Street Light Monitoring - Introduction- Part 1

As mentioned in my previous blog, I would now mention about the various aspects of Street Light Monitoring in a multi- session feature.

Before we go into the depth of the Street Light Monitoring, we should understand the various types of lamps used in Street Light.( All reference is made with respect to the Indian context).

Street Lights are a important asset of utilization in our everyday societal life. Street Light imparts us the confidence to venture out on the streets,provides safety and security, provides a good ambiance, draws positivism and influence buying habits, attracts customers at a well lit place etc.

Street lights are lit by various types of lamps like, incandescent , fluorescent, T5-HO, High Pressure Sodium, Metal Halide, Mercury Vapor, LED lamps of recent , and the more sophisticated Induction lamps which I am not sure of its use in generally in India.

For every lamp to be lit, they need a ballast, but the common types of incandescent lamps are self ballasted and therefore they do not require any separate ballast. They come in various wattages from 25-1000W, and is one of the most common form of lighting in India in the villages and even in some tier II and III cities for roadway/ street lighting. They come in with milky white configuration.

The advantages of this type of incandescent lamp is that they are very economical, easy to find, and replace, and is very economical.

They are easy to dim, and does not require any complicated mechanism, and of course they add to the warm requirements for an mood lighting with its own characteristics.

The disadvantages of this type of incandescent lamp is that they generate more heat than light, and is not a very effective source of lighting in the modern day parlance, but in places where there is utter darkness, a incandescent lamp can be the brightest shining star for a few yards. I often used to witness especially in Kerala a literal form of "light dance" being orchestrated due to the voltage fluctuation on the feeder pillars, and the colossal amount of energy waste and heat dissipation.

The next most common sight and a up gradation from these incandescent lamps on the streets was with the Fluorescent tube lights, the whiter long breed of lights which suddenly shot to fame as a preferred alternative , and it still persists in practically all areas where one could look for, be it railway stations, godowns, parking lots, alleys and galleys, street segments, factories, houses etc.

These tube lights or fluorescent lamps are effective, but they require a ballast to drive the lamp. In addition it employs a starter( capacitor) for providing the initial pulses to start the lamp along with the ballast.

The more recent ones to surface in the last one and half decades and proliferate as the preferred choices were the mercury vapor lamps, the sodium lamps ( because of the yellowish tinge) and the metal halide ( the very white light) of different wattages from 35W to 2000W and now commonly used for street lighting, area lighting. All these above mentioned lamps also use ballast to drive the lamps.

The 21st century witnessed a new breed of lights called the LED based street light, with a promising feature of reduced energy , but so far the technology is not matured for the Urban Local Bodies to accept it as a preferred source of lighting due to the enormous savings in energy it proposes. It does not require a ballast to drive the lamp, but uses a driving circuit. Theoretically the life of a LED lamp can be established to a 100 thousand burning hours, but in reality a claim of more than 50 thousand burning hours itself is a tall claim. The reason for my citation is, even if the LEDS remain to live that life, trying to find a driving circuit which will complement the life of the LED burning hours is yet to be seen.

The advantages of LED lamps is that they are easy to control, monitor, and dim, but the down side is the thermal and heat dissipation issues.

Internationally there has been initiatives in using LED as a preferred source of lamps for Street Lighting, but the prohibitive costs are the real dampener to adopt this low energy high bright alternative in our STREET LAMPS.

In the next part I will discuss about the the other aspects of Street Light.

Deepak Chandran