Telecom today has penetrated much deeper into India in comparison to electricity. Network availability is of prime importance to any telecom operator. However this is quite challenging owing primarily to non availability of good quality grid power supply at remote locations. Thus Indian telecom relies on diesel generator (DG) sets to provide greater than 99.95 per cent uninterrupted power uptime of telecom service, as these are the most reliable commercially available energy source. Despite availability of this source for many years there are multiple challenges in maintaining the network running, like:

• Frequent diesel filling at remote location
• Regular maintenance for 100 per cent uptime of DG sets
• Variable load during the day

Due to this high variation in load requirement, it becomes very difficult to optimally size the DG sets. Ideally DG sets should be run at 60-80 per cent of the rated capacity at which the diesel engine delivers the maximum efficiency but in telecom sites DG sets are sized to meet the peak requirement which runs at reduced efficiency during the low load times.

To meet this challenge of load variation and poor efficiency a solution has been developed along with DG OEM which helps in keeping the efficiency curve almost flat, i.e highest efficiency irrespective of load. This is done by electronically controlling the speed of the engine depending upon the load unlike conventional DG which runs at fixed speed irrespective of load.

This resulted into variable frequency AC power which is converted into DC power using the power electronics equipment available at telecom site.This has been done due to the fact that all telecom equipment runs on DC power.

Lower speed operation of DG sets results in high efficiency in DG sets which means lower diesel consumption and hence this technology helped telecom companies to meet all three challenges related with DG operations. i.e

1. Lower diesel consumption – lower diesel filling cycle
2. Lower speed helped in lower wear and tear and higher uptime of DG set along with less noise
3. High efficiency at all load points

(Contributed by Sachin Gupta, DGM - Technical Services, Bharti Infratel Limited)