How to save energy in street lighting with staggering ?

Generally there is no or less traffic on the roads after mid night and before early morning. At that time we can save a lot energy by switching off one or two phase.
Hear is a simple calculation for understanding monitory benefits of staggering.
Or See the presentation "How Technology saves Energy."

For calculating the payback time period of the system described, we can go through the following calculations. Say considering 10 KW load Total Investment of Unit cost will be Rs.30,000/-

Total unit consumption
@ 12 hours/day will be 10 x 12 = 120 Units a day
@ 365 Days will be 365 x 120 units = 43800 Units/annum
@ Rs. 4 per Unit rate total billing will be 4 x 43800 = Rs. 175200/- annum.

Staggering One phase.

If we switch OFF only one phase @ 12 AM say for 6 hours a day then total working hours of three phase are 36 hours out of we can save 6 hours will be around 16 % + minimum longitude can save 4 % Total 20 % saving can be achieve entire operation.
@ 20 % of 175200 will be Rs.35040/-
@ Max the unit cost will be recovered in 11 months.

Staggering two phase.

If we switch OFF only one phase @ 12 AM and another phase @ 2AM say for 4 hours a day then total working hours of three phase are 36 hours out of we can save 10 hours will be around 27 % + minimum longitude can save 4 % Total 31 % saving can be achieve entire operation.
@ 31 % of 175200 will be Rs.54312/-
@ Max the unit cost will be recovered in 7 months.

Staggering alternate phase.

If we operate on only two phase and used alternate systems then switch OFF only one phase @ 12 AM for 6 hours a day then total working hours of two phase are 24 hours out of we can save 6 hours will be around 25 % + minimum longitude can save 4 % Total 29 % saving can be achieve of entire operation.
@ 29 % of 175200 will be Rs.50808/-
@ Max the unit cost will be recovered in 8 months.

Advantages

1) No frequent time to be change according to season.
2) Redundant Power supply to controller. Any phase up to 150 Volt controller will work and contactor will be operated up to 170 VAC
3) Real-Time Clock with very high life of more then 5 years. No Battery.
4) Individual phase output with MCB for protection.
5) Input out put terminal of 35 MM sq.
6) Power wiring of feeder pillar with ISI mark fire retardant cable.

How to save energy in street lighting with staggering.

Generally there is no or less traffic on the roads after mid night and before early morning. At that time we can save a lot energy by switching off one or two phase with street light controllers or dimmer choke or even with three normal timers for each phase.

Hear is a simple calculation for understanding monitory benefits of staggering with street light controller.
For example we consider a switching point of 10 KW load. Total Investment for street light controller with staggering facility and astronomical timer will be roughly $ 665 /-

Total unit consumption for 10KW load (according to Indian Environment)
@ 11 hours/day will be 10 x 11 = 11 Units a day
@ 365 Days will be 365 x 110 units = 40150 Units/Annam
@ $ 0.09 per Unit rate total billing will be $ 0.09 x 40150(Units) = $ 3561/- Annam.

If we Stagger only one phase at midnight to 6:00

Then total working hours of three phase are 33 hours out of we can save 6 hours will be around 18 % + minimum longitude can save 4 % Total 22 % saving can be achieve entire operation.
@ 20 % of $3561/- will be $ 784/-
@ Max the unit cost will be recovered in 10.5 (315 Days) months.

If we Stagger one phase at midnight to 6:00 and second one for 2:00 A.M to 6:00 A.M.

Then total working hours of three phase (33 hours) we can save 10 hours will be around 30 % + minimum longitude can save 4 % Total 34 % saving can be achieve entire operation.
@ 34 % of $3561 will be $ 1211/-
@ Max the unit cost will be recovered in 7 months.

We can use dimmer choke which we have to replace in every luminary.
The two basic problems with dimmer choke are
1. Absence of intelligence and real time clock. So it will dim luminary after decided hours (i.e. 3 hours after ON time) and ever faced supply problem it will again starts on full lode and dim luminary after decided hours (i.e. 3 hours after ON time). That will cost laps of saving for the day.
2. We have to replace choke in every luminary, that costs high along with maintenance.

We can also use three normal timer for staggering.
We can set staggering time in each phase with one timer as there is hard to find single timer with three individual phase control.

Still it can not operate differently each day. We have to stagger each phase everyday for proper use of every luminary. i.e. We can stagger Phase R for Midnight to 2 A.M., Phase Y for 2 A.M to 4 A.M., Phase B for 4 A.M to 6 A.M. . So we can have energy conservation equal to staggering one phase by street light controller.

Note: We have to change On/Off time quarterly or monthly basis or have to buy little costlier almanac timer.


Advantages of using Insu street light controller for staggering.

1) No frequent time adjustment according to season.
2) Redundant Power supply to controller. Any phase up to 150 Volt controller will work and contactor will be operated up to 170 VAC
3) Real-Time Clock with very high life of more then 5 years. No external Battery. 4) Individual phase output with MCB for protection.
5) Input out put terminal of 35 MM sq.
6) Power wiring of feeder pillar with ISI mark fire retardant cable.

Why to use Astronomical Timer.

Benefit of astronomical timer for street lighting systems

Now a day cost of producing electricity is rising,simultaneously users are increasing as cities are expanding.New electricity generation plant installation costs are very high. Hence our electricity mfg. is not coping up with demand. So in such a condition optimum utilization of energy, and preventing wastage is must. Energy conserved is energy produce.

In our observation in industries and city lighting systems, we found street light operation very complicated & difficult as Sun set & sun rise timings varies season to season. Street light ON hour varies from 9.00 hours (during summer ) to 13.00 hours (during winter). Ordinary electromechanical and digital time switches are incapable of taking care of such annual variation. For entire year sunrise and sunset time changes by about 3 hours (i.e 180 minutes). This quiet big variation can served if we operate street lighting operation with the sunset and sunrise changes. Also it will provide better lighting services over conventional systems. Ideal street lighting hours are 4050 to 4100 per year. We have found more than 75 % of street light switching operation are done manually and rest are done by electromechanical timer. In both the case operations of street lighting does not efficiently cope up with sunrise and sunset time changes.

In India majority street lighting timers are reprogrammed for time setting every 15 or 30 day basis. (If we adopt for 15 days time setting systems then total 30 minute per day and if we go for monthly time setting systems then total 60 minutes per day we have to compromise.) That will leads to a huge wastage of power.

If we calculate for one point of 15 kW then only 30 minutes of daily saving in energy can save Rs.10, 800/- annually. Unit rate calculated at Rs. 4/- Per KW/Hr (Total 30 minutes per day X 360 days / 60 minutes = 180 hours. 15 KW equals to Rs. 60/- hours.