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.