27 1.28 1.3
  • Risk Co-efficient (K1) =1
  • Terrain category (K2) for Open terrain with well scattered obstructions having height generally between 1.5 m to 10 m is 1 as per following Table
  • Terrain category (K2)=1
Terrain Roughness Coefficient, K2 (As per IS 802-Part1)
Terrain Category Category 1 Category 2 Category 3
Exposed open terrain with no obstruction and in which the average height of any object surrounding the structure is less than 1.5 m. Open terrain with well scattered obstructions having height generally between 1.5 m to 10 m. Terrain with numerous
closely spaced obstructions.
Coefficient, K2 1.08 1 0.85
  • Reference Wind Speed (Vr)= Vb / K0.
  • Reference Wind Speed (Vr)= 44 / 1.37 =32 Mile/Second.
  • Design wind Speed (vd)= Vr X K1 X K2.
  • Design wind Speed (vd)= 32 X 1 X 1 =32 Mile/Second.
  • Design Wind Pressure (Pd)=0.6 x vd2
  • Design Wind Pressure (Pd)=0.6 x (32)2 =614.4 N/m2
  • Design Wind Pressure (Pd)=614.4/10 =61.4 Kg/m2

Foundation Detail:

  • Total Weight =Pole Weight +Foundation Weight.
  • Total Weight = 241 +(0.7×0.7×1.95×2500) =2620.75 Kg
  • Stabilizing Moment = Total Weight X (Foundation Length/2)
  • Stabilizing Moment = 2620.75 X (0.7/2) = 920.41 Kg/Meter.

Pole Detail:

  • First Part of Pole (h1) = 2.7 meter
  • Diameter of First Part (d1) =140mm
  • Second Part of Pole (h2) = 2.7 meter
  • Diameter of Second Part (d2) =146mm
  • Third Part of Pole (h3) = 5.6 meter
  • Diameter of Third Part (d3) =194mm .

Wind Pressure on Pole:

  • Overturning Moment due to the wind on 1st Part of the pole=pdxh1xd1x(h1/2+h2+h3)x0.6
  • Overturning Moment due to the wind on 1st Part of the pole=61.4×2.7x(140/1000)x(2.7/2+2.7+5.61)x0.6
  • Overturning Moment due to the wind on 1st Part of the pole=134.47 Kg/meter—I
  • Overturning Moment due to the wind on 2nd Part of the pole=pdxh2xd2x(h2/2+h3)x0.6
  • Overturning Moment due to the wind on 2nd Part of the pole=61.4×2.7x(146/1000)x(2.7/2+5.61)x0.6
  • Overturning Moment due to the wind on 2nd Part of the pole=112.76 Kg/meter.—-II
  • Overturning Moment due to the wind on 3rd Part of the pole=pdxh3xd3x(h3/2)x0.6
  • Overturning Moment due to the wind on 3rd Part of the pole=61.4×5.6x(194/1000)x(5.6/2)x0.6
  • Overturning Moment due to the wind on 3rd Part of the pole=112.14 Kg/meter.—III
  • Total Overturning Moment on Pole due to Wind=134.47+112.76+112.14=359.36 Kg/meter.

 Safety Factor:

  • Calculated Safety Factor= Stabilizing Moment / Total Overturning Moment on Pole.
  • Calculated Safety Factor=920.41/ 359.36 =2.56.
  • For safe Design Calculated Safety Factor > Safety Factor
  • Here Calculated Safety Factor (2.56) > Safety Factor (2) hence
  • Design is OK
  • B : If Calculated Safety Factor < Safety Factor then Change Foundation Size (Length, width or depth)

 

Calculate Size of Circuit Breaker/ Fuse for Transformer (As per NEC)


  • Calculate Size of Circuit Breaker or Fuse on Primary and Secondary side of Transformer having following Detail
  • Transformer Details(P)= 1000KVA
  • Primary Voltage (Vp)= 11000 Volt
  • Secondary Voltage (Vs)= 430 Volt
  • Transformer Impedance= 5%
  • Transformer Connection = Delta / Star
  • Transformer is in unsupervised condition.

Calculations:

  • Transformer Primary Current (Ip)= P/1.732xVp
  • Transformer Primary Current (Ip)=1000000/1.732×11000=49Amp
  • Transformer Secondary Current (Is)= P/1.732xVs
  • Transformer Secondary Current (Is)=1000000/1.732×430=71Amp
  • AS per NEC 450.3, Max.Rating of C.B or Fuse is following % of its Current according to it’s Primary Voltage,% Impedance and Supervised/Unsupervised Condition.

Max Rating of Over current Protection for Unsupervised Transformer More than 600 Volts (As per NEC)

%Imp Primary secondary
>600Volt >600Volt <600Volt
C.B Fuse C.B Fuse C.B/Fuse
 Up to 6% 600% 300% 300% 250% 125%
More than 6% 400% 300% 250% 225% 125%

 

Max Rating of Over current Protection for Supervised Transformer More than 600 Volts (As per NEC)

%Imp Primary secondary
>600Volt >600Volt <600Volt
C.B Fuse C.B Fuse C.B/Fuse
 Up to 6% 600% 300% 300% 250% 250%
More than 6% 400% 300% 250% 225% 250%

 

Max Rating of Over current Protection for Transformers Primary Voltage Less than 600 Volts (As per NEC)

Protection Primary Protection Secondary Protection
Method More than 9A 2A to 9A Less than 2A More than 9A Less than 9A
Primary only protection 125% 167% 300% Not required Not required
Primary and secondary protection 250% 250% 250% 125% 167%

 

Size of Fuse / Inverse Time C.B as per NEC (Amp)

1 25 60 125 250 600 2000
3 30 70 150 300 700 2500
6 35 80 160 350 800 3000
10 40 90 175 400 1000 4000
15 45 100 200 450 1200 5000
20 50 110 225 500 1600 6000

For Primary Side:

  • Transformer Primary Current (Ip) =52.49Amp and impedance is 5%
  • As per above table in not supervised condition Size of Circuit Breaker= 600% of Primary Current
  • Size of Circuit Breaker = 52.49 x 600% =315Amp
  • If Transformer is in supervised condition then Select Circuit Breaker near that size but if Transformer is in unsupervised condition then Select Circuit Breaker next higher size.
  • Rating of Circuit Breaker =350Amp (Next Higher Size of 300Amp)
  • Size of Fuse = 52.49 x300% =157Amp
  • Rating of Fuse =160Amp (Next Higher Size of 150Amp)

For Secondary Side:

  • Transformer Secondary Current (Is) =1342.70Amp and impedance is 5%
  • As per above table in not supervised condition Size of Circuit Breaker= 125% of Secondary Current
  • Size of Circuit Breaker = 1342.70 x 125% =1678Amp
  • If Transformer is in supervised condition then Select Circuit Breaker near that size but if Transformer is in unsupervised condition then Select Circuit Breaker next higher size.
  • Rating of Circuit Breaker =2000Amp (Next Higher Size of 1600Amp)
  • Size of Fuse = 1342.70 x125% =1678Amp
  • Rating of Fuse =2000Amp (Next Higher Size of 1600Amp)

 Results:

  • Size of Circuit Breaker on Primary Side=350Amp
  • Size of Fuse on Primary Side=160Amp
  • Size of Circuit Breaker on Secondary Side=2000Amp
  • Size of Fuse on Secondary Side=2000Amp

Selection of Various Types of UPS (Part-2)


(2) Line-Inter active UPS:

  • Working Principle of Line Interactive UPS is same as OFF Line/ stand UPS. It connected directly from mains, switching to battery (via the inverter) in mains Power cut condition.
  • The designing of line interactive UPS is same as OFF Line UPS in addition the design Line Interactive generally includes an automatic voltage regulator (AVR) or a tap-changing transformer. This enhances the regulation of voltage by regulating transformer taps as the input voltage differs.
  • The main difference between an off-line and a line-interactive UPS is that a line-interactive UPS in the stand-by mode has active voltage regulation.
  • Voltage regulation is a significant feature when the conditions of a low voltage exist, otherwise the UPS would transfer to battery and then finally to the load. The usage of more common battery can cause early battery failure.
  • It typically uses either a Ferro resonant transformer or a buck-boost transformer. Both helps to reduce the frequency of transfers to battery, slightly improving efficiency and reducing battery wear.
  • Ferro resonant designs also offer power conditioning and tight voltage regulation, as well as an energy store that can maintain uninterrupted power supply output while the inverter switches on.

Circuit Diagram:

1

Working Function:

  •  Normal Condition:
  • In Normal Power Condition, power supply will continuously provide to Load with some filtering and voltage regulation circuit.
  • During normal operation, the Line Interactive UPS takes utility power and passes it through a transformer with various tap selections on the output. When utility power is high, the Line Interactive UPS selects a tap to lower (buck) the output voltage. Similarly, when the utility voltage is low, the UPS selects a tap to increase (boost) the output voltage.
  • In Normal Condition Battery is charged continuous charge through Battery Charger
  • Battery charger convert AC power to DC Power and this DC Power charged Battery.
  • Power outage Condition:
  • When utility power fails, the device will start its internal inverter Circuit by Mechanical Switch.
  • Mechanically transfer Switch Transfer from utility power to Battery Power, inverter output.
  • This transfer can take as 2 to 4 ms.

 Advantage:

  • small Size
  • Low cost
  • High Efficiency (because less power conversion is when AC input is present).
  • Sine Way Output.
  • Battery life is good compared to OFF Line UPS.
  • Voltage regulation is fair (more than OFF Line UPS but Less than ON Line UPS)
  • EMI/RFI/Noise Rejection is good.
  • Change over Time is 2 to 4 Milliseconds.
  • Lower electricity consumption (less costly to operate).
  • Higher reliability (Lower component count and lower operating temperatures).

 Disadvantage:

  • No isolation between main supply and load
  • Higher Heat Output
  • More Expensive
  • Problematic with power factor corrected loads.

Applications:

  • For small business.
  • IT Racks, Network Switches, Medical Instrument System where data loss is a serious problem.
  • The line interactive UPS may not be the appropriate choice for installations where AC power is unstable or highly distorted, because battery power will be used too often to keep the UPS output within specifications.

 Capacity:

  • UPS in the range of 500VA to 5kVA power.

 (3) ON Line UPS/ Double Conversion UPS

  • It is truly uninterrupted power system (UPS) provide continuous power to load in any condition.
  • Online UPS sometimes called “double conversion” UPS. 
  • Today most users with highly-critical loads are choose online UPS .It is used to protect sensitive equipment and data from mains problems at all times with any extra cost.
  • This UPS have no power transfer switches and therefore no transfer time is existed under the mains power failure. Thus this is truly an uninterrupted system.
  • In Online UPS to maintain the charge of the battery, a battery charging unit is continuously powered from the AC mains.
  • Online UPSs are often called ‘double conversion’ types because incoming power is Firstly converted once AC to DC for the battery and then back Secondly Converter DC to AC before reaching the load which is therefore well-insulated from the mains like an electrical firewall between the incoming power and sensitive electronic equipments. It also control of the output voltage and frequency regardless of the input voltage and frequency.
  • The online UPS continuously filters power through the battery before sending it to your computer.
  • By contrast, online UPS systems draw power through the power conditioning and charging components during normal operation, so the load always receives conditioned power rather than raw mains.

 Circuit Diagram:

1

Working Function:

  • The designing of this UPS is similar to the Standby UPS, excluding that the primary power source is the inverter instead of the AC main.
  • In this UPS design, any cutoff of input AC Supply does not cause triggering of the transfer switch, because the input AC Supply is charging the backup battery source which delivers power to the o/p inverter. So, during failure of input AC Supply, this UPS operation results in no transfer time.
  • The Transfer switch will automatically transfer the load to mains in case of overload or UPS failure.
  • Normal Condition or Power outage Condition:
  • In Normal Power Condition, power supply will continuously feed from the Inverter, providing conditioned, stabilized sinusoidal voltage.
  • Input Power is filter and regularized by RFI Filter circuit then it is feed to Battery charger which is convert AC Power to DC Power. This DC Power is charged Battery continuously.
  • Battery DC power is converted to AC power by Inverter Circuit.

 Advantage:

  • The cost is high compare to other type of UPS.
  • It provides isolation between main supply and load.
  • The output is pure Sign wave.
  • 100% Power Conditioning
  • Constant voltage output.
  • Correction of Input Power Factor
  • Zero transfer time
  • The output voltage is free from distortion due to inverter is always ON.
  • It offers the best power protection, covering any and all types of mains disturbances of supply such as blackout, brownouts, spikes etc are absent in the output.
  • Voltage regulation is better
  • Transfer time is practically zero since inverter is always ON.
  • High Reliability, Units can be connected in parallel redundant configuration.
  • This is the best choice, considering such issues as modularity, ability to work from generator, power factor correction, maintenance, hot swapping, fault clearing, supervising, and communicating.

 Disadvantages:

  • More Expensive
  • Lower Efficiency (Due to inverter is always ON).
  • Higher Heat Output
  • Higher battery TCO
  • Higher operating cost (Supplies power is charge Battery Charger and Inverter both).
  • The wattage of the rectifier is increased since it has to supply power to inverter as well as charge battery

 Applications:

  • It the preferred choice for most business applications.
  • Induction motor drives and similar other motor control applications.
  • Medical equipments and Intensive care units.
  • Electronics manufacturers.
  • Data and call centers.
  • TV stations
  • Production-based manufacturers.

 Capacity:

  • From 1 KVA up to 5 MVA.

 Comparison of all types of UPS: 

Comparison of all types of UPS

Features OFFLINE Line-Interactive ON Line
Size of UPS Compact Moderate Big
Cost Cheap Cheaper expensive
Circuit Simplicity Simple Simple Complicated
Transfer Time 4 to 10 millisecond 2 to 4 millisecond 0
Efficiency High Moderate Low
Power Consumption Less Less High
Battery Charging Time More More Less
Battery Life Less Less More
Backup Time Short Short More
Surge Protection
Voltage Regulation Low Better Best
Load Protection Low Better Best
Size Up to 2KVA Up to 5KVA 5 to 500KVA
Reliability Low Better Best
Isolation from Mains Not Available Not Available Available
Noise Reduction Good Good Best
Frequency Stability Not Stable Not Stable Always Stable
Voltage Conditioning Low Better Best
Cost/KVA Low Medium High
Inverter always Operating Yes Yes Yes
Application For Domestic Desktops IT Racks ,Switches ,Distributed Server Data Center, Hospital, Banks
Capacity Up to 800VA 800VA to 1500VA 1000VA to 5000VA

Selection of UPS:

 (1) Size of the UPS (VA & Watts)

  • To decide Power Capacity of the required UPS, we should decide which should be protected and its power consumption in Amps, VA, or Watt.

(2) Back-up time

  • Battery Backup time is the time that batteries are able to back-up operation and feed the load upon failure of utility power. Load consumption and size of UPS batteries decide the back-up time.

(3) Type of the UPS you need

  • UPS’s are divided to three main classes.
  • The Off Line (Stand-by) UPS is the simplest and the least expensive.
  • The Line Interactive type, which overcomes the major disadvantages of  the off-line unit  
  • The On-Line UPS, which provides the best power protection.

(4) Cost:

  • For applications where low cost is critical and it does not matter if backup times are short, an OFF Line UPS is proper solution. However it will not provide adequate protection against spikes or sags from the grid.
  • For applications that require complete isolation from any changes in grid power, such as many medical applications then On Line UPS is the best solution.
  • For applications where power losses due to inefficiencies are less of a concern and eliminating the delay from grid power available to back power is paramount, online UPS is the only solution.
  • For typical applications where conditioning Power is required and very short transfer times from grid to backup power are acceptable and daily energy consumption is a concern, Line Interactive is the preferred solution

 (5) Non-Essential or Critical Load

  • For small office where PC loads is less and small network data protection is required, a small single-phase UPS is often an adequate solution.
  • Most single-phase UPSs use off-line or line-interactive topologies.
  • If the equipment to be protected is critical, an online UPS is the best choice.
  • For loads above 10kVA, the most practical solution is a three-phase UPS, which is most normally with true-online topology. Three-phase online UPSs offer the advantage of providing centralized protection using a single UPS.

 (6) Efficiency:

  • Efficiency is mainly affected on UPS design or operating mode.
  • standby and line-interactive UPSs are more energy efficient than ON Line UPSs because there is no power conversion from AC to DC and then back to AC
  • Efficiency is a factor of UPS size. Larger UPS modules typically have higher energy efficiency than smaller ones, because the support power required for control electronics and auxiliary components becomes a smaller portion of the total capacity of the UPS system.
  • For example, a 500 kW UPS module of a given design would typically be more efficient than a 5 kW UPS module of the same design.

Efficiency of UPS

Capacity Size Standby UPS Line-interactive UPS On Line UPS
5 kW 95 % 96  % 91 %
100 kW  98 % 97 % 98 %
500 kW 99% 98 % 99%

(7) Form Factor:

  • Form factor refers to the the outer-shape of the unit. The Form Factor refers outer shape of UPS.
  • Tower: This is smaller and a stand-alone unit, and It is primarily designed for simple home/office setups.
  • Rack mounted: is larger, designed for a standard rack shelf, and is primarily used for more complex commercial operations.

(8) Noise

  • UPS fan noise may or may not be an issue as per your requirement.
  • Smaller UPS does not normally require a fan for cooling, but larger ones often will.
  • If r work requires perfect silence, make sure your UPS is fan-free.

Resolve Power Quality problem by Type of UPS:

Power Quality Problems & solution by UPS

Power Quality

Problem

Description Effect Solved by UPS
Temporary Interruption Accidental total loss of utility power  (Seconds to minutes) Equipment shutdown, loss of  data, file , hard disk and operating system Corruption Off-line – Yes

Line-interactive – Yes

On-line – Yes

Long-Term

Interruption

Accidental total loss of utility power (minutes to Hour) Equipment shutdown, loss of  data, file , hard disk and operating system Corruption Off-line – No

Line-interactive –No

On-line – Yes

Momentary

Interruption

Very short planned or

Accidental power loss.

(Milliseconds to seconds)

Computer and network equipment reboots or hangs, loss of work and data, file Off-line – Maybe

Line-interactive – Maybe

On-line – Yes

Sag or Under-Voltage A decrease in utility

voltage Sags  (Milliseconds to a few seconds)

Shrinking display screens,

Computer hangs or reset,

equipment power supply

damage, loss of data, file

Off-line – No

Line-interactive – Yes

On-line – Yes

Swell or Over-Voltage An increase in Utility

Voltage ( Milliseconds to a

few seconds)

Permanent equipment damage, Computer and network equipment reboots or hangs, loss of data Off-line – No

Line-interactive – Yes

On-line – Yes

Transient, Impulse or

Spike

A sudden change in

voltage up to several

hundreds to thousands of

volts (Microseconds)

Network Errors, Burned or

damaged equipment, computer and network

equipment reboots or hangs,

loss of work and data, file

Off-line – Yes

Line-interactive – Yes

On-line – Yes, Higher level of protection.

Noise An unwanted electrical

signal of high frequency

from other equipment

Slow LAN, audible noise in

telephone and audio equipment.

 

Off-line – No

Line-interactive – No

On-line – Yes

Harmonic Distortion An alteration of the pure

sine wave, due to nonlinear

loads

Causes motors, transformers

and wiring to overheat, lowers operating efficiency

Off-line – No

Line-interactive – No

On-line – Yes

 

Selection of Various Types of UPS (Part-1)


Introduction:

  • Whenever there is a power cut, electricity supply to Computer, Desktop or other critical appliances is cut off and they stop working. However, if we have a backup supply device such as UPS, we can ensure uninterrupted supply of power to appliances to be not bothered with power cuts.
  • Electrical power supply comes from utility companies is not pure it has different Electrical abnormalities like surges, under voltage, Over Voltage, Voltage dips, voltage spikes, Noise and harmonics. These Electrical abnormalities can cause serious damage to Electronics equipments, Data Systems, Computer or Desktop.
  • To decrease the risk of power supply distortion, UPS systems are frequently integrated in electrical networks. Electronic power supply equipment makers can offer consistent, high-quality power flow for various Electrical / Electronic load gear likes continuous industrial processing applications, medical services, emergency gear, telecommunications, & computerized data systems.
  • Today’s UPS systems usually provide some level of power conditioning and protection against fluctuations in voltage from the grid.

UPS:

  • UPS means uninterrupted power supply.
  • Uninterruptible power supply (UPS) provides uninterrupted power to the equipment. It means switching time from power cut to battery power is very less hence important equipment like computer, desktop is not switch off and we can lose data.
  • A UPS is a complete system that is consisting of many parts that include batteries, a charge controller, circuitry any transfer switch for switching between the mains and back-up battery, and an inverter. An inverter is needed because the battery can only store DC power and we need to convert that back to AC in order to match the appliances connected in the main power line.
  • UPS= Battery charger + Inverter
  • UPS is nothing but inverter with inbuilt battery charger.
  • UPS is used only to backup your system. If we connect desktop computer on inverter. Inverter takes some seconds to give battery power to equipment hence equipment shutdowns for some second in  any power loss condition and we can lose important data of desktop or computer.
  • Inverter is not suitable for computer backup due to the delay in switching.
  • One of more useful functions of UPS is to provide surge protection so connected devices can be protected from line Surge and does not damage. UPS is also capable of conditioning the power from the lines to provide clean and stable power throughout.

Block Diagram of UPS:

  • The block diagram of this UPS is shown as below

1

  • The mains power comes to the UPS. The AC is converted to DC and this DC is constantly charging the battery. The output of the battery is fed to the Sine wave inverter and it converts DC to AC and this feeds the equipment. Since power out is always drawn from the battery, there is no time lag when mains switches off, it just stops the battery from being charged and the UPS continues to supply power till the battery runs out.
  • Battery Charger (Rectifier ): To convert AC Power (from Power Grid) to DC Power to charge Battery
  • Battery: To provide DC Power.
  • Inverter: To convert DC Power (from Battery) to AC Power (to power load i.e., electrical and electronic equipment.)
  • Controller: To control functions of Rectifier (Charger) and Inverter. (i.e., when to start or stop charging battery, when to start or stop power from battery to load, how fast to change from Grid Power to Battery Power and so on)

 Type of UPS:

  • The UPS is mainly categorized into three types according to their functions. They are as
  1. Offline Standby (where system or data loss is an inconvenience)
  2. Line-interactive (system or data loss is a serious problem).
  3. Online/Double Conversion (system or data loss is unacceptable).

 (1) OFF Line UPS / Standby UPS:

  • Off-line UPS systems are so-called “OFF Line” because load is normally connected directly to the incoming AC mains. When the incoming AC mains fails or fall below a pre-determined level, then the offline UPS turns on its internal DC-AC inverter circuitry, which is powered from an internal storage battery.
  • For switching purpose UPS consists mechanically / Static switches which immediately connect the load on its DC-AC inverter output under the mains power failure condition. During this changeover there is an inevitable break in power to the load of typically 2 to 10 milliseconds. In practice, however, most loads can ride through this period without any problems.
  • The switching process causes a momentary lapse in power which is dangerous for certain highly-sensitive equipment. This is why technically, the standby UPS is not considered a “true UPS”, as it is not truly “uninterruptible”.
  • The typical lapse time 5ms,is well within tolerance for normal desktop computers

 Circuit Diagram:

1

 Working Function:

  •  Normal Condition:
  • In Normal Power Condition, power supply will continuously provide to Load with some filtering (typically the same as on a surge protection power strip) from the utility.
  • In Normal Condition Battery is charged continuous charge through Battery Charger
  • Battery charger convert AC power to DC Power and this DC Power charged Battery.
  • Power outage Condition:
  • When utility power fails, the device will start its internal inverter.
  • When utility power fails mechanically transfer Switch Transfer from utility power to Battery Power, inverter output.
  • This transfer can take as 25 ms, which may be too long for some Electronics loads.
  • An Offline UPS will transfer to battery backup during Power cut condition.
  • Off-line systems are generally equipped with spike suppressors, aimed to protect the hardware from high voltages on the utility grid.

 Advantage:

  • Cheaper than other type of UPS.
  • Small size.
  • High efficiency.
  • More economical
  • More energy efficient.
  • Lower operating temperature (Due to Fewer parts)
  • Simple Internal control Circuit.
  • Lower initial cost (fewer parts) and lower operating cost (Supplies power is charge only Charger).

Disadvantage:

  • No isolation between main supply and load
  • No Power Conditioning.
  • Slower Transfer Time.
  • Harmonic distortion is high.
  • UPS output is Quasi square wave.
  • The output contains voltage spikes, brownouts, blackouts.
  • Output is not perfectly reliable.
  • A more serious problem of offline systems is that the load is continuously exposed to spikes, transients and any other abnormalities coming from the power line. This creates a risk of loss or damage to sensitive equipment and data. However in many systems this risk is mitigated but does not eliminated, by spike suppression and radio frequency filtering
  • Most of the short term spikes surges and high frequency harmonics are decayed by means of special filters but transient of mains power existence, like over voltages can harm protected data.

Applications:

  • small offices, personal home computers and other less critical application
  • Computers, printers, scanners etc.
  • Emergency power supplies, EPABX.

Capacity:

  • Up to 800VA.

Electrical Thumb Rules-Illumination-(Part-19).


Recommended Lighting Levels For Sports Areas  

TYPE OF SPORTS PRACTIVE LEVEL MINOR LEAGUE MAJOR LEAGUE PROV LEVEL
Bowls 20 lux 50 lux 100 lux 150 lux
Tennis 50 lux 100 lux 150 lux 250 lux
Football 50 lux 100 lux 250 lux 450 lux
Cricket Outfield 50 lux 100 lux 250 lux 450 lux
Cricket Pitch 100 lux 200 lux 400 lux 600 lux
Hockey 50 lux 100 lux 250 lux 350 lux
Swimming 50 lux 100 lux 150 lux 250 lux

 

Industrial & Office Applications Lux Level

WORK AREAS WORK TYPE LUX
General Engineering Rough Work 160 lux
General Engineering Medium Work 400 lux
General Engineering Fine Work 800 lux
General Engineering Very Fine Work 1600 lux
Inspection Areas Rough Work 160 lux
Inspection Areas Medium Work 320 lux
Inspection Areas Sub Assemblies 400 lux
Inspection Areas Fine Work, electric & high precision mechanical 800 lux
Offices Entrance halls and receptions areas 160 lux
Offices Conference facilities, general offices, typing and filing 500 lux
Offices Computer and business machine operation 630 lux
Offices Drawing Offices 800 lux
Outdoor Areas Mechanical loading 10 lux
Outdoor Areas Manual loading 10 lux
Outdoor Areas Service station forecourts 160 lux
Warehousing Inactive storage 20 lux
Warehousing Loading bays and large materials storage 100 lux
Warehousing Small material storage, packing and dispatch 200 lux

 

Recommended Lighting Levels

Characteristics of Activity Representative Activity Illuminance (lux)
Interiors rarely used for visual tasks (no perception of detail) Cable tunnels, nighttime sidewalk, parking lots 50
Interiors with minimal demand for visual acuity (limited perception of detail) Corridors, changing rooms, loading bay 100 – 150
Interiors with low demand for visual acuity (some perception of detail) Foyers and entrances, dining rooms, warehouses, restrooms 200
Interior with some demand for visual acuity (frequently occupied spaces) Libraries, sports and assembly halls, teaching spaces, lecture theaters 300
Interior with moderate demand for visual acuity (some low contrast, color judgment tasks) Computer work, reading & writing, general offices, retail shops, kitchens 500
Interior with demand for good visual acuity (good color judgment, inviting interior) Drawing offices, chain stores, general electronics work 750
Interior with demand for superior visual acuity (accurate color judgment & low contrast) Detailed electronics assembly, drafting, cabinet making, supermarkets 1000
Interior with demand for maximum visual acuity (low contrast, optical aids & local lighting will be of advantage) Hand tailoring, precision assembly, detailed drafting, assembly of minute mechanisms 1500 -2000+

 

Interior Light Levels

Environment Required Light Level
 Storage Area / Plant Room (minimal movement of people) 150 – 200 Lux
 Construction Areas & Loading Bays (minimal perception of detail) 300 – 500 Lux
 Factories & Kitchens (higher perception of detail) 500 – 750 Lux
 Inspection, Welding, And Machinery (demanding work) 750 – 1000 Lux
 Electronics & Textile Production (repetitive detail) 1000 – 1500 Lux
 Technical Offices (accurate detail) 1500 – 3000 Lux
 Jewelers & Goldsmiths (precision detail) 3000 + Lux

 

Outdoor Light Levels

Environment Required Light Level
Very Bright Summer Day Up To 100,000 Lux
Overcast Summer Day 30,000 – 40,000 Lux
Floodlit Football Match 700 – 16,000 Lux
Shady Room In Daylight 250 – 300 Lux
Night Light On A Building 60 Lux
Night-Time Urban Street 10 Lux
Night-Time Car Park 1 Lux
Security Floodlights 700-1300 Lux
Shed Lights 150-300 Lux
Lamp Posts 120-180 Lux
Landscape Spotlights 120 Lux
Outdoor Path Lighting 100 Lux
Path lighting. 100 Lux
Landscape Lights 100-300 Lux
Garden lights 20 Lux

 

Illumination Level

Light levels as per IS 1944
Classification of Road Type of road illumination (lux)
Group A1 Important traffic routes carrying fast traffic 30
Group A2 Other main roads carrying mixed traffic, like main city streets, arterial roads, throughways etc 15
Group B1 Secondary roads with considerable traffic like principal local traffic routes, shopping streets etc 8
Group B2 Secondary roads with light traffic Important traffic routes carrying fast traffic 4

 

Illumination Level

Roadway
Classification
Average Maintained Illuminance
High lux Medium lux Low lux
Major/Major 34 26 18
Major/Collector 29 22 15
Collector/Collector 24 18 12
Collector/Local 21 16 10
Local/Local 18 14 8

 

Interior Lighting Level

Chartered Institute of Building Services Engineers CIBSE  Part 2 (2002)

Illuminance (lux) Activity Area
100 Casual seeing Corridors, changing rooms, stores
150 Some perception of detail Loading bays, switch rooms, plant rooms
200 Continuously occupied Foyers, entrance halls, dining rooms
300 Visual tasks moderately easy Libraries, sports halls, lecture theatres.
500 Visual tasks moderately difficult General offices, kitchens, laboratories, retail shops.
750 Visual tasks difficult Drawing offices, meat inspection, chain stores.
1000 Visual tasks very difficult General inspection, electronic assembly, paintwork, supermarkets.
1500 Visual tasks extremely difficult Fine work and inspection, precision assembly.
2000 Visual tasks exceptionally difficult Assembly of minute items, finished fabric inspection.

 

Illumination levels of Switch Yard

AS/NZS 1158.3.1

Switchyard area lighting targets Illuminance (lx)
HV areas including any overhead line road crossings and any access path zone type infrastructure 10
Non-HV areas and general open areas 5
Isolated areas such as back of buildings, corners of switchyards away from HV Equipment 2

 

Sub Station Light Levels

WEST BENGAL STATE ELECTRICITY TRANSMISSION COMPANY LIMITED

Environment Required Light Level
CONTROL ROOM / Switch gear Room 300
Battery Room 150
Communication Room 300
Offices/Engineers’ Room/Other Office Room 300
Toilet 100
Outdoor Switchyard area including road 30
Stairs 100
Corridor 100
Road within campus including colony area 30
Maintenance room 150
Any other spot where high level of illumination required 150
Dormitory & ‘C’ type quarters 150
Auxiliary Buildings like Pump room and other houses 150
ACDB- DCDB room/Store / Store Office 150
Conference room 300
Tiffin room/Kitchen 150
GIS Hall 150

 

Sub Station Light Levels

ODISHA POWER TRANSMISSION CORPORATION LIMITED

Environment Required Light Level
Control Room 350
PLCC Room 300
LT Room 150
Charger Room 150
Cable Gallery 150
Heating Plant 100
Battery Room 100
Computer Room 300
Entrance lobby 150
Corridor and landing 150
Conference and display 300
Rest Room 250
AHU Room 100
DG Set Building 150
Fire Fighting Pump House 150
Switchyard – Main equipment 50
Switchyard – general equipment and balance 30
Street/Road 30

 

Electrical Thumb Rules-Illumination-(Part-18).


Recommended Lighting Levels

IESNA Lighting Handbook

Type of activity Lighting
Public spaces with dark surroundings

30 Lux

Simple orientation for short temporary visits 50 Lux
Working spaces where visual tasks are only occasionally performed 100 Lux
Performance of visual tasks of high contrast or large scale 300 Lux
Performance of visual tasks of medium contrast or small size 500 Lux
Performance of visual tasks of low contrast or very small size 1000 Lux
Performance of visual tasks near threshold of person’s ability to recognize an image 3000-10000 Lux

                              Industries Recommended Levels of Illumination
Area And Task Lux Level
Paper Manufacturing
Beaters, grinding 30
Finishing, cutting 50
Hand Counting 70
Paper machine reel, inspection 100
Rewinder 150
Warehousing, Storage
Inactive 5
Active:
Rough Bulky 10
Medium 20
Fine 50
Clothing Manufacture
Receiving, storing, shipping, winding, measuring 30
Pattern making, trimming 50
Shops, making 100
Textile Mills – Cotton
Opening, mixing, picking 30
Carding and drawing 50
Slubbing, roving, spinning, spooling 50
Beaming and splashing on combo Gray goods 50
Denims 150
Inspection
Gray goods (hand tuning) 150
Denims (rapid moving) 500
Automatic tying-in 150
Weaving 100
Drawing-in by hand 200
Machine Shops
Rough bench and machine work 50
Medium bench and machine work, ordinary automatic machines, rough grinding medium buffing and polishing 100
Fine bench and machine work, fine automatic machines, medium grinding, fine buffing and polishing 500
Extra-Fine bench and machine work, grinding fine work 1000

                                                Recommended Lighting Levels
                           International Standard Serial Number ISSN: 2278-6252
Area/task/ process Illuminance (lux)
Exterior circulating, walkways, stores, main entrances and exit roads, car parking, internal factory roads etc. 20-50
Boiler house, transformer yards, furnace rooms, entrances, corridors, stairs etc. 70-100
Circulation areas in industry, stores and stock rooms, canteen 100-150
Coarse work 200-300
Medium work 300-500
Fine work 500-1500
Very fine minute and precise work 1500-3000
Bale breaking, washing , Stock dyeing, tinting, Mixing, Blowing 200-300
Carding, drawing, roving 300-500
Spinning, doubling, reeling, winding 300-750
Warping 300-400
Sizing 400-500
Heading (drawing in) 750-1000
Weaving (plain gray fabrics) 200-300
Weaving (light colored) 300-750
Weaving (dark colored) 500-1000
Knitting 300-750
Dyeing 200- 450
Calendaring, chemical treatment 300-750
Grey cloth inspection 700-1000
Final inspection 1000-2000

                                              Recommended lighting levels
                                                    IESNA Lighting Handbook
Type of activity Lighting (Lux)
Public spaces with dark surroundings 30
Simple orientation for short temporary visits 50
Working spaces where visual tasks are only occasionally performed 100
Performance of visual tasks of high contrast or large scale 300
Performance of visual tasks of medium contrast or small size 500
Performance of visual tasks of low contrast or very small size 1000
Performance of visual tasks near threshold of person’s ability to recognize an image 3000-10000

                                Illuminance Values for Indoor Activities
                                                TABLE 10.4 IES
ACTIVITY CATEGORY LUX
Public spaces with dark surroundings large area (lobby space) 20-30-50
Simple orientation for short temporary visits large area (lobby space) 50-75-100
Working spaces where visual tasks are only occasionally performed large area (lobby space) 100-150-200
Performance of visual tasks of high contrast or large size localized tasks 200-300-500
Performance of visual tasks of medium contrast or small size localized tasks 500-750-1000
Performance of visual tasks of low contrast or very small size localized tasks 1000-1500-2000 100
Performance of visual tasks of low contrast  or very small size over a prolonged period extremely difficult visual tasks 2000-3000-5000
Performance of very prolonged and exacting visual tasks extremely difficult visual tasks 5000-7500-10000
Performance of very special visual tasks of extremely low contrast extremely difficult visual tasks 10000-15000-20000

                                                           Lighting levels-Sports
Sports Illumination
Football/Rugby  
National/ international     500 Lux
Regional/Local     200 Lux
Local/Training     75 Lux
Tennis  
National/ international   500 Lux
Regional/Local     300 Lux
Local/Training      200 Lux
Equestrian  
National/ international    500 Lux
Regional/Local     200 Lux
Local/Training      100 Lux
Badminton  
National/ international    750 Lux
Regional/Local     500 Lux
Local/Training      300 Lux
Court lighting
Social Play 310 Lux
Club Competition 435 Lux
International 1250 Lux
Swimming  
National/Internal      750 Lux
Regional/Local     500 Lux
Local/Training     200 Lux

                                                           Lighting levels-Sports
                                             Australian Standard  AS 2560.2.6 – 1994
Sport Illumination Level
Baseball  
Baseball (International & National) 1500 lux
Baseball (AAA Standard) 750 lux
 Baseball (Club Competition) 250 lux
Football  
Recreational Level 50 lux
Amateur Level (Training) 50 lux
Amateur Level (Competition) 100 lux
Semi-Professional level (Training) 50 lux
Semi-Professional (match Practice) 100 lux
Semi-Professional (Competition) 200 lux
Professional level (Training) 100 lux
Professional level (Match practice) 200 lux
Professional level (Competition) 500 lux
For all sports the minimum for TV coverage. 1500 lux

                        Recommended Lighting Levels For Sports Areas 
Area Type Lux
Archery, indoor
General Area 25
Shooting Zone 50
Target (Vertical) 100
Badminton
Recreational 300
Supervised Training 400
Club & County 400
National & International 500
Bowls, indoor
Practice 300
Club & County 400
National & International 500
Boxing
Club & Supervised Training 500
Regional 750
National 1000
International 2000
Special Events 2000
Cricket, indoor
Recreational & Supervised Training 400
Club & County 500
Cycle Racing,
Training 300
Club 500
National & International 750
Equestrian, indoor
Practice & Training, show jumping 400
Practice & Training, Dressage 300
Competition Show Jumping 700
Competition Dressage) 500
Five-A-Side Football, indoor
Recreational & Supervised Training 300
Club & County 400
National & International 500
Handball, indoor
Recreational & Supervised Training 300
Club 400
County & National 500
International 750
Hockey, indoor
Recreational & Supervised Training 300
Club 400
County & National 500
International 750
Ice Rinks, Indoor
Hockey & Figure Skating Training 200
Hockey & Figure Skating Competition 750
Skating, Recreational 100
Lawn Tennis, indoor
Recreational 300
Practice & Club 400
County 500
National & International 750
Lawn Tennis, outdoor
Recreational 200
Club 300
County 400
National & International 500
Martial Arts, indoor
Supervised Training 300
Club 400
National 500
Netball, indoor
Recreational & Supervised Training 300
Club & County 400
National & International 500
Shooting, indoor
Target (Vertical) 1000
Shooting Zone 300
Snooker & Billiards
Recreational & Club 750
 National & International 1000
Squash
Recreational & Supervised Training 300
Club & County 400
 indoor National 500
International 750
Swimming, indoors
Recreational 200
Club & County 300
 National 500
 International 10000
 Table Tennis
Recreational 200
Club & County 300
National 500
International 750
Volleyball
Recreational 200
Training, Club & County 300
 National 500
International 750
Weight Training
Supervised Training 400
Sports Halls
Recreational 300
 Club & County 400-500
 National & International 500-750
Televised (vertical/normal to camera) 1000-2000
 Indoor Arenas
Maintenance of Area 100
General Lighting & Training 300
Competition 500
Spectator Viewed Events 900
Televised (vertical/normal to camera) 1000-2000
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